Bartholin, Erasmus

Baade, Wilhelm Heinrich Walter A B B Baade, Wilhelm Heinrich Walter Born Died Schröttinghausen, Nordrhein-Westfalen, Germany, 24 March 1893 Göttingen, Lower Saxony, (Germany), 25 June 1960 German–American astronomer Walter Baade is remembered for three major contributions to observational, extragalactic astronomy: the recognition of two basic population types of stars, the characterization (with Fritz Zwicky) of supernovae as a distinct class of event with energy derived from the collapse of a normal star to a neutron star, and the optical identification (with Rudolph Minkowski) of Cygnus A and other strong radio sources, which led to the “colliding galaxy” theory of radio sources. Baade studied at Münster and Göttingen universities, where he received his Ph.D. in 1919 and became the scientific assistant to the mathematician Felix Klein. Baade was later appointed research assistant at the Hamburg Observatory, with access to a 1-m reflector, the largest telescope in Germany. In addition to working on a traditional program focused on comets and asteroids, Baade measured variable stars, recorded spectra of nebulae, and read research reports about the 60- and 100-in. reflectors at Mount Wilson, California. He dreamt of studying variable stars and globular clusters with the largest telescopes in the world. As a German in the postwar years, Baade could not follow in the footsteps of Henri Chrétien, who secured a fellowship to work on the 60-in. telescope the year after it opened (1909). Then in 1926, on an expedition to photograph a mid-Atlantic solar eclipse, Baade met Harlow Shapley, the director of the Harvard College Observatory. Shapley used his influence at the International Education Board to obtain a 1926–1927 Rockefeller Fellowship for Baade, who spent part of his fellowship year at Mount Wilson. There he impressed the staff with his observing skill as he conducted research that led to a paper on the Baade (later the Baade–Wesselink) method of determining the radius and therefore absolute magnitude of pulsating variable stars especially Cepheids. Baade also collaborated with Wolfgang Pauli on a theoretical paper explaining the curved shape of comet tails as a result of the solar wind. His growing reputation earned Baade a promotion to Observator (the equivalent of assistant director and next in line for the © Springer-Verlag Berlin Heidelberg 2007 directorship) at the Hamburg Observatory. Among his research interests, he identified novae so bright that he gave them the name “Hauptnovae,” his forerunner of the term supernovae. Baade also went on another solar eclipse expedition, this time to the Phillipines with Bernard Schmidt, the eccentric, one-armed Estonian optician of the Hamburg Observatory. On the long sea voyages they discussed the need for a wide-field, coma-free reflector telescope for survey searches for variable stars, galaxies, nebulae, and planets. Schmidt later used a spherical mirror with a thin corrector plate to build the first of the wide-field camera designs that bear his name. Baade continued to long for the large telescopes, clear weather, and the good seeing of southern California. In 1931, he was invited to become a permanent member of the staff at the Carnegie Institution of Washington [CIW] Observatory, and moved to Pasadena, California, with his wife Johanna (called Hanni by her friends, and Muschi by Baade). At Mount Wilson, Baade amassed an incomparable collection of fine astronomical photographs as he experimented with emulsions, filters, auxiliary lenses, and focusing, guiding, and development techniques. Milton Humason and Edwin Hubble drew on Baade’s work, though he never collaborated with them on publications. Baade’s own research program focused on stellar populations, globular clusters, cepheid variables, and understanding stellar evolution. He remarked to colleagues that while the study of cosmology, the nature of the Universe in the large, might be hopeless, cosmogony, the origin of the Universe was quite accessible to solution. Baade worked quietly, avoiding the publicity that Hubble constantly sought. He was most at home in the domes of the big telescopes, where his insistence on observing in a coat and tie did not hinder his mastery of the temperamental mirror of the 100-in. or the occasionally sticky mounting of the 60-in. telescope. Baade brought to Pasadena a photograph Schmidt had taken with his new wide-field camera in Hamburg. As a result, the Palomar Observatory project included an 18-in. Schmidt camera as the first working telescope at the new site. With Zwicky, a Caltech physicist, Baade extended his earlier explorations of supernovae. Zwicky searched with the Schmidt telescope for supernovae; Baade would follow up with studies of their light curves with the bigger telescopes on Mount Wilson. Their 1934 paper, still much cited, contained four key ideas: supernovae are completely distinct from ordinary novae; the energy source is the collapse of a normal star to a neutron star; some of the energy goes into accelerating cosmic rays; and the Crab 73 74 B Babcock, Harold Delos Nebula and S Andromeda (SN 1885A) are examples of supernovae. The collaboration collapsed when Zwicky, who notoriously had trouble with colleagues, claimed that he had introduced the idea of the Schmidt camera, accused Baade of stealing credit and reneging his part of the collaboration, and called Baade a Nazi sympathizer. Others found Baade a model colleague – witty, enthusiastic about a wide range of astronomical questions, and a born raconteur. Despite a marked limp from a congenital hip defect, Baade enjoyed walking with colleagues, taking advantage of the pauses while he rested his leg to drive home his points. A perfectionist in his writing as in his observations, he published little, but a staff member at the Carnegie Institutions commented that despite the paucity of articles, Baade “is one of the most prolific of our staff members. He ‘publishes’ his data by conversations in his office with the world’s astronomers.” During World War II, when the other CIW astronomers joined war efforts at Caltech or elsewhere, Baade, who had never applied for American citizenship, was restricted to Pasadena and Mount Wilson as an enemy alien. With unlimited access to the big telescopes, he undertook a task considered beyond the capability of the 100-in. Hooker telescope, then the largest in the world – resolving stars in the nucleus of the Andromeda galaxy and its companions M32 and NGC 205. Using red-sensitive plates, special precautions to stabilize the temperature of the primary mirror, a dilute ammonia bath to increase the sensitivity of the plates, and taking advantage of nights of optimum seeing and the wartime brownouts in the Los Angeles basin, Baade guided for 4 hours on a faint off-axis guide star magnified 2,800 times. His patience and diligence paid off. Joel Stebbins called Baade’s resolution of stars in the nucleus of M31 and its companions a “pure steal” from the prestige of the nearly complete 200-in. telescope. The images were published as specially developed enlargements bound into an issue of the Astrophysical Journal. Baade’s article generated a flood of ideas about the types of stars constituting galaxies. Baade’s own contribution, in two important articles of 1944, was the articulation of two distinct population types: The populations were distinguished by their locations, colors of the brightest stars, and morphology of their Hertzsprung– Russell [HR] diagrams. Population I, in the disk of the Milky Way and other spirals, has its brightest stars blue and an HR diagram with a main sequence and supergiants. Population II, in the halo of the Milky Way, in globular clusters and in elliptical galaxies, has its brightest stars red and an HR diagram with giants and a horizontal branch. Later work showed that the Population I stars also are systematically younger and contain a larger component of heavy elements. This elegant formulation, expanded when more data was available and later the focus of a conference in Rome in 1957, was one of Baade’s great contributions to the understanding of stellar populations. After the war, Baade took on two doctoral students, Allan Sandage and Halton Arp, from the new astrophysics program at Caltech and served as a mentor to Nicholas Mayall, Olin Wilson, and others. He took many of the test plates for the commissioning of the 200-in. telescope at Palomar, including some that Hubble used in his announcements about the telescope. When the Palomar telescope entered service, Baade attempted to resolve RR Lyrae stars in M31, a task that calculations showed should have been possible with the 200-in. telescope. The failure to image the stars, together with increasing knowledge of the absolute magnitude of the globular cluster giants he had resolved in 1944, led Baade to postulate a new distance scale, replacing the one that had been used since Hubble’s 1924 proof that Andromeda was an extragalactic system. Baade’s paper, presented in 1952, famously doubled the distance scale and age of the Universe. Confirmation was available on the spot at the General Assembly of the International Astronomical Union in Rome, because David Thackeray had resolved the RR Lyrae stars in the Large Magellanic Cloud with a smaller telescope in South Africa, and, sure enough, they were about 1.5 magnitudes fainter than expected. At Palomar, Baade made extensive studies of the Crab Nebula and its central star, discovered the polarization of light in the jet of M87, and worked with Rudolph Minkowski to provide optical identifications of radio sources, including Cygnus A and Cassiopeia A. Little of Baade’s work on the 200-in. telescope was published. He remained a perfectionist, and the possibilities of the telescope were still to be explored. Baade retired from the CIW in 1958, then taught a course on “The Evolution of Stars and Galaxies” at Harvard and observed on the 74-in. telescope at Mount Stromlo. He told his students and colleagues that his failure to become an American citizen was absentmindedness, but he remained German – his dog Li was notoriously unfriendly to anyone speaking any language but German – and in 1959 returned to Germany to accept the Gauss Professorship at Göttingen. Walter Baade died from complications after an operation on his hip. Cecilia Payne-Gaposchkin edited and published Baade’s Harvard lectures, which were for many years a standard text on stellar and galactic evolution. The Carnegie Institution has named one of the new 6.5-m telescopes at Las Campanas, with a beautifully figured f/1.25 mirror and superb optics, the Walter Baade telescope. Ronald Florence Selected References Arp, Halton C. (1961). “Wilhelm Heinrich Walter Baade, 1893–1960.” Journal of the Royal Astronomical Society of Canada 55: 113–116. Florence, Ronald (1994). The Perfect Machine: Building the Palomar Telescope. New York: HarperCollins. Osterbrock, Donald E. (2001). Walter Baade: A Life in Astrophysics. Princeton, New Jersey: Princeton University Press. Sandage, A. (1961). “Wilhelm Heinrich Walter Baade.” Quarterly Journal of the Royal Astronomical Society 2: 118–121. Babcock, Harold Delos Born Died Edgerton, Wisconsin, USA, 24 January 1882 Pasadena, California, USA, 8 April 1965 American laboratory and stellar spectroscopist Harold D. Babcock produced very high-quality ruled gratings for spectrometers and used them (in collaboration with his son, Horace Babcock) to map out the magnetic fields of the Sun and stars with great precision. Babcock was the son of the owner of a general store and received his Babcock, Harold Delos early education in the public schools of Wisconsin. He completed an additional 4 years of secondary school in Los Angeles after the family moved there in 1896, acquiring a good grounding in science, languages, and the arts. It was during this time that he also began private experimental work, particularly radio, and developed a fascination that led to his enrolling in electrical engineering at the University of California at Berkeley in 1901. Babcock quickly decided, however, that his principal interests lay in physics – especially spectroscopy – and he obtained a BS degree (the only university degree he obtained) in 1906. From 1906/1907, he served as an assistant at the National Bureau of Standards, married Mary Henderson in 1907, and in 1908 briefly taught physics at Berkeley. In February 1909, Babcock accepted an invitation by George Hale to join the staff of the Mount Wilson Observatory, California– as a physicist, not an astronomer–where he remained for the rest of his scientific life. His son, Horace Welcome, was born in 1912. In later years, the two were both staff members at the Mount Wilson Observatory and collaborated on many projects even after the elder Babcock’s retirement. Babcock was a spectroscopist of first magnitude at a time when laboratory astrophysics was being cultivated by Hale as vital for interpreting the Sun and stars. His work required developing techniques for ruling very high-resolution diffraction gratings; he also used interferometers in laboratory studies. Babcock’s earliest investigations dealt with Zeeman effect measurements for iron peak elements whose lines are well-represented in the solar spectrum, especially vanadium, chromium, and iron. As a by-product of this work, he redetermined the charge-to-mass ratio for the electron (i. e., the value of e/m) independent of other, nonspectroscopic measurements (e. g., the Thomson cathode ray deflection experiment and the Millikan oil drop technique). Babcock also studied pressure broadening and developed techniques for producing large format, very high-resolution diffraction gratings. In this last activity, which continued after his official retirement in 1948, he was a principal contributor to the quick successes of the Palomar 5-m telescope. In 1914, Babcock and Charles St. John began a protracted study of laboratory atomic spectra with the intent to provide a comprehensive list of solar spectral line identifications using high-resolution gratings and, more significantly, the Fabry–Perot interferometer. Their technique for stabilizing emission arcs was adopted by the International Astronomical Union [IAU], and their measurements became one of the standard sets used by the IAU to establish standard wavelengths. Babcock and St. John were joined by Charlotte Moore, L. M. Ware, and E. F. Adams in the revision of the Rowland atlas of the solar spectrum. In addition to extending the infrared cutoff for the list from 7,730 Å to 10,218 Å, their 1928 publication listed identifications for over 22,000 lines. Subsequent studies by Babcock and Moore extended the known solar lines to 2,935 Å in the ultraviolet and to 13,500 Å in the infrared. In 1927, during this study of the solar spectrum, Babcock and Gerhard H. Dieke reported the discovery of two very weak terrestrial absorption bands near the O2 A-band at 7,596 Å. Designated A′ and A″, these consisted of narrow lines and appeared to be similar to the A band. William F. Giauque and Herrick Lee Johnston soon showed, in 1929, that they are due to isotopic molecules, 18 O – 16O and 17O – 16O with abundances of about 4 × 10−3 and 10−4, respectively. Raymond T. Birge and Babcock used the molecular band constants to determine the mass ratio for these isotopes, the first discovered in nature, and showed that the scale used for mass needed revision. Subsequently, Harold Urey announced discovery of deuterium, and the field of isotope chemistry and spectroscopy was opened. In separate work, Babcock interferometrically studied the auroral and night sky light at 5577.350 Å, achieving a resolution better than 0.035 Å (his quoted upper limit for the line width) and permitting its identification as a forbidden transition of neutral oxygen. Although Babcock engaged in solar physics throughout his career at Mount Wilson, his most important work was done in collaboration with his son after he retired from the scientific staff. Their invention of the solar photoelectric magnetograph changed the study of stellar magnetism. Babcock’s last original research work dealt with measurements of the solar polar field, successfully detecting a reversal of the dipole component of the field. Babcock’s work did not go unrecognized. He was elected to the National Academy of Sciences, shared the Pacific Division Prize of the American Association for the Advancement of Science with Giauque and Johnston (1927), and was awarded the Bruce Medal of the Astronomical Society of the Pacific (1953). He received an honorary LL.D. from Berkeley (1957). The lunar crater Babcock is named in his honor. The minor planet (3167) Babcock was named in his honor and also that of his son. Steven N. Shore Selected References Babcock, H. D. (1933). “The Construction and Characteristics of Some Diffraction Gratings. ” Publications of the Astronomical Society of the Pacific 45: 283. ——— (1953). “What’s in the Air?” Astronomical Society of the Pacific Leaflet, no. 291. ——— (1959). “The Sun’s Polar Magnetic Field.” Astrophysical Journal 130: 364–365. Babcock, H. D. and H. W. Babcock (1951). “The Ruling of Diffraction Gratings at the Mount Wilson Observatory.” Journal of the Optical Society of America 41: 776–786. Babcock, H. D. and R. T. Birge (1931). “Precision Determination of the Mass Ratio of Oxygen 18 and 16.” Physical Review 37: 233. (Paper abstract.) Babcock, H. W. and H. D. Babcock (1952). “Mapping the Magnetic Fields of the Sun.” Publications of the Astronomical Society of the Pacific 64: 282–287. ——— (1955). “The Sun’ s Magnetic Field, 1952–1954.” Astrophysical Journal 121: 349–366. Bowen, Ira S. (1974). “Harold Delos Babock.” Biographical Memoirs, National Academy of Sciences 45: 1–19. (Additional material by H. W. Babcock.) Dieke, G. H. and H. D. Babcock (1927). “The Structure of the Atmospheric Absorption Bands of Oxygen.” Proceedings of the National Academy of Sciences 13: 670–678. Hearnshaw, J. B. (1990). The Analysis of Starlight: One Hundred and Fifty Years of Astronomical Spectroscopy. 1st pbk. ed. Cambridge: Cambridge University Press. Kron, Gerald E. (1953). “The Award of the Bruce Gold Medal to Harold Delos Babcock.” Publications of the Astronomical Society of the Pacific 65: 65–69. Plaskett, H. H. (1969). “Harold D. Babcock.” Quarterly Journal of the Royal Astronomical Society 10: 68–72. St. John, Charles E. et al. (1928). Revision of Rowland’s Preliminary Table of Solar Spectrum Wavelengths. Carnegie Institution of Washington Publication No. 396. Washington, DC: Carnegie Institution of Washington. Wright, Helen (1994). Explorer of the Universe: A Biography of George Ellery Hale. New York: AIP Press. (Reprinted with a new introduction by Allan Sandage.) B 75 76 B Babcock, Horace Welcome Babcock, Horace Welcome Born Died Pasadena, California, USA, 13 September 1912 Santa Barbara, California, USA, 29 August 2003 Horace Babcock was the son of Harold Babcock; the two shared many scientific interests, collaborated on some important studies of the Sun and instrument design, and received several of the same honors (though never together). Horace Babcock was born in Pasadena, where his father was on the staff of the Mount Wilson Observatory (1908–1948). Babcock attended Caltech as an undergraduate, completing his B.S. in physics in 1934. He obtained a Ph.D. in astronomy from the University of California at Berkeley in 1938, studying the dynamics of M31 using Lick long-slit spectra. His thesis established the trailing nature of the spiral pattern and considerably extended the earlier studies of Vesto Slipher, Frances Pease, and Ernst Öpik. Babcock’s spectra showed a large rotation speed for M31 very far from its center, implying a mass and mass-to-luminosity ratio for the galaxy much larger than what Edwin Hubble and others were finding. The thesis, which appeared as a Lick Observatory Bulletin, therefore was greeted with some distrust, and he never worked again in extragalactic astronomy. Yet the publication is now often cited as a pioneering work in the detection of dark matter. Babcock remained briefly at Lick Observatory as an assistant after his degree. From 1939 to 1941, he was a postdoctoral fellow at MacDonald Observatory. During World War II, he worked first at the Massachusetts Institute of Technology on radar and related problems as a staff member at the Radiation Laboratory (1941/1942) and then moved to Caltech to work on rocketry (1942–1945). In 1946 Babcock joined the staff of the Mount Wilson and Palomar observatories. He remained there for the rest of his scientific career, becoming assistant director (under Ira Bowen) from 1957 to 1964, and then serving as director from 1964 until his retirement in 1978. One of the first changes he made in observatory policy was the decision to allow women astronomers to apply for and be assigned time at Palomar Mountain. His administrative career coincided with the extension of the observatory operations to the Southern Hemisphere, with the addition of the Carnegie Southern Observatory at Las Campanas in Chile. The Mount Wilson Observatory had been organized by George Hale around the study of solar magnetic fields and, especially given the elder Babcock’s deep interest in such work, it is not surprising that a single physical phenomenon, the Zeeman effect, formed the kernel of Babcock’s scientific career. Whether dealing with the analysis of the spatial and temporal structure of the resolved solar magnetic field or the analysis of large-scale ordered fields in stars, he directed his energies, and those of many members of the observatory staff, toward the study of cosmic magnetism. The younger Babcock was a gifted instrument designer, and the photoelectric solar magnetograph, invented with his father, was the most significant innovation in solar instrumentation since Hale’ s invention of the spectroheliograph. The device used an electro-optical ammonium– dihydride phosphate retarding plate followed by a Nicol prism to separate the polarization states, switched at 120 Hz, upstream from the spectrograph slit followed by a grating with a resolution of 600,000 lines/in. at the Fe I 5250.216 Å line. The device produced an image by scanning the Sun’s disk and recording the local polarity with comparatively high-spatial resolution using photomultipliers that separately recorded the signal from the alternate wings of the Zeeman-split polarized line. Although the initial measurements were limited to relatively low sensitivity, the maps provided the first synoptic view of the global organization of the solar magnetic field with a resolution of about 10 G (a shift of about 0.08 mÅ) and provoked much of the modern work on stellar dynamos. The magnetograph showed, for the first time, that the photospheric magnetic field is organized into filaments, rather than a global dipole, which extend into the chromospheric network and ultimately into the corona. The general field is a weak dipole at most times. The dynamo that drives the surface field must be rooted deep in the convection zone. None of these insights would have been possible without the imaging capabilities of the magnetograph. The design has been extended in the last decade to all four Stokes parameters (providing both linear and circular components), and the chromospheric field can be measured now using the Hanle effect. Still, the work ultimately rests on the basic Babcock design. The original Babcock magnetographic maps also presaged the era of space weather forecasts, when such images produced at high spatial and temporal resolution with full vector magnetographs can be used to predict the onset of coronal mass ejections and flare activity. Babcock also invented a photoelectric autoguider for large astronomical telescopes (1948) and later adapted the technology to a device for measuring astronomical seeing by observing Polaris through crossed Ronchi gratings imaged onto a photomultiplier (1963), a basic technique used in many later site surveys to monitoring seeing automatically. Interestingly, although his research publications appeared to end with his assumption of the directorship – evincing a complete absorption in the scientific administration of a vibrant institution – on retirement Babcock reemerged as a leading advocate for adaptive optics techniques and was recognized as one of the guiding spirits in this rapidly evolving technology. His 1953 paper is now considered one of the pioneering works in the field. Applying a photographic adaptation of the magnetograph to stellar spectroscopy, in 1946 Babcock discovered a large longitudinal magnetic field in the main sequence chemically peculiar A star 78 Vir (HD 118022). This was not only the first direct detection of a global magnetic field in a nonsolar type star but also the first measured largescale, stable ordered field in a star other than the Sun. It immediately created a new area in stellar astrophysics. Babcock’ s idea was to use these extremely sharp-lined stars (presuming their low rotational broadening was an inclination effect rather than intrinsic) to search for strong fields using an adaptation of the solar magnetograph. Although there were some speculations, especially by Patrick Blackett, about how such fields might arise, the discovery was serendipitous, and the association with the chemically peculiar stars largely coincidental at first. The fields were both ordered and enormous, up to tens of kilogauss – global magnetic fields as strong as those typically observed in sunspots. With the first success, new discoveries quickly followed. Almost immediately, Babcock reported the reversing magnetic field in HD 125248, a known spectrum variable included by Armin Deutsch in his 1947 analysis of the Ap stars. (A curiosity is that this study, which neither makes use of nor acknowledges the magnetic observations, appeared in the same volume of the Babinet, Jacques Astrophysical Journal.) Babcock separated the variations into three basic types, ostensibly denoted by a prototype: alpha (α2 CVn), periodic and reversing; beta (β CrB), reversing but not definitively periodic; and gamma (γ Equ), constant or fluctuating but neither periodic nor reversing. Although known since the discovery of periodic photometric variations in α2 CVn early in the days of photoelectric photometry, there were no indications of magnetic fields associated with these stars. Babcock assumed a solar analog for the magnetic field generation, even with such short timescales. It was Martin Schwarzschild (1950) and Deutsch (1958) who developed the oblique-rotator hypothesis to explain the magnetic field and spectrophotometric variations. Interestingly, it was Babcock’s discovery of the crossover effect, when the polarity of the magnetic field reverses due to rotation (so the combined Doppler shifts of the intensified line cancel the magnetic displacement), that provided the vital clue to the oblique-rotator model that has since proved so successful. Anticipating later work on line formation in strongly magnetized atmospheres, Babcock realized that the Zeeman effect can delay the onset of saturation in transitions with large Landé factors, thus altering the curve of growth and affecting abundance determinations by such methods. Later work quantified this, including polarized radiative transfer, but Babcock’s physical insight was also important in determination of elemental abundances in the chemically peculiar A stars. Babcock also discovered the strongest field yet detected in a main sequence star, a 34 kG longitudinal field in HD 215441, a silicon star also called Babcock’s star. Subsequent observations, by Babcock and later, in the mid-1960s, by G. W. Preston at Lick Observatory, discovered the transverse component of the Zeeman effect in the resolved lines of HD 215441 and other strong field stars; the study of such stars has developed rapidly since the 1990s with the use of Charged-Couple Devices [CCDs]. Among numerous honors, Babcock was awarded the Draper Prize of the National Academy of Sciences (1957) for his work on solar magnetic fields, the Bruce Medal of the Astronomical Society of the Pacific (1970), the Eddington Medal (1957) and the Gold Medal (1970) of the Royal Astronomical Society, and the Hale Prize of the American Astronomical Society (1992) for his broad contributions to solar physics. Steven N. Shore Selected References Abell, George O. (1969). “Award of the Bruce Gold Medal to Dr. Horace W. Babcock.” Publications of the Astronomical Society of the Pacific 81: 179–184. Babcock, Horace W. (1953). “The Solar Magnetograph.” Astrophysical Journal 118: 387–396. ——— (1960). “Stellar Magnetic Fields.” In Stellar Atmospheres, edited by Jesse L. Greenstein, pp. 282–320. Vol. 6 of Stars and Stellar Systems. Chicago: University of Chicago Press. ——— (1960). “The 34-Kilogauss Field of HD 215441.” Astrophysical Journal 132: 521–531. ——— (1963). “The Sun’s Magnetic Field.” Annual Review of Astronomy and Astrophysics 1: 41–58. Babcock, Horace W. and Harold D. Babcock (1952). “Mapping the Magnetic Fields of the Sun.” Publications of the Astronomical Society of the Pacific 64: 282–287. Lovell, Bernard (1970). “Presidential Addresses on the Society’s Awards: The Gold Medal.” Quarterly Journal of the Royal Astronomical Society 11: 85–87. Babinet, Jacques Born Died Lusignan, (Vienne), France, 5 March 1794 Paris, France, 21 October 1872 Jacques Babinet’s major work was devoted to the diffraction of light. He used diffraction to measure wavelengths more accurately than before, and did theoretical work on general diffraction systems. He was the son of Jean Babinet, mayor of Lusignan, and Marie-Anne Félicité Bonneau du Chesne, daughter of a lieutenant general. He married Adelaide Laugier; they had two sons. Babinet began his studies at the Lycée Napoléon, then at the École Polytechnique, where he later became an examiner. He left the École Polytechnique in 1812 to enter the Military School at Metz. For some time he was attached to the Fifth Regiment of Artillery, but at the Restoration he left the army and took up teaching. He was professor of mathematics at Fontenay-le-Comte, then professor of physics at Poitiers and, from 1820, at the Lycée Saint-Louis, Paris. From 1825 to 1828 Babinet delivered a course of lectures on meteorology. In 1838 he succeeded Félix Savary at the Collège de France. Two years later, Babinet was elected to the Académie des sciences as a member of the General Physics Section. Babinet’s major scientific contribution was in optics, although his contributions to science include the other branches of physics and mechanics. Babinet’s theorem states that there is an approximate equivalence between the diffraction pattern of a large system and that of the complementary system, which is opaque where the original system is transparent and vice versa. He showed an interest in the optical properties of minerals, developing new instruments for the measurement of angles and polarizations, especially Babinet’s compensator, a double quartz wedge used in the study of elliptically polarized light. He was the first to suggest (1829) that the wavelength of a given spectral line could be used as a fundamental standard of length, an idea eventually used in metrology in 1960. He constructed a portable goniometer, improving upon E. L. Malus’ device. Babinet’s interests in physics transcended laboratory work and included all phenomena in nature. Thus, the study of meteorology, particularly meteorological optics, occupied much of his career. He began his work in this field with an investigation of interference phenomena produced in the atmosphere: rainbows and “coronas,” or colored rings surrounding the Sun or the Moon under certain weather conditions. Later work included modifications of the theory of atmospheric refraction and a study of polarization of skylight, especially the mysterious existence of neutral or unpolarized points in the sky. He also constructed a hygrometer. In mechanics, he improved the valves of the air pump, attaining a very high vacuum. Babinet also achieved considerable fame as a popularizer of science, explaining natural phenomena to lay audiences in public courses and in articles in popular journals. Speaking about geology, mineralogy, astronomy, and meteorology, Babinet exhibited his rare ability to reduce complex phenomena to an easily comprehensible level. Christian Nitschelm B 77 78 B Bache, Alexander Dallas Selected References Selected Reference Anon. (1872). Revue des cours scientifiques de la France et de l’étranger 3: 409–410. Beauchat-Filleau, E. (1891). Dictionnaire historique et généalogique de Poitou. 2nd ed. Vol. 1, p. 120. Poitiers. Anon. (1921). “Thomas William Backhouse.” Monthly Notices of the Royal Astronomical Society 81: 254–255. Backlund, Jöns Oskar Bache, Alexander Dallas Born Died Philadelphia, Pennsylvania, USA, 19 July 1806 Newport, Rhode Island, USA, 17 February 1867 United States Coast Survey Superintendent Alexander Bache was involved in establishing several major American observatories of the 19th century. Under his supervision, the Coast Survey was a major employer of astronomers at a time when other sources of employment for American astronomers were sparse. See also his solar observations with Stephen Alexander. Selected Reference Slotten, Hugh Richard (1994). Patronage, Practice, and the Culture of American Science: Alexander Dallas Bache and the US Coast Survey. Cambridge: Cambridge University Press. Backhouse, Thomas William Born Died Sunderland, England, 14 August 1842 Sunderland, England, 13 March 1920 Thomas Backhouse, well educated and independently wealthy, devoted his life to the observation and cataloguing of astronomical and meteorological phenomena. His publications (Monthly Notices of the Royal Astronomical Society; Publications of the West Hendon House Observatory) include a wide variety of topics ranging from the green flash, aurorae, and the zodiacal light to variable stars and novae, meteors and comets, and the structure of the Universe. Backhouse was one of the earliest observers to call attention to the “… Zodiacal Light opposite the Sun” now commonly known as the gegenschein. A similar achievement was his observation of the nebulosity surrounding Merope in the Pleiades, later confirmed by Isaac Roberts in one of his dramatic early photographs of nebulae. Backhouse’s Catalogue of 9,842 Stars Visible to the Naked Eye (1911) formed the basis for several atlases published for the benefit of amateur observers, but he was perhaps best recognized for his valuable contributions to variable star and meteor astronomy. Thomas R. Williams Born Died Wermland, Sweden, 28 April 1846 Pulkovo, Russia, 29 August 1916 Jöns Backlund is best known for his lifelong research on the motion and brightness of comet 2P/Encke. A mathematician and theoretical astronomer, Backlund earned his doctorate degree in astronomy from the University of Uppsala, Sweden, in 1875. He was hired as assistant director of the Russian Royal Observatory at Pulkovo in 1879 by Otto Wilhelm Struve. In 1883, Backlund was elected to the Imperial Russian Academy of Sciences of Petrograd, which allowed him to move to Saint Petersburg. Backlund was called upon by the Russian Academy to become the director of Pulkovo Observatory in 1895, following the resignation of Fedor Bredikhin. Backlund served in this capacity for 21 years, during which time he successfully improved the work of the observatory by employing large numbers of staff. Backlund devoted himself to what became the passion of his lifetime, computing the orbit of the comet named for Johann Encke, who had devoted much of his own career to computing its puzzling orbit. Encke had proposed that there was a resisting medium near the Sun, which affected the comet’s orbit. Following Encke’s death, this problem was taken up by Friedrich von Asten until his death in 1878. Subsequently, Backlund devoted his major research efforts for the rest of his life to computing the orbit of this comet. Because of the contradictory implications of earlier observations, Backlund decided that it was necessary to recalculate the gravitational perturbations of the planets from Mercury to Saturn on Comet Encke’s orbit. Backlund participated in several international scientific projects and conferences. He also published a large volume of papers summarizing his observations related to the motion of Encke’s comet. Backlund won worldwide renown for his accurate and thorough investigations; he was honored by Cambridge University with a “Doctor in Science” in 1904. He was also awarded the Royal Astronomical Society Gold Medal in 1909. In 1914, he was presented the Bruce Gold Medal of the Astronomical Society of the Pacific for his work on Encke’s comet, as well as for his other notable scientific achievements and contributions to theoretical astronomy. Backlund has a lunar crater named for him, along with a minor planet (856) Backlunda. Raghini S. Suresh Selected References Baker, H. F. (1917). “Johan Oskar Backlund.” Monthly Notices of the Royal Astronomical Society 77: 310–314. Bacon, Roger McAdie, Alexander (1914). “The Award of the Bruce Medal to Dr. J. O. Backlund.” Publication of the Astronomical Society of the Pacific 26: 15–18. Newall, H. F. (1909). “Address Delivered by the President, Mr. H. F. Newall, on Presenting the Gold Medal of the Society to Dr. Oskar Backlund.” Monthly Notices of the Royal Astronomical Society 69: 324–331. Tenn, Joseph S. (1991). “Oskar Backlund: The Eleventh Bruce Medalist.” Mercury 20, no. 6: 175–179. Bacon, Francis Born Died London, England, 22 January 1561 London, England, 9 April 1626 was probably the first ever devised, and was perceived to suffer from notable difficulties, such as the fact that the nearer planets vary in brightness in a continuous and systematic way. Ptolemy had tried to resolve the complexities of the astronomical data by abandoning concentric spheres and introducing epicycles and movable eccentrics, but his system appeared to many to be merely a device for saving the appearances and lacked a natural–philosophical rationale. From the 12th century onwards there were attempts, most notably in the work of al-Bitruji, to revive a homocentric system. Bacon was very much in this tradition, but he showed even less interest in the astronomical detail than his predecessors, seeing disputes over heliocentrism as being purely mathematical, and having no interest whatsoever in accounting for retrograde motions. Secondly, the system Bacon devised had fluid spheres, as opposed to solid crystalline spheres or to a void, and the ether filling the celestial regions thinned out as one moved away from the Earth, which facilitated the daily rotation of the heavens around the Earth. Bacon had a complex matter theory underlying his cosmology, but the Earth was at the center of the cosmos because it is a cool, massive body. His one concession to saving the phenomena – to account for various observed phenomena such as retrograde motions and systematic variations in brightness – was to assume that the outer planets followed tight “spirals” (actually helices wound around spheres rather than strict spirals). These approximated to circles, whereas the inner ones followed more open “spirals.” Evidence of the motion of the heavens around the Earth was evident in the winds and tides, Bacon believed, although here he did introduce a number of devices to save the phenomena. Bacon’s cosmological writings were not published in his lifetime, and the heliocentric theory (in one version or another) was sufficiently well established by the middle of the century for them to appear hopelessly behind the times. They represent the last attempt to pursue cosmology purely in terms of matter theory, without regard to detailed astronomical observations and mathematical calculation. Stephen Gaukroger Selected References Francis Bacon is probably best known for his work on scientific method, but he also developed the last significant geocentric cosmology, around 1611–1612. Bacon was the youngest son of Sir Nicholas Bacon, Lord Keeper of the Great Seal, and Ann Cooke. Educated at Trinity College, Cambridge (1573–1575), he studied law at Gray’s Inn intermittently from 1576, and was admitted to the bar in 1582. Subsequently he was a Member of Parliament, Solicitor General, Attorney General, Lord Keeper of the Great Seal, and Lord Chancellor. In 1611/1612, Bacon developed a geocentric cosmology, the last significant such cosmology outside Jesuit circles. This cosmology had a number of distinctive features. First, it was homocentric, the Earth lying at the center of a system of spheres, all the planets and other celestial bodies having regular orbits around the Earth. Such a system Bacon, Francis (1996). The Oxford Francis Bacon. Vol. 6, Philosophical Studies, c. 1611–c. 1619, edited with introduction, notes and commentaries by Graham Rees. Oxford: Clarendon Press. (For Bacon’s writings on cosmology.) Gaukroger, Stephen (2001). Francis Bacon and the Transformation of Early-Modern Philosophy. Cambridge: Cambridge University Press. Rossi, Paolo (1968). Francis Bacon: From Magic to Science. Chicago: University of Chicago Press. Bacon, Roger Born Died England, circa 1214–1220 England, circa 1292 Roger Bacon is known for promoting the mathematical sciences, and encouraging the use of observation and experience in scientific study. Very little of Bacon’s life can be dated securely. His date of birth is calculated backwards from a comment in his Opus tertium, written B 79 80 B Bacon, Roger about 1267, in which he states that he had learned his alphabet 40 years ago, and spent all but two of those forty years in studio. If in studio refers to Bacon’s time at universities, this places his entrance into university life at about 1227; typically, students entered a university at age 13, thus placing his birth in about 1214. On the other hand, if he truly learned his alphabet in 1227, this would place his birth in about 1220, as his elementary education would probably have begun around age seven. No authoritative records of Bacon’s birthplace have survived, though both Ilchester in Somerset and Bisley in Gloucestershire have been suggested. Because he was able to spend large sums of money on books and instruments for his scholarly work, he was probably from a relatively well-to-do family. Bacon seems to have received his education at both the universities of Oxford and Paris, and received his MA around 1240 from one of these universities. In the early 1240s he was in Paris, lecturing on Aristotle in the faculty of arts at the university; he left the faculty around 1247. For the next 10 years Bacon spent time at both Oxford and Paris, perhaps earning a Master’s degree in theology. In 1256 or 1257, Bacon entered the Franciscan Order. The next 10 years were a somewhat difficult time for him, as he later complained that his superiors hampered his efforts to continue his studies. In the early 1260s, he contacted Cardinal Guy le Gros de Foulques, asking for patronage. The cardinal responded positively, asking to see the writings Bacon had produced, misunderstanding that Bacon in fact wished support to produce writings. In 1265, the cardinal became Pope Clement IV, and Bacon received an order from him in 1266 to begin producing the works they had previously discussed. This put Bacon in a difficult situation, as rules of the Order prevented friars from publishing books without the approval of their superiors, approval he would have been hard-pressed to receive, as many of his ideas about philosophy and the arts were suspect. Nonetheless, Bacon produced a large number of works after 1266, including his Opus maius, Opus minus, Opus tertium, De multiplicatione specierum, De speculis comburentibus, Communia mathematica, Communia naturalium, Compendium studii philosophie, and Compendium studii theologie, all of which include portions on astronomy and natural philosophy. He died around 1292, probably shortly after completing the final work in the preceding list. Bacon has been pictured both as a magician and as a protomodern experimental scientist. Neither of these characterizations accurately portrays the medieval context in which he operated. Bacon’s foremost concern was to promote an educational program that would benefit Christendom. Among the more revolutionary aspects of this program were an increased role for the mathematical sciences, which included astronomy, and the establishment of a scientia experimentalis, often translated as “experimental science,” but perhaps better translated as “experiential science.” Bacon’s arguments promoting the mathematical sciences were largely practical ones: that a greater understanding of the mathematical sciences would ultimately benefit theology; aid in directing Christendom, for example, by predicting famines and wars or creating marvelous new inventions; and assist in the conversion of infidels. Astronomy, one of those mathematical sciences, brought with it a complication, for medieval astronomy was bound up inextricably with notions of astrological influence, and had thus been the subject of theological polemic for a number of centuries. Aristotelian science, which was becoming better known to Latin readers through the translation efforts of the 12th and the 13th centuries, assumed that the eternal, unchanging celestial realm exerted an influence upon the changeable terrestrial realm. Bacon wished to promote the practical benefits that astrological prediction was assumed to hold under this principle of celestial influence. A significant issue for Bacon was to determine the limits of astronomy and the astrological predictions it could make, and in particular to differentiate between proper astronomy and “magic.” Bacon proposed that, through the refinement of astronomical knowledge, the astronomer could produce accurate predictions of the future, though within certain limitations, such as those imposed by an incomplete knowledge of the positions and motions of the heavenly bodies. Material things are more strongly influenced by the heavens; for example, Bacon reinforced the medical knowledge of the day by stating that astrological influences upon the body and its parts are a necessary consideration for the physician. The human soul, on the other hand, while it can be influenced, cannot be compelled by celestial influences. Bacon repeated the Ptolemaic dictum that astrological predictions by necessity remained fallible, and were more accurate when concerned with universals rather than particulars. Bacon also argued that the study of astronomy would aid in the correction of the calendar. It had been recognized that the solstices did not fall on the proper days, and that the length of the year in the Julian calendar was not correctly calculated. Incorrect dates could lead to religious festivals, especially Easter, being celebrated on the wrong day. Bacon advocated the removal of one day every 125 years. (Essentially the same as the later Gregorian reform, Bacon was not the first to propose this.) Bacon argued that astronomy, along with the other mathematical sciences, would benefit from the increasing application of a scientia experimentalis. Experience, as an aid to (but not a replacement for) reason, could establish the certainty of deductive reasoning, add new knowledge to the existing sciences, and reveal new sciences that might lead to marvelous new inventions. Bacon’s ideas about the role of experience surely had some effect in increasing the role of observation and experimentation in natural philosophy. Bacon himself was no astronomer, though his works do demonstrate familiarity with the basics of the astronomy that was being taught in the universities of that period, such as the motions of the planets and the nature of the celestial bodies. His works range over a much wider variety of issues than just astronomy. He promoted, for example, the study of perspectiva, a science related to optics, as well as the science of alchemy. He composed Greek and Hebrew grammars, and wrote on a number of other philosophical and theological issues. But an examination of Bacon’s astronomical concerns demonstrates the different methods and goals that medievals used to investigate a scientific field, as well as Bacon’s place within the history of astronomy. Matthew F. Dowd Selected References Burke, Robert Belle (trans.) The Opus Majus of Roger Bacon. 2 Vols. Philadelphia: University of Pennsylvania, 1928; New York: Russell and Russell, 1962. (Bacon’s works in Latin can also be found in the following sources: The “Opus Majus” of Roger Bacon. 3 Vols. Edited by John Henry Bridges. Oxford, 1897 (Vols. 1–2) and London, 1900 (Vol. 3); Brewer, J. S., Fr. Rogeri Bacon, Opera quaedam hactenus inedita. London, 1859; and Steele, Robert, Opera hactenus inedita Rogeri Baconi. 16 Fascicles. Oxford, 1905–1940.) Bailey, Solon Irving Crowley, Theodore (1950). Roger Bacon: The Problem of the Soul in His Philosophical Commentaries, Editions de l'Institut Supériur de philosophie, pp. 17–78. Louvain: Editions de l'Institut Supérieur de Philosophie. Easton, Stewart C. (1952). Roger Bacon and His Search for a Universal Science. New York: Columbia University Press. (Reprint, New York: Russell and Russell, 1971.) Frankowska-Terlecka, Malgorzata (1969). “Scientia as Conceived by Roger Bacon.” Organon 6: 209–231. Hackett, Jeremiah (1983). “The Meaning of Experimental Science (Scientia Experimentalis) in the Philosophy of Roger Bacon.” Ph.D. diss., University of Toronto. ——— (1995). “Scientia Experimentalis: From Robert Grosseteste to Roger Bacon.” In Robert Grosseteste: New Perspectives on His Thought and Scholarship, edited by James McEvoy, pp. 89–117. Turnhout: Brehols. ——— (1997). “The Published Works of Roger Bacon.” Vivarium 35: 315–320. ——— (1997). “Roger Bacon on Astronomy–Astrology: The Sources of the Scientia Experimentalis.” In Roger Bacon and the Sciences, Leiden-New YorkKöln, pp. 175–198. ——— (ed.) (1997). Roger Bacon and the Sciences. Leiden: Brill. ——— (2000). “Aristotle, Astrologia, and Controversy at the University of Paris (1266–1274).” In Learning Institutionalized, edited by John Van Engen, pp. 69–110. Notre Dame: University of Notre Dame Press. Hackett, Jeremiah and Thomas S. Maloney (1987). “A Roger Bacon Bibliography (1957–1985).” New Scholasticism 61: 184–207. Lindberg, David C. (1983). Roger Bacon’s Philosophy of Nature. Oxford: Clarendon Press. ——— (1996). Roger Bacon and the Origins of Perspectiva in the Middle Ages. Oxford: Clarendon Press. (For a translation of the fifth part of the Opus maius, on perspectiva.) Little, A. G. (1914). “Roger Bacon’s Works, with References to the MSS. and Printed Editions.” In Roger Bacon: Essays, edited by A. G. Little, pp. 375–425. Oxford: Clarendon Press. Maloney, Thomas S. (1997) “A Roger Bacon Bibliography (1985–1995).” In Roger Bacon and the Sciences, edited by Jeremiah Hackett, pp. 395–403. Molland, George (1997). “Roger Bacon’s De laudibus mathematicae: A Preliminary Study.” In Texts and Contexts in Ancient and Medieval Science, edited by Edith Sylla and Michael McVaugh, pp. 68–83. Leiden: Brill. O’Loughlin, Thomas (1994). “Astrology and Thirteenth Century Philosophy: A New Angle on Old Problems.” Milltown Studies 33: 89–110. Bailey, Solon Irving Born Died Lisbon, New Hampshire, USA, 29 December 1854 Norwell, Massachusetts, USA, 5 June 1931 Solon Bailey, a prominent American astronomer in the late 19th and early 20th centuries, was known primarily for his discovery and study of variable stars in globular clusters, now known as RR Lyrae stars, and for his extensive long-exposure photographic surveys of southern skies and photometric catalog of southern stars. After receiving an M.A. from Boston University, in 1884, and teaching at Tilton Academy for a short period, Bailey entered graduate studies at the Harvard College Observatory, where he earned a second M.A. in 1888. In 1889, Edward Pickering, the Harvard College Observatory director, sent Bailey to survey the Andes Mountains for possible sites for a southern extension of the Harvard College Observatory. After several arduous years of travel up and down the Andes chain, Bailey recommended a site near Arequipa, Peru, as the best of several possible sites for an astronomical observatory. Pickering accepted that recommendation, and sent his brother, William Pickering, along with Andrew Douglass and a small staff of other Harvard personnel, to Arequipa. W. H. Pickering directed the construction of the observatory and establishment of the observing program. However, after several years of poor communication between Cambridge and Arequipa, during which W. H. Pickering spent much more of the available money than anticipated for construction, and failed to establish the type of stellar observing program desired, in 1893 E. C. Pickering recalled his brother to Cambridge, and asked Bailey to again take charge of Harvard’s southern station. Bailey and his family returned to Arequipa, where they remained until he was replaced by Frank Hinkley in 1909. The Baileys returned to Peru a total of five times. One of Bailey’s primary accomplishments after returning to Arequipa was the extension of the Harvard Photometry to the South Celestial Pole. Using a meridian photometer brought from Cambridge, Bailey cataloged the brightness of 7,922 stars not visible from Massachusetts. This southern extension to provide full sky coverage contributed substantially to the later acceptance of the Harvard system as an international standard. Among the other projects Bailey initiated as part of the observing program of the Arequipa station was photography of nebulae and globular clusters. That project included taking objective prism plates for the Henry Draper Memorial project with the Bruce 24-in. doublet photographic telescope. Bailey’s assistants carefully examined the plates they took to ensure adequate quality of the recorded spectra, and were thus the first to have the opportunity for discoveries of new objects photographed on each plate. After resolving a minor dispute over roles and priorities with Williamina Fleming, Harvard’s first famous woman astronomer, Bailey and his assistants discovered a number of new variable stars based on the presence of certain characteristic hydrogen emission lines in the stellar spectra. Between 1895 and 1898 he and his assistants found over 500 globular cluster variables, most of which were to be later to be classified as the RR Lyrae stars. Bailey’s determinations of the periods of these variables, all within the range of 0.5 to 1.5 days, proved extremely accurate. The long exposure plates collected during this survey constituted a rich resource for later studies of clusters, galaxies, and nebulae in the southern skies. The short focal length of the Bruce telescope limited its ability to resolve stars in the crowded regions of globular clusters. Bailey realized that a large telescope and very sensitive plates were critical for his work. At that time there was only one observatory in the world with the necessary equipment – the Lick Observatory in California. E. C. Pickering requested that Lick make plates of M3 with the 36-in. Crossley reflector. The Lick plates would be an important part of Bailey’s 1913 presentations of the variable stars in Messier 3. Bailey’s studies of variable stars in clusters were extended to M5, M15, and Omega Centauri. From his site survey work, Bailey recognized the value of regular meteorological observations, and established a series of meteorological stations along the Andes. The stations included what was then the highest meteorological station in the world atop a nearby Andean volcano, 19,000-ft “El Misti.” Other meteorological stations were placed along the coast at sea level as well as on various peaks and high plateaus in the Andes. Over the next 41 years B 81 82 B Baillaud, Edouard-Benjamin (from 1889 to 1930) Bailey published regular Peruvian Meteorology reports for this South American network. After returning from Peru, Bailey was active in the astronomical community in the Boston area. In 1912, after the retirement of professor Arthur Searle, Bailey was appointed Phillips Professor of Astronomy. In 1918, he served as one of the incorporators of the American Association of Variable Star Observers [AAVSO]. After Edward Pickering’s death in 1919, Bailey became acting director of the Harvard College Observatory. However, it was the young Harlow Shapley who would eventually become director of the observatory, and not Bailey. Perhaps it was Bailey’s age (64), and Shapley’s youthful exuberance, which prevailed in that decision. To a great degree, Shapley’s success in the area of globular clusters and variables was due to his collaboration and communications with Bailey. Solon Bailey’s legacy remains his observations, which are considered a foundation for those of the likes of Shapley who would follow him. He was elected president of the International Astronomical Union’s Commission on Variable Stars in 1922. He was elected a member of the National Academy of Sciences in 1923. The University of San Augustine, Peru, conferred an honorary Ph.D. degree on Bailey in that same year. Bailey’s wife, Ruth Poulter Bailey, and young son Irving Widmer accompanied him on many trips to Peru. Irving spent most of his boyhood in Peru, accompanying his father on trips in the Andes, trips which ranged from jungle to barren mountain slopes. Bailey and his family also were to endure the death throes of the Peruvian Aristocratic Republic’s “Revolution of 1895.” This revolution culminated in the Aristocratic Republic, during which Peru experienced relative political harmony and rapid economic growth as well as social and political change. Robert D. McGown Selected References Bailey, Solon Irving (1895). “A Catalog of 7922 Southern Stars Observed with the Meridian Photometer during the Years 1889–91.” Annals of the Astronomical Observatory of Harvard College 34. ——— (1931). The History and Work of Harvard Observatory, 1839 to 1927. Harvard Observatory Monographs, no. 4. New York: McGraw-Hill. Cannon, Annie J. (1934). “Biographical Memoir of Solon Irving Bailey.” Biographical Memoirs, National Academy of Sciences 15: 193–203. Jones, Bessie Zaban and Lyle Gifford Boyd (1971). The Harvard College Observatory: The First Four Directorships, 1839–1919. Cambridge: Harvard University Press, pp. 287–324, 350–356, 379, 444. Smith, Horace A. (2000). “Bailey, Shapley, and Variable Stars in Globular Clusters.” Journal for the History of Astronomy 31: 185–201. Baillaud, Edouard-Benjamin Born Died Chalon-sur-Saône, Saône et Loire, France, 14 February 1848 Toulouse, Haute-Garonne, France, 8 July 1934 French astronomer Benjamin Baillaud is best remembered today for his seminal roles in the founding of the Carte du Ciel project (the first photographic atlas of the sky) in the late 19th century and in the establishment of the International Astronomical Union just after World War I. He was, in many ways, the French counterpart of George Hale. Baillaud, whose father was an employee at the city hall of Chalon, came from a large and modest Burgundian family of seven children and received scholarships to the Lycée of Lyon, where he studied special mathematics. Passing through the École Normale Supérieure (1866–1869), he taught in several French lycées until 1878, even as he became an assistant to Urbain Le Verrier (1872) at the Paris Observatory and a specialist in mathematical astronomy (1874). After obtaining his doctorate in science (1876), Baillaud lectured at the Sorbonne on dynamical astronomy (1877) as a substitute for Le Verrier who was ill. In 1878, Baillaud was appointed director of Toulouse Observatory and the year after as dean – he was the youngest in France – of the Faculty of Science of Toulouse University. He gave a great impetus to both institutions, attracting collaborators and teachers of talent. At the university, Baillaud developed considerably the Faculty of Science, with the construction of new buildings, an increase in the number of chairs from nine to 20, and the appointment in Toulouse of scientists, since famous, such as Emile Picard, Marie Henri Andoyer, Aimé Cotton, and Paul Sabatier. In 1886, the journal Annales de la Faculté des Sciences de Toulouse, for mathematical and physical sciences, was created following his proposal. Baillaud remained director of the Observatory of Toulouse for 30 years, and converted a small establishment into an important one. The domain surrounding it was enlarged, new instruments were acquired, and laboratories relating to meteorology, magnetism, mechanics, electricity, measures, and calculations were reorganized or developed. The work done under his direction includes observations of sunspots from 1879 onwards and equatorial observations of satellites, double stars, comets, and asteroids. On Baillaud’s Bailly, Jean-Sylvain initiative, the Toulouse Observatory was involved, in 1887, in the plan for the photographic Carte du Ciel and its catalog. Baillaud himself was interested in planetary theory. He wrote several memoirs on the development of the perturbing function, investigated the orbits of the five interior satellites of Saturn, and discussed the numerical calculation of definite integrals by methods of quadrature. In this regard his part in the founding of an astronomical station (1903) at the Pic du Midi (2865 m) elevation, in the French Pyrenees, was very important. The small meteorological station existing at Pic du Midi was turned into a major astronomical observatory. Pic du Midi went into regular use in 1908, the very year that Baillaud was appointed director of the Paris Observatory. The next year he set up a small telescope (1909) so that planetology could be developed at Pic du Midi. After Toulouse Observatory, Paris Observatory for twenty years took advantage of Baillaud’s expertise in organizing and leadership. Soon after his arrival, he convened at Paris the Standing Committee for the Carte du Ciel, to regulate celestial photography, to produce the astrographic catalog, and to discuss the results obtained from the observations of Eros in 1900/1901. He was elected as its president (1909). In 1911, again, Baillaud held an international meeting on astronomical ephemerides, where the directors of the principal astronomical almanacs agreed to the standardization of working methods, and a suitable division of work among them, to establish a fundamental star catalog. The Paris Observatory did not actually permit astrophysical research. Instead, Baillaud improved the meridian service and took advantage of the advancement of wireless telegraphy to use it for a more accurate determination of longitudes by transmitting time information. General Ferrié was in charge of the wireless station at the Eiffel Tower, and in 1910, for the first time, signals were emitted from the Eiffel Tower according to a clock at the Paris Observatory. After this the two men conceived a vast project for continuation of the universal adoption of Greenwich Meridian Time. Two international conferences (1912 and 1913) were convened at Paris to institute a Commission internationale de l’heure (International Hour Council) and a Bureau International de l’Heure at the Paris Observatory. Baillaud was chosen as the director. During World War I (1914–1918) he never failed to maintain the transmission of time from the Eiffel Tower, although the monument was particularly threatened by gunfire. Immediately after the armistice, scientists began reorganizing, and in July 1919, the Conseil International des Recherches (International Research Council) was instituted at Brussels. Under its wing the Unions Internationales (International Unions) were formed. Baillaud was one of the most active creators of the International Unions (which owe to him their French names). Among them was the Union Astronomique Internationale (International Astronomical Union [IAU]), combining the Carte du Ciel, the Solar Union, and the Bureau International de l’Heure. Baillaud was elected the first IAU president (1919–1922). Baillaud was a member of the Académie des sciences (1908), a member of the Bureau des longitudes (1908), an associate member of the Royal Astronomical Society (1908), a corresponding member of the Imperial Academy of Sciences of Saint Petersberg (1913), and an associate member of the Accademia dei Lincei (1918). He was awarded the Bruce Medal (1923) of the Astronomical Society of the Pacific. Baillaud continued the directorship of the Paris Observatory until 1926, his main interest being the Astrographic Chart and the Wireless Time Service. Then he retired in Toulouse. Baillaud was known as a remarkable professor and was admired for his modesty, integrity, cordiality, and administrative proficiency. He had eight children; two among them were astronomers: Jules and René Baillaud. (René Baillaud was director of Besançon Observatory: 1930–1957.) Raymonde Barthalot Selected References Anon. (1934). “Benjamin Baillaud.” Astronomische Nachrichten 253: 15–16. Anon. (1934). “Obituary.” Observatory 57: 308–309. Baillaud, E. B. (1876). Exposition de la méthode de M. Gylden pour le développement des perturbations des comètes. Paris: Gauthier-Villars. (Publication of his thesis.) ——— (1893–1897). Cours d’Astronomie à l’usage des Etudiants des Facultés des Sciences. 2 Vols. (For his lectures on astronomy for university students of science.) ——— (1915). L’astronomie. Paris: Larousse. Baillaud, E. B. and Henry Bourget (1903). “Les conditions qu’offrent les observations astronomiques à l’observatoire du Pic du Midi.” Comptes rendus de l’Académie des sciences 136: 1417–1420. ——— (1907). “Installation d’un grand instrument astronomique au sommet du Pic du Midi.” Comptes rendus de l’Académie des sciences 145: 662–665. Baume-Pluvinel, A. de la (1934). L’Astronomie 48: 537–543. Borel, E. (1934). “Benjamin Baillaud.” Comptes rendus de l’Académie des sciences de Paris 199: 107–109. Dyson, F. W. (1935). “Edouard Benjamin Baillaud.” Monthly Notices of the Royal Astronomical Society 95: 334–336. Paloque, E. (1935). Annales de l’Observatoire astronomique de Toulouse 11: 8. Sampson, R. A. (1934). “M. B. Baillaud.” Nature 134: 279–280. Tenn, Joseph S. (1993). “Benjamin Baillaud: The Eighteenth Bruce Medalist.” Mercury 22, no. 3: 86–87. Bailly, Jean-Sylvain Born Died Paris, France, September 1736 Paris, France, 12 November 1793 Jean-Sylvain Bailly, a French astronomer and politician, was largely known for his contributions to astronomy and his tragic political career. After studying with Nicolas de La Caille and Alexis Clairaut, Bailly computed orbits of various comets and, using Clairaut’s theory, made the first effort to improve the tables of the satellites of Jupiter. Such tables were widely used for navigation and surveying purposes at the time. By applying theoretical rather than empirical methods, Bailly attempted to predict the perturbations in their orbits more accurately and thus make the tables more accurate. In 1771, Bailly published his most noteworthy scientific work, a study of the inequalities of light observed in the immersion and emersion of Jupiter’s satellites during their eclipse in the Jovian shadow. Using a new observational technique, Bailly related those anomalies to the characteristic amount of light reflected by each satellite and its diameter, and suggested further improvements in the observational methods involved. B 83 84 B Baily, Francis As a result of his various works, Bailly was elected to the Académie des sciences in January 1763, elected to the Académie française in 1783, and appointed by the king to the Académie des inscriptions et Belles-Lettres. Only one other individual had ever been a member of all three academies prior to Bailly. Commission appointments and other services on behalf of the Académie des sciences led Bailly into nonastronomical investigations, the result of which was a greater public appreciation of his skills. He was named spokesman for the Paris delegation to the Estates General, and on 20 June 1789, Bailly led the Third Estate in taking the Tennis Court Oath that led to the creation of the National Assembly. Bailly was then elected first president of the assembly. On 15 July 1789, Bailly was unanimously proclaimed the first mayor of Paris, a position to which he was reelected in 1790. After the massacre on the Champ de Mars, Bailly fell from popularity and retired, but was still charged with conspiracy and guillotined. Ednilson Oliveira Selected References Chapin, Seymour L. (1970). “Bailly, Jean-Sylvain.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 1, pp. 400–402. New York: Charles Scribner’s Sons. Conner, S. P. (1985). “Bailly, Jean-Sylvain.” In Historical Dictionary of the French Revolution, 1789–1799, edited by Samuel F. Scott and Barry Rothaus, pp. 53–56. Westport, Connecticut: Greenwood. Baily, Francis Born Died Newbury, Berkshire, England, 28 April 1774 London, England, 30 August 1844 Although he is better known for his recording of the solar eclipse phenomenon now known as Baily’s beads, Francis Baily’s most important contributions to astronomy include his recomputation and republication of important star catalogs, and his determination of the ellipticity and density of the Earth. Before turning his wealth to his interest in astronomy, Baily had many adventures. The third son of banker Richard Baily, he had been apprenticed to a London mercantile firm at the age of 14. But by the age of 21, when he had completed his apprenticeship, Baily had instead decided on a career as an explorer. In October 1795, Baily sailed to the United States, where his youthful energy carried him through 2 years of exploration along the Ohio and Mississippi rivers from Pittsburgh, Pennsylvania, to New Orleans, Louisiana. He returned to New York City overland through the rugged back-woods areas. A romantic attachment nearly induced Baily to remain in the United States, but his ambitions for exploration were apparently strong. Returning home in March 1798, he failed to find financial backing for exploration in Africa, and instead became a stockbroker the following year. During his successful business career, Baily acquired a substantial reputation for the accuracy of his actuarial computations, publishing a number of successful monographs on the subject. He retired with a large fortune in 1825 at the age of 54 and pursued his interest in astronomy, a field in which he was very active until his death. Before his retirement from business, Baily’s interest in history and the tabulation of data drew him to publish several historical works, including a paper on the solar eclipse that Thales was said to have predicted. Although that paper was later corrected by George Airy based on improved lunar tables, Baily apparently enjoyed both the historical and the mathematical aspects of calculating the date on which that ancient eclipse had occurred. The project launched his career in astronomy. At the time of his retirement, Baily already had been one of the leading founders of the Astronomical Society of London, later chartered as the Royal Astronomical Society [RAS]. He served as the RAS president for 8 years. Baily’s next astronomical achievement involved methods of determining latitudes and local times. He aimed to improve the notoriously erroneous British Nautical Almanac by recalculating the positions of 2,881 stars for the epoch 1 January 1830. His revised catalog was published by the Astronomical Society in 1826. For his efforts on this catalog, Baily was awarded the RAS Gold Medal in 1827. It was on the basis of Baily’s protests in 1819 and 1822, as well as his revised catalog of stars, that the Nautical Almanac reforms of 1827 were undertaken. On the basis of that experience, Baily made an astronomical career of revising and republishing a number of important star catalogs. In 1835, he published a revised edition of John Flamsteed’s Historia Coelestis of 1712, including in the accompanying text a vindication of Flamsteed in the latter’s acrimonious dispute with Isaac Newton and Edmond Halley. Baily displayed considerable understanding in concluding that “even amongst men of the most powerful minds, science is not protection against the common infirmities of human nature: and that however much we may admire their intellectual attainments, we must ever regret their exhibition of any human frailty.” Baily secured the sponsorship of the British Association for the Advancement of Science for his pursuit of correcting and republishing tables of star positions, and for the most part carried out these revisions himself. Baily’s revision of Joseph de Lalande’s Histoire céleste française of 1801, listing 47,390 objects including nebulae, was published in 1847. Other catalogs revised and republished by Baily included the historic catalogs of Ptolemy, Ulugh Beg, Tycho Brahe, Johannes Hevelius, and Tobias Mayer, and the important catalogs of Southern Hemisphere stars of Halley and Nicolas de La Caille, with the help of Thomas Henderson. Baily also worked on a number of problems related to the size and density of the Earth. He completed and discussed the pendulum experiments of H. Foster, applying a correction that had previously been overlooked, and deduced from them an ellipticity of the Earth of 1/289.5. Baily also repeated and extended the work of Henry Cavendish aimed at determining the mean density of the Earth, an effort for which the RAS awarded him a second Gold Medal in 1843. Baily is one of only four persons to be so recognized twice, the others being John Herschel, William Huggins, and David Gill. Today Baily is mainly known for the so called Baily’s beads phenomenon, transient light irregularities that may appear on the lunar limb during solar eclipses. He first observed the phenomenon during an annular eclipse on 15 May 1836 at Inch Bonney, Roxburghshire, England. Baily gave a vivid description of the phenomenon as like a string of bright beads, and gave the correct explanation: Sunlight Bainbridge, John is blocked by lunar mountains, but passes through the intervening valleys. Although others had reported seeing this phenomenon at earlier eclipses, Baily’s description was so graphic that his name has been associated with it since that time. Since then, eclipse chasers from all countries have hoped to see once in their lives this rare and spectacular phenomenon. Baily was elected a member of the Royal Society in 1821. He served for a number of years as a vice president, and also as a treasurer of that organization. Jean-Pierre Luminet Selected References Anon. (1854). “Biographical note.” Memoirs of the Royal Astronomical Society 23: 81–83. Baily, Francis (1835). An Account of the Revd. John Flamsteed. (Reprint, London: Dawson, 1966.) ——— (1838). “On a Remarkable Phenomena that occurs in Total and Annular Eclipses of the Sun.” Memoirs of the Royal Astronomical Society 10: 1–42. ——— (1846). “Some remarks on a Total Eclipse of the Sun, on July 8th, 1842.” Memoirs of the Royal Astronomical Society 15: 1–8. Clerke, Agnes M. (1921–1922). “Francis Baily.” In Dictionary of National Biography, edited by Sir Leslie Stephen and Sir Sidney Lee. Vol. 1, pp. 899–904. London: Oxford University Press. Bainbridge, John Born Died Ashby-de-la-Zouch, Leicestershire, England, 1582 Oxford, England, 3 November 1643 As one of the first astronomers to observe a comet telescopically and compute its parallax, and as the first Savilian Professor of Astronomy at Oxford University, John Bainbridge established a high standard for both research and pedagogy for his successors in academic astronomy. Bainbridge, the son of Robert and Anne (née Everard) Bainbridge, attended grammar school in Ashby, England, and later entered Cambridge University where he received his B.A. in 1603, M.A. in 1607, and M.D. in 1614. Bainbridge returned to Ashby in 1614 where he established his medical practice, and started a grammar school at which he taught for 4 years. In what little leisure time was available to him, he occupied himself with the study of mathematics and astronomy. On the advice of some friends, Bainbridge moved to London in early 1618, where he soon became a member of the “Gresham Circle,” a group of Puritan scholars and college professors that included Robert Hues, Nathaniel Carpenter, and Henry Briggs, the first professor of geometry at Gresham College. During his brief London stay, Bainbridge lectured on astronomy and medicine at Gresham College and was made a licentiate of the College of Physicians of London on 6 November 1618. In 1619 Bainbridge published his major contribution to astronomy, a small tract entitled An Astronomicall Description of the late Comet from the 18. of Novemb. 1618. to the 16. of December following. In the tract, Bainbridge detailed his personal observations of the historic comet, including drawings of its relative position and appearance in the sky, dating from 18 November to 16 December 1618 (Julian calendar, new calendar dates – 28 November to 26 December 1618). In a fascinating series of observations during the 2nd week of December, Bainbridge became one of the first astronomers to observe a comet telescopically. He followed the comet with respect to two nearby stars, and by comparing the relative positions of the comet and the stars, both near the horizon and at the zenith, he estimated that the comet’s distance from the Earth had to be more than ten times the Earth–Moon distance. Bainbridge’s telescopic estimation of the parallax of comet C/1618 W1, his criticism of the Ptolemaic system, and his preference for a heliocentric worldview, all combine to make An Astronomicall Description a remarkable publication for its time. While the observations as set down in the book make plain Bainbridge’s conviction that the comet had natural causes and a natural movement, and thus insufficient cause to deem it a miracle, Bainbridge does retain the miraculous as a theoretical possibility. Yet Bainbridge devotes the majority of An Astronomicall Description to presenting newly gathered astronomical information and its analysis. More curious, however, is Bainbridge’s use of astrological conventions in interpreting the comet. Bainbridge wrote how he deplored the illusory principles of “vulgar Astrologie,” yet could not refrain from proffering his own prognostications. What is striking in this is that in an age when astrology was an important topic for most men of learning, Bainbridge’s closest associates strongly opposed it. Perhaps Bainbridge did at that point believe in the colloquial notion of comets being omens, but it is known that in the year before he died, Bainbridge wrote Antiprognosticon, in which “is briefly detected the vanity of astrological predictions grounded upon the idle conceits of celestial houses and triplicities.” As the title of this unpublished treatise suggests, Bainbridge argued for astronomical events as being matters that agree with stated natural laws. Thus, Antiprognosticon constituted his rejection of all astrological tenets. At some point in late 1618 or early 1619, Henry Briggs introduced Bainbridge to Sir Henry Savile at Gresham College, probably to exchange observational information regarding the comet and various eclipses. Savile was in the process of establishing two professorships for the teaching of mathematics and astronomy at the University of Oxford. Savile (an ardent Puritan) appointed Bainbridge to be the first Savilian Professor of Astronomy at Oxford University in 1619 partly on the basis of Bainbridge’s astronomical work with the comet, his enthusiasm for the subject, and perhaps also the growing anti-Puritan climate of London. Savile laid down very precise conditions on how astronomy was to be taught. The Savilian professor was required to teach the classical texts, such as Ptolemy’s Almagest, but new theories were to be presented as well, explicitly the De Revolutionibus of Nicolaus Copernicus. Other requirements included the teaching of spherics, optics, geography, elements of navigation, and calculation with sexagesimal numbers, and to conduct independent research. He likewise had to make his own instruments and carry out his own observations with them, which, like the lecture notes, were to be deposited in the Bodleian Library. These conditions were given to ensure that astronomy would develop and not be simply a subject fixed by the classical writers. One final condition prohibited the teaching of astrology in any B 85 86 B Baize, Paul-Achille-Ariel guise, which makes Bainbridge’s appointment intriguing in light of his recently published An Astronomicall Description. Bainbridge, in accordance with the statutes of his professorship, also conducted research in ancient astronomy and chronology. In 1620, he published a combined Latin translation of the ancient Greek astronomical works Proclus’s On Spheres, Ptolemy’s On the Hypotheses of Planets, and Canon regnorum. Because of his studies in chronology and ancient astronomy, and very probably his mutual friendship with Henry Briggs, Bainbridge joined a vibrant milieu of Oxonians working with James Ussher. Beginning in 1622, Bainbridge engaged in correspondence with Ussher and set to work on a method for calculating eclipses at his request. Such was their relationship that Bainbridge bequeathed his lecture notes, unpublished manuscripts, and personal correspondence to Ussher. Bainbridge also wrote what many consider the most original of all 17th-century works on ancient chronology, the Canicularia, which dealt with the risings and calendrical import of Sirius in the ancient world. Considered to be Bainbridge’s last publication, this work displays “a formidable knowledge of ancient literature as well as of astronomy and chronology.” Begun in 1626, it was published posthumously in 1648 under the care of John Greaves, Bainbridge’s former pupil and immediate successor as Savilian Professor of Astronomy. Bainbridge’s lasting legacy in chronology is often associated with his role in calendar reformation, principally his correction of Joseph Scaliger. In addition to the Canicularia, his compositions on chronology are found in several works of the period, including George Hakewill’s An Apologie or Declaration of the Power and Providence of God in the Government of the World (1627), Ralph Winterton’s Hippocratis magni aphorismi (1633), and the Theatrum Botanicum of John Parkinson (1635). Oxford University witnessed a qualitative leap forward in the improvement of scientific teaching and learning during Bainbridge’s 24-year tenure as the first Savilian Professor of Astronomy. In planning and conducting research, Bainbridge proved himself to be meticulous and passionate. In the Bainbridge papers at Trinity College, Dublin, for example, there is his “Catalogue of Instruments” that includes proportional compasses (i. e., sectors); the mesolabium; the armillary sphere; the solid sphere; the ordinary and universal astrolabes; the astronomer’s cross-staff; the geometrical staff; quadrants; dials; the astronomer’s ring; the ordinary; variation and declination compasses; various telescopes; and numerous maps. In addition, Bainbridge’s observations may be found in the papers of his contemporaries, both in England and abroad, for example Ismaël Boulliau and Pierre Gassendi. Reciprocally, Bainbridge often sought out their advice on astronomical matters. Bainbridge’s notebooks indicate a deep interest in all types of astronomical phenomena, and his observations of various eclipses, the Moon, and the 1631 transit of Venus illustrate meticulous attention to detail in recording as well as his drive to gather the requisite observations. Despite the unkind fate that plagued Roger Fry’s 1631 expedition to South America, Bainbridge orchestrated several observations in England that provided data for the eventual explication of the longitude problem. Bainbridge also determined the latitude of Oxford in 1623. The Bainbridge papers reflect, as Mordechai Feingold suggests, “an indefatigable astronomer familiar with the most recent observations and speculations, who both applied such contemporary accounts to his own research and integrated them into his teaching.” Patrick A. Catt Selected References Anon. (1747). “Bainbridge, John.” In Biographia Britannica. Vol. 1, pp. 419–421. London: Printed for W. Innys. Austin, Preston Bruce (1921–1922). “Bainbridge, John.” In Dictionary of National Biography, edited by Sir Leslie Stephen and Sir Sidney Lee. Vol. 1, p. 906. London: Oxford University Press. Bainbridge, John (1619). An Astronomicall Description of the late Comet from the 18. of Novemb. 1618. to the 16. of December following. With certain Morall Prognosticks or Applications drawne from the Comets motion and irradiation amongs the celestiall Heiroglyphicks. London: Edward Griffin. ——— Correspondence. MS Smith 92 and MS Add. A. 380. Oxford: Bodleian Library. ——— Eleven volumes of unpublished manuscripts. MSS 382–86, James Ussher Collection. Dublin: Trinity College. Feingold, Mordechai (1984). The Mathematicians’ Apprenticeship: Science, Universities and Society in England, 1560–1640. Cambridge: Cambridge University Press, esp. pp. 143–149, 161–165. Genuth, Sara Schechner (1997). Comets, Popular Culture, and the Birth of Modern Cosmology. Princeton, New Jersey: Princeton University Press, pp. 53–55. Parr, Richard (1686). The Life of … James Usher. London: Printed for Nathanael Ranew, pp. 141, 320, 370–371, 390, and 411. Taylor, E. G. R. (1954). “Bainbridge, John.” In The Mathematical Practitioners of Tudor and Early Stuart England. Cambridge: University Press, p. 197. Yeomans, Donald K. (1991). Comets: A Chronological History of Observation, Science, Myth, and Folklore. New York: John Wiley and Sons, pp. 66–67. Baize, Paul-Achille-Ariel Born Died Paris, France, 11 March 1901 Laval, Mayenne, France, 6 October 1995 Paul Baize pursued a distinguished career in pediatrics while developing an equally distinguished astronomical career as a specialist in binary stars. As an amateur astronomer, Baize made over 24,000 exceptionally accurate binary star measurements using the 30-cm and the 38-cm refractors of the Paris Observatory, and calculated nearly 300 orbits based on his observations. His publications included a catalog of binary star orbits (1950), a stellar mass–luminosity relationship (1957), a catalog of red dwarf binary stars (1966), and over 200 other astronomical papers. Baize was elected to membership in the International Astronomical Union in 1936. He was honored with the Amateur Achievement Award of the Astronomical Society of the Pacific in 1987, and elected an Officier of the Legion of Honour. Paul Couteau Selected References Clouet, B. (1996). “Paul Baize dans mon micromètre.” L’Astronomie 110: 34. Couteau, P. (1996). “Commentaires sur l’activité scientifique du docteur Paul Baize.” L’Astronomie 110: 33. Minois, J. (1996). “Adieu à Paul Baize, Coutances, le 11 octobre 1995.” L’Astronomie 110: 32. Baker, James Gilbert Bājja > Ibn Bājja: Abū Bakr Muḥammad ibn Yaḥyā ibn al-Ṣā’igh al-Tujībī al-Andalusī al-Saraqusṭī Baker, James Gilbert Born Died Louisville, Kentucky, USA, 11 November 1914 Bedford, New Hampshire, USA, 30 June 2005 Although trained chiefly in mathematics and astrophysics, James Baker also possessed a deep and abiding interest in optical design and fabrication, his particular forte being the design of telescopes and cameras of unprecedented fast photographic speed, wide field of view, and overall high image quality including the Baker–Nunn camera. Baker had a keen appreciation for what instrumentation could produce in terms of data, and also a fundamental understanding of how instruments worked on both a practical and theoretical basis. An experienced observer from his student days, Baker was able to define problems with existing astronomical instrumentation and combine aspects of theory, observation, design, and fabrication to produce new, more perfect, and more useful astronomical and photographic instruments. Even while creating new optical designs not directly associated with astronomy, Baker always kept in mind possible astronomical applications. Baker was the son of Jesse Blanton and Hattie May (née Stallard) Baker. His interest in astronomical optics began as a high-school student when he produced his first optical component, a simple 3-in. lens that he used to view the Moon. While studying as much astronomy as possible, Baker graduated with a B.S. in mathematics from the University of Louisville in 1935. He then entered Harvard University as a graduate student in astronomy. On the basis of his success as an undergraduate, Baker was awarded a Junior Fellowship to attend the first Harvard Summer School. Baker’s first year in Cambridge, Massachusetts, proved important for his eventual career. At the Harvard University Tercentenary Celebration, in the fall of 1936, Baker met Richard Scott Perkin who, at that time, was looking for opportunities for self-employment. At that same meeting, Perkin also met Charles Elmer, and it was in that chance meeting that the two agreed to form the Perkin–Elmer Corporation. A close friendship between Baker and Perkin evolved over subsequent years. In addition to many consulting assignments for Baker on Perkin–Elmer projects, Perkin attempted several times to recruit Baker as an employee, and twice invited Baker to become a director of the corporation. Preferring to stay focused on science, especially astronomy, Baker was consistent in refusing all such entreaties. The Baker and Perkin families became close friends socially; Baker eventually served as a director and a key contact for the Perkin Foundation. Baker’s primary research work as a Harvard Junior Fellow and graduate student involved spectroscopy and the physics governing gaseous nebulae. His graduate research in astrophysics was done in collaboration with Donald Menzel as well as Harlow Shapley. After passing qualifying exams in 1938, Baker’s interest in optics and instrumentation as well as the astrophysics of the nebulae led him to construct a new grating spectrograph to replace an aged prism-type instrument that had been used on the 61-in. reflector at Harvard’s Oak Ridge Observatory. He taught a course on mathematical optics in Harvard’s mathematics department in 1941. Baker defended his doctoral thesis, Investigations in the Theory of Optics with Astronomical Applications and was awarded a Ph.D. in the summer of 1942. Like other scientists at the beginning of World War II, Baker was harnessed to the war effort, working as an advisor on military optics for the United States. In 1941, Shapley brought Baker’s talent as an optical designer to the attention of the Kodak Corporation and the United States Army Air Corps. In addition to his involvement in other wartime projects, Baker headed the Harvard Observatory Optical Project from its inception in the summer of 1941 to its closing in 1945. Working originally in the basement of the Harvard College Observatory, Baker and a team of as many as 25 professional and amateur optical workers produced prototypes of very high-quality large-aperture aerial camera lenses. Baker also participated in optical research work at the Air Force’s Wright Field in Dayton, Ohio. After the war, Baker continued optical design work for the government, industry, and for Harvard. Significantly, the lenses designed by Baker during and after World War II were, almost without exception, designed not only for military reconnaissance, but also as potential astrographic cameras. Baker never lost sight of these possible dual applications, although military security often prevented such use until much later. Baker was appointed associate professor at the Harvard College Observatory in 1945. He continued to work intermittently as a professor and later as an associate until his retirement. Although not primarily a teacher, Baker did conduct courses from time to time in celestial mechanics, astrophysics, and, of course, optics. Among Baker’s astronomy-related Harvard projects in the 1950s were a “Super-Schmidt” meteor camera working at f/0.6 with a 55° field of view for Fred Whipple, and an improved flat-field Schmidt camera with one additional element that was the basis for the Armagh– Dunsink–Harvard 33-in. aperture camera installed at Harvard’s Boyden Station at Bloemfontein, South Africa. A further Schmidt refinement with a three-element corrector plate became famous as the Baker–Nunn camera used for satellite tracking and other widefield astrophotographic applications. One of Baker’s more publicized projects in the 1950s was the Medial refractor, also known as the Schupmann telescope, a refracting telescope system in which a series of lenses, mirrors, and prisms can be so designed and adjusted to eliminate instrumental and atmospheric chromatic aberration. Typically, it was difficulties he encountered while observing, in this case with the 36-in. refractor at the Lick Observatory, which prompted Baker’s design work with the Medial telescope. Baker proposed a 29-in. Medial refractor for astrometric applications at the Sacramento Peak Observatory in 1954, but the project was never funded. In the 1960s, Baker produced a design known as the Paul–Baker telescope, a very fast ( f/2), wide-field, three-element reflecting telescope, an example of which is the 1.8-m CCD/transit telescope now at the Steward Observatory in Arizona. In the 1980s, Baker continued work on astrographic telescopes, in particular designs that could be used over a wide spectral region. B 87 88 B Baldwin, Ralph Belknap Baker’s career was primarily one of quiet but steady consulting. In addition to his work with Harvard University, the United States Air Force, and Perkin–Elmer Corporation, Baker also served as consultant at the Lick Observatory in California, Aerospace Corporation, and Polaroid Corporation. Baker was elected to both the National Academy of Sciences and the National Academy of Engineering. He was a member of the American Astronomical Society, and the Optical Society of America, serving as its president in 1960. Baker received numerous awards including the Adolph Lomb Medal (1942), the Presidential Medal of Merit (1947), the Alan Gordon Award of the Society of Photooptical Instrumentation Engineers (1976), and the Fraunhofer Award of the Optical Society of America (1991). In 1938, Baker married Elizabeth Katherine Breitenstein. They had four children. Gary L. Cameron Selected References Baker, James G. (1942). “Investigations in the Theory of Optics with Astronomical Applications.” Ph.D. diss., Harvard University. ——— (1954). “The Catadioptric Refractor.” Astronomical Journal 59: 74–83. Baker, James G. and George Z. Dimitroff (1945). Telescopes and Accessories. Philadelphia: Blakiston. Fahy, Thomas P. (1987). Richard Scott Perkin and the Perkin–Elmer Corporation. Privately published. Ingalls, Albert G. (ed.) (1953). Amateur Telescope Making, Book Three. Kingsport, Tennessee: Scientific American. (In addition to an article by Baker on photographic lenses, an appendix of this book contains the only published biography of Baker, up to 1953, that has been easily obtained.) Schroeder, Daniel J. (2000). Astronomical Optics. 2nd ed. San Diego: Academic Press. Baldwin, Ralph Belknap Born Grand Rapids, Michigan, USA, 6 June 1912 Astronomer and businessman Ralph Baldwin received bachelor’s and master’s degrees in astronomy and a Ph.D. in astrophysics from the University of Michigan, where he was a student of Heber Curtis and Dean McLaughlin. After completing his doctoral dissertation in 1937, on the spectroscopic study of novae, Baldwin taught at the University of Pennsylvania (1937/1938) and Northwestern University (1938–1942) while continuing work on the development of physical models of novae and unusual binary stars. In 1942, Baldwin accepted an appointment as a senior physicist at the Johns Hopkins University’s Applied Physics Laboratory, where, in a wartime group led by the geophysicist Merle Tuve, he helped to develop the radio proximity fuze. In 1947, Baldwin returned home to Grand Rapids to help run the family business, Oliver Machinery Company. Between then and his retirement in 1984, he rose from product manager to chairman of the board of the firm, which specialized in producing woodworking machinery. Well respected in his industry, Baldwin served as president of the Wood Machinery Manufacturers of America from 1964 to 1968. While teaching at Northwestern University, Baldwin lectured part-time at Chicago’s Adler Planetarium, where he became intrigued by large photographs of the Moon exhibited there. After noticing radial markings cutting across mountains ringing Mare Imbrium, the largest lunar “sea,” he concluded that this surface feature was too big to be volcanic and that the grooves were valleys “caused by material ejected radially from the point of an explosion.” He determined that lines projected from the major axes of these valleys all intersected in the mare. By 1941, Baldwin had become convinced that the impact of a meteorite of “asteroidal proportions” had caused both the valleys and the mare. In a lecture that year at Yerkes Observatory, and in papers published in Popular Astronomy in 1942 and 1943, he argued that other circular lunar maria and virtually all lunar craters had an impact, rather than volcanic, origin. Over the next few years, Baldwin studied not only existing literature on lunar craters, terrestrial meteorite craters, and small solar-system bodies, but using his wartime security clearance, also reviewed classified United States Army records of bomb, artillery shell, and mortar explosions; the diameters of the craters they produced; and the shapes of craters caused by explosions at, above, and below ground level. In Baldwin’s book The Face of the Moon (1949), which presented a synthesis of these studies, he plotted the depths and diameters of the various types of craters and found that they fell along a single logarithmic curve “too startling, too positive, to be fortuitous.” He thus became the first person to demonstrate a quantitative relationship among bomb explosion craters, terrestrial meteorite craters, and lunar craters. Baldwin concluded that most lunar craters had been formed by meteoroid impacts early in the Moon’s history. He published an expanded version of his work as The Measure of the Moon (1963). Baldwin also wrote A Fundamental Survey of the Moon (1965), The Deadly Fuze: Secret Weapon of World War II (1980), and They Never Knew What Hit Them (1999). He was awarded the Barringer Medal Citation of the Meteoritical Society in 2000. In 1975, 1989, and 1998 he received honorary doctorates from the University of Michigan; Grand Valley State University in Allendale, Michigan (in whose library a collection of his papers is held); and Aquinas College in Grand Rapids, where he was instrumental in the development of an observatory that bears his name. Craig B. Waff Selected References Baldwin, Ralph B. (1949). The Face of the Moon. Chicago: University of Chicago Press. ——— (1963). The Measure of the Moon. Chicago: University of Chicago Press. ——— (1965). A Fundamental Survey of the Moon. New York: McGraw-Hill. Doel, Ronald E. (1996). Solar System Astronomy in America: Communities, Patronage, and Interdisciplinary Science, 1920–1960. Cambridge: Cambridge University Press, esp. pp. 161–169. Hoyt, William Graves (1987). Coon Mountain Controversies: Meteor Crater and the Development of Impact Theory. Tucson: University of Arizona Press, esp. pp. 357–360. Wilhelms, Don E. (1993). To a Rocky Moon: A Geologist’s History of Lunar Exploration. Tucson: University of Arizona Press, esp. pp. 14–19. Balmer, Johann Jakob Ball, Robert Stawell Born Died Dublin, Ireland, 1 July 1840 Cambridge, England, 25 November 1913 constraints), on which he published widely between 1871 and 1904. For these efforts, Ball received the Gold Medal of the Royal Irish Academy (1879). He was likewise the recipient of two honorary degrees – an M.A. (Cambridge University) and LL.D. (University of Dublin). Ball’s popular writings included The Story of the Heavens, Starland, In the High Heavens, Time and Tide, A Romance of the Moon, The Cause of an Ice Age, The Story of the Sun, and Great Astronomers. He likewise wrote a standard textbook, Elements of Astronomy, along with A Treatise on Spherical Astronomy. Ball also did popular lecturing: on one occasion (1907), he addressed a group of convicts at Dartmoor Prison. In 1892, Ball was appointed to the Lowndean Chair of Astronomy and Geometry at Cambridge University (succeeding John Adams) and director of its observatory, a post he retained until his death. Ball received the honor of knighthood in 1866. He served as president of the Royal Astronomical Society (1877–1879) and of the mathematical section of the British Association for the Advancement of Science, among other titles. Politically, Ball remained a strong Unionist. Jordan D. Marché, II Selected References Knobel, E. B. (1915). “Robert Stawell Ball.” Monthly Notices of the Royal Astronomical Society 75: 230–236. Paterson, John A. (1916). “Sir Robert Ball: The Astronomer, the Mathematician and the Man.” Journal of the Royal Astronomical Society of Canada 10: 42–63. Rambaut, A. A. (1914). “Sir Robert Stawell Ball.” Observatory 37: 35–41. Balmer, Johann Jakob Robert Ball was a noted lecturer and popularizer of astronomy. He was the eldest son of Irish naturalist Dr. Robert Ball. His preliminary education was completed at Abbot’s Grange, Chester, whereupon he entered Trinity College, Dublin, in 1857. As an undergraduate, Ball was a gold medalist in mathematics, in the experimental and natural sciences, and was awarded a University Scholarship in 1860. He graduated in 1865. Ball served as assistant astronomer (1865–1867) to William Parsons, the Earl of Rosse, at Parsonstown, Ireland, where he observed and measured faint nebulae with the 6-ft. reflector at Birr Castle. In 1867, Ball was appointed professor of applied mechanics at the newly opened Royal College of Science at Dublin and wrote a text on experimental mechanics. He married Frances Elizabeth Steele in 1868; the couple had six children. Upon the resignation of Franz Brünnow in 1874, Ball became Astronomer Royal for Ireland and Andrews Professor of Astronomy at the University of Dublin. His principal work in astronomy concerned the investigation of stellar parallax; he employed visual methods with the 12-in. refractor at Dunsink Observatory. Ball’s search for stars of large parallax, however, only netted two (out of some 368 stars examined). More successful were Ball’s mathematical investigations into the theory of screws (a study of the dynamics of rigid bodies under particular Born Died Lausanne, Switzerland, 1 May 1825 Basel, Switzerland, 12 March 1898 Johann Balmer’s empirical formula was shown to predict the wavelength of electromagnetic energy emitted by the quantized transition of an electron to a lower energy level in an atom. Balmer was born to Johann Jakob Balmer and Elizabeth Rolle Balmer. He was the eldest son and attended his first school at Liestal, the capital of what was known as the half canton of Basel-Landschaft. For his secondary education, Balmer returned to Basel where he excelled at mathematics, propelling him into a university mathematics track beginning at the University of Karlsruhe, taking him through the University of Berlin, and ending with his doctorate, which he received at the University of Basel in 1849. Balmer lived the relatively quiet life of a schoolteacher, taking up a mathematics post at a girls school in Basel, a job he held until his death. He did lecture at the University of Basel, from 1865 until 1890, in geometry. However, his publication record indicates that teaching was his primary focus, and Balmer never made any significant contribution to geometry. B 89 90 B Banachiewicz, Thaddeus Julian Balmer married late in life, in 1868, at the age of 43. However, he and his wife Christine Pauline Rinck had six children. There is a crater on the Moon named for Balmer. Balmer is remembered for a discovery he first published at the age of 60 (1885). In fact, he only published two papers on his discovery, the second being in 1897. Balmer’s discovery was a formula for calculating wavelengths for the spectral lines of elements. His first paper dealt only with the spectral lines of hydrogen. An initial reading of his work gives one the impression that it was Balmer’s mathematical ability that gave him the insight to produce the equation, because he gives no physical explanation for it in the paper. This formula, which predicts the wavelengths of the spectral lines, is deceptively simple: 1 1 1 = RH  2 − 2  , m n  λ where RH is the Rydberg constant for hydrogen. In Balmer’s second and last paper, he applied the same concept to other elements including helium and lithium, with results that matched observation to within a fraction of a percent. (They came to be referred to as Balmer lines or the Balmer series.) Balmer correctly predicted that many invisible spectral lines of hydrogen existed. Balmer’s formula is one of the most fundamental in all of modern astrophysics, for it allows astronomers and physicists to predict to a high degree of certainty where certain spectral lines will occur and thus provides a great deal of information on the atomic processes in astrophysical objects. But it is important to remember that despite the incredible accuracy of the prediction, the physical explanation for this phenomenon did not come until Niels Bohr first developed his model of the atom in 1913, fifteen years after Balmer’s death. Still, Balmer’s discovery stands with Bohr’s as one of the most important in modern astrophysics. Ian T. Durham Selected References Balmer, J. J. (1897). “A New Formula for the Wave-lengths of Spectral Lines.” Astrophysical Journal 5: 199–209. Carroll, Bradley W. and Dale A. Ostlie (1996). An Introduction to Modern Astrophysics. Reading, Massachusetts: Addison Wesley Longman, Whittaker, Sir Edmund (1951). A History of the Theories of Aether and Electricity. Vol. 1, The Classical Theories. New York: Harper. Banachiewicz, Thaddeus Julian Born Died Warsaw, Poland, 13 February 1882 Cracow, Poland, 17 November 1954 Thaddeus Banachiewicz combined unusual talents as a theoretician and an astronomical observer to make substantial contributions in celestial mechanics, mathematics, and geophysics. He was the youngest of the three children of Artur Banachiewicz, a landowner at Cychry (a village near Warsaw) and Zofia (née Rzeszotarski). Banachiewicz studied astronomy at Warsaw University; he received a bachelor’s degree in physical and mathematical sciences in 1904. His dissertation on the reduction constants of the Repsold heliometer earned a Gold Medal from the university senate. Banachiewicz continued his studies in Göttingen, Germany (1906–1907) under Karl Schwarzschild and later in Pulkovo, Russia (1908) under Jöns Oskar Backlund. On his return to Warsaw, Banachiewicz was appointed junior assistant at the University Observatory. In January 1910, following further studies in Warsaw and Moscow, Banachiewicz was engaged as an assistant at the Engelhardt Observatory near Kazan, Russia, where he stayed till 1915. Banachiewicz then moved to Dorpat (now Tartu, Estonia) in 1915 as an assistant, but in September 1917 – when he obtained the degree of Magister Astronomiae – he was appointed assistant professor, and later promoted to associate professor and director of the University Observatory. In 1918, Banachiewicz returned to Poland, as a Dozent of geodesy at the Warsaw Polytechnic School, but was soon appointed full professor, chairman of the astronomy department, and director of the observatory at the Jagiellonian University in Cracow. Banachiewicz held these positions until his death in 1954, excluding an interruption of over 5 years during the German occupation of Poland, when Nazi forces removed the university faculty, including Banachiewicz, to the Gestapo concentration camp at Sachsenhausen near Berlin. After 3 months at Sachsenhausen, Banachiewicz was allowed to return to the observatory, renamed “Die Krakauer Sternwarte” by the Germans, where he was allowed to resume his astronomical work. After World War II, in addition to his duties at the Jagiellonian University, Banachiewicz also accepted the duties of professor of higher geodesy and astronomy at the Cracow University of Mining and Metallurgy for 6 years (1945–1951). The areas of Banachiewicz’s scientific interest were wide, so one finds his contributions in astronomy, geodesy, geophysics, mathematics, and mechanics. His principal scientific achievements were generated through the use of the Cracovian calculus, a method that he invented. As Witkowski and Mietelski have noted, before 1927 there was only one way of solving spherical polygons – by resolution into triangles. By using the Cracovian calculus, in 1927 Banachiewicz obtained the general relations of spherical polygonometry in two forms: one which presents the generalized formulae of Gauss–Cagnoli previously known in spherical trigonometry, while the other yields the generalized formulae of Jean Delambre. In 1942, Banachiewicz developed a practical but elegant Cracovian algorithm for the least-squares method. Other achievements include Banachiewicz’ methods of solving the systems of linear equations (both symmetrical and unsymmetrical), and rapid computation of determinants of any degree. Another astronomical area in which Banachiewicz’ theoretical contributions were important is in the determination of a parabolic orbit. He demonstrated that the various approaches of the classical authorities (Carl Charlier, Adrien Legendre, Armin Leuschner, S. D. Tscherny, and Hermann Vogel) could, at times, give three different solutions. Banachiewicz showed that the equation of Johann Lambert could not be used in these singular Banneker, Benjamin circumstances. He then adapted Heinrich Olbers’ method to arithmetic calculations using vectorial elements and eliminating some auxiliary angles. Textbooks today identify this thoroughly modified way of determining parabolic orbits as the Banachiewicz (Olbers) method. Banachiewicz also simplified existing procedures for the determination of elliptical orbits by introducing the chord-joining positions of the body instead of their heliocentric angles; some years earlier he had published several papers on Gauss’s equation, and provided useful tables for solving it. The practical worth of Banachiewicz’ orbital calculation methods may be illustrated by the fact that in 1930 an early orbit of Pluto was determined by Banachiewicz and Charles Smiley of Brown University, who was, at that time, studying in Cracow. As an observational astronomer in Kazan, Banachiewicz carried out a 5-year series of heliometer observations of the Moon. Reductions of these observations by J. Mietelski (1968) by applying the Cracovian method yielded values of the principal physical libration parameters very close to modern values derived from the lunar laser ranging techniques and from perturbations of lunar orbiters. As a student, Banachiewicz began to observe occultations of stars by the Moon in 1901, and to calculate their ephemerides (and also those of occultations by planets and their satellites). He viewed these as important phenomena for the study of the motion of the Moon. In this respect, Banachiewicz anticipated, by two decades, the work of Ernest Brown. In a similar way, Banachiewicz anticipated the work of Bertil Lindblad and others using solar eclipse phenomena for geodesy. Banachiewicz organized geodetic surveys in Poland and conducted a few Polish solar eclipse expeditions. Using the Baily’s bead phenomenon, Banachiewicz’ chrono-cinematographic method established the difference (Moon–Sun) in right ascension with a standard error of only ±0.04″ at the Lapland eclipse on 12 June 1927. As a result, Banachiewicz proposed, at the 1928 meeting of the Baltic Geodetic Commission in Berlin, the use of total eclipses for the purpose of connecting distant points of the Earth’s surface; in this way a “lunar triangulation” could facilitate a geodetic bridging of the oceans. Banachiewicz’ ideas and techniques were applied to good advantage in the 1940s and 1950s on eclipse expeditions sponsored by the National Geographic Society and various US defense agencies. Banachiewicz founded the Polish journal Acta Astronomica in 1925 and many publications of the Cracow Observatory. He was the first in Poland to recognize the importance of the emerging field of radio astronomy and inaugurated the first Polish radio telescope near Cracow in 1954. Banachiewicz was a member of the Warsaw Scientific Society, Poznań Society of Friends of Sciences, Polish Academy of Arts and Sciences, and Padova Academy. He was a foreign associate of the Royal Astronomical Society. He was also a founder of the Polish Astronomical Society in 1923 and served for 10 years as its president. In 1952, Banachiewicz was a titular member of the Polish Academy of Sciences. From 1924 to 1926, Banachiewicz served as vice president of the Baltic Geodetic Commission. He was also a vice president and a member of the Executive Committee of the International Astronomical Union [IAU] from 1932 to 1938, and president of IAU Commission 17 (movements and figure of the Moon) from 1938 until 1952. Three universities conferred the doctor honoris causa upon Banachiewicz: Warsaw (1928), Poznań (1938), and Sofia (1950). The minor planet (1286) was named Banachiewicz, as was a 70-km crater on the farside of the Moon. In 1931, Banachiewicz married Laura (or Larysa) SolohubDykyj, a Ukrainian poetess. There were no children from this marriage. The personal data of Banachiewicz and documents concerning his Cracow collaborators and the Cracow University Observatory under his direction are held in the Archives of the Jagiellonian University, Cracow, Poland. The “Notaty codzienne” (a daily diary kept by Banachiewicz during the years 1932–1954, five volumes) is held privately by Jerzy Kordylewski in Cracow and may be accessed through the Jagiellonian University Observatory. Jan Mietelski Selected References Banachiewicz, Thaddeus (1955). “The Role of Cracovians in Astronomy.” Vistas in Astronomy 1: 200–206. Dworak, T. Z., J. M. Kreiner, and J. Mietelski (2000). “Tadeusz Banachiewicz (1882–1954)” (in Polish). Universitas Iagellonica, Liber Aureus Facultatis Mathematicae et Physicae, edited by B. Szafirski, pp. 161–179. Cracow: Uniwersytet Jagielloński. (A biographical essay.) Mietelski, J. (1968). “The Moon’s Physical Libration from the Observations of T. Banachiewicz.” Acta Astronomica 18: 91–147. Witkowski, J. (1955). “The Life and Work of Professor Dr. Thaddeus Banachiewicz.” Acta Astronomica, ser. C, 5: 85–94. ——— (1970). “Banachiewicz, Thaddeus.” In Dictionary of Scientific Biography, edited by Charles Coulson Gillispie. Vol. 1, pp. 428–430. New York: Charles Scribner’s Sons. Banneker, Benjamin Born Died Baltimore County, Maryland, (USA), 9 November 1731 near Ellicott Mills, Maryland, (USA), 9 October 1806 Benjamin Banneker was a mathematician, astronomer, writer, inventor, landowning farmer, and important African American intellectual. His parents were Mary Banneky, a free African American, and Robert, a freed African slave, who adopted his wife’s surname upon marriage. (Over the years, the spelling of the surname became fixed as Banneker.) In 1737, Benjamin, their firstborn and only son, was named co-owner on the deed to their 100-acre farm that was located in the Patapsco River Valley of rural Baltimore County, Maryland. Benjamin had three younger sisters. He never married and had no offspring. Banneker was taught to read and write by his maternal grandmother, Molly Welsh, a white woman who arrived from England as an indentured servant, completed her contract, and managed to assemble sufficient assets to purchase land for a farm on the Patapsco River. Banneker attended a rural Quaker school during winter months when work on his father’s farm was limited, and was otherwise largely self-taught. At the age of 22, Banneker demonstrated his advanced understanding of mathematical principles when he constructed an accurate wooden striking clock using a pocket watch as a model. However, his demanding farm activities and rural B 91 92 B Banū Mūsā surroundings ruled out any pursuit of a formal education. Banneker’s three sisters married and moved from the farm; his father died in 1758, leaving Benjamin and his mother as its sole occupants. By all accounts, he was an industrious and successful farmer. In 1772, the Ellicott brothers, Andrew and George, emigrated from Pennsylvania to Maryland and bought land along the Patapsco Falls, very near Banneker’s farm, for the purpose of developing a gristmill. The community of Ellicott Mills attracted Banneker who was contracted to provide farm produce for the workmen. Soon, a friendship developed between Banneker and the young George Ellicott who introduced him to the science of astronomy. Ellicott loaned him some astronomy texts and some basic instruments that Banneker used to teach himself mathematical and astronomical principles. With the encouragement of Ellicott, Banneker began calculating an ephemeris patterned after those published in almanacs of the period. He attempted to have his first ephemeris published in 1791, but was not successful. Banneker’s quiet rural life changed at the age of 60 years when major Andrew Ellicott, who had received a commission to survey the Federal Territory (Washington), was in need of competent assistants. Ellicott, who had reviewed Banneker’s ephemeris for 1791 and was impressed by his abilities, offered him a position with the survey team that he accepted. Banneker, whose role it was to care for the delicate instruments and assist in making the daily calculations necessary to conduct the survey, spent 3 months assisting Ellicott. While engaged with the survey expedition and following his return to his farm, Banneker conducted the necessary astronomical observations to calculate an ephemeris for 1792. With the assistance of the Ellicotts, he succeeded in having the ephemeris published in the form of an almanac. In 1791, Banneker wrote a letter to then US Secretary of State Thomas Jefferson in which he enclosed a manuscript copy of his ephemeris for 1792. His correspondence concerned Jefferson’s published opinions on the alleged mental inferiority of Negroes as presented in his Notes on the State of Virginia, which had been published in 1788. Banneker offered his own accomplishments as evidence of the equal mental abilities of blacks and whites. Banneker’s 1793 almanac published a copy of this letter as well as Jefferson’s reply. Jefferson, for his part, sent the almanac to the secretary of the French Royal Academy as evidence of the mental abilities of Negroes. From 1792 to 1797, Banneker calculated ephemerides for six separate almanacs that were published in various cities in 28 editions. Pertaining to the mid-Atlantic region, in addition to astronomical observations these almanacs included practical advice for farmers, notations of holidays, general forecasts of weather trends, and miscellaneous writings by Banneker and his contemporaries. During his later life, Banneker devoted less time to farming and began leasing and selling small plots of his farm. In 1799, he legalized an informal arrangement to sell his remaining land to the Ellicotts in exchange for an annuity and life tenancy on the farm. He continued his astronomical observations and some routine farming chores as late as 1803, despite his failing health. Just shy of his 75th birthday, Banneker died at his farm in Baltimore County, Maryland. The site of his house, which is said to have burned to the ground on the day of his funeral, has been rediscovered near Oella, Maryland, and preserved by Baltimore County as a park dedicated to his memory. Robert J. Hurry Selected References Banneker, Benjamin (1792–1797). Benjamin Banneker’s Pennsylvania, Delaware, Maryland, and Virginia Almanack and Ephemeris. Baltimore. (Banneker’s almanacs were printed in 28 editions, under various titles and publishers.) Bedini, Silvio A. (1972). The Life of Benjamin Banneker. New York: Charles Scribner’s Sons. Cerami, Charles A. (2001). Benjamin Banneker: Surveyor, Astronomer, Publisher, Patriot. New York: John Wiley and Sons. Elliott, Clark A. (1979). Biographical Dictionary of American Science: The Seventeenth through the Nineteenth Centuries. Westport, Connecticut: Greenwood. Hurry, Robert J. (1983). An Archeological Survey of the Benjamin Banneker Property, Baltimore County, Maryland. Annapolis: Maryland Historical Trust, Manuscript Series Number 34. ——— (1989). “An Archeological and Historical Perspective on Benjamin Banneker.” Maryland Historical Magazine 84, no. 4: 361–369. ——— (2002). The Discovery and Archeological Investigation of the Benjamin Banneker Homestead, Baltimore County, Maryland (18BA282). Crownsville, Maryland: Archeological Society of Maryland and Maryland Historical Trust Press. Kaplan, Sidney (1972). The Black Presence in the Era of the American Revolution, 1770–1800. Greenwich, Connecticut: New York Geographic Society in association with the Smithsonian Institution Press. Banū Mūsā Ja�far Muḥammad Born Died Baghdad, (Iraq), beginning of the 9th century January or February 873 Abū al-Qāsim Aḥmad Born Died Baghdad, (Iraq), beginning of the 9th century Baghdad, (Iraq), 9th century Ḥasan Born Died Baghdad, (Iraq), beginning of the 9th century Baghdad, (Iraq), 9th century The three brothers, the three sons of Musā ibn Shākir, generally known under the single name of the Banū Mūsā, were among the most important scientists of Baghdad in the 9th century; they played a prominent role as private patrons of scientific translations and research, and excelled in the fields of astronomy, mechanics, and mathematics. It is quite impossible to write separate biographies of them. Their father, Mūsā ibn Shākir, is described as a reformed bandit who became a renowned astronomer or astrologer and a close Banū Mūsā friend of Ma’mūn (reigned: 813–833) before he was a caliph, while residing in Marw in Khurāsān. After Mūsā’s death, the brothers became the wards of Ma’mūn, who cared for their education and sent them to the House of Wisdom (Bayt al-ḥikma), which was the major scientific institution in his time. After finishing their education, the Banū Mūsā collaborated with Ma’mūn and his successors in a variety of activities, which ranged from scientific matters (such as geodetic surveys) to managerial affairs (such as contracting for the building of public works and structures), thus becoming wealthy and powerful. This allowed them to devote a great deal of their acquired fortune to sponsoring scientific research. They actively sought classical works by ancient writers and sent agents or went themselves to Byzantium to purchase manuscripts that they translated on returning to Baghdad. On one such trip, Muḥammad met the famous mathematician and translator Thābit ibn Qurra of Ḥarrān and brought him back to Baghdad, where Thābit joined the circle of scientists and translators who were working under the patronage of the Banū Mūsā. The Nestorian Christian Ḥunayn ibn Isḥāq (died: circa 877), considered one of the most prolific and significant translators of 9th-century Baghdad, was also part of the Banū Mūsā team. In sum, these brothers promoted to a great extent the movement of translations that made it possible to assimilate the main classical scientific works into Arabic. Their significance to science and astronomy is not limited to this sponsorship of translations alone; like the scholars gathered around them, the Banū Mūsā also authored very important original scientific works of which there is a known list of some 20 books on astronomy, mechanics, and mathematics. Almost a dozen of the works attributed to the Banū Mūsā are related to astronomical research. Muḥammad, the eldest son, wrote a treatise On the Visibility of the Crescent, a Book on the Beginning of the World, and a book variously known under the titles of Book on the Motion of Celestial Spheres (Kitāb Ḥarakāt alaflāk), Book of Astronomy (Kitāb al-Hay’a), or Book on the First Motion of the Celestial Sphere (Kitāb Ḥarakāt al-falak al-ūlā), which contains a critique of the Ptolemaic system of the Universe. In it Muḥammad explains the daily motion of the heavens by the rotation of all the spheres of the Sun, the Moon, the five planets, and the fixed stars, denying the existence of the 9th sphere, which is the origin of movement in Ptolemy. Aḥmad is reportedly the author of a Book on the Mathematical Proof by Geometry That There Is Not a Ninth Sphere Outside the Sphere of the Fixed Stars, two texts on two questions that he discussed with his contemporary Sanad ibn �Alī, and a zīj (astronomical handbook), which is mentioned by the Egyptian astronomer Ibn Yūnus, who also says that there is another zīj by the three brothers. Finally, listed under the name of the Banū Mūsā are: A Book of Degrees on the Nature of Zodiacal Signs, regarding which it is stated in the manuscript that it is a translation of a Chinese work; a Book on The Construction of the Astrolabe, quoted by Bīrūnī; and, a Book on the Solar Year. The latter has traditionally been attributed to Thābit ibn Qurra, but recent research has shown that this is most likely a misattribution and that the treatise is actually by the Banū Mūsā. The majority of these books are now lost; however, the list of titles and the studies on the extant works show that the Banū Mūsā dealt extensively with the major concerns of astronomy in their time. Moreover, the interest of the Banū Mūsā in astronomy is also attested by reports that the brothers were involved in various activities, such as leading the astronomical observations that were made in Baghdad during the course of the 9th century or collaborating in the expeditions mounted by Ma’mūn for the purpose of making a geodetic measurement of the length of a degree along a terrestrial meridian. The Banū Mūsā produced major work in the field of mechanics. Their efforts show important advances over those of their Greek predecessors: writers such as Philo of Byzantium (end of third century BCE) and Hero of Alexandria (middle of first century), whose works were extensively known by Muslim engineers. The Banū Mūsā also wrote many works in the field of mathematics, many devoted to geometrical problems. One of their most important works, Book on the Measurement of Plane and Spherical Figures, was the object of a recension by Naṣīr al-Dīn al-Ṭūsī in the 13th century and of a Latin translation by Gerard of Cremona in the 12th century under the titles Liber trium fratrum de geometria and Verba filiorum Moysi filii Sekir. This treatise was one of the fundamental texts on geometry in the Middle Ages, and its contents (in both the Arabic and European contexts) are found in authors such as Thābit ibn Qurra, Ibn al-Haytham, Leonardo Fibonacci of Pisa (died: 1250), Jordanus de Nemore (died: 1260), and Roger Bacon (died: circa 1292). The other works on geometry attributed to the Banū Mūsā are three books related to the Conic Sections of Apollonius of Perga (third century BCE), a Book on a Geometric Proposition Proved by Galen, a Reasoning on the Trisection of an Angle (by Aḥmad), and a Book on an Oblong Round Figure. The latter concerns the ellipse and contains a description of what is known as the gardener’s construction, a procedure for drawing an ellipse by means of a string fastened to two pegs and based on the fact that the sum of the two focal radius vectors of any point belonging to a given ellipse is constant. Finally, the family tradition of the Banū Mūsā seems to have been continued to a certain extent by a son of the eldest brother, Nu�aym ibn Muḥammad ibn Mūsā, who wrote Book on Geometric Propositions. Josep Casulleras Selected References Al-Dabbagh, J. (1970). “Banū Mūsā.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 1, pp. 443–446. New York: Charles Scribner’s Sons. Al-Hassan, Ahmad Y. (2001). “Mining and Metallurgy.” In The Different Aspects of Islamic Culture. Vol. 4, Science and Technology in Islam. Part 2, Technology and Applied Sciences, edited by A. Y. al-Hassan, Maqbul Ahmed and A. Z. Iskandar, pp. 85–87. Beirut: UNESCO. Banū Mūsā ibn Shākir (1981). Kitāb al-Hiyal, edited by A. Y. al-Hassan. Aleppo. Clagett, Marshall (1964). Archimedes in the Middle Ages. Vol. 1, The Arabo-Latin Tradition. Madison: University of Wisconsin Press. Hill, D. R. (trans.) (1979). The Book of Ingenious Devices. Dordrecht: D. Reidel. ——— (1993). “Mūsa, Banū.” In Encyclopaedia of Islam. 2nd ed. Vol. 7, pp. 640–641. Leiden: E. J. Brill. ——— (1993). Islamic Science and Engineering. Edinburgh: Edinburgh University Press. ——— (2001). “Mechanical Technology.” In The Different Aspects of Islamic Culture. Vol. 4, Science and Technology in Islam. Part 2, Technology and Applied Sciences, edited by A. Y. al-Hassan, Maqbul Ahmed and A. Z. Iskandar, pp. 165–192. Beirut: UNESCO. B 93 94 B Bär, Nicholaus Reymers Hogendijk, Jan P. (2003). “The Geometrical Problems of Nuʕaim ibn Muhammad ibn Mūsā (9th century).” SCIAMVS 4: 59–136. Rashed, R. (1995). Les mathématiques infinitésimales du IXe au XIe siècle. Vol. 1, Fondateurs et commentateurs: Banū Mūsā, Ibn Qurra, Ibn Sinān, al-Khāzin, al-Qūhī, Ibn al-Samh, Ibn Hūd. London. Rosenfeld, B. A. and Ekmeleddin Ihsanoğlu (2003). Mathematicians, Astronomers, and Other Scholars of Islamic Civilization and Their Works (7th–19th c.). Istanbul: IRCICA, pp. 34–36. Youschkevitch, Adolph P. (1976). Les mathématiques arabes (VIIIe-Xve siècles): Traduction française de M. Cazenave et K. Jaouiche. Paris: J. Vrin. Bär, Nicholaus Reymers Flourished Prague, (Czech Republic), 1584 Itinerant German Nicholaus Bär seems to have plagiarized most of his cosmological ideas from Tycho Brahe. However, in his variation of the Tychonic system, Mars’ orbit enclosed that of the Sun. Brahe replaced Bär as imperial mathematician. Alternate name Raimarus Ursus Selected Reference Jardine, N. (1984). The Birth of History and Philosophy of Science: Kepler’s A Defence of Tycho against Ursus with Essays on Its Provenance and Significance. Cambridge: Cambridge University Press. Barbier, Daniel Born Died Lyon, France, 10 December 1907 Marseilles, France, 1 April 1965 French observational astronomer Daniel Barbier made his most significant contributions to the study of the background light of the night sky. His student, G. Weill, also worked in this area. Along with Daniel Chalonge, Barbier set up the first quantitative, threedimensional system of photometric classification of stars (further described in the article on Chalonge). He was the theoretician of the pair, responsible for a textbook on stellar atmospheres and for the definition of the parameter in the classification system that describes the chemical composition of the stars. After World War II, Barbier turned his attention to the night skylight, especially the 6,300 Å forbidden line of neutral oxygen and the variations of its strength and the height of the level in the atmosphere (the F layer of the ionosphere) where it is emitted. He died just at the end of an observing run at Observatoire de Haute-Provence. Roger Cayrel Selected Reference Barbier, Daniel (1952). Les atmosphères stellaires. Paris: Flammarion. Barhebraeus: Gregory Abū al-Faraj Born Died Malaṭya, (Turkey), 1225/1226 Marāgha, (Iran), 29/30 July 1286 Barhebraeus, a Syrian (or Syriac) Orthodox (“Jacobite”) prelate and polymath, is the foremost representative of the “Syriac Renaissance” of the 12th and 13th centuries. He was also closely associated with several members of the “Marāgha School” of astronomers, and he wrote several works dealing with various aspects of astronomy. Barhebraeus’ birthplace of Malaṭya (or Melitene) was at the time under the rule of the Saljūqs of Rūm (Asia Minor), a Turkish– Islamic dynasty. It had an important community of Syrian Orthodox Christians that included Barhebraeus’ family. His father Aaron (Ahrōn) was a physician. The view that links the name Barhebraeus to a Jewish ancestry is best rejected in favor of one linking it to the village of �Eḇrā on the Euphrates, downstream of Melitene. After periods of study in Antioch, Tripoli (both then still in the hands of the Crusaders), and possibly Damascus, he was raised to the episcopate at the age of 20 in 1246 and was appointed, successively, to the sees of Gubos and Laqabin in the vicinity of Melitene. Sometime around 1253, Barhebraeus was transferred to Aleppo, where he would witness the fall of the city to the Mongols in 1260. In 1264, he was raised to the office of the Maphrian of the East, the second highest office in the Syrian Orthodox Church with jurisdiction over an area roughly coinciding with today’s Iraq and Iran. His normal place of residence as Maphrian was Mosul and the nearby monastery of Mar Mattai, but a significant part of his maphrianate was spent in Marāgha and Tabrīz, the new centers of power under the Mongol īlkhānids. Barhebraeus composed over 40 works covering a diverse range of subjects, most of which are in Syriac, although some are in Arabic. Typical of Barhebraeus is the manner in which he takes an Arabic (occasionally Persian) work as his model and structures his own work around it. He then incorporates into this framework materials taken from both Arabic and Syriac sources, thus making a new synthesis out of older Syriac and more recent Arabic materials. In his philosophical works he is influenced by Ibn Sīnā, while in his moralmystical theology he stands under the influence of Al-Ghazālī (died: 1111), the preeminent Islamic theologian, jurist, and Sufi. Barhebraeus’ interest in astronomy and related sciences is likely to have been prompted by his acquaintance with Naṣīr al-Dīn alṬūsī and other scholars gathered around the newly founded observatory and library in Marāgha. Evidence for this is provided by a manuscript of a collection of mathematical texts revised by Ṭūsī, which was once in Barhebraeus’ possession and bears his signature (today in Istanbul-üsküdar, Selim Ağa MS 743). We are also told by Ḥājjī Khalīfa that Ibn Abī al-Shukr al-Maghribī, one of Ṭūsī’s collaborators, composed an epitome of Ptolemy’s Almagest at Barhebraeus’ behest (Kashf al-ẓunūn, Vol. 5, pp. 387, 389). Barhebraeus’ major work in the field of the exact sciences is the Ascent of the Mind (Sullāqā hawnānāyā), a textbook of astronomy and mathematical geography composed in 1279 and modeled on Ṭūsī’s Tadhkira fī �ilm al-hay’a, but incorporating materials taken from other sources. Especially for his Syriac terminology, Bar Hiyya Barhebraeus must have been dependent upon earlier Syriac works, among them the works of Severus Sebokht, who is mentioned by name at one point (Nau, p. 106f.). The lists of Barhebraeus’ works mention a work, now lost, called “Astronomical tables (zīj) for Beginners,” composed, according to the older manuscript witnesses of the lists (Vatican, Borgia syr. 146 and Florence, Laur. or. 298), in Arabic. It is unclear what exactly Barhebraeus means when he tells us in his Chronicon ecclesiasticum (II.443.1f., 443.19f.) that he “solved/explained” (shrā, corresponding to Arabic ḥalla) the “Book of Euclid” (i. e., the Elements) in Marāgha in 1267/1268 and Ptolemy’s Almagest similarly in Marāgha in the summer of 1272. Perhaps the meaning is “lectured on” or simply “studied.” It is unlikely, at any rate, that it involved the composition of written works. Astronomy and related disciplines occasionally play a role in Barhebraeus’ other works, as in the second part (“On Creation,” composed circa 1267) of his major theological work, the Candelabrum of the Sanctuary (Mnāraṯ qudshē). The principal source for the parts of this work dealing with mathematical geography, astronomy, and chronology is Bīrūnī’s Kitāb al-tafhīm li-awā’il ṣinā�at al-tanjīm; here too, Barhebraeus has used a number of additional sources, as may be seen from the fact that the values given for the latitudes of the seven climes are neither those given in Bīrūnī’s Tafhīm nor those in Ṭūsī’s Tadhkira (which Barhebraeus later adopted in the Ascent of the Mind) but the traditional values as given in the Almagest. Traces of Severus Sebokht’s works are found again among the newly added materials in Barhebraeus’ later, shorter work on theology, the Book of Rays (Kṯāḇā d-zalgē), which is otherwise largely a summary of the Candelabrum. Barhebraeus’ historical works are of interest to the historian of science for the information they provide on earlier scholars and have frequently been used for this purpose since the first publication of his Arabic history, the Mukhtaṣar ta’rīkh al-duwal, in 1663. While the publication of those works used as sources by Barhebraeus (e. g., Qifṭī and Ṣā�id al-Andalusī) has diminished the value of Barhebraeus’ works in this respect, there are instances where he reveals his knowledge of older Syriac sources inaccessible to Arabic historians. One example is the passage on the trepidation of the fixed stars taken from Theon of Alexandria’s Small Commentary on the Handy Tables (in Barhebraeus’ Syriac Chronicon; also in the Ascent of the Mind and his major philosophical work, the Cream of Wisdom/Ḥēwaṯḥeḵmṯā). Hidemi Takahashi Alternate names Grīḡōriyōs Bar �Eḇrāyā Grīḡōriyōs Bar �Eḇroyo Selected References Abbeloos, Joannes Baptista and Thomas Josephus Lamy (1872–1877). Gregorii Barhebraei Chronicon ecclesiasticum. 3 Vols. Louvain: Peeters. Bakoš, Ján (1930–1933). Le Candélabre des sanctuaires de Grégoire Aboulfaradj dit Barhebraeus. Paris: Firmin-Didot. (Reprint, Patrologia Orientalis nos. 110 and 118. Turnhout: Brepols, 1988. [Candelabrum of the Sanctuary, Bases I–II; with French translation.]) Barhebraeus (1997). Book of Zelge by Bar-Hebreaus [sic], Mor Gregorius Abulfaraj, the Great Syrian Philosopher and Author of Several Christian Works. Istanbul: Zafer Matbaası. (Book of Rays, facsimile edition.) Baumstark, Anton (1922). Geschichte der syrischen Literatur mit Ausschluβ der christlich-palästinensischen Texte. Bonn: A. Marcus und E. Weber. (Reprint, Berlin: Walter de Gruyter, 1968, pp. 312–320.) Çiçek, YūliyōsYeshūʕ (1997). Mnorath Kudshe (Lamp of the Sanctuary) by Mor Gregorios Yohanna Bar Ebryoyo [sic]. Glane/Losser: Bar Hebraeus Verlag. (Candelabrum of the Sanctuary; whole work, in Syriac only.) Graf, Georg (1944–1953). Geschichte der christlichen arabischen Literatur. 5 Vols. Vatican City: Biblioteca Apostolica Vaticana. Vol. 2, pp. 275–281. Moosa, Matti (ed. and trans.) (2000). The History of Syriac Literature and Sciences. Pueblo, Colorado: Passeggiata Press, pp. 152–158. (Originally published as I. Aphram Barsoum, Kitāb al-Lu’lu’ al-manthūr fī ta’rīkh al-ʕulūm wa-’ lādāb al-suryāniyya. Hims, Syria, 1943; 4th ed., Glane/Losser: Bar Hebraeus Verlag, 1987, pp. 411–430.) Nau, François (1899). Le livre de l’ascension de l’esprit sur la forme du ciel et de la terre. Cours d’astronomie rédigé en 1279 par Grégoire Aboulfarag, dit Bar-Hebraeus. 2 Vols. Paris: émile Bouillon. (Ascent of the Mind, with French translation.) Sayılı, Aydın (1960). The Observatory in Islam. Ankara: Turkish Historical Society, pp. 219–222. Takahashi, Hidemi (2004). Aristotelian Meteorology in Syriac: Barhebraeus, Butyrum Sapientiae, Books of Mineralogy and Meteorology. Leiden: E. J. Brill. ——— (2005). Barhebraeus: A Bio-Bibliography. Piscataway, New Jersey: Gorgias Press. Teule, Hermann G. B. (1997). “Ebn al-ʕEbrī.” In Encyclopaedia Iranica. Vol. 8, pp. 13–15. London: Routledge and Kegan Paul, ff—f ff. Bar Ḥiyya: Abraham Bar Ḥiyya Savasorda Born Died Barcelona, (Spain), 1070 1136 Bar Ḥiyya is credited with writing the first works in Hebrew on astronomy and mathematics. He held several official positions in Barcelona, although that city was under Christian control. Bar Ḥiyya was fluent in Arabic, the leading language of science at the time. In response to requests from his Jewish coreligionists in Provence, Bar Ḥiyya produced a series of Hebrew texts in astronomy and mathematics, the first of their kind to be written in that language. He also created an entirely new Hebrew technical terminology. His Ṣurat ha-Aretz (Form of the earth) is a representative of a nontechnical exposition of astronomy genre that was immensely popular in the medieval period, especially among the Hebrew reading public. Bar Ḥiyya also compiled a set of tables, known as Luḥot ha-Nasi (Nasi being one of the titles borne by Bar Ḥiyya) or the Jerusalem Tables. These tables are for the most part based upon the tables of Battānī. However, some manuscripts (for example, Chicago, Newberry College, MS. Or 101) have appended to them a set of short essays and accompanying tables. These addenda have never been properly studied; one of them, which investigates the differences between the tables of Ptolemy and Battānī, may be of particular interest. Bar Ḥiyya’s tables were later used by Abraham ibn � Ezra; some manuscripts, such as the one just mentioned, bear tables of Ibn �Ezra as well as some glosses by students of the latter. Y. Tzvi Langermann B 95 96 B Barker, Thomas Selected References Goldstein, Bernard R. (1980). “Star Lists in Hebrew.” Centaurus 28: 185–208. (Publishes lists of astrolabe stars from Bar Hiyya’s tables.) Langermann, Y. Tzvi (1999). “Science in the Jewish Communities of the Iberian Peninsula.” In The Jews and the Sciences in the Middle Ages. Aldershot: Ashgate. (General assessment of Bar Hiyya’s work and impact, with full references to publications of his texts in Spanish or Catalan by J. M. Millás-Vallicrosa.) ——— (2000). “Hebrew Astronomy: Deep Soundings from a Rich Tradition.” In Astronomy Across Cultures, edited by Helaine Selin, pp. 555–584. Dordrecht: Kluwer Academic Publishers. (Discussion of utilization of Bar Hiyya’s tables by Ibn ʕEzra and his students.) Barker, Thomas Born Died Lyndon, Leicestershire, England, 1722 Lyndon, Leicestershire, England, 29 December 1809 Besides being a noted vegetarian, Thomas Barker is known primarily for his catalog of comets and their orbital elements. Inspired by the cometographic theories of his grandfather William Whiston, Barker investigated comets and provided a handy table for determining parabolic trajectories and orbits. Marvin Bolt Selected References Anderson, Robert Edward (1921–1922). “Barker, Thomas.” In Dictionary of National Biography, edited by Sir Leslie Stephen and Sir Sidney Lee. Vol. 1, p. 1131. London: Oxford University Press. Barker, Thomas (1757). An Account of the Discoveries concerning Comets, with the Way to find their Orbits. London: T. B. Gent. Poggendorff, J. C. (1863). “Barker.” Biographisch-literarisches Handwörterbuch. Vol. 1, col. 101. Leipzig: J. A. Barth. Barnard, Edward Emerson Born Died Nashville, Tennessee, USA, 16 December 1857 Williams Bay, Wisconsin, USA, 7 February 1923 As both a visual and a photographic observer who made a multitude of discoveries that of extended interstellar absorption regions, or dark nebulae, being perhaps the most important, Edward Barnard became one of the greatest astronomers of his time, but his beginnings were extremely humble. He was born into impoverished circumstances just before the American Civil War. After his father, Reuben Barnard, died 3 months before Edward was born, his mother, Elizabeth Jane (neé Haywood) Barnard, who was already 42, raised him and his elder brother Charles (who seems to have been feeble-minded) by herself. Elizabeth’s broad literary interests are attested by the unusual middle name she chose for her second son, that of American writer and philosopher Ralph Waldo Emerson. She taught Edward to read, mainly from the Bible; otherwise Barnard had only 2 months of formal schooling. At the tender age of nine, just after the Civil War ended and with Nashville under occupation by Union troops, Barnard’s mother sent him to work in the photograph gallery of John H. Van Stavoren. As his first assignment, Barnard guided a large “solar camera” (“Jupiter”) on the Sun. Jupiter provided intense light for portrait enlarging in that slow, wet-plate era. Barnard performed these humble duties well, and advanced to doing other photographic work, thus gaining broad experience in photographic techniques that he later put to spectacular use as an astronomer. Several of Van Stavoren’s assistants, notably James W. Braid, who had wide-ranging interests in electricity and other technical matters, and Peter and Ebenezer Calvert, native Yorkshire men who were employed as artists at the studio, supported young Barnard intellectually and emotionally during this time. By now, Barnard’s mother was an invalid, and he had become the sole provider for the family. The Calverts introduced Barnard to their sister, his future wife, Rhoda. As a young child, Barnard had a naive interest in the stars, watching them passing overhead from a small wagon in his yard. He recalled seeing one of the great comets that appeared during the Civil War. At the age of 18, he received by chance a book on astronomy, loaned to him as the surety of a small loan from an acquaintance he suspected had stolen it; he never saw the acquaintance again. The book, The Practical Astronomer by Reverend Thomas Dick, a Scottish writer of sermons and “moral and religious reflections” on astronomy, contained star charts from which Barnard identified the constellations of the Summer Triangle. His interest piqued, Barnard acquired, with Braid’s help, a 2-in. telescope, with which – in the spring of 1876 – he observed the phases of Venus and the satellites of Jupiter. The impression they made, he later noted, was “more profound and pleasing … than the celebrated discovery of the fifth satellite of Jupiter.” In 1877, Barnard acquired a 5-in. refractor for $380 – twothirds of his annual salary at the photography studio – with which he began to make a serious study of the sky. The American Association for the Advancement of Sciences held its annual meeting in Nashville that year. At the meeting, Barnard introduced himself to America’s leading mathematical astronomer, Simon Newcomb, asking him what useful work might be done by a young man with a telescope. Newcomb responded, “put away that telescope and study mathematics.” Barnard was devastated, but soon recovered. He married Rhoda Calvert, who was 37 at the time, he was 23. While working at the photography studio during the day, Barnard searched diligently for comets at night, lured by a cash award of $200 for each comet discovery offered by patent-medicine vendor H. H. Warner of Rochester, New York. Barnard became one of the most successful visual comet seekers of all time. He discovered his first comet in 1881 (now designated C/1881 S1). His eventual record of 16 new comets and three recovered periodic comets was surpassed only by that of William Brooks, his contemporary, and the legendary Jean Pons of the Marseilles Observatory, who observed during Napoleon’s time. The Warner comet discovery prizes helped Barnard to obtain the mortgage for a small lot in a not-very-desirable part of Nashville, where he built a house, which became known as Comet Barnard, Edward Emerson House. Here Barnard and Rhoda lived until, in 1883, largely owing to the recognition for his comet discoveries, he received a fellowship to Vanderbilt University and moved to university-provided housing on campus. Barnard remained at Vanderbilt until 1888, when he moved to Lick Observatory as one of its original staff astronomers. At that time Lick Observatory possessed the world’s most powerful telescope, the 36-in. Clark refractor. In addition to West Point trained observatory director Edward Holden, the Lick Observatory staff included pioneer spectroscopist James Keeler and double-star observer Sherburne Burnham, who became a father figure and mentor to Barnard. At Lick, Barnard was at first encouraged to continue his comet seeking, and he made visual observations, especially of the planets, with the 12-in. Clark refractor. Among Barnard’s most remarkable feats was his 1 November 1889 observation, with the 12-in. Clark, of the eclipse of Saturn’s satellite Iapetus by the shadow of the crepe ring. This event, which was not recorded anywhere else – and specifically, not with the 36-in. refractor, which Holden, as was his custom, shut down early that night – triggered indignant comments from other astronomers on the use of that great instrument, and ignited a smoldering disagreement between Holden and Barnard. Holden did not allow Barnard to use the 36-in. refractor on a regular basis; this led to a long, unseemly, and bitter argument between the director and the assistant astronomer. In the end, Barnard would be vindicated; but by barring him from the large telescope, Holden had unwittingly played up the circumstances of deprivation of Barnard’s emotionally scarred childhood. There were times when Barnard – always high-strung and overwrought – came close to suffering a nervous breakdown. Barnard finally took his case directly to the Regents of the University of California, and they ruled in his favor. Beginning in August 1892, Barnard was given the great telescope to use every Friday night, and within a month – on 9 September 1892 – he galvanized the astronomical world and the wider public by discovering the fifth satellite of Jupiter. Camille Flammarion recommended the name Amalthea, after the nurse of Jupiter, for the new satellite, but Barnard disliked that name and continued to refer to it only as “the fifth satellite.” Barnard recorded some of the most extraordinary drawings of Mars ever made during its 1892 and 1894 oppositions, with the 36in. refractor. His drawings did not support the view of a canal crisscrossed planet then being promoted by the controversial planetary astronomer Percival Lowell, but few of Barnard’s drawings were ever published. Meanwhile, Barnard was pursuing another front line of research. Beginning in August 1889, he used a 6-in. Willard portrait lens to obtain wide-angle photographs of comets and the Milky Way. By 1895, Barnard had obtained scores of images revealing both the structure of comet tails and hitherto unknown dark markings in the Milky Way. Barnard initially believed that the dark markings of the Milky Way were chasms, regions of vacancy, among the stars. However, the English astronomer Arthur Ranyard, who published Barnard’s photographs in the journal Knowledge, disagreed with Barnard. “The dark vacant areas or channels …” Ranyard wrote, “seem to me to be undoubtedly dark structures, or absorbing masses in space.” Ranyard died soon thereafter, and the whole issue remained unresolved, but continued to nag Barnard for years. In 1895, Barnard left Mount Hamilton, and his troubled relationship with Holden, to join George Hale and the University of Chicago’s Yerkes Observatory with its 40–in. Clark refractor, at Williams Bay, Wisconsin. At Yerkes, Barnard initially worked very hard, just as he had at Lick and at Vanderbilt. He was a remarkably versatile observer, known for his keen eye, his skill with the micrometer, and, above all, his abilities with the photographic plate and in the darkroom. His work is not easily summarized, since there was hardly anything in the heavens that did not interest him; he was “an observer of all that shines – or obscures.” Hale gave him two nights a week on the 40-in. refractor, and he used every scrap of clear night – summer and winter – on it and other telescopes without respite. When a visitor asked how he kept warm in the unheated dome, during the cold nights of winter in Wisconsin, he replied: “We don’t!” Barnard left the Willard lens with which he had pioneered the photography of the Milky Way in California. However, he was able to obtain funding, from a reclusive New York heiress, Catherine Bruce, for a better instrument – the 10-in. Bruce photographic telescope – that he mounted in a tin dome on the grounds at Yerkes by 1904. A year later, Hale, seeking clearer and sunnier skies, started to transfer his astronomical base to Mount Wilson, near Pasadena. The master fund-raiser obtained a grant to allow Barnard to ship the Bruce telescope to Mount Wilson at the beginning of 1905, so that he could use it to photograph the more southerly portions of the Milky Way. Over a period of 8 months, Barnard – keeping hours that would have “horrified any medical man” – obtained 500 plates, which would form the basis of his Atlas of Selected Regions of the Milky Way. The plates are masterpieces showing detail that helped Barnard decide that the dark areas were indeed clouds of obscuring matter between the stars. The final epiphany came, however, on a clear transparent moonless night in the summer of 1913 when Barnard observed a group of ordinary cumulus clouds standing silhouetted and inkyblack against the great Sagittarius star clouds. He cataloged many of the more prominent dark masses of the Northern Milky Way, which continue to be referred to by their Barnard catalog numbers. Barnard began to suffer from diabetes in 1914, and in later years he was in failing health. He knew that his greatest legacy to astronomical science was his photographic catalog of the Milky Way. He struggled to find a collotype or photogravure process that would do justice to those images, but finally refused to compromise on his masterpiece. Instead he decided to use actual photographic prints, and personally inspected each of them, 35,000 in all, to make sure they achieved his standard. Unsurprisingly, the work was not completed in his lifetime. It appeared 4 years after his death, having been completed by Edwin Frost, who had succeeded Hale as director of Yerkes, and Barnard’s niece, Mary Calvert, who had served as his personal assistant. As a self-made man himself, and a perfectionist who believed he could more easily do by himself than teach another to do for him, Barnard never had formal students. Nevertheless, he was a generous correspondent with students and schoolboys, encouraging them in their own efforts to become astronomers. Over the course of his career, Barnard was honored frequently for his contributions to astronomy. In addition to the five Warner Prizes and three Donohue Comet Medals he received for his comet discoveries, Barnard received the Lalande, Arago, and Janssen Gold Medals and prizes from the French Academy of Sciences and B 97 98 B Barnothy, Jeno M. French Astronomical Society. He was awarded the Gold Medal of the Royal Astronomical Society and the Bruce Gold Medal from the Astronomical Society of the Pacific. He was elected to the American Academy of Arts and Sciences and the National Academy of Sciences and was a foreign associate of the Royal Astronomical Society. Vanderbilt University conferred an honorary D.Sc. on Barnard for his achievements after leaving that institution. Three archives have significant Barnard holdings, including manuscripts, notebooks, and his extensive correspondence with astronomers of his time: the Joseph Heard Library of Vanderbilt University, the Mary Lea Shane archives of the Lick Observatory, and the library of the Yerkes Observatory. to the appearance of quasars and active galaxies is still sometimes cited. Virginia Trimble Selected Reference Fenyves, Ervin J. and Antal Somogyi (1997). “Jeno M. Barnothy, 1904–1996.” Bulletin of the American Astronomical Society 29: 1467–1468. Barnothy Forro, Madeleine William Sheehan Selected References Barnard, Edward Emerson (1907). “On a Nebulous Groundwork in the Constellation Taurus.” Astrophysical Journal 25: 218–225. ——— (1913). “Photographs of the Milky Way and of Comets.” Publications of the Lick Observatory 11. ——— (1919). “On the Dark Markings of the Sky with a Catalogue of 182 Such Objects.” Astrophysical Journal 49: 1–23. ——— (1927). A Photographic Atlas of Selected Regions of the Milky Way, edited by Edwin B. Frost and Mary R. Calvert. 2 Vols. Washington, DC: Carnegie Institution of Washington. Frost, Edwin Brant (1926).”Edward Emerson Barnard.” Memoirs of the National Academy of Sciences 21, no. 14: 1–23. (Vol. 11 of Biographical Memoirs, National Academy of Sciences.) Sheehan, William (1995). The Immortal Fire Within: the Life and Work of Edward Emerson Barnard. Cambridge: Cambridge University Press. Barnothy, Jeno M. Born Died Kassa (Košice, Slovakia), 28 December 1904 Evanston, Illinois, USA, 11 October 1996 Cosmologist Jeno Barnothy received his Ph.D. in 1939 from the Peter Pazmany (now Lorand Eötvös) University in Budapest, Hungary, for work on cosmic-ray physics, carried out with MadeleineBarnothy Forro. (They married in 1938.) He was associated with that university from 1935 to 1948, receiving awards from the Hungarian Academy of Sciences in 1939 and 1948. The cosmic-ray work, partly carried out in the Dorog coal mine near Budapest, led to the establishment of a small group of students working in the field. Most of them turned their attention to other fields when cosmic-ray physics could not be reestablished in Hungary after World War II. The best-known is Ervin J. Fenyves, a relativist at University of Texas, Dallas. After moving to the United States, the Barnothys were associated first with Barat College (Lake Forest, Illinois) and later with Northwestern University in Evanston, primarily in the medical school, where they taught some physics and some biophysics. The Barnothys' later work was in cosmology and astrophysics. His nonconventional (“FIB”) cosmology is not much remembered, but the suggestion (partially endorsed by the younger astrophysicist, Beatrice M. Tinsley) that gravitational lensing might be important Born Died (Hungary), 21 August 1904 Evanston, Illinois, USA, March 1993 Madeleine Forro participated in the construction of large Geiger– Müller counters and one of the first underground cosmic-ray “telescopes,” suitable for study of the very high-energy spectrum, isotropy, temporal variability, and absorption of cosmic rays in the atmosphere. Forro carried out her Ph.D. research at the Institute for Experimental Physics of the Peter Pazmany (now Lorand Eötvös) University in Budapest, Hungary, receiving her degree in 1928 for work on measurements of dielectric constant. That year, she began work in cosmic-ray physics with Jeno Barnothy. (They married in 1938.) After failing at an effort to reestablish cosmic-ray physics in Hungary after World War II, the Barnothys left for the United States, crossing the border in the trunk of a car and living on nothing but potatoes in a cellar for a week. The two astronomers turned their attention partly to astrophysics, putting forward an unconventional cosmology (in which photons might circle a closed universe, returning as cosmic rays) and the idea that quasars were gravitationally lensed images of Seyfert galaxies. The latter is approximately correct, in the sense that a small fraction of quasars (at large redshift) do indeed appear brightened by lensing. Barnothy Forro held positions at Barat College (Lake Forest, Illinois), Northwestern University (Evanston, Illinois), and the University of Illinois Medical School at Chicago. Some of these positions were connected with the Barnothys’ interests in biophysics, particularly the effects of strong magnetic fields on mammals. Virginia Trimble Selected Reference Fenyves, Ervin J. and Antal Somogyi (1995). “Madeleine Barnothy Forro, 1904–1993.” Bulletin of the American Astronomical Society 27: 1475. Baron Blackett of Chelsea > Blackett, Patrick Maynard Stuart Bartholin, Erasmus Baron Kelvin of Largs of mathematics, but also the suitability of mathematical methods for investigating and reasoning about nature. James M. Lattis > Thomson, William Alternate name Franciscus Barocius Barozzi, Francesco Born Died Candia (Iráklion), Crete, (Greece), 9 August 1537 Venice, (Italy), 23 November 1604 Francesco Barozzi is important to the history of astronomy both for his attempts to reform the teaching of astronomy and in his advocacy of the value of mathematics and mathematical sciences. Barozzi was born into a noble Venetian family with extensive holdings in Rettimo (modern Rethymnon) in Crete, and spent many years of his life there on family business. He received a humanistic education culminating in the University of Padua, where Barozzi studied mathematics and philosophy. By 1559, he was lecturing there on the Sphere of John of Holywood. Barozzi actively labored in the Renaissance effort to recover classical texts and study them critically. In that spirit he searched for, collected, copied, edited, translated, and (in some cases) also published ancient Greek mathematical works, including those of Proclus, Hero, Pappus, and Archimedes. Barozzi possessed one of the finest collections in his era of ancient manuscript texts on mathematical topics, and actively patronized the activity of others. He also published an original work on the geometry of parallel lines and a cosmography intended to replace Sacrobosco’s Sphere. (See below.) Barozzi’s interests extended well beyond mathematics to include dabbling in astrology, natural magic, and sorcery. He was tried, convicted, and penalized by the Venetian Inquisition at least once, in 1587, for a variety of conjurations in Crete, inspired, apparently, by his reading of Cornelius Agrippa and Peter d’Abano. (He was condemned and confined by the Holy Office on at least one other occasion for unknown reasons.) Though Barozzi regained his freedom by 1588, he published little during the rest of his life. In publishing his Cosmographia (Venice, 1585, 1598, and translated into Italian, 1607), Barozzi attempted to replace what he saw as a flawed basis for astronomical teaching, namely the venerable Sphere of Sacrobosco and the commentaries on it. His new text corrected, so he claimed, the numerous errors of the old, and Barozzi devoted many pages of his text to listing and explaining these errors (most of which were procedural or didactic in nature). His criticisms provoked an amicable exchange of correspondence with Christoph Clavius, author of one of the foremost contemporary Sphere commentaries. Though Barozzi offered no important corrections or innovations to the subject matter of astronomy itself, his attempts at reform are a further example of the strength of the sentiments for such change in the middle and late 16th century, and especially in the ambit of the University of Padua. In an era when the value of teaching mathematical subjects and the status of mathematical sciences themselves were being called into question (usually by Aristotelian philosophers such as Alessandro Piccolomini), Barozzi defended not only the utility Selected References Boyer, Marjorie Nice (1970). “Barocius, Franciscus.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 1, p. 468. New York: Charles Scribner’s Sons. Giacobbe, Giulio Cesare (1972). “Francesco Barozzi [1537–1604] e la Quaestio de certitudine mathematicarum.” Physis 14: 357–374. Rose, Paul Lawrence (1977). “A Venetian Patron and Mathematician of the Sixteenth Century: Francesco Barozzi (1537–1604).” Studi Veneziani, n.s., 1: 119–178. (This is the best treatment of Barozzi; it includes a complete bibliography of primary sources and also prints a number of his letters.) Spiazzi, G. (1964). “Barozzi, Francesco.” In Dizionario biografico degli italiani. Vol. 6, pp. 495–499. Rome: Istituto della Encicilopedia italiana. Barringer, Daniel Moreau Born Died 25 May 1860 30 November 1929 American mining engineer Daniel Barringer correctly claimed that a crater in northern Arizona was the result of impact. He drilled in vain, hoping to discover a large mass of metal ore that he could exploit economically. Selected Reference Hoyt, William Graves (1987). Coon Mountain Controversies: Meteor Crater and the Development of Impact Theory. Tucson: University of Arizona Press. Bartholin, Erasmus Born Died Roskilde, Denmark, 13 August 1625 Copenhagen, Denmark, 4 November 1698 Erasmus Bartholin was a transitional figure in Danish astronomy. He edited works of Tycho Brahe and taught Ole Römer. Foremost a physician, Bartholin observed the comet of 1665 (C/1665 F1). He is better known for describing the optical phenomenon of double refraction. Selected Reference Christianson, John Robert (2000). On Tycho’s Island: Tycho Brahe and His Assistants, 1570–1601. Cambridge: Cambridge University Press. B 99 100 B Bartholomaeus Anglicus Bartholomaeus Anglicus Flourished Paris, France 13th century Bartholomaeus Anglicus’s early encyclopedia, De Proprietatibus Rerum, was (in the words of philologist S. K. Heninger, Jr.) “… a monument of erudition that transmitted intact the medieval worldview to the Renaissance.” Selected Reference Anon. (1977). The Cosmographical Glass. San Marino, California: Huntington Library. Bartsch, Jakob Flourished (Poland), 1624 Either Johann Bayer or uranographer Jakob Bartsch is responsible for introducing Musca, one of the most obscure modern constellations. Alternate name Bartschius Selected Reference Sesti, Giuseppe Maria (1991). The Glorious Constellations: History and Mythology. New York: Harry N. Abrams. Bartschius > Bartsch, Jakob Bāṣo > Ibn Bāṣo: Abū �Alī al-Ḥusayn ibn Abī Ja�far Aḥmad ibn Yūsuf ibn Bāṣo Basṭūlus > Nasṭūlus: Muḥammad ibn �Abd Allāh Bates, David Robert Born Died Omagh, Northern Ireland, 10 November 1916 Belfast, Northern Ireland, 5 January 1994 Sir David Bates carried out innovative research in atomic, molecular, and optical physics, which he applied to problems of aeronomy and astronomy. He was educated at the Royal Belfast Academic Institution in Belfast, after which he entered the faculty of science of the Queen’s University of Belfast. He graduated in 1937 with B.Sc. degrees in experimental physics and mathematical physics, obtaining first-class honors in both. In 1938, Bates was awarded the M.Sc. degree. He married Barbara Morris in 1956, and they had two children, Kathryn Maud and Adam David. After wartime research and before departing for Belfast in 1951, Bates was lecturer in the Department of mathematics and then reader in the Department of Physics at University College London. He was professor and head of the Department of Applied Mathematics of the Queen’s University of Belfast from 1951 to 1973, and then occupied a special research chair until 1982, when he became professor emeritus. During his tenure in the Department of Applied Mathematics (later the Department of Applied Mathematics and Theoretical Physics), Bates built a research school in atomic, molecular, and optical physics that became world renowned. With graduate students and postdoctoral fellows, Bates drew deep connections between atomic, molecular, and optical physics and astronomy. In his studies, Bates combined physical insight with mathematical formulations constructed so that numerical calculations could be carried out to enable quantitative comparisons to be made of theory and measurement. He investigated a diverse range of processes and made significant contributions to the accurate description of photoionization, photodetachment, collisional excitation, ionization and charge transfer, chemical reactions, mutual neutralization, radiative association, dissociative recombination, dielectronic recombination, collisional-radiative recombination, and ion–ion recombination. He profoundly influenced and inspired generations of graduate students. Bates’ applications to the terrestrial atmosphere established the foundation and fundamental concepts for later studies of the physics and chemistry of planetary atmospheres and astrophysical plasmas. His approach, first employed in studies of the terrestrial ionosphere, has become standard. In it, he identified the detailed microscopic processes that produced the free electrons and the recombination processes that removed them, made estimates of their rates, and evaluated their consequences. The original analysis of ionospheric structure with Sir Harrie Massey led to the recognition that the process they called dissociative recombination is the dominant recombination process in molecular plasmas, and Bates demonstrated that it plays a decisive role in determination of the luminosity and chemistry of many atmospheric and astrophysical environments and laboratory plasmas. Working with Marcel Nicolet, Bates identified the chemical source of the infrared hydroxyl bands in the airglow of the atmosphere and pointed to the importance of methane and water vapor in the chemistry of ozone. Battānī With Agnes Witherspoon and Paul Hays, he demonstrated the profound effects of minor constituents in atmospheric chemistry and the role of industrial and microbiological sources and sinks. This research is fundamental to studies of global change and the effects of pollution. Bates made substantial contributions to astrophysics, perhaps none more enduring than work with Lyman Spitzer on the formation and destruction of molecules in interstellar clouds. From 1962 to 1993 Bates was editor of Planetary and Space Science, and for 28 years he was a coeditor of Advances in Atomic, Molecular and Optical Physics. Bates received many honors including election to the Royal Irish Academy in 1952, the Royal Society of London in 1958, the International Academy of Astronautics in 1961, the American Academy of Arts and Sciences in 1974, the Académie royale de Belgique in 1979, the United States National Academy of Sciences in 1984, and the International Academy of Quantum Molecular Science in 1985. He received honorary degrees from seven universities. He was awarded the Hughes Medal of the Royal Society in 1970, the Chree Medal of the United Kingdom Institute of Physics in 1978, the Gold Medal of the Royal Astronomical Society in 1979, and the Fleming Medal of the American Geophysical Union in 1987. For his services to science and education Bates was knighted in 1978. Two medals were created in his honor: the Sir David Bates Medal of the Európean Geophysical Society and the Sir David Bates Medal of the UK Institute of Physics. Alex Dalgarno and founded the Variable Star Section [VSS] of the New Zealand Astronomical Society (later the Royal Astronomical Society of New Zealand [RASNZ]). Under his leadership, the number of active observers increased as did the number and types of variable stars covered. Bateson established close working relationships with professional astronomers and provided them with data obtained by the RASNZ observers using over 1,000 charts of southern variable stars that Bateson published (most with Mati Morel). The approximately one million observations recorded by RASNZ observers during Bateson’s tenure as the VSS Director provided the basis for hundreds of publications. In the late 1950s, Bateson promoted his vision of a professional observatory in New Zealand in collaboration with Frank Wood of the University of Pennsylvania. Bateson conducted an extensive site-testing program and recommended the site at Mount John. The Mount John Observatory was established with the University of Canterbury in 1965; Bateson served as its director until his retirement in 1969. In 1931, Bateson married Doris McGoldrick; they had two daughters. Bateson was awarded the Jackson–Gwilt Medal and Prize of the Royal Astronomical Society in 1960, and an honorary doctorate from the University of Waikato in 1979. His autobiography, Paradise Beckons, was privately published in 1989. Grant Christie Selected References Evans, R. W. (ed). (2005). Southern Stars. Wellington: Royal Astronomical Society of New Zealand. (Volume 44: number 1, pp. 1–40 contains papers from the Conference Celebrating Frank Bateson’s 80 Years of Astronomy, held 4 December 2004 at Tauranga, New Zealand.) Selected References Bates, David R. (1983). “Scientific Reminiscences.” In Proceedings of the International Symposium on Atomic, Molecular and Solid-State Theory, Collision Phenomena, and Computational Quantum Chemistry, edited by Per-Olov Löwden, pp. 5–32. International Journal Of Quantum Chemistry, Quantum Chemistry Symposium, no. 17. New York: John Wiley and Sons. Burke, P. G. and D. S. F. Crothers (1996). “Professor Sir David Bates, FRS.” Comments on Atomic and Molecular Physics 32: 127–130. Dalgarno, Alexander (1997). “Sir David Robert Bates.” Biographical Memoirs of Fellows of the Royal Society 43: 47–71. Battānī: Abū �Abd Allāh Muḥammad ibn Jābir ibn Sinān al-Battānī al-Ḥarrānī al-Ṣābi’ Born Died Bateson, Frank Maine Born Wellington, New Zealand, 31 October 1909 Frank Bateson organized variable star observing in New Zealand, providing leadership to the field in the Southern Hemisphere for 78 years. The son of Charles and Alice Bateson, he was educated at the Hurworth Preparatory School in Wanganui, New Zealand, and at Scots College, Sydney, Australia, and undertook a career in business administration and accountancy. After reading Robert Ball’s Great Astronomers, Bateson made his first observations of meteors in 1923 and then variable stars in 1924. He joined the British Astronomical Association’s New South Wales branch and was lent a small refractor and allowed to use the refractor at the Sydney Observatory. Bateson returned to New Zealand in 1927 Harran, (Turkey), before 858 near Samarra, (Iraq), 929 Battānī was one of the most influential astronomers of the early Islamic period. He was particularly well known for the accuracy of his observations, which he carried out at Raqqa in northern Syria over a period of 40 years. He wrote an important astronomical handbook with tables (zīj) and some astrological treatises in the tradition of Ptolemy’s Tetrabiblos. Battānī hailed from Harran in southern Anatolia, possibly from the district Battān of that city, which is mentioned by the famous 16th-century Egyptian scholar Suyūṭī in his lexicon of epithets of location, the Lubb al-lubāb. Battānī was born into a family of Sabians. Adherents of this pagan religion, mainly centered in Harran, were characterized by a type of star idolatry going back to Babylonian times, and included numerous prominent scholars such as Thābit ibn Qurra. From his first name Muḥammad and his kunya Abū � Abd Allāh, we see that Battānī himself was a Muslim. In European works up to the 19th century, Battānī was mistakenly presented B 101 102 B Battānī as a noble, a prince, or a king, but there is no justification for such attributions in Arabic sources. Battānī was probably the son of Jābir ibn Sinān al-Ḥarrānī, a well-known instrument maker from Harran mentioned by the earliest bibliographer of Muslim scientists, Ibn al-Nadīm (died: 990). So we may assume that Battānī learned about astronomical instruments from his father before he moved to Raqqa in northern Syria. In Raqqa, Battānī devoted considerable financial resources to establish a private observatory at which he regularly conducted observations during the period from 877 to 918. Among the instruments that he is known to have used are a gnomon, horizontal and vertical sundials, a triquetrum, parallactic rulers, an astrolabe, a new type of armillary sphere, and a mural quadrant with an alidade. For several of these instruments, Battānī recommended sizes of more than a meter in order to increase the accuracy of the observations. In 901, Battānī observed a solar and a lunar eclipse in Antioch. The accuracy of Battānī’s observations of equinoxes and solstices, as judged from the one existing report and his determination of the lengths of the seasons, is not much inferior to that of Tycho Brahe 700 years later. This remarkable achievement must have been due to a careful construction and alignment of his large instruments, as well as to a clever method of combining multiple observations of the same type of phenomenon (which was certainly not simple averaging). The value obtained by Battānī for the Ptolemaic solar eccentricity, expressed sexagesimally as 2;4,45 parts out of 60, is almost exact. In fact, it is clearly better than the values found by Nicolaus Copernicus, who was troubled by refraction because of his high geographical latitude, and Brahe, who incorporated the much too high Ptolemaic value for the solar parallax in the evaluation of his observations. Battānī also made accurate measurements of the obliquity of the ecliptic, which he found as 23° 35′ (the actual value in the year 880 was 23° 35′ 6″), and the geographical latitude of Raqqa (36° 1′, modern value 35° 57′). Furthermore, he determined all planetary mean motions anew. He found the parameters of the lunar model to be in agreement with Ptolemy and the eccentricity of Venus the same as derived by the astronomers working under Ma’mūn. (See, for example, Yaḥyā ibn Abī Manṣūr.) Battānī also confirmed the discovery of Ma’mūn’s astronomers that the solar apogee moves by 1° in 66 Julian years, and found the precession of the equinoxes to be equal to the motion of the solar apogee. He accurately measured the apparent diameters of the Sun and the Moon and investigated the variation in these diameters, concluding that annular solar eclipses are possible. In the 18th century, Battānī’s observations of eclipses were used by Richard Dunthorne to determine the secular acceleration of the motion of the Moon. Battānī’s most important work was a zīj, an astronomical handbook with tables in the tradition of Ptolemy’s Almagest and Handy Tables. Ibn al-Nadīm mentions that this work (later called al-Zīj alṢābi’) existed in two editions, “the second being better than the first,” but modern attempts to date or differentiate the two versions have been unconvincing. The Ṣabi’ Zīj is extant in its entirety (57 chapters plus tables) in the 12th- or 13th-century manuscript Escorial árabe 908, copied in the western part of the Islamic world. Five or six insignificant fragments are scattered over several libraries in Western Europe. Between 1899 and 1907, C. A. Nallino published his monumental edition, translation, and commentary of the Zīj in Latin, and this remains the standard work on Islamic astronomy in general and on Battānī and zījes in particular. The Ṣābi’ Zīj is the earliest extant zīj written completely in the Ptolemaic tradition with hardly any Indian or Sasanian–Iranian influences. As with many Islamic zījes, its purpose was much more practical than theoretical. Although the planetary models and the determination of the solar parameters are explained in some detail (but with various errors), most of the text in the Zīj consists of instructions for carrying out practical calculations by means of the tables, which constitute a third of the book. With the exception of Ptolemy and some other Greek observers, Battānī does not express indebtedness to any of his predecessors. On the basis of linguistic arguments, it can be seen that he used an Arabic translation of the Almagest made from the Syriac. A remarkable characteristic of the text is the almost complete absence of foreign technical terminology. Although Battānī copied some of the planetary tables directly from the Handy Tables, he also computed many tables anew. His star table (containing approximately half the number of stars found in the Almagest) was obtained by increasing Ptolemy’s stellar longitudes by 11° 10′, the precession in the period of 743 years between the respective epochs 137 and 880. The Ṣābi’ Zīj enjoyed a high reputation in the Islamic world and was very influential in medieval and Renaissance Europe. Bīrūnī wrote a treatise entitled Jalā’ al-adhhān fī zīj al-Battānī (Elucidation of genius in al-Battānī’s Zīj), which is unfortunately lost. Later zījes such as those of Kūshyār ibn Labbān, Nasawī, and Ṭabarī were based on Battānī’s mean motion parameters. In Spain, the Ṣābi’ Zīj exerted a large influence on the earliest astronomical developments and left many traces in the Toledan Tables. Two Latin translations of the canons of the Zīj were prepared in the 12th century. The one by Robert of Chester has not survived, but the translation by Plato of Tivoli, made in Barcelona, was printed in Nuremberg in 1537 (together with Farghānī’s introduction to Ptolemaic astronomy) and again in Bologna in 1645 under the title Mahometis Albatenii de scientia stellarum liber, cum aliquot additionibus Ioannis Regiomontani ex Bibliotheca Vaticana transcriptus. The Castilian translation made from the Arabic around 1260 on the order of Alfonso X is partially extant with tables in the manuscript Paris, Arsenal 8.322, which was prepared for Alfonso himself. Hebrew versions or reworkings of the Ṣābi’ Zīj were written by Bar Ḥiyya (12th century) and Immanuel ben Jacob Bonfils (14th century); furthermore, Battānī’s influence can also be seen in the works of Ibn �Ezra, Maimonides, and Levi ben Gerson (Gersonides). Finally, European scholars such as Regiomontanus, Copernicus, Brahe, Johannes Kepler, and Galileo Galilei made use of Battānī’s work. Besides the Ṣābi’ Zīj, the following smaller works by Battānī are known: 1. The Kitāb fī dalā’il al-qirānāt wa- ‘l-kusūfāt (On the astrological indications of conjunctions and eclipses) is extant in Ankara, İsmail Saib Library 199/2. This astrological treatise presents horoscopes and astrological interpretations in connection with Saturn–Jupiter conjunctions during the life of the prophet Muḥammad and the early period of Islam. It is written in the tradition of Ptolemy’s Tetrabiblos. 2. The Sharḥ Kitāb al-arba�a li-Baṭlamiyūs (Commentary on Ptolemy’s Tetrabiblos) is extant in the manuscripts Berlin Spr. 1840 (Ahlwardt #5875) and Escorial árabe 969/2. 3. A small work on trigonometry, Tajrīd uṣūl tarkīb al-juyūb (Summary of the principles for establishing sines) is extant in the Baxendell, Joseph manuscript Istanbul Carullah 1499/3. Since Battānī does not use the Indian loanword jayb for “sine” in the Ṣābi’ Zīj, the authenticity of this work has been questioned. 4. A Kitāb taḥqīq aqdār al-ittiṣālāt [bi-ḥasab �urūḍ al-kawākib] (On the accurate determination of the quantities of conjunctions (?) [according to the latitudes of the planets]) is mentioned by Ibn al-Nadīm and is probably identical with Chapter 54 of the Ṣābi’ Zīj. It deals with the astrological concept of the projection of the rays, for which Battānī was the first to take into account the latitudes of the planets. 5. A Kitāb Maṭāli� al-burūj fī mā bayna arbā� al-falak (On the ascensions of the zodiacal signs between [the cardinal points of] the quadrants of the sphere) is also mentioned by Ibn al-Nadīm and is probably identical with Chapter 55 of the Zīj. It provides methods of calculation needed in the astrological problem of finding the tasyīr (aphesis or directio). According to Ibn al-Nadīm, Battānī lived for some time in Baghdad towards the end of his life, because of financial difficulties brought about by dealings with the family of the Banū al-Zayyāt (presumably descendents of the famous poet and vizier �Abd al-Malik ibn Abān alZayyāt) in Raqqa. On his way back to Raqqa, Battānī died at the castle Qaṣr al-Jaṣṣ near Samarra, 100 km north of Baghdad. Benno van Dalen Alternate name Albategnius [Albatenius] Selected References Al-Qiftī, Jamāl al-Dīn (1903). Ta’rīkh al-hukamā’, edited by J. Lippert. Leipzig: Theodor Weicher. Bagheri, Mohammad (1992). “Battâni’s Version of Trigonometric Formulas.” Tahqīqāt-i Islāmī (Journal of the Encyclopaedia Islamica Foundation, Tehran) 7, no. 2: 176–169 [sic]. (Edition and translation of Battānī’s small treatise on the sine.) Bossong, Georg (1978). Los canones de Albateni. Tubingen: Niemeyer. (Edition and philological discussion of the Castilian translation of the canons of the Sābi’ Zīj.) Bruin, Frans (1977). “The First Visibility of the Lunar Crescent.” Vistas in Astronomy 21: 331–358, esp. 345–357. Hartner, Willy (1970). “Al-Battānī.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 1, pp. 507–516. New York: Charles Scribner’s Sons. (With a summary of the most important results found in Nallino 1899–1907.) Hogendijk, Jan P. (1988). “New Light on the Lunar Crescent Visibility Table of Yaʕqūb ibn Tāriq.” Journal of Near Eastern Studies 47: 95–104. (Describes and analyzes Battānī’s method for solving the typical Islamic problem of predicting the first visibility of the lunar crescent after New Moon.) Ibn al-Nadīm (1970). The Fihrist of al-Nadīm: A Tenth-Century Survey of Muslim Culture, edited and translated by Bayard Dodge. 2 Vols. New York: Columbia University Press. (This and al-Qiftī are the main sources for information on al-Battānī’s life.) Kennedy, E. S. (1956). “A Survey of Islamic Astronomical Tables.” Transactions of the American Philosophical Society, n.s., 46, Pt. 2: 121–177, esp. 132–133 and 154–156. (Reprint, Philadelphia: American Philosophical Society, 1989.) King, David A. (1986). “The Earliest Islamic Mathematical Methods and Tables for Finding the Direction of Mecca.” Zeitschrift für Geschichte der ArabischIslamischen Wissenschaften 3: 82–149. (Discusses Battānī’s approximate method for the determination of the qibla.) Kunitzsch, Paul (1974). “New Light on al-Battānī’s Zīj.” Centaurus 18: 270–274. (Corrects mistakes in Nallino’s edition of the star table on the basis of a treatise by Ibn al-Salāh, and confirms that Battānī used a Syriac or “old” Arabic version of the Almagest.) Maeyama, Yasukatsu (1998). “Determination of the Sun’s Orbit: Hipparchus, Ptolemy, al-Battānī, Copernicus, Tycho Brahe.” Archive for History of Exact Sciences 53: 1–49. (Analyzes the sources of error in the solar observations of five important premodern astronomers.) Nallino, Carlo Alfonso (1899–1907). Al-Battānī sive Albatenii Opus astronomicum (al-Zīj al-Sābi’). 3 Vols. Milan: Ulrich Hoepli. ——— (1960). “Al-Battānī.” In Encyclopaedia of Islam. 2nd ed. Vol. 1, pp. 1104– 1105. Leiden: E. J. Brill. Ragep, F. Jamil (1996). “Al-Battānī, Cosmology, and the Early History of Trepidation in Islam.” In From Baghdad to Barcelona: Essays on the History of the Islamic Exact Sciences in Honour of Prof. Juan Vernet, edited by Josep Casulleras and Julio Samsó. Vol. 1, pp. 267–298. Barcelona: Instituto “Millás Vallicrosa” de Historia de la Ciencia árabe. (Argues that Battānī provided a physical–cosmological alternative to Theon’s simple arithmetic theory of trepidation and therewith influenced later developments in the western Islamic world.) Said, Said S. and F. Richard Stephenson “Solar and Lunar Eclipse Measurements by Medieval Muslim Astronomers.” I: Background, II: Observations. Journal for the History of Astronomy 27 (1996): 259–273; 28 (1997): 29–48. (Translates and recomputes Battānī’s eclipse reports.) Sayılı, Aydın (1960). The Observatory in Islam. Ankara: Turkish Historical Society, esp. pp. 96–98. Sezgin, Fuat. Geschichte des arabischen Schrifttums. Vol. 5, Mathematik (1974): 287–288; Vol. 6, Astronomie (1978): 182–187; Vol. 7, Astrologie – Meteorologie und Verwandtes (1979): 158–160. Leiden: E. J. Brill. Swerdlow, Noel (1973). “Al-Battānī’s Determination of the Solar Distance.” Centaurus 17: 97–105. (Shows that Battānī’s treatment is different from Ptolemy’s but likewise mathematically problematic, and that it involves some Indian elements.) Yano, Michio and Mercè Viladrich (1991). “Tasyīr Computation of Kūshyār ibn Labbān.” Historia Scientiarum, no. 41: 1–16. (Relates Kūshyār’s method of calculating tasyīrs to those of Battānī.) Baxendell, Joseph Born Died Smedley near Manchester, England, 19 April 1815 Birkdale (Mersey), England, 7 October 1887 Joseph Baxendell, an astronomer and meteorologist, is noted for his pioneering work on solar–terrestrial relationships, and studies of variable stars, of which he discovered 18. His work typifies that of the devotee so prominent before the professionalization of science. Baxendell was the eldest of the eight children (six sons and two daughters) born to Thomas Baxendell, a self-made man who farmed at Smedley. His mother (née Mary Shepley), is said to have had a strong love of astronomy, and it is possible that Joseph’s interest in science dates back to her influence. This inclination was further encouraged by Thomas Walley. Joseph received his early education at his school at Cheetham Hill, Manchester. Here he proved himself a rapid learner, and demonstrated his aptitude for mathematics. Baxendell does not appear to have devoted much time to experimental enquiry, but did so in his observational abilities and inclination towards mathematics. He gave early indications of the direction of his later development. Having quickly acquired all his teacher could impart, Baxendell left school at age 14; hence, in the B 103 104 B Bayer, Johann words of his biographer, James Bottomley, he can be said to have been largely self-taught. A weak constitution in childhood necessitated frequent trips to Southport, a nearby seaside resort, and led to a lifelong enthusiasm for all things maritime. At the age of about 14, in the hope that a sea voyage would invigorate his health, Baxendell embarked on the Mary Scott, bound for Valparaiso, Chile. Over the next 6 years, he made several voyages, and in 1833 off the Pacific coast of Central America, Baxendell made good use of his powers of observation when he had the good fortune to witness the extraordinary Leonid meteor shower of 13 November. Two years later, he experienced the shock of the earthquake that devastated the Pacific coast of South America. That same year, he abandoned the sea, though not through disgust with seafaring life; Baxendell returned to Manchester, where he assisted his father before setting up in business as an estate agent. He also worked in a quiet unobtrusive way on his studies of astronomy and meteorology. At first, Baxendell settled in Stocks Street, Cheetham, but moved to Crescent Road, Cheetham Hill, not far from where his friend Robert Worthington of Crumpsall Old Hall had set up an observatory. This housed a large 13-in. reflector, the speculum of which Baxendell had cast, ground, and polished, as well as a 5-in. equatorial refractor. As an accident to his right eye debarred Worthington from its use, Baxendell utilized the facility until its removal in 1869. The excellent work done at the Crumpsall Observatory, which included observations of variable stars, meteors, comets, planets, sunspots, and eclipses, won it a high place among private observatories, and put Baxendell in contact with leading astronomers across the globe. Among these was Norman Pogson, Government Astronomer at Madras, whose sister Baxendell married in 1865. They had one son, Joseph. The year 1858 seems to have been a watershed. In January, Baxendell joined the Manchester Literary and Philosophical Society [MLPS], and later that year was enrolled as a yellow of the Royal Astronomical Society. The following year he became a Council member of the former society, and was appointed Manchester’s municipal astronomer in succession to the Reverend Henry Halford Jones. Two years later, in 1861, Baxendell became joint secretary of the MLPS as well as assuming responsibility for publication of the society’s Memoirs and Proceedings. He held the former position until 1885, the latter until his death. Baxendell’s colleagues in the secretaryship were Sir H. E. Roscoe (until 1873), and professor Osborne Reynolds. In 1884, Baxendell was elected as fellow of the Royal Society, by which time he had published over 70 papers and several catalogs of variable stars. Although most of his work appeared in the Proceedings of the Manchester Literary and Philosophical Society, he also published in the Proceedings of the Royal Society, and contributed to the Astronomische Nachrichten, the Observatory, the Journal of the Liverpool Astronomical Society, and the Monthly Notices of the Royal Astronomical Society. Baxendell’s earliest work on variable stars appeared in the latter publication and was entitled “On the Variability of λ Tauri.” Apart from his studies of variable stars, Baxendell is best remembered for what professor Balfour Stewart eulogized as his pioneering contributions to meteorology. In his paper “On Solar Radiation,” Baxendell deduced that the maxima and minima of heat energy given off by the Sun correspond with sunspot frequency, while in one of his most original and important papers (“On a Periodic Change …”), he thought it highly probable that changes in the output of solar energy were more complicated than previously assumed. To explain a short variable period that he had detected, Baxendell conjectured the existence of a ring of nebulous matter circling the Sun in a plane nearly coincident with the plane of the ecliptic. This, he supposed, acted not only to reflect and absorb part of the radiation that would otherwise have reached the Earth, but altered the direction of the lines of magnetic force, that influence being more marked than the thermal influence. Subsequent to his appointment as Manchester’s municipal astronomer, Baxendell supervised the construction of the Fernley meteorological observatory in Hesketh Park, Southport. He also became meteorologist to the corporation of that town. His service to the community in this capacity was highly effective. Baxendell took an intense interest in the issue of storm warnings, and objected vigorously when the Board of Trade proposed their abolition. His warnings of the summer drought of 1868 enabled the Manchester Corporation Water Works to implement effective precautions. Baxendell was also correct, it seems, in alerting the authorities in Southport to an outbreak of smallpox epidemic. Towards the end of his life, Baxendell showed great interest in the manner in which the Great Pyramid of Egypt had been constructed. At his last residence in Birkdale, near Southport, he erected a small observatory; with the help of his son, who succeeded him as meteorologist to the corporation of Southport, he resumed his astronomical work. Baxendell lived a quiet, retired life. He is said to have been of an amiable disposition, and had a firmness of character. In his later years, he experienced difficulty in breathing and was afflicted by a painful disease of the lower jaw. Richard Baum Selected References Anon. (10 October 1887). “Obituary.” Manchester Guardian. Anon. (1887). “Obituary.” Nature 20 October: 585. Anon. (1888). “Joseph Baxendell.” Monthly Notices of the Royal Astronomical Society 48: 157–160. B. S. (1888). “Joseph Baxendell.” Proceedings of the Royal Society of London 43: iv–vi. Baxendell, Joseph (1848). “On the Variability of λ Tauri.” Monthly Notices of the Royal Astronomical Society 9: 37–38. ——— (1871). “On Solar Radiation.” Memoirs of the Manchester Literary and Philosophical Society 4: 128, 147. ——— (1872). “On a Periodic Change in the Magnetic Condition of the Earth and the Distribution of Temperature over its Surface.” Proceedings of the Manchester Literary and Philosophical Society 5: 251–260. Bottomley, James. “Memoir of the late Joseph Baxendell, F. R. S., F. R. A. S.” Proceedings of the Manchester Literary and Philosophical Society. 4th ser., 1: 28–58. Kargon, Robert H. (1977). Science in Victorian Manchester. Manchester: Manchester University Press. Bayer, Johann Born Died Rain, (Bavaria, Germany), 1572 Augsburg, (Bavaria, Germany), 1625 Johann Bayer is known mainly for his celestial atlas entitled Uranometria (Augsburg, 1603), and for having introduced the star nomenclature that is still in use. Astronomer and lawyer, Bayer studied in Ingolstadt and Augsburg and became legal adviser to the city council of Augsburg. Although Beals, Carlyle Smith collections of celestial maps were published in Italy during the 16th century, as part of astronomical treatises by Alessandro Piccolomini and Giovanni Gallucci, Uranometria presented for the first time all the characteristics typical of the great celestial atlases of the modern age: the large format, the maps of constellations with the corresponding mythological figures, and the catalog of the stars contained in the celestial charts. (Bayer drew his data from the catalog of Tycho Brahe.) While Piccolomini identified the stars by means of Latin letters, Bayer introduced a nomenclature based on the use of Greek letters followed by the genitive of the constellation name. So, for example, Aldebaran and Deneb were identified by Bayer as α Tauri and α Cygni, respectively. Another important novelty of Uranometria resides in the first printed representation of the southern sky according to the new constellations introduced by the Dutch navigators Pieter Keyser and Friedrich de Houtman. They proposed to add 12 asterisms to the 48 Ptolemaic constellations, in order to cover the region of the sky around the South Pole, which had remained unknown to European astronomers until the age of great geographic discoveries. After Uranometria, Bayer continued his activity in celestial cartography and, in the last years of his life, offered his collaboration to the preparation of a new atlas, entitled Coelum Stellatum Christianum, published by Julius Schiller in 1627. Davide Neri Selected References Ashbrook, Joseph (1984). “Johannes Bayer and His Star Nomenclature.” In The Astronomical Scrapbook, edited by Leif J. Robinson, pp. 411–418. Cambridge, Massachusetts: Sky Publishing Corp. Rosen, Edward (1970). “Bayer, Johann.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 1, pp. 530–531. New York: Charles Scribner’s Sons. Tooley, R. V. (1979). Tooley’s Dictionary of Mapmakers. Tring, England: Map Collector Publications, p. 44. Warner, Deborah J. (1979). The Sky Explored: Celestial Cartography, 1500–1800. New York: Alan R. Liss, pp.18–20. Beals, Carlyle Smith Born Died Canso, Nova Scotia, Canada, 29 June 1899 Ottawa, Ontario, Canada, 2 July 1979 Canadian astrophysicist Carlyle Beals is most widely remembered for relatively late work on identifying impact (meteorite) craters in northern Canada and using their properties in analysis of lunar cratering, but he also discovered that the interstellar medium consists partly of discrete clumps or clouds. Beals was the son of the Reverend Francis H. P. Beals and Annie Florence Nightingale Smith. He married Miriam White Bancroft in 1931, and they had one daughter, Janitza. His sister married Roderick Redman. Beals attended local schools and then Acadia University, taking a B.A. in mathematics and physics in 1919. After a period of rural teaching, he entered the University of Toronto, obtaining an M.A. in 1923. Following further teaching, Beals moved to Imperial College, London, where, as a student of Alfred Fowler, he specialized in spectroscopy. He took a diploma in 1925 and a Ph.D. in 1926. After a year as an instructor at Acadia University (1926–1927), Beals joined the staff of the Dominion Astrophysical Observatory, where he became assistant director in 1940. London University awarded him the D.Sc. in 1934. In 1946, Beals moved to Ottawa to become Dominion Astronomer and director of the Dominion Observatory. He was the first astrophysicist to head the observatory, and brought in sweeping changes. Under his direction, staff publication increased significantly and new fields were developed, such as geophysics, meteor studies, radio astronomy – with the creation of the Dominion Radio Astrophysical Observatory in 1960 – and Beals’ own research into meteorite impact features. He retired in 1964, but continued consulting work in lunar and planetary sciences. Beals was particularly interested in analysis of the spectra of hot stars displaying emission lines. He laid down a basic classification scheme for the Wolf–Rayet [WR] stars, with separate sequences for spectra dominated by carbon and nitrogen lines. Beals’ explanation of the complex shapes of lines in the P Cygni stars (that an expanding cloud around the star imposed blueshifted absorption lines as well as adding redshifted and undisplaced emission lines) proved to be correct, and he also attempted to determine the outflow structure of material expelled by nova explosions, though less successfully. His attempt to determine the temperatures of WR stars by a method analogous to that of Hermann Zanstra, for the central stars of planetary nebulae, revealed that WR atmospheres are not really in a state of local thermodynamic equilibrium. In 1939, examining a spectrogram of the bright, hot star R Leonis, Beals recognized that the sharp (hence interstellar) absorption feature of ionized calcium had several partially separated components at different velocities, implying that it was produced by several discrete gas clouds rather than a continuous distribution. He and younger Canadian–American astronomer J. Beverly Oke later calibrated the strength of the calcium feature as a distance indicator for stars within the galactic plane. More extensive work on multiple components was done by Walter Adams and Alfred Joy. Upon arriving in Ottawa, Beals began examining Royal Canadian Air Force photographs of the northern regions of Canada. He picked out a number of craters which later geological investigation identified as being the products of impacts rather than of (commoner) volcanoes, and later applied that expertise to the analysis of images of lunar craters (most of which are impact products). Beals was a fellow of the Royal Society of London, an officer in the Order of Canada, a fellow of the Royal Society of Canada (and a recipient of its Tory Medal), president of the Royal Astronomical Society of Canada (1952), and president of the American Astronomical Society (1962–1964), the only Canadian so to serve. The Meteoritical Society awarded him its first Leonard Medal in 1966. He had honorary degrees from Acadia, New Brunswick, Queen’s, and Pittsburgh universities. Richard A. Jarrell Selected References Jarrell, Richard A. (1988). The Cold Light of Dawn: A History of Canadian Astronomy. Toronto: University of Toronto Press. Whitman, Kenneth (1979). “Carlyle Smith Beals.” Proceedings of the Royal Society of Canada, 4th ser., 17: 57–62. B 105 106 B Becquerel, Alexandre-Edmond Becquerel, Alexandre-Edmond Born Died Paris, France, 24 March 1820 Paris, France, 11 May 1891 Edmond Becquerel was both son and father of famous French physicists. Edmond photographed the solar spectrum into the ultraviolet. He is better known for the discovery of the photoelectric effect, later explained by Albert Einstein. Selected Reference Zworykin, V. K. and E. G. Ramberg (1949). Photoelectricity and Its Application. New York: J. Wiley. Bečvář, Antonín Born Died Stará Boleslav, Bohemia, (Czech Republic), 10 June 1901 Brandýs nad Labem, (Czech Republic), 10 January 1965 Though Antonín Bečvář suffered all through his life from a skeletal irregularity, he made important contributions to astronomy through both his observational programs and the very detailed atlases and catalogs that he developed to support those programs. Bečvář began systematic observations of the night sky from a modest observatory he built in 1927 in his family’s garden. Although he started his studies at Charles University in Prague, those studies were interrupted, and he did not graduate until 1934. He received a Ph.D. degree in meteorology from the Institute of Meteorology where he also found his first employment. Bečvář’s personal illness led him to Slovakia’s High Tatras Mountains, where he would later spend most of his astronomical career. Bečvář became fascinated with the weather and climate of the Tatras, especially with the many different kinds of clouds that formed in and around the mountains. He would later become an authority on clouds, writing a well-illustrated book on the subject in 1953. In 1937, Bečvář accepted a position as climatologist at the Štrbské Pleso Spa in the Tatras. At Štrbské Pleso, Bečvář realized from the daily meteorological data he collected that the Tatras region offered optimal conditions for astronomy. Bečvář built his own telescope and used it primarily for solar observing. He also designed and constructed a battery of wide-field cameras that he used to photograph comets and meteors. In 1941, Bečvář founded the Skalnaté Pleso (Rocky Lake) Observatory, serving as its first director from 1943 to 1950. At an altitude of 1,783 m, it was one of the highest in Europe. Skalnaté Pleso Observatory’s inaccessibility saved it from destruction during World War II. In January 1945, Bečvář’s extended negotiations saved the telescopes and other astronomical equipment from removal by German forces. Later the same month, retreating Fascist troops tried to ascend the Tatras mountain peak with the intent of blowing up the observatory, but were thwarted by workers who operated the funicular that provided the only transport to the top. Instead, they only blew up the bottom station of the funicular. Despite frequently fierce winds, observers at Skalnaté Pleso enjoyed an excellent climate for astronomical research. In 1946, Skalnaté Pleso observers recorded meteors on 27 consecutive cloudless nights and were able to get accurate sunspot counts for 250 days in a row. Bečvář equipped the observatory with reflecting telescopes of 24-cm and 60-cm apertures. Under his leadership, Skalnaté Pleso became known for its solar astronomy, discoveries of comets, and photography of meteors using an improved version of the wide-field cameras, first used by Bečvář at Štrbské Pleso. Bečvář became an expert observer of meteors, especially the Ursid shower, and of comets, discovering comets C/1942 C1 (Whipple– Bernasconi–Kulin) and C/1947 F2 (Bečvář). Sixteen other comets were discovered at Skalnaté Pleso in the first two decades of the observatory’s existence – an amazing achievement in the decades before Charge-Coupled Device [CCD] detectors became available. Today, Bečvář is best known for his beautiful and informationpacked celestial atlases, the creation of which was motivated by Skalnaté Pleso’s searches for comets. Bečvář realized that no prior star atlas had adequately plotted nonstellar objects. In 1948, Bečvář completed his Atlas Coeli (1950), charting 35,000 objects at a scale of 1° = 0.75 cm. The Atlas Coeli (commonly referred to by English speaking observers as the Skalnaté Pleso Atlas) includes stars to the visual magnitude limit of 7.75; visual double stars and spectroscopic binary stars; novae and supernovae; Milky Way isophotes; and many globular and open star clusters, diffuse and dark nebulae, and galaxies. This atlas was notable as the first to include the many sources of extraterrestrial radio waves discovered after World War II. Bečvář used the General Catalogue of 33,342 Stars (1937) by Benjamin Boss as the basis for the stellar data in Atlas Coeli, supplemented by data from Harvard’s Henry Draper Catalogue (1918–1924) for the fainter stars. In 1950, Bečvář published his own comprehensive catalog of 12,000 selected objects that appeared in Atlas Coeli. From 1958 to 1964, he produced three large-scale (1° = 20 cm) spectroscopic atlases covering the declination zones +90° to +30°, +30° to −30°, and −30° to −90°. Titled Atlas Borealis, Atlas Eclipticalis, and Atlas Australis respectively, these charts depicted stars to a limiting magnitude of about 9.0 with six different colors to reflect their spectral types. The Yale Zone Catalogues provided the stellar data for these three atlases. In 1951, Bečvář was suddenly released from his position as director. He returned to his family home in Brandýs nad Labem and continued his meteorological and astronomical studies. However, most of his effort was devoted to improving editions of his atlases and catalog. He never married; the last years of his life were spent with his sister in their family house. Bečvář was a devoted photographer and a sensitive piano player. For his contributions to celestial cartography, Bečvář was honored by having a crater on the Moon’s farside and asteroid (4567) Bečvář named for him. Peter Wlasuk and Martin Solc Selected References Kopal, Zdenĕk (1948). “A New Atlas of the Heavens.” Sky & Telescope 8, no. 1: 13–16. Kovář Š. I. (2001). “Antonin Bečvář – An Astronomer Who Liked Clouds” (in Czech). Brandýs nad Labem, Czech.: Dr. Novak Publications. Kresak, L. (1961). “Dr. A. Bečvář is Sixty” (in Slovak). Říše hvězd (The realm of stars) 42: 11–113. Beer, Wilhelm Bede Born Died England, circa 673 735 Bede’s main and best-known work in astronomy concerns the problem regarding the calendar and his construction of a table for determining Easter. Bede was born in or about 673 in the coastal region of the northeast of England lying between the estuaries of the rivers Tyne and Wear (possibly in Jarrow), which was in the Anglo–Saxon Kingdom of Northumberland. At the age of seven, he was admitted to the newly built abbey of Wearmouth nearby and, soon after, transferred to the even newer abbey at Jarrow, these twin monasteries having been founded by Bishop Benedict. (Saint Paul’s Church in Jarrow, where Bede spent most of his life, was, unusually for the time, built from stone and still stands complete, as do the remains of the monastery.) He was made deacon at the age of 19 and a priest when 30, and was also choirmaster in the monastery. Bede probably never travelled outside this region during his entire life. Bede was a man of extraordinary learning and, although much of his literary output was religious, he contributed significantly to astronomy and also to history. Although he is best known for his Historia Ecclesiastica, written in 725 (a detailed history of Britain and her church, much quoted by Anglo–Saxon historians), he also wrote three other books that are particularly important for science and astronomy. These are De Natura Rerum (701), Liber de Temporibus (703), and De Temporum Ratione (725), of which the last is the most significant, being an updated and expanded version of Liber de Temporibus. Bede made full use of the excellent library that Benedict had accumulated during his European travels and set up in Jarrow. He was also much influenced by, and drew heavily upon the works of, Augustine, Pliny, and Isidore. The date-of-Easter problem had attracted attention for many centuries, but was confused by a multiplicity of different calculational techniques, varying equinox dates, religious ideology, and by its link with the Jewish Passover. Since the Jewish calendar (and many others) was lunar, and since Passover and Easter are closely linked, the main idea was to unify the solar year with the lunar month and to try and find a period of time that was, as nearly as possible, equal to a whole number of years, and at the same time, equal to a whole number of lunar months. Many systems were tried, including the 8-year (99 months) “octaeteris” cycle and the 84-year (1,039 months) cycle. But the most accurate cycle came from an Athenian of the 5th century BCE, Meton; it consisted of a 19-year (235 months) cycle. Bede, developing an earlier idea, chose a period of 532 years. This is 28 successive cycles of the 19year cycle, Bede recognizing that, since there is a leap year every 4 years, and 7 days in the week, and since 4, 7, and 19 are coprime, a cycle of length equal to the product of 4, 7, and 19 (equals 532) years would be the shortest period based on the 19-year cycle that would “repeat” itself exactly. In De Temporum Ratione, Bede drew up a table from 532 until 1063 that, among other things, gave the Easter (full) Moon and Easter Sunday for each of these 532 years. (In the Historia Ecclesiastica, Bede gives an interesting discussion of the dispute between the Roman and Celtic Churches in Britain and Ireland regarding the date of Easter, which was settled at the Synod of Whitby in 664 with victory to the Roman Church.) Bede taught extensively at Jarrow, and it is encouraging to note that he distanced himself completely from astrology. From his teachings and writings, he had a clear concept of the relationship between latitude and hours of daylight, and explained how this arose from the inclination of the “orbit” of the Sun (around the Earth) to the celestial equator. Bede also experimented with sundials and shadows, described both solar and lunar eclipses and even postulated on the structure of stars. He gave a careful discussion of the phases of the Moon and of the relationship between the Moon and tides (the latter being probably the best until Isaac Newton’s work nearly a thousand years later). Bede also showed that the vernal equinox was not on 25 March, as taken by the Julian calendar, and is credited with the introduction of the “AD” dating terminology, following a suggestion by Dionysius Exiguus. Graham Hall Selected References Bede (1943). Bedae opera de temporibus, edited by Charles W. Jones. Cambridge, Massachusetts: Mediaeval Academy of America. (Contains much information on the development of the calendar, together with the Latin text of several of Bede’s works.) Hunter Blair, Peter (1970). The World of Bede. London: Secker and Warburg. Stevens, Wesley M. (1995). “Bede’s Scientific Achievement.” In Cycles of Time and Scientific Learning in Medieval Europe. Aldershot: Variorum. (For a modern view of Bede’s contribution to science.) Wallis, Faith (1999). The Reckoning of Time. Liverpool: Liverpool University Press. (For a translation of and commentary on De Temporum Ratione.) Ward, Benedicta (1998). The Venerable Bede. London: Geoffrey Chapman. Beer, Wilhelm Born Died Berlin, (Germany), 4 January 1797 Berlin, (Germany), 27 March 1850 Wilhelm Beer, a banker and amateur astronomer, is noted mainly for his contributions to the mapping of Mars and the Moon. Beer was the head of a family banking firm in Berlin, and half-brother of the composer Giacomo Meyerbeer. Alexander von Humboldt introduced Wilhelm Beer to the astronomer Johann von Mädler, who became his friend and mentor. Beer established a small observatory with a 12-ft. dome at his villa in the Tiergarten of Berlin, where he installed a 3.75-in. Fraunhofer refracting telescope that he had purchased from another amateur astronomer, Johann W. Pastorff. With the telescope, Beer and Mädler made an excellent series of observations of Mars at its opposition of 1830 that led to the first map of its surface, and laid the foundation for modern study of the planet. The names of Beer and Mädler are inseparably linked as joint authors of the epoch-making Mappa Selenographica (1834–1836), a chart in four sections of the visible hemisphere of the Moon begun in 1830, and of its accompanying book Der Mond (1837). Though joint B 107 108 B Behaim, Martin authorship is specified, it is known that most of the actual observation and mapping of the lunar surface was done by Mädler. In turn, Mädler related his system of 105 micrometrically measured reference points to the previous measurements of Wilhelm Lohrmann. Beer was the patron who provided Mädler with facilities to pursue his interest. Beer and Mädler also produced a book on the Solar System that contains their observations of Mars. After Mädler’s departure to take charge of the Czar’s observatory at Dorpat in 1840, Beer did no further astronomical work of significance. Richard Baum Selected References Beer, Wilhelm and Johann Heinrich von Mädler (1830). Physikalische Beobachtungen des Mars in der Erdnähe. ——— (1837). Der Mond nach seinen kosmischen und individuellen Verhältnissen, oder, Allgemeine vergleichende Selenographie. Simon Schropp & Comp. Berlin. ——— (1841). Beiträge zur physischen Kenntniss der himmlischen Körper im Sonnensysteme. Weimar. Kopal, Zdeněk (1970). “Beer, Wilhelm.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 1, pp. 568–569. New York: Charles Scribner’s Sons. Behaim, Martin Born Died Nuremberg, (Bavaria, Germany), 6 October 1459 Lisbon, Portugal, 29 July 1507 Martin Behaim originated the oldest extant globe of the Earth (1492). Son of Martin Behaim the Elder and Agnes Schopper, he was the offspring of an influential noble family that was involved in long-distance trade in the city republic of Nuremberg. After the death of his father in 1474, Martin’s uncle Leonhard sent him at the age of 15 to Flanders (Mecheln, Antwerp) for professional training as a textile merchant. After 1484, Behaim lived in Portugal; the reasons that led him to this foreign country are unknown but probably related to the spice business. Quickly playing an important role as a counselor at the court of King John (Joao) II, he certainly got in touch with prominent cartographers and navigators. In fact, there has been much speculation about Behaim’s life in Portugal, and many legends arose for which there is no evidence from archival sources. It can no longer be claimed that he taught celestial navigation to the Portuguese, because the scientific elements that made celestial navigation possible were already present on the Iberian Peninsula before his arrival. But he may have acted as an importer of scientific instruments, the finest of which were produced at that time in his native town of Nuremberg. In 1490, Behaim visited the city of his fathers to settle a will case, and he stayed in Nuremberg for 3 years. He managed to convince leading members of the city council to finance the manufacturing of the famous globe of the Earth under his direction. The decisive reasons still are unknown, but many inscriptions on the globe indicate an economic motivation. Whereas the final financial account of 1494 indicates clearly which craftsmen were involved in its making, the Behaim globe must be regarded as a joint achievement of the Nuremberg humanist circle. It is an early masterpiece of many kinds of scientific and technological achievements, establishing the intellectual and economic leadership of Nuremberg in late medieval Germany. Behaim died in the hospice of Saint Bartholomew while on one of his trips to Lisbon. In fact, nothing can be said about whether Behaim contributed to astronomy at all. Certainly, he was not a student of Johann Müller (Regiomontanus), as has often been claimed. Regiomontanus’s house was next to the Behaim house at the central market place in Nuremberg, However, when Regiomontanus lived there, Martin Behaim was a boy of 12–15 years, and there is no indication that Regiomontanus gave lessons to Behaim. Furthermore, one can no longer defend the thesis that celestial navigation was possible only because of Behaim’s teaching the Portugese how to use the cross staff (Jacob’s staff or ballestilla) and the astronomical tables of Regiomontanus. The cross staff, invented by Levi ben Gerson (Gersonides), already was well-known on the Iberian Peninsula. Moreover, the declination of the Sun given in the Tabula Directionum of Regiomontanus is different from that found in the Regimento do astrolabio … Tractado da spera do mundo prepared by the Portuguese Council of Mathematicians for use by navigators. The same holds for the use of the astrolabe on ships. Behaim’s great merit lies in his origination of the oldest extant terrestrial globe – although probably not the first at al – which must be regarded as a complex cosmographical model. Nevertheless, his life and his globe give clear evidence that he was not a great navigator, mathematician, and astronomer, as many publications still celebrate him. The globe is luxuriously decorated. It contains more than 2,000 place names, 100 pictorial illustrations (plus 48 banners and 15 coats of arms), and more than 50 long legends. Many of them deal with peculiarities and fabulous monsters of foreign countries, their inhabitants, plants and animals, and (in particular) with overseas trade, explorations, and famous travels like that of Marco Polo. Not the quality of the information, but its quantity and selection make the globe an important primary source for historical research. Obviously, Behaim had no main source for his Erdapfel. He gathered the geographical information from different sources, probably from a nowadays missing Portuguese sea chart, travel narratives like that of Marco Polo, Mandeville, and the Portuguese explorer Diego Gomes, and of course traditional cosmographical writings like Ptolemy’s Geography. For that reason, the Behaim Globe is one of the very few existing cartographical works where different “schools” of mapmaking are bound together. Guenther Görz Alternate name Martin of Bohemia Selected References Berninger, O. (1959). “Martin Behaim – zur 500. Wiederkehr seines Geburtstages am 6. Oktober 1959.” Mitteilungen der Fränkischen Geographischen Gesellschaft 6: 141–151. Bott, Gerhard and Johannes, Willers (eds.) (1992). Focus Behaim Globus. 2 Vols. Nuremberg: Germanisches Nationalmuseum. Ben Solomon: Judah ben Solomon ha-Kohen Bräunlein, Peter J. (1992). Martin Behaim: Legende und Wirklichkeit eines berühmten Nürnbergers. Bamberg: Bayerische Verlagsanstalt. Crone, G. R. (1961). “Martin Behaim, Navigator and Cosmographer; Figment of Imagination or Historical Personage?” In Congresso internacional de historia dos descobrimentos, Lisboa 1960. Lisbon. Hennig, Richard (1956). Terrae Incognitae: Eine Zusammenstellung und kritische Bewertung der wichtigsten vorcolumbischen Entdeckungsreisen an Hand der darüber vorliegenden Originalberichte. Vol. 4. Leiden: Brill. Muris, O. (1943). “Der ‘Erdapfel’ des Martin Behaim und Der Behaim-Globus zu Nürnberg. Eine Faksimile-Wiedergabe in 92 Einzelbildern.” IberoAmerikanisches Archiv 17, no. 1–2: 1–64. Ravenstein, E. G. (1908). Martin Behaim: His Life and His Globe. London: George Philip and Son. Willers, Johannes (1992). “Leben und Werk des Martin Behaim.” In Focus Behaim Globus. Nuremberg: Germanisches Nationalmuseum, pp. 173–188. Belopolsky, Aristarkh Apollonovich Born Died Moscow, Russia, 13 July 1854 Pulkovo, (Russia), 16 May 1934 Aristarkh Belopolsky was a pioneer in the application of spectroscopy, and especially radial velocity measurements, to the study of the stars. Belopolsky’s father was a well-educated teacher whose ancestors had immigrated to Russia from the Serbian town of Belopolje, from which the family’s name was derived. After an excellent secondary education, Belopolsky studied at Moscow University and graduated in 1877. During his studies, he came under the tutelage of Fedor Bredikhin, director of the Moscow Observatory. On account of Belopolsky’s mental vigor and technical skills, Bredikhin appointed him as an assistant at the observatory and encouraged him to participate in its solar observations. In 1886, Belopolsky completed his Magister’s thesis on the motions of sunspots. He then obtained several photographs of the corona during the total solar eclipse of 19 August 1887 near Pogoste (approximately 100 miles northeast of Moscow). Belopolsky’s talents eventually attracted the attention of Otto Wilhelm Struve, who invited him to join the staff of the Pulkovo Observatory in 1888. Three years later, Bredikhin succeeded Struve as Pulkovo’s director and placed his former student in charge of all astrophysical equipment. Belopolsky was directed to purchase a standard Carte du Ciel astrograph and several stellar spectrographs. In 1891, he journeyed to Potsdam, where, along with American astronomer Edwin Frost, he learned the techniques of radial velocity measurements from spectroscopist Hermann Vogel. Armed with new spectroscopic equipment and fresh ideas, Belopolsky set to work on the new field of observational astrophysics. Independently of James Keeler, he demonstrated the differential rotation of Saturn’s rings (1895). In 1894, he discovered periodic changes in the radial velocity of δ Cephei, and noted the phase shift between its brightness variations and the Doppler oscillations. Continued studies of this star netted Belopolsky his Ph.D. in 1896, from which the first hypotheses of stellar radial pulsations originated. Belopolsky likewise reported analogous behavior for η Aquilae (1896) and ζ Geminorum (1899). In 1906, he announced the long-period oscillation in the radial velocities of Algol (β Persei), thereby confirming the eclipsing binary hypothesis of John Goodricke and Edward Pigott. Equally important were Belopolsky’s contributions to the study of novae. Beginning with the appearance of Nova Aurigae (1892) through Nova Aquilae (1918), he observed each one, often catching them in their earliest pure-absorption stage. It was perhaps consideration of the expansion of novae that led him to think of expansion as an important phenomenon in general, an attitude that appears to have influenced Victor Ambartsumian. Belopolsky maintained an interest in solar studies throughout the remainder of his career, measuring the effective temperature of sunspots, timing the Sun’s rotation from the motion of faculae, and securing a large solar spectrograph of the Littrow type from Sir Howard Grubb. In 1902, Belopolsky was appointed to the editorial board of the Astrophysical Journal, and the following year was elected a member of the Russian Academy of Sciences. He became an associate member of the Royal Astronomical Society in 1910. From 1917 to 1919, he served as director of the Pulkovo Observatory, but then resigned his position due to the impact of administrative duties on his research activities. Of Belopolsky, his colleague Boris Gerasimovich wrote: “His most striking qualities were modesty, moral courage, clear vision and enormous devotion to science and industry. In the terrible years of the civil war, this old man, cold and hungry, continued his work as usual – an example of true heroism.” Belopolsky was named honorary director of the Pulkovo Observatory in 1931 and continued his research on stellar spectra until his death. Thomas J. Bogdan Selected References Gerasimovič, B. P. (1934). “Aristarch A. Belopolsky.” Astrophysical Journal 80: 81–85. ——— (1934). “Aristarch Belopolsky.” Astronomische Nachrichten 252: 203–204. H. F. N. (1935). “Aristarch Belopolsky.” Monthly Notices of the Royal Astronomical Society 95: 338–339. Kulikovsky, P. G. (1970). “Belopolsky, Aristarkh Apollonovich.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 1, pp. 597–599. New York: Charles Scribner’s Sons. Struve, Otto (1935). “A. A. Belopolsky.” Popular Astronomy 43: 16–17. Ben Solomon: Judah ben Solomon ha-Kohen Born Died Toledo, (Spain), circa 1215 probably (Italy), after 1274 Judah ben Solomon was born and educated in Toledo, where the Jewish community, despite a century and a half of Christian rule, maintained a tradition of Arabic learning in science and philosophy. At the age of 18, he entered into correspondence with some savants B 109 110 B Bennot, Maude Verona at the court of Frederick II. Apparently as a result of these exchanges, Judah immigrated to Italy. There he translated into Hebrew his major work, an encyclopedia called Midrash ha-ḥokhmah (The study of wisdom), which he had earlier compiled in Arabic. The astronomical section of Midrash ha-ḥokhmah is a combination of the theories of Ptolemy and Biṭrūjī. For matters of timekeeping, mathematical geography, and solar and lunar theory, Judah relies upon Ptolemy. However, when moving on to planetary theory, he abandons Ptolemy in favor of Biṭrūjī. Judah preferred Biṭrūjī for theological reasons. In the latter’s system, in which the motions of the planetary orbs were all powered by a mechanical link to the swiftly moving outermost orb, the connection between God and the Universe was patently clear: God set in motion the outermost orb, with the daily revolution, and this energized the entire cosmos. Biṭrūjī was not the only Andalusian astronomer whose work influenced Midrash ha-ḥokhmah. Jābir ibn Aflaḥ, Ṣā�id alAndalusī, and an otherwise unknown Jewish astronomer by the name of David ben Naḥmias are also cited. Judah knew as well the discussion of the “moon illusion” in Ibn al-Haytham’s commentary to the Almagest. To the extent that there are original investigations in Midrash ha-ḥokhmah, they are motivated by theology or mysticism. Thus, for example, Judah noticed that Ptolemy’s value for the ratio in volume between the Sun and the Moon, 6644.5, is an approximation (Almagest V.16; cf. ibid., V.14). The exact value, which Judah asserts to be 6,300, is obtained not by observation, but by an operation upon the alphanumerical values of the two letters of the Hebrew alphabet that are said to stand for the Sun and the Moon. Y. Tzvi Langermann Selected Reference Langermann, Y. Tzvi (2000). “Some Remarks on Judah ben Solomon ha-Cohen and His Encyclopedia, Midrash ha-Hokhmah.” In The Medieval Hebrew Encyclopedias of Science and Philosophy, edited by Steven Harvey, pp. 371–389. Dordrecht: Kluwer Academic Publishers. Bennot, Maude Verona Born Died Thornton, Illinois, USA, 5 June 1892 Rochester, Minnesota, USA, 9 September 1982 Planetarian Maude Bennot, daughter of Charles and Amelia (née Dickel) Bennot, graduated as valedictorian of her class from Thornton Township High School in Harvey, Illinois. She was accepted into Northwestern University in 1912, but did not complete her bachelor’s degree until 1919, with intervening stints of employment at the National Research Council, the War Labor Board, and coursework taken at George Washington University. Between 1921 and 1924, Bennot served as an editor at the Mayo Clinic, Rochester, Minnesota, and then returned to Northwestern University to pursue graduate studies in astronomy. Working with Dearborn Observatory director Philip Fox, in 1927 Bennot completed requirements for a master’s degree in astronomy, writing a thesis on the proper motions of forty stars. Her results were published in the Astronomical Journal. Fox was chosen to direct Chicago’s Adler Planetarium in 1929. He quickly secured Bennot’s appointment as assistant director. Together they designed the planetarium’s schedule of monthly programs as an introductory course in astronomy. Bennot traveled to Europe in 1933 to examine Zeiss planetaria operations at Jena, Berlin, Hamburg, Stockholm, Milan, and Rome. When Fox left the Adler Planetarium in 1937 to direct Chicago’s Museum of Science and Industry, Bennot was appointed the Adler Planetarium’s acting director, a position she held until 1945. She thus became the first woman to head a planetarium facility in the United States, and probably the world. Since no additional staff was provided, Bennot’s responsibilities were in fact doubled to include both the director’s and assistant director’s duties. Continued economic depression and the coming of war brought cuts in budget, personnel, and attendance, leaving Bennot as the one-person planetarium staff by 1944. Yet her wartime workload was actually increased as a consequence of teaching celestial navigation to naval midshipmen. But in spite of thrifty management policies, popularity with the public, and fifteen years of devoted service, Bennot was suddenly removed from her position in 1945, following the death of her mentor, Fox, from a cerebral thrombosis the previous year. The decision to replace Bennot with a man – Wagner Schlesinger, the son of astronomer Frank Schlesinger, was appointed director of the Adler Planetarium – was engineered by Robert J. Dunham, Chicago Park District board president, and undertaken with full approval of planetarium donor Max Adler. Under Dunham’s plan, Bennot would receive only three months salary in 1945. Afterwards, the assistant director’s position would be eliminated, preventing Bennot from reacquiring even her original means of employment. Bennot charged that this action constituted a subterfuge and deliberate evasion of the civil service laws. She was represented by Marvin J. Bas, an attorney for the civil service employee’s association, who termed the board’s failure to offer her a full year’s salary a willful circumvention of the merit system. Bas, however, was unable to reverse the board’s predetermined objective. Bennot left the field of astronomy education forever. Her subsequent career remains unknown. During the 1930s, Bennot was elected treasurer and second vice president of Sigma Delta Epsilon, the national graduate women’s scientific association. She served faithfully as secretary of the Chicago Astronomical Society from 1938 to 1944. In 1943, Bennot was appointed by the Midwest Committee of the Polish Institute of Arts and Sciences to serve as commentator at the observance of the 400th anniversary of the publication of Copernicus’s De Revolutionibus. She was, by any measure, a woman of substantial ability who deserved better treatment than she received from Chicago Park District authorities after Philip Fox was no longer able to shield her from their prejudices. Ironically, in 1932 Bennot observed a total solar eclipse from an aircraft, which sparked her interest in aviation. She later admitted, “Amelia Earhart’s was the only job I might have preferred to my own.” Had she then known the outcome of her career in astronomy, she might well have decided to pursue that alternate goal more seriously. Jordan D. Marché, II Bergstrand, Östen Selected References Anon. (1941). “Bennot, Maude.” In Encyclopedia of American Biography, edited by Winfield Scott Downs, pp. 24–26. New. ser. New York: American Historical Company. Bennot, Maude (1926). “Proper-Motions of Forty Stars.” Astronomical Journal 36: 177–181. Hall, Kay (16 January 1938). “Woman Plays Lead in Celestial Show.” New York Times, sec. 6, p. 5. Harris, Sydney J. (24 March 1944). “Here is Chicago.” Chicago Daily News, p. 16. Marché II, Jordan D. (2002). “Gender and the American Planetarium Community.” Planetarian 31, no. 2: 4–7, 36. ——— (2005). Theaters of Time and Space: American Planetaria, 1930–1970. New Brunswick, New Jersey: Rutgers University Press. Benzenberg, Johann Friedrich Born Died Schöller near Elberfeld, (Nordrhein-Westfalen, Germany), 5 May 1777 Bilk near Düsseldorf, (Germany), 7 June 1846 Johann Benzenberg, the codiscoverer of the upper-atmospheric (nontropospheric) location of meteors, later funded a private observatory at Bilk, which became an important center of minorplanet research. He was the son of Heinrich Benzenberg, a Protestant theologian (1744–1809), and Johanna Elisabeth (née Fues). In 1807, he married Charlotte Platzhoff (1789–1809) of Elberfeld. After studying theology (at Herborn and Marburg), Benzenberg went to Göttingen, where he developed a strong interest in science by attending the lectures of Georg Christoph Lichtenberg and Abraham Gotthelf Kästner. Following Lichtenberg’s death, Benzenberg received his Ph.D. from the University of Duisburg in 1800. In 1805, he became a professor of mathematics at the Lyzeum (women’s college) of Düsseldorf and the director of surveying for the Duchy of Berg. After immigrating to Switzerland during the Napoleonic occupation of his country, Benzenberg returned to concentrate on a political career, with particular interests in constitutional law and economics. His proficiency in experimental physics led to engineering work, including a strong involvement in local railway projects. In 1844, Benzenberg built a private observatory at Bilk, which he donated to the city of Düsseldorf with a grant to pay for the salary of a resident astronomer. This position was subsequently filled by Johann Schmidt, Franz Brünnow, and Karl Luther, under whose directorship Bilk became one of the more important centers of minor-planet observations in Europe. Benzenberg’s practical skills made him an ideal collaborator with Heinrich Brandes in their observing campaign to determine the atmospheric altitude of meteors at Göttingen. Later, Benzenberg successfully demonstrated the Earth’s rotation by conducting “falling body” experiments originally suggested by Isaac Newton. The first was conducted in 1802 from a church staple at Hamburg; this was repeated in 1804 within a mine shaft in the countryside. His textbooks on applied geometry and surveying were intended to establish solid procedures for the systematic mapping tasks on the public agenda at that time. Benzenberg’s sometimes original and imaginative approach to scientific matters resulted in his proposal to use simultaneous meteor observations for the determination of geographical longitude differences (an idea that had been put forward for fireballs by Edmond Halley). It also caused him to retain throughout his life the early notion of meteors being ejecta from lunar volcanoes, despite the strong contrary evidence that accumulated in the meantime. Wolfgang Kokott Selected References Benzenberg, J. (1802). “De determinatione longitudinis per stellas transvolantes” (On the determination of longitude by shooting stars). Ph.D. thesis, Hamburg. ——— (1804). Versuche über das Gesetz des Falls, über den Widerstand der Luft und über die Umdrehung der Erde. Dortmund. (The falling body experiments.) ——— (1839). Die Sternschnuppen. Hamburg. (His up-to-date monograph, largely chronological, of the first four decades of meteor research. It was evidently intended as an homage to his deceased associate of 1798, H. W. Brandes.) Benzenberg, J. and H. Brandes (1800). Versuche die Entfernung, die Geschwindigkeit und die Bahnen der Sternschnuppen zu bestimmen. Hamburg. (A tract documenting meteor observations at Göttingen.) Bruhns (1875). “Benzenberg: Johann Friedrich.” In Allgemeine Deutsche Biographie. Vol. 2, pp. 348–349. Leipzig: Dunker and Humblot. Poggendorff, J. C. (1863). “Benzenberg.” In Biographisch-literarisches Handwörtenbuch. Vol. 1, col. 145. Leipzig: J. A. Barth. Bergstrand, Östen Born Died Sweden, 1 September 1873 Sweden, 27 September 1948 Östen Bergstrand’s greatest contribution to astronomy was the fostering of the ideals of precision astrometry and astrophysics in Sweden, which he handed on to a younger generation of better-known astronomers. He was the son of Carl Erik Bergstrand and Jenny Rosalie Wallin, and married, first, Anna Elfrida Ericsson (1901) and, second, Ingrid Svensson (1942). Bergstrand received his Ph.D. in astronomy at Uppsala University in 1899, working under Nils Dunér, who modernized the instrumentation at Uppsala, obtaining a double refractor useful for both classical astronomy (astrometry) and astrophysics. Bergstrand worked in both of these fields. Bergstrand was appointed assistant professor (docent) at Uppsala Observatory in 1901 and professor from 1911 to his retirement in 1938. He was elected to the Royal Swedish Academy of Sciences in 1924 and as a vice president of the International Astronomical Union in 1935. He studied the theoretical aspects of photographic determination of stellar parallaxes, as well as measuring a number of parallaxes himself. Bergstrand also participated in the international campaign to measure the positions of the minor planet (433) Eros, with the aim of improving the precision in the value of the solar parallax. Together with astronomers such as Ejnar Hertzsprung, Bergstrand developed the method of effective wavelengths for B 111 112 B Berman, Louis determining the temperatures of stars. Very low resolution spectral plates are obtained by placing a coarse grating in front of an astrograph. The distance on the plate between the zeroth and almost point-like first-order spectra is proportional to the wavelength where most of the star's energy falls, and so to its temperature. The observation of the color of a star could thus be reduced to the measurement of a distance between two points on a photographic plate. The method was used for survey-type work to determine the colors of large numbers of stars, using astrographs with wide fields of view. It was an outcome of the practice in the local scientific milieu cultured by Dunér, which combined an ethos of precise measurement with modern astrophysical observation. Bergstrand continued to pursue the method and tried, after the World War I, to organize an international scheme of standardization to calibrate it. He also worked in photographic photometry of stars and the solar corona. Among Bergstrand’s astrometric contributions was a determination of the ellipticity of the mass figure of Uranus, from the advance of the perihelion of one of its satellites. Perhaps of greater significance was the fact that Bergstrand fostered a group of young astronomers who later would become very successful in transforming Swedish astronomy. Both Knut Lundmark and Bertil Lindblad studied at Uppsala University under Bergstrand, as did Carl Schalén and Yngve Öhman. Especially Lindblad continued and developed Bergstrand’s work in stellar spectral photometry, a field that became a corner stone of the observational programs that dominated Swedish astronomy for a major part of the 20th century: the mapping of the structure of the Milky Way with an array of statistical, photometrical, and spectroscopical methods. Bergstrand’s papers can be found at the Uppsala University library. Gustav Holmberg Selected References Holmberg, Gustav (1999). Reaching for the Stars: Studies in the History of Swedish Stellar and Nebular Astronomy, 1860–1940. Lund: Lund University. Lindblad, Bertil (1965). “Östen Bergstrand: Minnesteckning.” Levnadsteckningar över Kungl. Svenska Vetenskapsakademiens ledamöter 9. Stockholm. Berman, Louis Born Died London, England, 21 March 1903 San Francisco, California, USA, 31 January 1997 American astronomer and educator Louis Berman carried out the first detailed analysis of the spectrum of a star, which showed that it demonstrably had a different chemical composition from that of the Sun. That star, R Coronae Borealis, was very rich in carbon. Louis Berman was the son of George and Jennie Berman, immigrants from Lithuania to England, who arrived in Saint Paul, Minnesota, when he was 3 years old. Berman entered the University of Minnesota where he earned his AB in 1925 and AM in 1927, and was also assistant at the observatory (1925–1927). He was then awarded a Lick Observatory Fellowship at the University of California where Berman earned his Ph.D. in astrophysics in 1929. By then he had already published six papers, five of them dealing with double stars and one on the orbit and ephemeris of comet C/1925 V1 Wilk-Peltier. From 1929 through 1968 Berman taught astronomy and mathematics successively at Carleton College, San Mateo Junior College, and the City College of San Francisco. From 1942 to 1945 he served in the United States Naval Reserve where he earned the rank of lieutenant commander. Berman returned to the City College of San Francisco in 1946, officially retiring in 1968, but continuing as a lecturer in astronomy at the University of San Francisco until 1979 and always taking his classes on field trips to Lick Observatory. While his earlier publications, 21 articles through 1941, dealt mainly with original research on double stars, planetary nebulae, stellar spectra, and novae, after World War II Berman concentrated on teaching and was particularly concerned with introducing nonscience-minded students to the essentials of astronomy. From 1942 through 1968 he is cited in astronomical bibliographies as having published only one paper, a book review in 1957 on Richard van der Riet Woolley’s A Key to the Stars. Three subsequent short articles may still be of interest to laymen and teachers of introductory astronomy. His 1969 The 80th Anniversary of the Astronomical Society of the Pacific is a history of a society whose membership is steadily increasing and whose publications have continued to be of benefit to both professional and amateur astronomers. The Wayward Heavens in Literature (1970) reveals Berman’s extensive knowledge of English literature. This paper should be of lasting interest to educators in both astronomy and literature. He cites more than 20 poets or novelists who have erroneously described celestial objects or events. The “sinners” include Samuel Coleridge, Charles Dickens, Bernoulli, Daniel Henry Longfellow, Edgar Poe, Pearl Buck, and Zane Gray. There is praise for just one poet, Alfred, Lord Tennyson, who refrained from blundering mistakes because he consulted the Astronomer Royal before committing himself to the use of anything astronomical. At a meeting of the American Astronomical Society in San Francisco in 1980, Berman gave an oral presentation On Teaching a Course: Life on Other Worlds, of which a mere outline of topics covered has been published. As a strong advocate of teaching astronomy on a nontechnical basis for nonscience majors, Berman published his textbook, Exploring the Cosmos, in 1973. Although highly appreciated, it was written at a time of rapid advancements in astronomy and consequently was soon dated. With the collaboration of John C. Evans, four additional editions were published, in 1977, 1979, 1983, and 1986. Most of the updating was done by Evans. This treatise contains questions not only from scientists but also from poets. Berman was a member of the American Association for the Advancement of Science, the American Astronomical Society, and the Astronomical Society of the Pacific. Louis Berman married Esther Goldberg of Saint Paul in 1934. They had one daughter, Susan B. Zimmerman, who became a member of the faculty of City College of San Francisco. Dorrit Hoffleit Selected References Anon. (1992). “Berman, Louis.” In American Men and Women of Science, 1992–93. 18th ed. Vol. 1, p. 500. New Providence, New Jersey: R. R. Bowker. Berman, Louis (1969). “The 80th Anniversary of The Astronomical Society of the Pacific.” Astronomical Society of the Pacific Leaflet, no. 476. ——— (1970). “The Wayward Heavens in Literature.” Astronomical Society of the Pacific Leaflet, no. 488. ——— (1973). Exploring the Cosmos. Boston: Little, Brown and Co. ——— (1980). “On Teaching a Course: Life on Other Worlds.” Bulletin of the American Astronomical Society: 667. (Paper abstract.) Osterbrock, Donald E. (1997). “Louis Berman, 1903–1997.” Bulletin of the American Astronomical Society 29: 1468–1469. Almagest itself was widely known in Europe. He also discussed the motions of the fixed stars and entered into the arguments over precession and trepidation, reflecting the teachings of his fellow Dominican and contemporary Albert the Great. On the issue of celestial causes, Bernard defended the position of Thomas Aquinas (another Dominican contemporary) that angels move the celestial spheres by will alone, which was later condemned in 1277 by the Bishop of Paris. Some of Bernard’s questions bear upon matters that we would call astrological. Bernard spent most of his career teaching at various posts in his native southern France – he entered the Dominican Order in Provence – or in Paris, where he studied sometime between 1260 and 1265, and where he taught from about 1279 until 1287. Only two 14th-century manuscript copies of his Questiones are known, of which Pierre Duhem published some extracts in French translation. James M. Lattis Alternate name Bernardus de Trilia Selected References Duhem, Pierre (1915). Le système du monde. Vol. 3. Paris: A. Hermann. Grant, Edward (1994). Planets, Stars, and Orbs: The Medieval Cosmos, 1200–1687. Cambridge: Cambridge University Press. Thorndike, Lynn (1949). The Sphere of Sacrobosco and Its Commentators. Chicago: University of Chicago Press. Wallace, William A. O. P. (1970). “Bernard of Le Treille.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 2, pp. 20–21. New York: Charles Scribner’s Sons. Bernardus de Trilia > Bernard of Le Treille Bernard of Le Treille Born Died near Nîmes, Gard, France, circa 1240 Avignon, Vaucluse, France, 4 August 1292 Bernard of Le Treille is known as a medieval European astronomy educator and textbook author who composed an early commentary on Sacrobosco’s Sphere. A didactic text divided into lectiones (lectures), Bernard’s Questiones on the Sphere were presumably composed for use in Dominican schools and take the form of scholastic disputation. In his Questiones Bernard expounded the simplified Ptolemaic cosmology presented by Sacrobosco. Bernard’s text treated, among other topics, the fundamental Ptolemaic constructions of the epicycle and eccentric, which distinguish Ptolemy’s from other geocentric theories such as those of Eudoxus. Bernard thus belonged to one of the earliest generations of scholars to assimilate Ptolemaic astronomy and cosmology even before Ptolemy’s Bernardus Silvestris > Silvester, Bernard Bernoulli, Daniel Born Died Groningen, the Netherlands, 8 February 1700 Basel, Switzerland, 17 March 1782 Daniel Bernoulli should rank among the founders of modern mathematical physics, and made important contributions in hydrodynamics, wave physics, and mathematical biology. Daniel was the son B 113 114 B Bernoulli, Jacob [Jacques, James] of Johann Bernoulli and the nephew of Jacob Bernoulli. Though the roots of the Bernoulli family were in Basel, Switzerland, and Daniel’s father Johann would have dearly loved to teach at the university there, the chair in mathematics was held by Johann’s older brother Jakob. Thus Johann was teaching at the University of Groningen when Daniel was born. Johann’s father forced Johann to study medicine, and Johann rebelled by studying mathematics and physics with his older brother, Jakob. Now Johann forced Daniel to study philosophy and logic, and Daniel likewise rebelled by studying mathematics and physics with his older brother Nicholas. Thus, a second generation of Bernoulli brothers (Daniel and Nicholas) would pursue mathematics and physics. Bernoulli received his baccalaureate in 1715 and his master’s in 1716, then went to study medicine in Heidelberg, Strasbourg, and finally Basel in 1720. A crucial meeting occurred when he went to Venice in 1724. There he met Christian Goldbach, who was sufficiently impressed by the young Bernoulli that he offered him a position at the newly established Russian Academy of Science in Saint Petersburg; an offer was also extended to Daniel’s older brother, Nicholas. The Bernoulli brothers arrived in 1725. Unfortunately, Nicholas died from a fever the next year, and Daniel suggested that Goldbach offer an appointment to one of Daniel’s friends from the University of Basel, Leonhard Euler. Isaac Newton’s Principia was published in 1687, but the system of physics it contained was widely rejected outside England. Instead, most physicists adhered to René Descartes’s system of vortices, where particles swept endlessly about the Sun, carrying the planets along like leaves in a stream. It had undergone many modifications since the time of Descartes, but its central tenets remained. There were two main reasons why Newton’s theory was not readily accepted. The primary issue was, as Albert Einstein pointed out, that gravity required the existence of a sort of “spooky action at a distance.” The other was that Newton’s physics could predict, but not explain. For example, the planets all orbit the Sun in the same direction and in very nearly the same plane. Newton’s physics could just as easily explain planetary orbits that were not in the same direction and at varying angles of inclination. For Newton, this was not an issue: The fact that it could be otherwise but was not gave evidence for the existence of God. Rather than rely on such arguments, the Paris Academy offered as its prize question for 1732 the explanation of the fact that the planets orbited the Sun in, more or less, the same plane. The academy received no entrants worthy of the prize, so they posed the question anew in 1734, with a double prize. Johann and Daniel entered. To explain the lack of extreme inclinations among the orbits of the planets, Daniel assumed the existence of a solar atmosphere, which was densest not at the surface of the Sun, but instead around the orbit of Jupiter. Further assuming that the solar atmosphere rotated with the Sun would imply that objects moving in planes not parallel to the solar equator would face enormous resistance. (He does not explain details.) Thus only orbits that are parallel or nearly parallel to the Sun’s equator would exist. Unfortunately for Daniel, he and his father were judged equally worthy of the prize. Earlier, Johann’s jealousy had poisoned his relationship with his brother Jakob. Now the fact that his son was ranked his equal would poison the relationship between father and son. Daniel himself (probably the only personable member of the mathematical Bernoullis) tried to mend the relationship, but Johann refused to be reconciled, and banned him from the house in Basel, where he returned in 1734 to lecture in botany. Despite his early training, Bernoulli did not remain a dogmatic Cartesian for long, and was in fact one of the very first to apply the powerful techniques of Leibnizian calculus to the essentially correct axioms of Newton’s physics. In 1743, he began to lecture in physiology, but it was not until 1750 that he was finally appointed to the chair of physics, a post he retained until 1776. Jeff Suzuki Selected References Bernoulli, Daniel (1982). Die Werke von Daniel Bernoulli, edited by David Speiser. Basel: Birkhäuser. Straub, Hans (1970). “Bernoulli, Daniel.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 2, pp. 36–46. New York: Charles Scribner’s Sons. Suzuki, Jeff A. (1996). “A History of the Stability Problem in Celestial Mechanics.” Ph.D. diss., Boston University. Bernoulli, Jacob [Jacques, James] Born Died Basel, Switzerland, 27 December 1654 Basel, Switzerland, 16 August 1705 Jacob Bernoulli was a member of a family of celebrated mathematicians and physicists; he was a prominent Cartesian. His father and grandfather were spice merchants, and his mother came from a prominent family of bankers and city councilors. He was sent to the University of Basel to study philosophy and theology, taking a degree in philosophy in 1671 and in theology in 1676. Against the wishes of his parents, he also studied mathematics and astronomy, and became the first of the mathematicians among the Bernoullis. After graduation in 1676, Bernoulli first went to Geneva, then to Paris, where he studied with the followers of René Descartes under Nicolas Malebranche. Descartes had postulated a vast system of vortices, subtle particles that whirled endlessly around the Sun. This could explain the motion of the planets, and the properties of the vortex could be derived from Johannes Kepler’s three laws. However, the system of vortices could not explain comets, and in particular, how the comets could pass through the whirling vortex particles without deflection. An explanation was advanced by Bernoulli in 1680. Rather than have the comets cut through the vortices of the planets, he suggested that a comet was an object that circled a stationary point that lay outside the orbit of Saturn, a system reminiscent of the Ptolemaic system of deferents and epicycles. This was rewritten a number of times, appearing in final form in 1682. Shortly after, Bernoulli wrote Dissertatio de Gravitate Aetheris (1683), where he attempted to explain all physical phenomena using the motion of the subtle particles of the Cartesian vortices. Bernoulli eventually returned to Basel and taught mechanics at the University of Basel from 1683, and became a professor of mathematics in 1687. When Jacob’s brother Johann entered the Berossus university under parental orders to study medicine, Johann asked Jacob to teach him mathematics; the brothers became early converts to Gottfried Leibniz’s calculus. The two attempted to collaborate, but they were both headstrong, arrogant, vindictive, and convinced of the mathematical inferiority of the other, causing them to part as bitter rivals. An impartial observer would judge that Jacob was the better mathematician, and Johann the more creative. Jacob held the chair of mathematics at the University of Basel until his death in 1705. 19th century at the Stockholm Academy – one finds avatars for the extension of the observing apparatus by mathematical means, the culmination of which had to await the Fourier series (discovered by Jean Fourier and used to fit sets of data and approximate functions). And although Bernoulli’s own work in probability, recurring decimal numbers, the theory of equations, etc., did not itself break much new ground, for over a dozen years – from 1776 to 1789 – he published the Leipzig Journal for Pure and Applied Mathematics, which served as a unique and extremely important bridge between practical and theoretical mathematics. Jeff Suzuki Daniel Kolak Selected References Bernoulli, Jakob (1969). Die Werke von Jakob Bernoulli, edited by J. O. Fleckenstein. Basel: Birkhäuser. Fleckenstein, J. O. (1949). Johann und Jakob Bernoulli. Basel: Birkhäuser. Hofmann, J. E. (1970). “Bernoulli, Jakob (Jacques) I.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie Vol. 2, pp. 46–51. New York: Charles Scribner’s Sons. Selected Reference Fleckenstein, J. O. (1970). “Bernoulli, Johann (Jean) III.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 2, p. 56. New York: Charles Scribner’s Sons. Berossus Bernoulli, Johann III Born Died Basel, Switzerland, 14 December 1744 Berlin, (Germany), 10 July 1807 Johann Bernoulli III was another one of the famous line of child prodigies of the famous Swiss family of mathematicians and scientists. He was a director of the Berlin Observatory. His father, Johann Bernoulli II (brother of Nikolaus and Daniel Bernoulli), succeeded the elder Jacob Bernoulli, for whom are named the famous Bernoulli numbers (a sequence of rational numbers that occur in many branches of mathematics), to the chair of mathematics at the University of Basel. Bernoulli’s studies began in law, and at the age of 14 he became a doctor of law. He had already by then shown an extraordinary gift for encyclopedic mastery of diverse subjects well beyond the bounds of his family’s mathematical heritage. In 1763, when Bernoulli was still only 19, he was promoted to a chair at the Berlin Academy. Bernoulli authored several astronomical works full of new and previously unknown details that were not, in and of themselves, particularly important, nor have they since then been generally regarded as such – except that Bernoulli derived them using means that go well beyond the data available through direct empirical observation. Closer scrutiny in fact reveals that what Bernoulli lacked as an observer – he was of poor health and had not very good eyesight – he more than compensated for with his mathematical prowess. In retrospect it is therefore not surprising that one of the greatest rulers of the 18th century, Frederick II (Frederick the Great, king of Prussia), appointed Bernoulli to the post of director of the astronomical observatory in Berlin. Many historians, including some historians of science, have since questioned the appointment. But in Bernoulli’s work and letters – nearly 3,000 of which were discovered only toward the end of the Born Died circa 330 BCE probably after 270 BCE Berossus was the Babylonian priest of Marduk at the main temple, Esagila, in Babylon, and later moved (probably after 280 BCE) to the Greek island of Cos, a center for medical studies, where he continued his astronomical and astrological teaching. Berossus is neither known to have founded any school in the Greek world, nor is he credited with disciples or students who continued his work. Berossus’s only known literary work is a history of Babylonia written in Greek, most likely composed in Babylon around 280 BCE. His astronomical teachings, published either as a part of his history of Babylonia or as a separate work, were known in the Greek world by the title Creation. Only a few of Berossus’s theories are known: (1) the Moon is a sphere, only one half of which emits light, and the phases of the Moon are caused by its passing through the orbit of the Sun; (2) there will be a great world conflagration caused by the alignment of the planets (the then five known planets, the Moon, and the Sun) in Cancer; and (3) there will be a great flood caused by the alignment of the planets in Capricorn. His teaching about a world conflagration may have influenced the Stoics and their ideas about a world conflagration. Berossus is credited with the invention of the sundial, and was also famous in Antiquity for his prophecies based on his ability to cast horoscopes. No manuscripts of his prophecies or of his horoscopes survive. Gerald P. Verbrugghe Selected References Burstein, Stanley Mayer (1978). The Babyloniaca of Berossus. Sources from the Ancient Near East, Vol. 1, no. 5. Malibu: Udena Publications. Verbrugghe, Gerald P. and John M. Wickersham (1996). Berossos and Manetho, Introduced and Translated: Native Traditions in Ancient Mesopotamia and Egypt. Ann Arbor: University of Michigan Press. B 115 116 B Bessel, Friedrich Wilhelm Bessel, Friedrich Wilhelm Born Died Minden, (Nordrhein-Westfalen, Germany), 22 July 1784 Königsberg (Kaliningrad, Russia), 17 March 1846 Friedrich Bessel, one of the most skilled astronomical observers of his time, made the first published determination of stellar parallax and distance, produced numerous volumes of his own observations, reduced observations of others, and contributed to advanced mathematics and celestial mechanics. Bessel was one of three sons and six daughters born to Carl Friedrich Bessel, a government secretary, and Friederike Ernestine (neé Schrader), daughter of a pastor. In 1812, he married Johanna Hagen (1794–1885); they had one son (Wilhelm, 1814–1840) and three daughters (Marie, 1816–1902; Elisabeth, 1820–1913; and Johanna). In January 1799, Bessel went to Bremen to contract with the Kulenkamp mercantile firm for a 7-year apprenticeship. In addition to rapidly developing his accounting skills, he trained himself in geography, navigation, mathematics, and astronomy. In 1804, he contacted Wilhelm Olbers concerning his determination of the orbit of comet 1P/Halley using data from observations made by Thomas Harriot in 1607. Olbers’s encouragement, and recognition of Bessel’s mathematical abilities, led to the publication of this work and to Bessel’s career shift to astronomy when, in 1806, Olbers successfully recommended Bessel for a post as an assistant at a private observatory in Lilienthal (near Bremen) owned by Johann Schröter. There, Bessel observed comets and planets, studied atmospheric refraction, and started to reinvestigate the astrometric observations of James Bradley. In 1809, Bessel took two positions that he would keep for the rest of his life – director of King Frederick William III of Prussia’s new Königsberg Observatory, and professor of astronomy at Albertus University in Königsberg. Bessel arrived in May 1810 and started lectures that summer. The observatory was completed in 1813, with its first instrumentation purchased from the estate of amateur astronomer Friedrich von Hahn. Later additions included a Reichenbach meridian circle (1819), a Fraunhofer heliometer (1829) suitable for very accurate position measurements, and a Repsold meridian circle (1841). During his 36 years at Königsberg, Bessel taught many students, including Friedrich Argelander, Carl Steinheil, and Heinrich Schlüter. Bessel contributed significantly to mathematics and physics, developing the Bessel or cylinder functions beyond the work done earlier by Daniel Bernoulli and Leonhard Euler. Bessel was ordered to undertake a geodetical survey of East Prussia, performed together with Johan Bayer in 1831/1832 and published in 1838. From the differences between geodetic and astronomical coordinates, Bessel derived the figure of Earth as an oblate spheroid with ellipticity 1/299.15. In 1839, his physical studies led to the introduction of a new Prussian measurement system. Bessel’s first major work in Königsberg was a reduction of Bradley’s astrometric observations to a fixed date (1755). Published in 1818, it contained the reduced positions of 3,222 stars, together with a complete theory of spherical astronomy and data reduction. From these observations, supplemented by his own and by those of Giuseppi Piazzi, Bessel extracted a list of 71 stars with notable proper motion. As Bessel became particularly interested in factors impacting the accuracy of measurements, he studied precession, nutation, aberration, and refraction, and developed a theory of errors. His results, summarized in his Tabulae Regiomontanae, also contain the positions of two pole stars (α and δ in Ursa Minor) and Nevil Maskeleyne’s 36 “fundamental stars” from 1750 to 1850. These tables laid the groundwork for precision measurements and theories concerning solar, lunar, planetary, and stellar motions. In 1821, Bessel put forth the notion of the “Personal Equation,” the effect of the observer’s personality and circumstances on astrometrical measurements (especially the timing of transits) and evidence for suspected variations of the obliquity of the ecliptic. Bessel was also concerned with the quality of his instruments, and effects of instrumental errors on observations, which he thought could be eliminated by expanded data reduction; according to Rudolph Engelmann, Bessel produced at least 23 articles on his investigations of astronomical instruments for angular measurements. With the new Reichenbach meridian circle, Bessel (together with Argelander) started a project in August 1821 to determine accurate positions for all stars down to the 9th magnitude with declinations between +15° and −15°. In 1825, the range was extended to +45°, and concluded in 1835 with a catalog of 75,011 stars, organized into 536 zones. Later, Argelander continued this work to create the Bonner Durchmusterung (Bonn Survey). Also in 1825, Bessel initiated the endeavor to create an accurate atlas, the Akademische Sternkarten (Academic star maps), carried out at various observatories and finished only in 1859. From Bessel’s first efforts relating to Halley’s comet, he expressed his interest in comets both by observing and by calculating their orbits, improving orbit calculation methods. Following his observations of the return of Halley’s comet in 1835, Bessel published a physical theory of comets (1836), stating that comets consist mainly of volatile matter. In 1839, he proposed methods to calculate meteoroid orbits from meteor observations. Bethe, Hans Albrecht Bessel’s continued interest in planetary astronomy led him to observe the orbits of the satellites of Jupiter and Saturn (and, in particular, Saturn’s satellite Titan) using the Fraunhofer heliometer, resulting in accurate determinations of the masses of the two planets. In 1837, he investigated the theory of Uranus, and supported the hypothesis of another planet further from the Sun. That planet, Neptune, was finally found in the year of Bessel’s death. Bessel’s ability to make very precise measurements led to his greatest discovery. After determining with unprecedented precision the position of the vernal equinox and proper motions of nearby stars, Bessel published in 1833 a catalog of 38 double stars, measured with the Fraunhofer heliometer. With that instrument, Bessel became the first to measure and publish (in Astronomische Nachrichten, 1838) a stellar parallax, and calculate the distance to a star (double star 61 Cygni) from observations during 18 months in 1837 and 1838. His parallax value of 0.314″, corresponding to a distance of 3.18 parsecs or 10.4 light years, is very close to the modern value of 0.292″, corresponding to 3.42 parsecs (11.2 light years). He had selected 61 Cygni because it had the largest known proper motion. Concerned with the accuracy of his parallax, Bessel redetermined together with Schlüter the parallax of 61 Cygni in 1840, yielding a somewhat less accurate value of 0.348″, corresponding to 2.87 parsecs (9.4 light years). Concurrently, Thomas Henderson published a parallax for α Centauri in 1839, derived from observations made in 1832/1833 at the Cape of Good Hope, and in 1840, Friedrich Struve of Dorpat presented his (less accurate) parallax for Vega from observations made during 1835–1837. In 1841, Bessel announced his conclusion, based on variations in their proper motion, that Sirius and Procyon each had an invisible companion. An orbit for Sirius’s companion, Sirius B, was calculated 10 years later; the star was eventually found by Alvan Clark in 1862 while testing the 18.5-in. objective of a new telescope commissioned for the University of Mississippi. Procyon B was not discovered until 1896 by John Schaeberle with the 36-in. telescope at Lick Observatory. Both companions were later revealed to be white dwarfs. Bessel’s scientific publications total at least 400 items addressing most of contemporary astronomy; his particular expertise was precision measurements. Bessel’s early works in Lilienthal include observations of comets, asteroids, planets, occultations, eclipses and atmospheric effects as well as instrumental studies; most of them were published in Johann Bode’s Berliner Astronomisches Jahrbuch. Bessel was honored during his lifetime by academy memberships (Berlin, Palermo, Saint Petersburg, and Stockholm), by memberships in scientific societies (Edinburgh, Göttingen, Copenhagen, and London), and by memberships in the British Royal Astronomical and Royal Meteorological Societies. Later, he was honored by the astronomical community by the naming of a lunar crater for him (21°.8 N, 17°.9 E; 15.0 km in diameter) in 1935. Minor planet (1552) Bessel was discovered on 24 February 1938 at Turku by Yrjo Vaisala. Hartmut Frommert Selected References Anon. (1847). “Obituary.” Monthly Notices of the Royal Astronomical Society 7: 199–214. Bessel, F. (1818). Fundamentae Astronomiae pro Anno MDCCLV deducta ex Observationibus viri incomparabilis James Bradley (Foundations of Astronomy for the year 1755, deduced from the Observations of the incomparable man, James Bradley). ——— (1830). Tabulae Regiomontanae reductionum observationum (Königsberg tables for reducing observations ). Engelmann, Rudolf (1875–1876). Abhandlungen von Friedrich Wilhelm Bessel. Leipzig. Fricke, Walter (1985). “Friedrich Wilhelm Bessel (1784–1846).” Astrophysics and Space Science 110: 11–19. Hamel, Jürgen (1984). Friedrich Wilhelm Bessel. Leipzig: B. G. Teubner. Hirschfeld, Alan W. (2001). Parallax: The Race to Measure the Cosmos. New York: W. H. Freeman. (Addresses the story of the discovery of parallax and Bessel’s role in it.) Van de Kamp, P. (1985). “Friedrich Wilhelm Bessel.” Astrophysics and Space Science 110: 103–104. Bethe, Hans Albrecht Born Died Strasbourg, (France), 2 July 1906 Ithaca, New York, USA, 6 March 2005 German–American theoretical physicist and astrophysicist Hans A. Bethe received the 1967 Nobel Prize in Physics for his 1939 work that clarified the sequences of nuclear reactions that provided the energy sources for the Sun and other stars engaged in hydrogen fusion (the vast majority of stars). His later significant contributions to astrophysics included providing arguments for a solution to the solar-neutrino problem drawn from weak interaction physics (rather than the details of solar models) and for work on the explosion mechanism of core-collapse supernovae. Bethe’s father was a physiologist and his mother a musician and writer of children’s plays. The family moved to Kiel, Germany in 1912 and to Frankfurt in 1915. He graduated from the Goethe Gymnasium in 1924 and spent 1924–1926 at the University of Frankfurt, before moving on to the University of Munich where he received a Ph.D. in 1928 for work with Arnold Sommerfeld in theoretical physics. Bethe was an instructor in physics at Frankfurt (1928/1929) and at the University of Stuttgart (1929), where he worked with Paul Ewald, whose daughter Rose he married in 1939. He spent time in Rome (with Enrico Fermi) under a Rockefeller fellowship, also holding positions at Munich and Tübingen (1930/1933). His work in Germany included discussions of the behavior of electrons in metals and of one- and two-electron atoms. The son of a Jewish mother, Bethe left Germany in 1933, holding temporary positions at Manchester (1933/1934) and Bristol (1934/1935), and working with Rudolph Peierls on the structure of the deuteron (a hydrogen nucleus with a neutron as well as a proton and a vital intermediate stage in the fusion of hydrogen to helium in stars). Cornell University appointed Bethe to an assistant professorship in 1935, and he remained there, retiring as John Wendell Anderson Professor in 1975, with portions of the cold Cornell winters spent in California. His contributions to the early development of nuclear physics were summarized in a series of 1936/1937 review articles with Robert F. Bacher and M. S. Livingston. These were, in effect, a complete text of the field as it then existed and guided experimental work into the war years and beyond. A pair of 1938/1939 papers, one (on the proton–proton chain) with Charles Critchfield, explained the two possible reaction sequences by which stars might convert hydrogen to helium with B 117 118 B Bevis [Bevans], John the liberation of energy. Bethe initially thought that the CN-cycle (also called the carbon cycle, and, later, CNO tricycle) would operate in the Sun and the proton–proton (p–p) chain only in smaller stars. Later work by others made clear that the Sun actually runs on the p–p chain, with the CNO cycle dominant in stars of more than about 1.1 solar masses. A very similar set of reactions was written down in the same time frame by Carl von Weizsacker. Early in World War II, Bethe (on the basis of an encyclopedia article indicating that the armor-piercing mechanism of grenades was not understood) formulated a theory that became the foundation for research on the problem. He was a member of the staff at the Radiation Laboratory at the Massachusetts Institute of Technology (which focused on radar and related studies) in 1942/1943 before becoming chief of the Theoretical Division of Los Alamos Scientific Laboratory (1943–1946). Bethe remained a consultant to the lab for more than 30 years. Following World War II, Bethe’s interests turned increasingly to astrophysics (though he was not, in fact, one of the authors of the short 1948 paper on cosmological nucleosynthesis on which his name appears euphoniously as Alpher, Bethe, and Gamow). He contributed to the equation of state for white dwarfs with Robert Marshak and wrote texts on atomic and nuclear physics relevant to astrophysics with Cornell colleague Edwin E. Salpeter. In the 1970s (following the discovery of neutron stars), Bethe turned his attention to studying the properties of nuclear matter. In 1979, in collaboration with Gerald E. Brown, postdocs, and students, he turned his attention to understanding the mechanism of core-collapse supernovae, where the elements necessary for life as well as neutron stars are produced. Bethe's first key insight was that the entropy was very low and thus neutrons would be confined into atomic nuclei, allowing the collapse to reach and exceed nuclear matter density. Later, analyzing the numerical results of James R. Wilson, he suggested that neutrino energy deposition would be important in the production of a successful supernova explosion. Work on the mechanism continues today. As early as 1934, Bethe and Peierls had wondered whether the neutrino, first hypothesized by Wolfgang Pauli and named by Enrico Fermi, might ever be observable. They concluded that the answer was probably no, but Bethe followed closely the research undertaken by Raymond Davis, Jr. for the detection of solar neutrinos. The detected flux hovered at about one-third of the predicted flux for more than 15 years, while astrophysicists, nuclear physicists, and weak-interaction physicists blamed each other for the discrepancy. In 1986, Bethe quickly saw the implications of a series of papers by S. P. Mikheyev and A. Yu. Smirnov (and related earlier publications by Lincoln Wolfenstein) concerning the possibility that the “flavor” of neutrino (electron) produced in the Sun might rotate into another flavor (the muon neutrino) that would not be detectable by Davis’s experiment. A sequence of later observations and experiments in Japan and Canada have shown definitively that this is the right answer, but Bethe’s stature in the community was such that most astrophysicists had come around to his point of view well before the definite 2001 data appeared. Bethe was a classic example of the scientist–statesman. He was one of the founders of the Bulletin of Atomic Scientists (devoted to not using the bombs that its founders had helped to develop), and he donated a portion of his Nobel Prize to help establish the Aspen (Colorado) Center for Physics, which he continued to visit and use as a base for both science and hiking for many years. He served as a member of the US delegation to the first, 1958, International Test Ban Conference in Geneva and, with Richard Garwin, wrote an influential article in Scientific American that contributed to the adoption of the Anti-Ballistic Missile [ABM] Treaty. When it was later threatened, Bethe wrote a number of popular and technical articles explaining why several proposed forms of missile defense were unlikely to be successful. He was also an advocate of the Comprehensive Test Ban Treaty. In addition to the Nobel Prize, Bethe received 10 honorary doctorates, the United States National Medal of Science, and other awards from American and German organizations. He was elected to the United States National Academy of Sciences in 1944 and as a foreign member to the Royal Society (London) in 1957. Bethe served as president of the American Physical Society in 1954. Edward Baron Selected References Bethe, Hans A., et al., (1989). From a Life in Physics. Singapore: World Scientific. Bethe, Hans A., R. E. Marshak, and J. W. Blaker (eds.) (1996). Perspectives in Modern Physics, Essays in Honor. New York: Wiley Interscience. Bethe, Hans A. (1996). Selected Works of Hans A. Bethe with Commentary, World Scientific Series in 20th Century Physics, Vol. 18. Singapore: World Scientific. Betz, Martha > Shapley, Martha Bevis [Bevans], John Born Died West Harnham near Salisbury, England, 31 October 1695 (or 10 November 1695) London, England, 6 November 1771 John Bevis is best known for his discovery in 1731 of the Crab Nebula, subsequently classified by Charles Messier as M1, though Bevis also merits recognition for his important but stillborn atlas, Uranographia Britannica. Bevis was born into a well-to-do family. He studied at Christ Church, Oxford, gaining his B.A. on 13 October 1715 and M.A. on 20 June 1718. It is said that Isaac Newton’s Opticks was his favorite book during this period. Before settling in London in 1729 and becoming a successful medical practitioner, he traveled widely throughout France and Italy for several years gaining medical information and practical experience. Astronomy was Bevis’s passion; he became friendly with Edmond Halley, whom he assisted at Greenwich in observing the transit of Mercury on 31 October 1736. Bevis observed Mercury occulted by Venus at Greenwich in the late evening of 28 May 1737. This difficult observation, with the planets barely 2° above the western horizon, remains the only recorded observation of the occultation of one planet by another. In early 1738, Bevis moved to Stoke Newington, on the northeast outskirts of London, and constructed an observatory. There, Bevis [Bevans], John on 6 March, he began to observe the meridian transits of stars. Throughout 1738 and until 6 March 1739, he made transit timings of up to 160 stars per night. Later in 1739, Bevis confirmed the observations by James Bradley on the effect of the aberration of starlight. On 23 December 1743, he independently discovered the second-magnitude Great Comet of 1744 (C/1743 X1). Bevis combined his own transit observations with those in the star catalog of John Flamsteed and those made of Southern Hemisphere stars by Halley on Saint Helena, intending to produce a great star atlas more detailed than Flamsteed’s Atlas Coelestis. Bevis likely started his Uranographia Britannica in 1745. Its first mention is in a newspaper advertisement, placed by Thomas Yeoman in the Northampton Mercury of 11 April 1748, calling for subscriptions to fund the proposed atlas. Bevis is not mentioned. The publisher listed is John Neale, a London instrument-maker. Later in 1748, Bevis wrote to Abbé Nicolas de La Caille, offering to send him a copy of the atlas. This letter and another sent to Bradley, in which he intimates his involvement in “correcting of the press in Mr. Neale’s affair,” link him directly with the Uranographia Britannica. Although Neale financed it, Bevis clearly instigated and compiled the atlas, along with a star catalog and tables to accompany each of the 51 plates. One hundred and eighty-one contributors gave money in exchange for a copy of the atlas or entitlement to purchase individual plates at a reduced cost. In October 1750, John Neale was declared bankrupt. The London Courts of Chancery sequestered the engraved copper plates individually dedicated to the subscribing institutions and individuals. These dedications date the 51 star charts to 1748–1750. The project ended, and the Uranographia Britannica never reached publication. Bevis continued his astronomical observations. He edited Halley’s Tabulae Astronomicae, published posthumously in Latin (1749) and in English (1752), to which Bevis added supplementary tables. Bevis was one of the first observers to see Halley’s comet in May 1759 on its first predicted return to the inner Solar System. He also observed the transits of Venus on 6 June 1761 and 3 June 1769. In 1750, Bevis was awarded membership in the Berlin Academy of Sciences, perhaps for his eminent contribution to astronomical cartography. On the death of Nathaniel Bliss in September 1764, Bevis failed to be elected as the fifth Astronomer Royal, although his name had been put forward. Instead, he reassumed his medical practice, taking chambers in the Middle Temple, London. Bevis was elected to the Fellowship of the Royal Society on 21 November 1765 and became its foreign secretary the following year. Bevis died suddenly in November 1771 after apparently suffering a fall from his telescope while observing a meridian transit of the Sun. After his death, Bevis’s library was left to his executor, James Horsfall, also a fellow of the Royal Society. After Horsfall died in 1785, his wife auctioned his library, including three almost complete atlases, together with plates printed before Neale’s bankruptcy. Of these three, one is owned by the American Philosophical Society in Philadelphia, another is at Saint John’s College, Cambridge, whereas the third atlas is now missing. The following year, an anonymous seller offered star atlases entitled Atlas Celeste for one and a half guineas apiece. This atlas has neither the star catalog nor tables, nor does it bear any mention of Bevis or of Neale. It does suggest by an anonymous reference to its history and via a broadsheet or title page dated 1786 that the Atlas Celeste is indeed the surviving core of the unpublished Uranographia Britannica. The known atlases, comprising 51 star charts, including northern and southern planisphere charts, frontispiece, and index, are all first impressions, probably made circa 1750. Some lack individual plates. Only 10 of the 25 identified atlases have indexes, suggesting that these sheets may have been printed before Neale’s bankruptcy. Few atlases from the Atlas Celeste (1786) include the title page. Though it is unknown how many atlases were compiled in 1786, only two with complete title pages are presently known. In total, ten atlases survive in the United Kingdom, eleven in the United States, one in Sweden, and one in Australia. Most are in university or library collections, three in private hands. Two other identified atlases are missing. Several loose plates survive, owned by private collectors or fine-art dealers, as well as many in an important collection of proof copies of certain plates in the map collection of the British Library, London. Bevis’s atlas deserves recognition as a significant contribution to mid 18th-century astronomical cartography. It was the first star atlas to show extended objects, many of which were later cataloged by Charles Messier. It was superior in some respects to previous atlases; it showed many more stars than Flamsteed’s Atlas Coelestis and was more representationally accurate than Johann Bayer’s Uranometria. Conversely, Bevis’s atlas was the last atlas to be ecliptic-oriented, rather than using the equatorial coordinate system of modern star maps. As such, it would have soon become outdated. Nevertheless, it stands as one of the great, albeit forgotten, star atlases. Kevin J. Kilburn Selected References Ashworth, William B., Jr. (1981). “John Bevis and his Uranographia (ca. 1750).” Proceedings of the American Philosophical Society 125, no. 1: 52–73. (This is by far the most comprehensive study of Bevis and his Uranographia.) Bevis, J. (1743). “Epistola Johannis Bevis … de Transitibus Mercurri sub Sole, Oct. 31. 1736. & Oct. 25. 1743.” Philosophical Transactions 42: 622–626. (Regarding transit-of-Mercury observations with Halley.) ——— (1759). “An Account of the Comet seen in May 1759.” Philosophical Transactions 51: 93–94. (Regarding observations of Halley’s comet.) Clerke, Agnes M. (1921–1922). “Bevis or Bevans, John.” In Dictionary of National Biography, edited by Sir Leslie Stephen and Sir Sidney Lee. Vol. 2, pp. 451–452. London: Oxford University Press. (Biographical summary of Bevis and his scientific works, including a comprehensive list of his publications.) Gingerich, Owen (1987). Introduction to the facsimile edition of Atlas Celeste, by John Bevis. Alburgh, Norfolk: Archival Facsimiles. (This gives a concise biography of Bevis together with a description of his intended Uranographia Britannica. This modern facsimile is a compilation of the atlas in the British Library map collection, catalog number C.21.c.5, together with examples of some of the proof plates. Augmented with the star catalogs and tables found in the A.P.S. copy.) Hawkes, Nigel. “The Unluckiest Stargazer of All.” Times (London), 24 February 1999, p. 18. Kilburn, Kevin J., Michael Oates, and Anthony W. Cross. (1998). “The Ghost Book of Manchester.” Sky & Telescope 96, no. 5: 83–86. (Describes the discovery of the most recent and possibly the most complete Atlas Celeste. Also offers evidence that Bevis may have observed Uranus in 1738.) Kilburn, Kevin J., Jay M. Pasachoff, and Owen Gingerich (2003). “The Forgotten Star Atlas: John Bevis’s Uranographia Britannica.” Journal for the History of Astronomy 34: 125–144. (This paper lists and compares all currently known copies of Bevis’s atlas. The list is maintained by M. Oates on the website of the Manchester Astronomical Society.) Sinnott, Roger W. and Jean Meeus (1986). “John Bevis and a Rare Occultation.” Sky & Telescope 72, no. 3: 220–222. (Analyzes Bevis’s observation of the occultation of Mercury by Venus.) Wallis, Ruth (1982). “John Bevis, M. D., F.R.S., (1693–1771), Astronomer Loyal.” Notes and Records of the Royal Society of London 36: 211–225. Yeoman, Thomas (11 April 1748 ). “Uranographia Britannica.” Northampton Mercury, p. 7, col. 2. (This is the first public proposal to publish the atlas.) B 119 120 B Beyer, Max Beyer, Max Born Died Hamburg, Germany, 22 October 1894 Hamburg, (Germany), 14 November 1982 In spite of a career as a high school teacher and administrator, and military service in two world wars, Max Beyer was a dedicated amateur comet and variable star observer for over 40 years. For several decades Beyer was the only astronomer studying temporal changes in cometary brightness. His observations thus form an invaluable historical record. He also discovered one comet. Beyer’s other original contributions to astronomy include preparation (with professional astronomer Kasimir Graff) of a star atlas to a limiting magnitude of 9.3 that was reprinted in three editions and widely used by variable star observers. In addition to receiving the Donohoe Medal from the Astronomical Society of the Pacific for his comet discovery, Beyer was designated a doctor honoris causa by Hamburg University in 1951. A biographical sketch and bibliography appeared in International Comet Quarterly 22 (Oct. 2000): 105–114. Thomas R. Williams Selected Reference Luthen, Hartwig; Ferrin, Ignacio; Green, Daniel W. E.; and Bortle, John E. (200). “Max Beyer (1894–1982): A master of comet observing.” International Comet Quarterly 22:105. models, in which both manda-correction (equation of center) and śīghra-correction (annual parallax in the case of outer planets, and the planet’s own revolution in the case of inner planets) must be applied. This is a special feature of the Mahābhāskarīya. The peculiarity of this method shows that the Hindu model of planetary motion was not a purely geometrical model. Bhāskara I’s contemporary, Brahmagupta, used another method, involving successive approximations, to calculate the longitudes of the planets. The Āryabhaṭīyabhāṣya is extant only up to the middle of the sixth verse of Chapter IV in the original Āryabhaṭīya. In an edition of this work printed by Kripa Shankar Shukla, the commentary of Someśvara (which summarizes Bhāskara I’s commentary) is provided for the rest of the work. The Laghubhāskarīya is a revised and abridged version of the larger Mahābhāskarīya and consists of eight chapters. The works of Bhāskara I were widely employed in India, particularly in South India, from the 7th to the 15th century or so. Selected References Chattopadhyay, Anjana (2002). “Bhaskara I.” In Biographical Dictionary of Indian Scientists: From Ancient to Contemporary, pp. 168–169. New Delhi: Rupa. Dikshita, Sankara Balakrshna (1969). Bhāratīya Jyotish Śāstra (History of Indian Astronomy), translated by Raghunath Vinayak Vaidya. Delhi: Manager of Publications (Government of India). ——— (1978). “History of Mathematical Astronomy in India.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 15 (Suppl. 1), pp. 533–633. New York: Charles Scribner’s Sons. Shukla, Kripa Shankar (ed.) (1976). Āryabhatīya of Āryabhata I with the Commentary of Bhāskara I and Someśvara. Āryabhatīya Critical Edition Series, pt. 2. New Delhi: Indian National Science Academy. Bhāskara I Flourished Valabhī, (Gujarat, India), 629 Bhāskara I was an Indian (Hindu) astronomer of the 7th century. The number “I” is added by modern historians in order to differentiate him from his namesake (Bhāskara II) of the 12th century. Bhāskara I probably belonged to the Aśmaka country but lived on the western shore of the Gulf of Khambhat (now in Gujarat). Bhāskara I was an ardent follower of Āryabhaṭa I, the earliest astronomer of the Hindu classical period (from late 5th to 12th centuries). Bhāskara I composed three works, namely, the Mahābhāskarīya (large work of Bhāskara), the Āryabhaṭīyabhāṣya (629; a detailed commentary on the Āryabhaṭīya of Āryabhaṭa I), and the Laghubhāskarīya (small work of Bhāskara). Bhāskara I was a contemporary of another Indian astronomer, Brahmagupta, but it is not known whether they knew each other. The classical period produced a number of works that are still considered to be authoritative by traditional Hindu calendar makers. Bhāskara I belonged to the Ārya School, one of four principal schools of astronomy active during the classical period. The extant works of mathematical astronomy prior to Bhāskara I, namely the Āryabhaṭīya of Āryabhaṭa I, and the Pañcasiddhāntikā of Varāhamihira, are only small, versified compendiums. Thus, Bhāskara I’s commentary on the Āryabhaṭīya is the earliest detailed prose exposition of mathematical astronomy in India. The Mahābhāskarīya is a systematic textbook of mathematical astronomy; it consists of eight chapters. In this work, planetary motion is explained by means of both epicyclic and eccentric Bhāskara II Born Died Vijjayapura (Bījāpur, Karnātaka, India), 1114 Ujjain, (Madhya Pradesh, India), 1185 Bhāskara II was an Indian (Hindu) astronomer of the 12th century. The number “II” is added by modern historians to differentiate him from his namesake (Bhāskara I) of the 7th century. Bhāskara II is frequently called Bhāskarācārya (Master Bhāskara). He probably lived in Vijjayapura; his father was Maheśvara who was also an astronomer. Bhāskara II composed several works on astronomy, most notably the Siddhāntaśiromaṇi (1150), along with his own commentary, the Vāsanābhāṣya or Mitākṣarā, the Karaṇakutūhala (1183), and the Vivaraṇa on the Śiṣyadhīvrddhidatantra of Lalla. Bhāskara II’s grandson, Can- gadeva, founded an institution for the study of the Siddhāntaśiromaṇi that received an endowment in 1207 from the king, Soïdeva the Nikumbha. Bhāskara II’s lineage produced several noted astronomers and astrologers who promoted these teachings. Bhāskara II was a follower of the Brāhma School of Brahmagupta, one of four principal schools of astronomy active during the classical period (from late 5th to 12th centuries). He was the last great figure of Hindu astronomy, preceding the introduction of Islamic astronomy in the 13th and 14th centuries. Bianchini, Francesco The Siddhāntaśiromaṇi was written when Bhāskara II was 36 years old and forms a comprehensive treatise of mathematics and astronomy. It consists of two principal parts: (1) the Grahagaṇitādhyāya, which contains 12 chapters on the motions of the planets, problems of time and direction, lunar and solar eclipses, conjunctions, and so forth; and (2) the Golādhyāya, which contains 13 chapters, chiefly on the celestial sphere. This latter text also contains a discussion of the precession of the equinoxes. Here, Bhāskara II seemingly refers to a lost work of Maṇjāla, as Bhāskara II’s theory of precession is not contained in any extant work of Maṇjāla. The Karanakutūhala is a practical work of astronomy and consists of ten chapters that provide simplified rules and methods for solving astronomical problems. Bhāskara II’s Vivarana, the commentary on the Śiṣyadhīvrddhidatantra, is a textbook belonging to the Ārya School of astronomy. Selected References Arka Somayaji, Dhulipala (trans.) (2000). Siddhantasiromanih. 2nd rev. ed. Tirupati, India: Rāstriyasamśkrtvidyapitham. Chattopadhyay, Anjana (2002). “Bhaskara II.” In Biographical Dictionary of Indian Scientists: From Ancient to Contemporary, pp. 169–170. New Delhi: Rupa. Dikshita, Sankara Balakrshna (1969). Bhāratīya Jyotish Śāstra (History of Indian Astronomy), translated by Raghunath Vinayak Vaidya. Delhi: Manager of Publications (Government of India). Pingree, David (1970). “Bhāskara II.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 2, pp. 115–120. New York: Charles Scribner’s Sons. ——— (1978). “History of Mathematical Astronomy in India.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 15 (Suppl. 1), pp. 533–633. New York: Charles Scribner’s Sons. Bianchini, Francesco Born Died probably Verona, (Italy), 1662 Rome, (Italy), 13 February 1729 Francesco Bianchini was an observational astronomer, a discoverer of three comets, who published his account of observations of Venus. Bianchini was a papal officer in Rome and librarian to Cardinal Ottoboni (later Pope Alexander VIII). Bianchini’s observations were carried out chiefly at Albano, the supposed site of the Alba Longa. Some idea of his skill, assiduity, and sagacity can be obtained from a selection of these observations edited, with a preface, by Eustachio Manfredi of Bologna (with a portrait of Bianchini as a frontispiece), published posthumously at Verona in 1737. Bianchini discovered three comets: One was discovered on 30 June 1684, of which he was not only the discoverer but also the sole observer (C/1684 N1); another was a codiscovery on 20 April 1702 (C/1702 H1); and a third was on 17 October 1723, but which had already been seen, notably by William Saunderson, at Bombay (C/1723 T1). That of 1684 was last seen on 19 July, and its orbit was one of those determined by Edmond Halley. Bianchini’s attempt to measure the parallax of Mars at its opposition in 1685 gave a result not quite two-thirds of the true value. He observed many eclipses of the Moon, and saw the solar eclipse of 22 May 1724. He studied Jovian satellite phenomena, and made numerous drawings of the mountains and craters of the Moon, being credited with the discovery of the great Alpine Valley. Hesperi et phosphori nova phaenomena, sive observationes circa planetam Veneris, the work for which Bianchini is principally known, was published at Rome in 1728. It details his meticulous studies of the fugitive markings of Venus, and fixed the diurnal spin rate of the planet at 24 days 8 hours. His chart of the markings honors Christopher Columbus, Galileo Galilei, Henry the Navigator, Amerigo Vespucci, and others. However, he was utterly mistaken in his assumptions. His book is today best known for two oftenreproduced plates of aerial telescopes, of extremely long focal length, with lenses by Giuseppe Campani. Bianchini’s attempt to measure the diurnal parallax of Venus in July 1716, which gave a result of 14.3˝ (near to the modern value), is of more permanent interest. His last recorded observation was of the lunar eclipse of 13 February 1729. Richard Baum Alternate name Blanchinus, Francisco Selected References Bianchini, Francesco (1996). New Phenomena of Hesperus and Phosphorus or rather Observations Concerning the Planet Venus, translated by Sally Beaumont and Peter Fay. London: Springer-Verlag. Binder, Alan (1992). “A Telescope of the 17th Century.” Sky & Telescope 83, no. 4: 444–450. Hussey, T. J. (1833). “On the Rotation of Venus.” Astronomische Nachrichten 11: 121–136, 139–146. B 121 122 B Bickerton, Alexander William Bickerton, Alexander William Born Died Alton, Hampshire, England, 7 January 1842 London, England, 22 January 1929 impact would result in a third and highly luminous body being removed by tidal interactions. The theory was later extended to account for other types of variable stars, double stars, the origin of the Solar System, planetary nebulae, and even evolution of the Milky Way. His ideas lacked mathematical detail and were widely shunned by the scientific establishment. Both Nature and the Royal Astronomical Society, London, rejected Bickerton’s papers, but he continued to promote his partial impact theory through popular lectures, at which he excelled, as well as through articles in the Transactions of the New Zealand Institute and the magazine Knowledge. Thomas Chamberlin and Forest Moulton further developed the idea of stellar collisions or near approaches as a way of forming planetary systems. A stellar collision model of supernovae was put forward by Fred Whipple in 1939, and one for quasars in the early 1960s. The phenomenon is now thought to be important only in dense clusters of stars and near the centers of galaxies, and Bickerton’s work has not been credited by anyone working on these topics in recent years. After leaving Canterbury University College, Bickerton returned to Britain where he founded the London Astronomical Society, of which he became the president. He also wrote a series of popular books on astronomy, including the Romance of the Heavens in 1901. From the point of view of astronomical history, Bickerton’s work is now largely forgotten. From the point of view of the intellectual and social development of the early Canterbury settlement in New Zealand, he is still remembered for the excellence of his teaching, the notoriety of his social nonconformity, and the bitter battles he fought with the college council. John Hearnshaw Selected References Alexander Bickerton was a controversial and flamboyant figure in British and New Zealand astronomy, a fine teacher and popularizer, but exponent of unconventional ideas (now known to be wrong). He was the son of Richard Bickerton and Sophia Matilda (née Eames) and was educated at Alton Grammar School and at the Royal School of Mines and Royal College of Chemistry in London. He married, in 1865, Anne Phoebe Edwards (died: 1869) and in 1920 Mary Wilkinson. Bickerton studied science subjects at the Royal School of Mines in South Kensington, London, from 1866, where his considerable academic successes resulted in Bickerton himself giving public lectures. Then, after teaching at the Hartley Institute in Southampton for 3 years, he accepted the position of professor of chemistry in 1874 at the recently founded Canterbury University College in Christchurch, New Zealand. Bickerton stayed there until 1902, when he was eventually dismissed by the college council, ostensibly for poor management, but in reality for his unconventional scientific views and social mores. His most famous student at Canterbury was Ernest Rutherford. Bickerton’s astronomical reputation rests almost entirely on his theory of partial impact, in which he attempted to account for the phenomenon of novae by the proposal that two stars in an oblique Anon. (January 1912). “Professor A. W. Bickerton.” Knowledge 35, no. 522: 14–16. Bickerton, A. W. (1900). “Cosmic Evolution.” Philosophical Magazine 50: 216–223. ——— (1901). The Romance of the Heavens. London: Swan–Sonnenschein and Co. Burdon, R. M. (1956). Scholar Errant: A Biography of Professor A. W. Bickerton. Christchurch, South Island, New Zealand: Pegasus Press, pp. 149. Gilmore, G. F. (1982). “Alexander William Bickerton: New Zealand’s Colourful Astronomer.” Southern Stars 29: 87–108. (For a complete bibliography by Bickerton.) Jaki, Stanley L. (1977). Planets and Planetarians. New York: John Wiley and Sons. (See pp. 167–168 for a critique of Bickerton’s theory for the origin of the Solar System based on partial impact.) Biela, Wilhelm Freiherr von Born Died Rossla near Stolberg, (Sachsen-Anhalt, Germany), 19 March 1782 Venice, (Italy), 18 February 1856 Wilhelm von Biela is noted for a short-period comet that bore his name (now known as 3D/Biela) and broke into fragments that, for several returns, created spectacular meteor showers. Biela Biermann, Ludwig Franz Benedikt served as an officer in the Austrian army, eventually rising to the rank of Major. He participated in a number of military campaigns against Napoleon between 1805 and 1809. After the Napoleonic Wars, Biela served in numerous places, including Prague and Josephstadt, Bohemia, and Naples and Vicenza, Italy. Eventually, he was appointed commandant of Rovigo, Venetia, a post from which he retired in 1846 to live out his life in Venice after suffering a stroke. During the period of his military service, Biela was an active amateur astronomer, having attended the astronomical lectures of Alois David in Prague while recuperating from war-related injuries. Biela made independent discoveries of three comets, in 1823, 1827, and 1831, of which those in 1823 and 1831 were codiscoveries of comets that had been observed some days earlier by other astronomers. Biela’s only original discovery, and his most interesting one, was the comet of 1826 (3D/1826 D1). It was discovered on 27 February in the constellation of Aries while Biela was observing from Josefstadt. When Biela calculated the comet’s orbit, he found it to have a short period of 6.62 years. He also recognized that former appearances of this comet had been observed in 1772 (Jacques Laibats-Montaigne and Charles Messier) and 1805 (Jean Pons). It became known as Biela’s comet (only the third comet to have been shown to be periodic by observations on different appearances). Comet Biela was observed telescopically as it decayed into two comets in 1846, and seen visually for a last time in 1852. Its fragments are probably the source of a meteor shower called Andromedids, or Bielids, first observed in spectacular showers in November 1872 and November 1885 but occurring only sporadically since 1940. Biela published several astronomical papers, mainly on his comet observations and calculations, most of which appeared in the Astronomische Nachrichten. In addition to the three comets in the discovery of which he was involved, his papers include observations of a light pillar emerging from the Sun after sunset, sunspot observations, some theoretical considerations on comets falling into the Sun, historical studies on comets and Tycho Brahe, and stellar occultations by the Moon. In his 1836 monograph, Die zweite grosse Weltenkraft, Biela attempted to develop a theory to explain supposed relations between planetary rotation and satellite revolution periods, a popular theme in the 19th century. Biela was honored by having his name assigned to the minor planet (2281) Biela. His name also lives on in his eponymous comet, and in one of the designations of the meteor shower formed by the remainder of that comet, the Bielids. Hartmut Frommert Selected References Biela, Wilhelm von (1836). Die zweite grosse Weltenkraft, nebst Ideen über einige Geheimnisse der physischen Astronomie, oder Andeutungen zu einer Theorie der Tangentialkraft. Prague. Lynn, W. T. (1898). “Letter to the Editor.” Observatory 21: 406–407. ——— (1905). “Letter to the Editor.” Observatory 28: 423–425. Mayerhöfer, Josef and Thomas Widorn (1970).“Biela, Wilhelm von.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 2, pp. 125–126. New York: Charles Scribner’s Sons. Biermann, Ludwig Franz Benedikt Born Died Hamm, (Nordrhein-Westfalen), Germany, 13 March 1907 Munich, (Germany), 12 January 1986 German astrophysicist Ludwig Biermann gave his name to a method of generating magnetic fields in strongly ionized gas (the Biermann battery) and also introduced mixing length theory into stellar structure and developed our initial understanding of ionization and acceleration of comet tails. Biermann obtained his Ph.D. from Göttingen University in 1932, following initial studies at Munich (1925–1927) and Freiburg (1927–1929). He was an exchange scholar at Edinburgh (1933/1934) and, following his habilitation at Jena (1934–1937), held positions at the Hamburg University and Observatory. At the end of World War II, Biermann served as a principal author for the Field Information Agencies Technical [FIAT] report on the state of German science during the war years (1948), summarizing work on opacity and stellar interior structure. He was appointed the head of the newly formed Max Planck Institute for Astrophysics in Göttingen – later relocated to Munich – after the restructuring of the Kaiser Wilhelm Institute into the Max Planck Institute [MPI] at the end of the war (1948), a post he held for the rest of his life. Among the younger people he mentored at the MPI were Aarnulf Schluter, Eleonora Trefftz, Reimer Lüst, Rhea Lüst (his collaborator in understanding comet tails), Rudolf Kippenhahn, Friedrich Meyr, and Stefan Temesvary. Biermann’s first important work centered on stellar interior structure and convection, beginning with a series of papers on stellar models starting in 1931. These were elaborated in his habilitation thesis for Jena in 1935, where he demonstrated that the Schwarzschild sriterion, applied in radiative stellar interiors, leads to vigorous convection, restricting the superadiabatic gradient to extremely small values (of order one part in a million). Since the adiabatic temperature gradient depends only on the equation of state through the exponent of the barotropic (pressure–density) relation, the result provided a simple, reliable prescription for computing energy transport in stellar convection zones and made possible efficient numerical computation of stellar interior models. Biermann also studied convection in rotating stars and, along with Thomas Cowling, models for centrally condensed stars that mimic the structure expected for red giants. Although Biermann and Cowling did not meet until the 1952 Rome general assembly of the International Astronomical Union, they had corresponded regularly about their work on stars during the 1930s. Biermann was the first to apply Ludwig Prandtl’s concept of mixing length (a sort of macroscopic mean free path) to calculate the transport of energy by convection. His student Erika Böhm-Vitense developed the modern version of mixing length theory [MLT] in the early postwar years. Throughout his career, but especially during the 1940s, Biermann maintained an interest in atomic physics. Recognizing the need for quantitative data on opacity and abundances for the proper modeling of the solar interior and atmosphere, he was thus involved in a program to compute oscillator strengths for intermediate mass ions B 123 124 B Bigourdan, Camille Guillaume such as sodium, potassium, magnesium, silicon, and aluminum; these were among the first such computed data. During the 1950s, Biermann studied the dynamics of ion (type I) cometary tails, assuming the observed accelerations were due to collisional momentum transfer from the outer solar atmosphere. These observations, confirmed by satellite measurements by 1961, proved pivotal to the discovery of the solar wind. He demonstrated that the velocity of the comet produces an aberration of the tail relative to the outflow, although the density he derived, of order 103 cm−3, was later revised by in situ measurements to about 1 cm−3. The deviation resulted from Biermann’s neglect of the magnetic field structure, later shown to be the dominant factor in controlling the outflow. Nevertheless, this prediction proved fundamental in the determination of the rate of both mass and angular momentum loss from the Sun (and, ultimately, all solar-type stars) and served as the earliest demonstration of the existence of the solar wind, later theoretically explained by Eugene Parker (1958, 1963). Biermann’s later work on comets focused on the loss of hydrogen and Lyman α-scattering halos around cometary nuclei, disconnection events in tails, and the interaction of the cometary plasma with magnetic fields transported outward by the solar wind. Much of this work is continuing using detailed numerical magnetohydrodynamic modeling. He was also involved in design of the plasma experiments and camera for the European Space Agency’s Giotto cometary rendezvous mission for comet 1P/Halley, some of the results of which appeared posthumously. Always interested in astrophysical applications of plasma physics, Biermann and A. Schluter introduced a diffusive model for generation of magnetic fields in strongly ionized environments, known as the “Biermann battery” mechanism that has recently found applications in models for magnetic field generation in the early Galaxy. In the formative period, he played an important role in calling astronomers’ attention to developments in magnetohydrodynamics during a number of meetings of the Cosmic Gas Dynamics series in the 1950s. Biermann’s honors include the Bruce Medal of the Astronomical Society of the Pacific (1967), Gold Medal of the Royal Astronomical Society (1974), and the Karl Schwarzschild Medal of the Astronomische Gesellschaft (1980). He was a member or associate of scientific academies in West Germany, East Germany, Belgium, and the United States. The Biermann prize of the Astronomische Gesellschaft is named in his honor. His son, Peter, is also a theorist who carried out pioneering modeling studies of interacting (massexchanging) close binary systems and cosmic-ray acceleration. Steven N. Shore Selected References Antrack, D., L. Biermann, and R. H. Lüst (1964). “Some Statistical Properties of Comets with Plasma Tails.” Annual Review of Astronomy and Astrophysics 2: 327–340. Biermann, L. (1932). “Konvektionszonen im innern der Sterne.” Zeitschrift für Astrophysik 5: 117–139. ——— (1935). “Konvektion im Innern der Sterne.” Astronomische Nachrichten 257: 269–284. ——— (1948). “Konvektion in rotierenden Sternen.” Zeitschrift für Astrophysik 25: 135–144. ——— (1951). “Kometenschweife und solare Korpuskularstrahlung.” Zeitschrift für Astrophysik 29: 274–286. ——— (1955). “Mass Exchange between Stars and the Interstellar Medium.” Astronomical Journal 60: 149. ——— (1960). “Relations between Plasma Physics and Astrophysics.” Reviews of Modern Physics 32: 1008–1011. ——— (1971). “Comets and Their Interaction with the Solar Wind.” Quarterly Journal of the Royal Astronomical Society 12: 417–431. ——— (1988). Ludwig Biermann, 1907–1986. Munich: Max Planck Gesellschaft. Biermann, L. and A. Schlüter. (1958). “Magnetohydrodynamic Dissipation.” Reviews of Modern Physics 30: 975–978. Biermann, L., P. T. Giguere, and W. F. Huebner (1982). “A Model of the Comet Coma with Interstellar Molecules in the Nucleus.” Astronomy and Astrophysics 108: 221–226. Blackwell, D. E. (1974). “Presidential Addresses on the Society’s Awards: The Gold Medal.” Quarterly Journal of the Royal Astronomical Society 15: 219–220. Cowling, T. G. and L. Mestel (1986). “Ludwig Franz Benedickt Biermann.” Quarterly Journal of the Royal Astronomical Society 27: 698–700. Parker, E. N. (1958). “Dynamics of the Interplanetary Gas and Magnetic Fields.” Astrophysical Journal 128: 664–676. ——— (1963). Interplanetary Dynamical Processes. New York: Interscience. Ten Bruggencate, P. et al. (1948). Astronomy, Astrophysics, and Cosmology. FIAT Review of German Science, 1939–1946. Wiesbaden: Office of Military Government for Germany, Field Information Agencies Technical [FIAT]. (See “Physik der Sternatmospharen,” [with P. Wellmann] and “Der Innere Aufbau der Sterne.”) Bigourdan, Camille Guillaume Born Died Sistels, Tarn-et-Garonne, France, 6 April 1851 Paris, France, 28 January 1932 French astrometrist Guillaume Bigourdan specialized in problems of precise measurement and dissemination of time and directed the Bureau international de l’heure [BIH] for the first decade of its existence. Bigourdan was the son of Pierre Bigourdan and Jeanne Carrière, part of a peasant family whose name derives from a 7th-century association with land owned by the Comté de Bigorre. He began school in the town of Valence d’Agen and continued in Toulouse, where his aptitude drew the attention of Francois Tisserand, then professor of astronomy and director of the Observatoire de Toulouse. Bigourdan joined the Toulouse staff in 1877, and went on to Paris in 1879 when Tisserand moved there, marrying Sophie, the eldest daughter of admiral Ernest Mouchez, with whom he had nine children. Bigourdan completed a doctoral thesis with Tisserand on the effects of the “personal equation” (errors in determination of times of astronomical events like meridian crossings, which vary systematically from one observer to another) on measurements of double stars. He also compiled a catalog of nebulae and used meridian-circle telescopes for time determinations. France adopted “zone time” in 1891, and in 1911 switched from zones centered on Paris to ones centered on the Greenwich, England meridian defined by George Airy. Bigourdan participated in defining the new time zones and longitudes, and, with Gustave Ferrié (1868–1932) pioneered the dissemination of wireless telegraphy time signals from the Eiffel Tower over a distance of 5,000 km. During World War I, with the support of Benjamin Baillaud, then director of the Paris Observatory, Bigourdan took over the operation of the time service unofficially. The BIH was established officially in 1919 during the first, organizational meeting of the International Astronomical Union in Brussels, in which both Biot, Jean-Baptiste Baillaud and Bigourdan participated. Bigourdan was appointed its first director, holding the job until 1929. In addition to his work in timekeeping, he carried out a variety of research in the history of astronomy, publishing on the history of the Bureau des longitudes, the Observatoire de Paris, the metric system, and French observatories and astronomers, particularly Alexandre Pingré. Bigourdan was elected to the Académie des sciences in 1904 and served as both its vice president and president (1924). He received the Gold Medal of the Royal Astronomical Society, the Légion d’honneur, and several other honors for his work on time standards. Jacques Lévy was useful in associating the Crab Nebula with the supernova of 1054. Selected Reference Duan, Yibing and Han Qi (1997). “Biot’s Catalogue of Meteors Observed in Ancient China and its Modern Application.” In Proceedings of the 21st Century Chinese Astronomy Conference, edited by K. S. Cheng and K. L. Chan, p. 519. Singapore: World Scientific Publishing. Biot, Jean-Baptiste Selected Reference Anon. (1993). “Bigourdan, Guillaume.” Monthly Notices of the Royal Astronomical Soceity. 93: 233. Born Died Paris, France, 21 April 1774 Paris, France, 3 February 1862 Billy, Jacques de Born Died Compiègne, (Oise), France, 18 March 1602 Dijon, France, 14 January 1679 Jacques de Billy was an astronomical writer, who also made contributions to mathematics, particularly number theory and Diophantine analysis. After studying humanities, he entered the Jesuit order in 1619 and completed his divinity studies, equivalent to a doctorate, in 1638. He taught theology and mathematics at a number of Jesuit colleges in northeastern France, ending his career in Dijon. Between 1656 and 1670 Billy wrote at least three major works on astronomy in Latin: an advanced text book, a publication on eclipses entitled Tabulae Lodoicaeae (because it was dedicated to Louis XIV, the Sun King), and a book on the crisis in cometary motions. No one knew whether comets moved in straight lines, circular orbits, or some other variant, a confusion brought to the fore by the bright comets of 1664 (C/1664 W1) and 1665 (C/1665 F1). Billy also wrote Le Tombeau de l’Astrologie Judiciaire in which he condemned astrology and the casting of horoscopes. Among his manuscripts preserved in Dijon is an ephemeris of the comet of 1590 (C/1590 E1). Peter Broughton Selected Reference D’Amat, Roman (1954). “Billy.” In Dictionnaire de biographie français. Vol. 6, cols. 484–485. Paris: Letouzey et Ané. Biot, Edouard-Constant Born Died Paris, France, 1803 1850 French engineer Edouard-Constant Biot was the son of astronomer Jean-Baptiste Biot. He cataloged the meteors, comets, and novae that appear in ancient Chinese records. Biot’s catalog Jean-Baptiste Biot’s achievements in optics, geodesy, and geophysics improved the scientific grounding of astronomy. He proved the extraterrestrial origin of the meteorites and helped to unify the precise mathematics of astronomy with the experimental techniques of physics. Biot’s father Joseph, a Parisian bourgeois, wanted him to go into commerce. However, around 1791, after taking humanities at the Collège Louis-le-Grand, Biot began to study analysis and calculus. Briefly enlisting in B 125 126 B Biot, Jean-Baptiste the revolutionary army, he fought as a gunner in the 1793 battle of Hondschoote. Next year he entered the École des Ponts et Chaussées. He transferred to the École Polytechnique as soon as it opened and shone as a student, gaining the respect of faculty members such as Gaspard Monge and Gaspard-Marie Riche de Prony. On graduation Biot won a professorship of mathematics at Beauvais in February 1797 and then married Gabrielle Brisson, the 16-year-old sister of fellow Polytechnicien Barnabé Brisson. Mentored first by the young mathematician Sylvestre Lacroix and then by the celebrated Pierre de Laplace, Biot penned an arithmetic textbook and several scientific memoirs. In May 1800, backed by Lacroix, Joseph Lagrange, and Laplace, Biot joined the Institut de France as a nonresident associate of its First Class (later reborn as the Académie des sciences) and was elected a full member in 1803, replacing Jean Delambre. In November 1800, Biot became professor of mathematical physics at the Collège de France, allowing him to become one of the most active investigators of the First Class. In 1809, Biot was appointed professor of astronomy at the science faculty of the Université de France; he was dean from 1840 until his retirement in 1849. A member of the Société d’Arcueil, Biot espoused its cochair Laplace’s hopes of bringing astronomical accuracy and the language of mathematics to French experimental physics. In optics, Biot attempted to explain polarization of light using corpuscular theory, but his experimental work also included measurements of terrestrial magnetism, gas densities, heat diffusion, and the speed of sound in various media. Research with Félix Savart subsequent to H. C. Oersted’s discovery of the connection between electricity and magnetism yielded the Biot–Savart law relating the intensity of the magnetic field set up by a current flowing through a wire to the distance from the same wire. Other investigations in mathematics, electricity, and plant physiology were of less consequence, but Biot lent vital support to young Louis Pasteur’s work on the polarizing power of molecules, the first intimation of molecular chirality. It is unclear when Biot became interested in astronomy, though he later recounted that he first communicated with Laplace to read the unbound pages of his Mécanique céleste as they were printed. He repeated all the calculations and probably discussed the more difficult ones with Laplace. This led to the publication of his first significant astronomical work, the Analyse du Traité de mécanique céleste de P. S. Laplace in 1801. Biot’s first original research was a thorough investigation of the alleged fall of stones from the sky near l’Aigle in the Orne department in April 1803. When he reported back to the Institut in July, presenting testimonies, samples, and the results of chemical analyses, Biot established the reality of meteorites over the earlier objections of rationalists. Biot’s most concrete contributions were in the field of geophysics and geodesy. A balloon ascension with J. L. Gay-Lussac in August 1804 tested the variation of the Earth’s magnetic field with altitude and found no change up to 4,000 m. In a joint 1804 memoir with Alexander von Humboldt, Biot presented a theory of the magnetic field that agreed with part of Humboldt’s readings and stimulated others to produce a better general theory. Biot later observed the lack of polarization of the aurora borealis, concluding that the phenomenon could not result from either reflection or refraction. In 1806, Biot and François Arago were charged by the Bureau des longitudes with the measurement of an arc of the meridian in Spain to improve the value of the meter, still defined at that time as the ten-millionth part of a meridian quadrant of the Earth. Biot had previously worked with Arago on the refractive indices of various gases, and their result for air matched Delambre’s value derived from astronomical considerations to a high degree of precision. Biot would later return to the problem of atmospheric refraction. Between 1806 and 1825, Biot was part of several efforts to extend geodesic measurements, from the Balearic Islands to the Shetlands, and to make additional determinations of gravitational acceleration in several localities. The main results were included in the 1821 Recueil d’observations géodésiques, astronomiques et physiques coauthored with Arago. The results of his later geodesic work in Italy and Sicily were published in an 1827 memoir. The pendulum observations along selected parallels of longitude did not confirm expectations, pointing out the inadequacy of the simple ellipsoidal theory of the Earth’s shape. By 1822, however, Biot had developed an interest in ancient astronomy, which resulted in a paper on the Egyptian zodiac discovered at Denderah. He went on to publish on ancient chronology and compare the astronomical notions of the ancient Egyptians, Chinese, and Chaldeans. A later work on Hindu astrononomy sought to subordinate it to Chinese and Greek achievements, but its seemingly definitive conclusions relied overmuch on an atypical source. Biot’s work on Chinese chronology is still cited occasionally, though 20th-century scholarship has invalidated some of its conclusions. A noted textbook writer, Biot put out three editions of his Traité élémentaire d’astronomie physique, which grew to comprise six volumes and an atlas. While eschewing higher mathematics, the Traité was extremely detailed and incorporated the latest results of turn of the century research. Sir George Airy, later head of Greenwich, cited it as the spark of his interest for astronomy. In later years, Biot’s antiquarian work on Egyptian and Chinese astronomy won him election to the Académie des inscriptions et belleslettres in 1841. His writings, mainly in history of science, earned him a seat at the Académie française in 1856, making him one of the very few figures in the history of the Institut to have achieved triple recognitions as scientist, historian, and author. Awarded the Légion d’honneur in 1814, Biot went on to become an officer (1823) and a commander (1849) of the order. He was elected a fellow of the Royal Society in 1815. Biot’s wife died before him, as did his son Édouard, who belonged to the Académie des inscriptions et belles-lettres. Biot completed the work on Chinese astronomy begun by and with his son. A conservative monarchist in later life, Biot mostly stayed aloof from party politics, within and outside the Institut, though he served as mayor of the small town of Nointel in the Oise department. Having long been a skeptic in religious matters, Biot gradually returned to the Catholic faith in his fifties. Jean-Louis Trudel Selected References Frankel, Eugene (1977). “J. B. Biot and the Mathematization of Experimental Physics in Napoleonic France.” Historical Studies in the Physical Sciences 8: 33–72. Birkeland, Kristian Olaf Bernhard ——— (1978). “Career-Making in Post-Revolutionary France: The Case of JeanBaptiste Biot.” British Journal for the History of Science 11: 36–48. Picard, émile (1931). “La vie et l’œuvre de Jean-Baptiste Biot.” In Éloges et discours académiques. Paris. Birjandī: �Abd al-�Alī ibn Muḥammad ibn Ḥusayn al-Birjandī Died 1525/1526 Birjandī, a pupil of Manṣūr ibn Mu�īn al-Dīn al-Kāshī (who was a staff member of the Samarqand Observatory) and of Sayf al-Dīn Taftāzānī, was known for his numerous astronomical commentaries and supercommentaries. He wrote several commentaries on the works of Naṣīr al-Dīn al-Ṭūsī, including Ṭūsī’s al-Tadhkira fī �ilm al-hay’a, his Taḥrīr al-Majisṭī (recension of Ptolemy’s Almagest), and Ṭūsī’s book on astrolabes. In the preface to the last book Birjandī mentions some tables of the positions of stars that he calculated for the year 853 Yazdigird (1484). In addition, Birjandī wrote a commentary on Kāshī’s Zīj-i Khāqānī, which was Kāshī’s attempt to correct Ṭūsī’s Īlkhānī Zīj. Birjandī was also known for his commentary on the Zīj of Ulugh Beg (the last date provided in it being 929 H = 1523) as well as for his supercommentary (ḥāshiya) on Qāḍīzāde’s commentary (sharḥ) to Maḥmūd al-Jaghmīnī’s al-Mulakhkhaṣ fī �ilm al-hay’a al-basīṭa. In addition to these commentaries, Birjandī wrote several independent astronomical works, whose subjects included cosmology, ephemeredes, instruments of observation, as well as a treatise on the distances and sizes of the planets that was dedicated to Ḥabīb Allāh, and another work on the construction of almanacs completed in 1478/1479. Birjandī completed his Sharḥ al-Tadhkira (Commentary on the Tadhkira) in 1507/1508. Nayanasukha translated the 11th chapter of the second book of this work into Sanskrit. This is the chapter in which Ṭūsī deals with the device called the “Ṭūsī couple” and its applications, mainly to the lunar theory. From the colophon of the Sanskrit translation we learn that a Persian, Muḥammad Ābida, dictated it (presumably in a vernacular language) to Nayanasukha as he composed it in Sanskrit. Muḥammad Ābida had been at Jai Singh’s court since at least 1725. Birjandī’s commentary on the Tadhkira is a good example of the commentary tradition within Islam. In analyzing Ṭūsī’s work, Birjandī provides the reader with explanations of meanings, shows variants, provides grammatical explanations, and engages in philosophical discussions. He also provides different interpretations and examines the objections of his predecessors against Ṭūsī. In Book II, Chapter 11, Birjandī cites the following authors and works: Ṭūsī’s Risālah-i mu�īniyya; Ptolemy’s Almagest; Ibn al-Haytham; Euclid’s Elements; Quṭb al-Dīn al-Shīrāzī’s Tuḥfa and Nihāya; Theodosius’s Sphaerica; Menelaus; and Autolycus. In his commentary, Birjandī seems to follow Shīrāzī’s opinions and his devices. For example, Birjandī mentions an objection against the application of the Ṭūsī couple to the celestial spheres regarding the necessity of rest between two motions; such a discussion about rest between ascending and descending motions is given by Shīrāzī as well as Shams al-Dīn al-Khafrī (Ragep, pp. 432–433). Also when Birjandī discusses an application of the curvilinear or spherical version of the Ṭūsī couple, he mentions that this version produces a slight longitudinal inclination, which had been discussed by Shīrāzī in his Tuḥfa (Kusuba and Pingree, pp. 246–247). Finally we note that Birjandī gives a proof for a device that G. Saliba has called the “�Urḍī lemma,” after Mu’ayyad al-Dīn al-�Urḍī, but the proof is similar to that given by Shīrāzī rather than �Urḍī’s original in his Kitāb al-Hay’a. Takanori Kusuba Selected References Kusuba, Takanori and David Pingree (eds. and trans.) (2002). Arabic Astronomy in Sanskrit: Al-Birjandī on Tadhkira II, Chapter 11 and its Sanskrit Translation. Leiden: E. J. Brill. (The Arabic text and Sanskrit translation of Birjandī’s Sharh al-Tadhkira, Book II, Chap. 11; also contains commentary.) Ragep, F. J. (1993). Nasīr al-Dīn al-Tūsī’s Memoir on Astronomy (al-Tadhkira fī ʕ ilm al-hay’a). 2 Vols. New York: Springer-Verlag. Rosenfeld, B. A. and Ekmeleddin Ihsanoğlu (2003). Mathematicians, Astronomers, and Other Scholars of Islamic Civilization and Their Works (7th–19th c.). Istanbul: IRCICA, pp. 314–316. Saliba, George (1979). “The Original Source of Qutb al-Dīn al-Shīrāzī’s Planetary Model.” Journal for the History of Arabic Science 3: 3–18. Sayılı, Aydın (1960). The Observatory in Islam. Ankara: Turkish Historical Society. Birkeland, Kristian Olaf Bernhard Born Died Christiania (Oslo, Norway), 13 December 1867 Tokyo, Japan, 15 June 1917 Kristian Birkeland, perhaps Norway’s most famous scientist, produced the first artificial aurorae, organized polar expeditions to collect auroral data, and contributed to the theoretical understanding of these upper atmospheric phenomena. Birkeland was the son of Reinart Birkeland and Ingeborg (née Ege). His one brother, Tonnes Gunnar, was a medical doctor, and one of his cousins, Richard Birkeland, became professor of mathematics at the University of Oslo. Kristian Birkeland received his early education in Norway, at the University of Oslo, was appointed to a position there in 1893, and became full professor at the age of 31. He was elected to the Norwegian Academy of Science and Letters and received an honorary doctorate from the Technical University of Dresden, Germany, in 1909. Birkeland published his first three scientific papers (in mathematics) before he was 20. Among his early contributions to physics was his work on Maxwell’s equations with the first solution in 1894 as well as a general expression – still valid – for the Poynting vector in 1895. In 1896, Birkeland published, through the French Academy journal Comptes rendus de l'Académie des sciences, the first realistic auroral theory. His idea was that electrically charged particles (which he called cathode rays, because the electron had not yet been discovered) streamed out from sunspots at such high velocity that, guided by the Earth’s magnetic field, they could penetrate far into the polar atmosphere. Via collisions with the atmospheric gases, visible aurorae would be produced. Birkeland produced the first artificial aurorae in his laboratory in 1896. In order to substantiate his theory, Birkeland began rather complicated calculations of charged particles in magnetic fields. B 127 128 B Birkhoff, George David He also built the world’s first permanent auroral observatory, in northern Norway, in 1899. Birkeland organized expeditions to polar regions where he established a network of observatories under the auroral regions to collect aurora and magnetic field data. The results of the Norwegian polar expedition conducted from 1899 to 1900 contained the first determination of the global pattern of electric currents in the polar region from ground magnetic field measurements. Birkeland suggested that the polar electric currents – today referred to as auroral electrojets – were connected to a system of currents that flowed along geomagnetic field lines into and away from the polar region. He provided a diagram of field-aligned currents in his famous book, The Norwegian Aurora Polaris Expedition 1902–1903. The book also contains chapters on magnetic storms and their relationship to the Sun, the origin of the sunspots themselves, comet 1P/Halley, and the rings of Saturn. Birkeland’s vision of field-aligned currents became the source of a controversy that continued for half a century, because their existence could not be confirmed from ground-based measurements alone. The absolute proof of Birkeland’s field-aligned currents could only come from observations made above the ionosphere with satellites. A magnetometer onboard a US satellite, launched in 1963, observed magnetic disturbances on nearly every pass over the high-latitude regions of the Earth. The magnetic disturbances were originally interpreted as hydromagnetic waves, but it was soon realized that they were due to fieldaligned or Birkeland currents, as they are called today. Birkeland even estimated the total currents at 106 A – still a realistic value. The scale of Birkeland’s research enterprises was such that the time-honored matter of funding became an overwhelming obstacle. Recognizing that technical invention could bring wealth, he spent much time on applied science. In 1900, he obtained patents on what we now call an electromagnetic rail gun and, with some investors, formed a firearms company. The rail gun worked, except the high muzzle velocities he predicted (600 m/s) were not produced. At one demonstration, the coils in the rail gun shorted and produced a sensational inductive arc complete with noise, flame, and smoke. It easily could have been repaired and another demonstration organized. However, fate intervened in the form of an engineer named Sam Eyde. Eyde told Birkeland that there was an industrial need for the biggest flash of lightning that can be brought down to Earth in order to make artificial fertilizer. Birkeland’s climactic reply was “I have it.” He worked long enough to build a (the Birkeland–Eyde) plasma-arc device for the first industrial nitrogen-fixation process. Thus, the Birkeland fixation method was the founding of Norsk Hydro, still today a major industrial enterprise, and one of Norway’s largest companies. Birkeland then enjoyed adequate funding for his only real interest, basic research. Birkeland continued with industrial inventions and had altogether 60 different patents. Today, Birkeland’s plasma torches find application in the steel industry, tool hardening, and nitrification of radioactive waste. In his last years, Birkeland’s main scientific work was an extension of his theory on aurorae and geomagnetic disturbances to a more general theory of the cosmos. He concluded, in 1908, that charged particles are continuously emitted from the Sun and that electromagnetic forces are as important as gravity in the Universe. Birkeland based most of his ideas on models from the results of laboratory experiments. He contributed greatly to the study of solar-terrestrial physics. He introduced many ideas that still remain central to these fields. His work was truly the foundation for modern space physics. In the field of basic physics Birkeland had nearly 70 publications plus three books. His main contribution remains The Norwegian Aurora Polaris Expedition 1902–1903. It was published in two volumes in 1908 and 1913, respectively, and is nearly 850 pages long. It is still a good reference book for solar-terrestrial physics. Birkeland’s pioneering work underlies many of our present ideas concerning the three-dimensional nature of the Earth’s magnetosphere, the workings of polar geomagnetic activity, the aurora, and the connection of the Sun to the magnetosphere. His students included additional auroral observers and theorists Lars Vegard, Ole Andreas Krogness, and Olaf Devik, as well as professors of mathematics (Thoralf Sklem) and physics (Sem Saeland) at the University of Oslo. The Norwegian government (in 1994) honored its most famous scientist with a 200 kr banknote (equivalent to approximately US $30) bearing Birkeland’s likeness. Alv Egeland Selected References Alfvén, H. and Egeland, A. (1986). Auroral Research in Scandinavia (The First Birkeland Lecture). Oslo: Norwegian Academy of Science and Letters. Birkeland, K. (1895). “Solution générale des équations de Maxwell pour un milieu absorbant homogène et isotrope.” Comptes rendus de l’Académie des sciences 120: 1046–1050. ——— (1895). “Sur la transmission de l’énergie. ” Archives des sciences physiques et naturelles, 3ème période, 33: 297–309. ——— (1896). “Sur les rayons cathodiques sous l’action de forces magnétiques.” Archives des sciences physiques et naturelles, 4éme période, 1: 497–512. ——— (1898). “Sur le phénomene de succion de rayons cathodique par un pole magnétique.” Archives de sciences physiques et naturelles, 4éme période, 6: 205–228. ——— (1901). “Expédition Norvégienne de 1899-1900 pour l’étude des aurores boréales: Résultats des recherches magnetiques.” Videnskabsselskapets skrifter 1, Mat.-naturv. klasse, Christiania, no. 1. ——— (1908). The Norwegian Aurora Polar Expedition 1902-1903. Vol. 1, On the Cause of Magnetic Storms and the Origin of Terrestrial Magnetism. Sect. 1. Christiania: Aschehoug. ——— (1911). “Sur la constitution électrique du Soleil. ” Comptes Rendus de l’Académie des sciences 153: 513–516. ——— (1913). The Norwegian Aurora Polar Expedition 1902–1903. Vol. 1, On the Cause of Magnetic Storms and the Origin of Terrestrial Magnetism. Sect. 2, pp. 317–801. Christiania: Aschehoug. ——— (1915). “On a Possible Crucial Test of the Theories of Auroral Curtains and Polar Magnetic Storms.” Videnskaps-selskapets skrifter 1, Mat.-naturv. klasse, Christiania, No. 6. ——— (January–March 1917) “Simultaneous Observations of the Zodiacal Light from Stations of Nearly Equal Longitude in North and South Africa.” Cairo Scientific Journal 9, no. 100: l. Egeland, A. (1986). “Kristian Birkeland: The Man and the Scientist.” In American Geophysical Union Monograph. Washington, DC: American Geophysical Union. Birkhoff, George David Born Died Overisel, Michigan, USA, 21 March 1884 Cambridge, Massachusetts, USA, 12 November 1944 American mathematician George Birkhoff developed two theorems with astronomical applications, one (the ergodic theorem) relevant to systems where one wants to take averages over time Birmingham, John and space, and one (Birkhoff ’s theorem) showing that some results of Newtonian gravitation also apply to general relativistic models of the Universe under certain circumstances. He was the son of David Birkhoff, a doctor, and Jane Gertrude Droppers. At the age of 12, Birkhoff entered the Lewis Institute, a West Side Chicago liberal arts and sciences college that merged in 1940 with the Armour Institute to become what is now the Illinois Institute of Technology. In 1901, a year before his graduation from Lewis Institute, he began a correspondence with mathematician Harry Vandiver on number theory that would lead to his first publication in 1904. Upon graduation from Lewis Institute, Birkhoff entered the University of Chicago, spending only a year there before transferring to Harvard in 1903. He received an A.B. in 1905 and an A.M. in 1906, both in mathematics. Birkhoff returned to the University of Chicago in 1906 to study for his doctorate. His doctoral thesis, which was purely mathematical in nature, was submitted in 1907 under the title Asymptotic Properties of Certain Ordinary Differential Equations with Applications to Boundary Value and Expansion Problems. It was also in this year that Birkhoff accepted a post as a lecturer at the University of Wisconsin at Madison. It was in Madison where he married Margaret Elizabeth Grafius in 1908. The couple had three children including son Garrett Birkhoff, a well-known mathematician. In 1909, Birkhoff accepted the post of preceptor of mathematics at Princeton where he became a professor in 1911. However, in 1912, Birkhoff moved again, this time back to his alma mater, Harvard, where he became a full professor in 1919 and where he remained for the rest of his life. Also in 1919, he served as vice president of the American Mathematical Society [AMS]. In 1923, the AMS awarded Birkhoff the first Bôcher Memorial Prize, and he served as president in 1925 and 1926. In 1932, Birkhoff was given the post of Perkins Professor, and in 1936 he became the Dean of the Faculty of Arts and Sciences. There is a crater on the Moon named after Birkhoff; his other awards and honors are too numerous to name. However, he had one serious character flaw that had a significant effect on his relations with other scientists of his day: Birkhoff was unabashedly anti-Semitic. Some of his actions included hindering the appointment of Jews to posts at Harvard and making openly anti-Semitic remarks in his correspondence. During the 1930s and 1940s Birkhoff did help a few European refugees get jobs, though none at Harvard. Birkhoff was primarily a mathematician, but several aspects of his work were to become useful in astrophysics. Jules Poincaré was considered Birkhoff ’s greatest influence, though it was purely from Birkhoff ’s intense reading of Poincaré’s work that this influence was gained. In 1913, Birkhoff proved Poincaré’s last geometric theorem, which is a special case of the 3-body problem. His main body of work was on dynamics and ergodic theory. In fact he developed the ergodic theorem that turned the Maxwell–Boltzmann kinetic theory of gases into a rigorous principle using a process known as Lebesgue measure. Ergodic theory has been applied to numerous astrophysical processes including orbital mechanics, stellar dynamics, gravitation, the propagation of photons in the solar corona, and relativistic cosmology. Within astrophysics, Birkhoff was perhaps best known for what is now referred to as Birkoff ’s theorem. In 1923, he proved generally that there is a unique solution to Albert Einstein’s field equations for a spherically symmetric distribution of matter. One way of writing this solution is: (d2R)/(dt2) = −(4/3)πGρR(t) , where R(t) represents a dimensionless factor that describes an expansion, in this case, of the Universe. This equation describes the acceleration of a mass shell in the Universe and shows that it is dependent only on ρ and R. Birkhoff ’s theorem holds even when general relativity is included making it a vital component in the study of cosmology. It was, for example, an important starting point for Georges Lemaître in the evolution of his primeval-atom hypothesis. Ian T. Durham Selected References Birkhoff, George David (1942). “What Is the Ergodic Theorem?” American Mathematical Monthly 49: 222–226. ——— (1950). Collected Mathematical Papers. 3 Vols. Providence, Rhode Island: American Mathematical Society. Carroll, Bradley W. and Dale A. Ostlie (1996). An Introduction to Modern Astrophysics. Reading: Addison Wesley Longman. Kaplan, James and Aaron Strauss (1976). “Dynamical Systems: Birkhoff and Smale.” Mathematics Teacher 69: 495–501. Kragh, Helge (1996). Cosmology and Controversy: The Historical Development of Two Theories of the Universe. Princeton, New Jersey: Princeton University Press. Mac Lane, Saunders (1994). “Jobs in the 1930s and the Views of George D. Birkhoff.” Mathematical Intelligencer 16, no. 3: 9–10. Morse, Marston (1946). “George David Birkhoff and His Mathematical Work.” Bulletin of the American Mathematical Society 52: 357–391. Phillips, Ralph (1994). “Reminiscences about the 1930s.” Mathematical Intelligencer 16, no. 3: 6–8. Vandiver, H. S. (1963). “Some of My Recollections of George David Birkhoff.” Journal of Mathematical Analysis and Applications 7: 271–283. Wilson, Edwin B. (1945). “George David Birkhoff.” Science 102: 578–580. Birmingham, John Born Died probably Milltown near Tuam, Co. Galway, Ireland, May 1816 Milltown, Co. Galway, Ireland, 8 September 1884 John Birmingham was a talented amateur astronomer and polymath who is noted for his discovery of the recurrent nova T Coronae Borealis in 1866 and for his systematic study of red stars, which culminated in the publication of his Red Star Catalogue by the Royal Irish Academy in 1877. Birmingham was the only child of Edward Birmingham and Elly Bell of Millbrook House, Milltown. The Birminghams were descended from the Anglo–Norman family of De Bermingham, barons of Athenry, who owned large estates in Connaught until their confiscation in the 17th century. Land restorations by Charles II included the granting of an estate near Milltown, 200 acres of which were inherited by Major John Birmingham, grandfather of the astronomer. B 129 130 B Birmingham, John John Birmingham was educated at Saint Jarlath’s College in Tuam and also received private tuition in Latin at home. In 1832, at the age of 16, he was apprenticed to Richard Jennings, a neighboring solicitor. Little else is known about his education except that he is reputed to have spent 6 or 7 years studying in Berlin. During that time he traveled widely in Europe and became competent in several languages. By 1854, Birmingham was residing in Millbrook House and, apart from his duties as landlord, was studying the geology of the surrounding countryside. Although no portrait of him exists, he was said to have been tall and well built, and his athletic prowess earned him the sobriquet “The Big Fellow.” It is not difficult to imagine him striding over the east Galway landscape searching for fossils and mineral specimens. Richard Griffith, the distinguished Irish geologist, encouraged Birmingham to survey the glacial deposits of Galway Bay and southeast Mayo. This work resulted in his first scientific paper, presented at the Dublin meeting of the British Association for the Advancement of Science in 1857. More detailed presentations of his work were given to the Geological Society of Dublin in 1858 and 1859 and gave rise to a vigorous discussion between the leading experts of the time. Birmingham’s well-informed letters and articles on comets that appeared in The Tuam Herald between 1859 and 1861 attest to his keen interest in astronomy. However, his astronomical talents came to a much wider notice in 1866: On my way home from a friend’s house, on the night of May 12, I was struck with the appearance of a new star in Corona Borealis … . Its colour appeared to me nearly white, with a bluish tinge; and, during the two hours that I continued to observe it, I detected no change in its light or in its magnitude … . I regret to say that my instrumental means of observation were limited to an ordinary telescope with a power of about 25. [Monthly Notices of the Royal Astronomical Soceity, 26(1866): 310.] Birmingham immediately wrote a letter to The Times of London, but it was ignored, so he wrote directly to William Huggins at Tulse Hill. Huggins confirmed the nova and examined its spectra, which indicated that the star was surrounded by a shell of hydrogen. This nova was the brightest since that of 1604 and the first to be identified with an existing star; it had been listed at magnitude 9.5 in the Bonner Durchmusterung (Bonn survey), and by early June it had returned to ninth magnitude. A subsequent outburst occurred in 1946 with smaller ones in 1963 and 1975. Birmingham soon purchased a 4½-in. Cooke refractor on an equatorial mount. It was set up inside a large wooden house with a sliding roof beside Millbrook House. Using a regular magnifying power of 53× he was able to observe down to 12th magnitude. Using this telescope, Birmingham made a special study of red stars. In 1872, the Reverend Thomas Webb suggested that Birmingham should revise and update Hans Schjellerup’s renowned Red Star Catalogue. Birmingham’s catalog of 658 stars, with numerous spectroscopic observations, was presented to the Royal Irish Academy on 26 June 1876 and published the following year. On 14 January 1884, the Academy awarded him its highest scientific award, the Cunningham Gold Medal, for his outstanding research. In 1866, Johann Schmidt, the director of Athens Observatory claimed that he had observed an obscuration of the lunar crater Linné, implying an explosive volcanic event on the Moon. This claim caused Birmingham to write an article “A Crater on the Moon” for the journal Good Works for Young People. Although Schmidt’s claim was later discounted, the article is a cogent and well-argued commentary on the current theories of lunar craters, and it demonstrates Birmingham’s scientific integrity and ability to write clearly. He corresponded with Schmidt, Angelo Secchi, Webb, and others on lunar matters, and the naming for him of a feature in Mare Frigoris recognized Birmingham’s contributions. This designation was later changed to a 92 km-diameter crater at 65°.1 N, 10°.5 W, to the south of Anaxagoras. Apart from red stars and the Moon, Birmingham’s astronomical interests covered a wide range of other topics including comets, meteor showers, sunspots, occultations, and some of the planets. These findings were published mainly in Monthly Notices of the Royal Astronomical Society, Astronomische Nachrichten, and Nature. His last astronomical paper was an account of his observations of the transit of Venus across the Sun’s disk on 8 December 1882. In the course of his work Birmingham corresponded with many astronomers. They included the renowned stellar spectroscopist Secchi at Rome, Schjellerup and Heinrich d’Arrest at Copenhagen, Schmidt at Athens, Walter Doberck at Markree, County Sligo, Huggins at Tulse Hill, London, Robert Ball at Dunsink, and many others. Apart from his scientific work, Birmingham was accomplished in many other ways. As a gifted poet he often turned to verse to express his thoughts. He had a keen ear and played the violin and piano very well. He was a devout Roman Catholic, noted for his modesty and compassion and was loved and respected by his tenants and neighbors. Birmingham died from an attack of jaundice on the morning of 8 September 1884. As he never married, all his possessions were auctioned. His telescope was purchased for Saint Jarlath’s College in Tuam where it still remains. His 700-volume library and Cremona violin were among other items sold. Millbrook House became an isolated and roofless ruin, and the big trees around it were felled in the 1940s. At the time of his death, Birmingham was a local inspector of applications for loans under the Land Law (Ireland) Act and an inspector of the Board of Works. These duties must have weighed heavily on him, as he was also engaged in a revision of his 1877 catalog. The second edition was eventually completed by the Reverend Thomas Espin in 1888 and became a standard reference. In spite of his isolation, John Birmingham achieved much. Ian Elliott Selected References Birmingham, John (1866). “The New Variable near ε Coronae.” Monthly Notices of the Royal Astronomical Society 26: 310. ——— (1877). “The Red Stars: Observations and Catalogue.” Transactions of the Royal Irish Academy 26: 249–354. Mohr, Paul (1994). “John Birmingham of Tuam: A Most Unusual Landlord.” Journal of the Galway Archaeological and Historical Society 46: 111–155. ——— (1995). “Tuam, Rome and Berlin – Letters from John Birmingham.” Irish Astronomical Journal 22: 203–212. ——— (1996). “John Birmingham on ‘Coggia’s Comet. (Comet III., 1874.).’” Irish Astronomical Journal 23: 209–214. ——— (1997). “John Birmingham on ‘A Crater in the Moon.’” Irish Astronomical Journal 24: 59–72. ——— (1998). “A Cometary Conflagration in the West of Ireland: ‘Pædæophilus’ versus John Birmingham.” Irish Astronomical Journal 25: 179–206. ——— (2002). John Birmingham Esq. - Tuam and Ireland's New Star. Millbrook Nova Press, Coran Dola, Co. Galway. Bīrūnī Birt, William Radcliff Born Died Southwark, (London), England, 15 July 1804 Leytonstone, (London), England, 14 December 1881 William Birt is considered one of the leading selenographers during the 1860s and 1870s and contributed greatly to contemporary understanding of the surface of the Moon. He also studied sunspots and the solar rotation. Birt founded the Selenographical Society and Selenographical Journal in 1878. A crater on the Moon bears his name. Birt’s work with John Herschel influenced the search for a meteorological model of the Earth. Birt’s first published astronomical articles were on the periodical variations in the brightness of β Lyrae and α Cassiopeiae in the Monthly Notices of the Royal Astronomical Society. While living near Bethnal Green in London, Birt made an observational evaluation of a celestial map produced by the Astronomical Society (now the Royal Astronomical Society) for the Diffusion of Useful Knowledge during 1831 and 1832. He communicated a dozen corrections for the celestial map to John William Lubbock, and further proposed a Milky Way survey project. As a result of Birt’s early astronomical work, he came to the attention of John Herschel, who liked Birt’s mathematical thoroughness. Herschel employed Birt in making and analyzing meteorological measurements. Between 1839 and 1843 Birt acted as Herschel’s “computer,” compiling, arranging, and reducing many series of barometric measurements. The intent of this effort is well illustrated in a July 1843 letter Herschel wrote to Birt hypothesizing that the atmosphere might be considered “a vehicle for wave-like movement which may embrace in their single swell & fall a whole quadrant of a globe.” In the early 1840s, Herschel proposed to the British Association for the Advancement of Science that Birt be appointed as the director of the new project to discover laws of weather behavior. Birt enthusiastically accepted the offer. Birt’s first publication was a report to the British Association sharing a summary of Wilhelm Dove’s account of “Arial Currents in the Temperate Zone.” He also wrote on the popular topic of cloud formation in Louden’s Natural History Journal. After five reports for the British Association and several contributions to the Philosophical Magazine, however, Birt dropped the research in 1849 without a conclusive explanation of midlatitude atmospheric disturbances. He declared that the 6-year effort was less than rewarding. Birt’s last meteorological work was the Handbook of the Law of Storms (1853), a digest of the storm research meant to help with the navigation of ships. The Handbook was found useful by ship captains in avoiding storms; a second edition was published in 1879. Birt then returned to astronomy, his first scientific love. He built his own private observatory in 1866 and also spent many nights observing with his colleague, Dr. John Lee at the latter’s Hartwell Observatory. It was during the late 1860s and 1870s that Birt’s research reached its greatest productivity. In addition to founding the Selenographic Society, he was deeply involved in attempting to detect the exciting transient lunar phenomena then being reported frequently, particularly in the craters Geminus, Linné, and Plato. In May 1870, it was Birt’s opinion that the lights around the crater Plato were not from the effects of sunlight. “There was an extraordinary display” on 13 May according to Birt. By April of 1871, selenographers had recorded over 1,600 observations of the fluctuations of the lights in Plato, and had drawn 37 graphs of individual lights. (All these observations and graphs are in the archives of the Royal Astronomical Society.) Birt was among those in the astronomical community who leaned strongly toward the hypothesis that volcanic eruptions still took place on the Moon from time to time. The lights in the floor of Plato were considered strong possible evidence in support of that hypothesis. Also in support of that hypothesis, Birt published an article in the Student and Intellectual Observer in 1868 entitled: “Has the surface of the Moon attained its final condition?” Birt’s major selenographical contribution, however, was in an effort to upgrade the best lunar map then available, that of Wilhelm Beer and Johann von Mädler. Birt found at least 368 craters on the Moon’s surface, many of which were very small, that had not been cataloged by Beer and Mädler. Birt organized a committee on mapping the surface of the Moon, the membership of which included John Phillips, Sir John Herschel, Warren De La Rue, William Parsons (Lord Rosse), and Thomas Webb. The committee’s goal was to map the Moon’s surface at a scale of 200 in. to the diameter of the Moon. This was an ambitious project compared to the 37.5-in.-map of Beer and Mädler. As secretary of the committee, Birt published five reports on the committee’s progress in the Proceedings of The British Association for the Advancement of Science. Robert McGown Selected References Anon. (10 November 1871). “Selenographical.” English Mechanic 14: 194–195, see “W.R. Birt.” Anon. (1882). “William Radcliff Birt.” Monthly Notices of the Royal Astronomical Society 42: 142–144. Jankovic, Vladimir (1998). “Ideological Crests versus Empirical Troughs: John Herschel’s and William Radcliffe Birt’s Research on Atmospheric Waves, 1843–1850.” British Journal for the History of Science 31: 21–40. Sheehan, William P. and Thomas Dobbins (2001). Epic Moon: A History of Lunar Exploration in the Age of the Telescope. Richmond, Virginia, Willmann-Bell, 2001, p. 149. Bīrūnī: Abū al-Rayḥān Muḥammad ibn Aḥmad al-Bīrūnī Born Died 4 September 973 possibly Ghazna (Afghanistan), circa 1050 Bīrūnī was one of the most accomplished scientists of the entire Middle Ages, and his interests extended to almost all branches of science. The total number of his works, mostly in Arabic, is 146, of which only 22 are extant. Approximately half of these writings are in the exact sciences. In addition to mathematics, astronomy, and astrology, he was accomplished in the fields of chronology, geography, pharmacology, and meteorology. B 131 132 B Bīrūnī Bīrūnī was born in the “outskirts” (bīrūn) of Kāth, a city in the district of ancient Khwārizm, which is located south of the Aral Sea. At the beginning of his career, he worked for the Sāmānid ruler Manṣūr II, but due to political turmoil he had to change his patrons frequently. Eventually, he was captured as a political prisoner by the Ghaznawid Sultan Maḥmūd and was taken to Ghazna, where he remained until his death. In his youth, Bīrūnī studied Greek science, especially astronomy. He was convinced of the importance of observation, and he recorded many of his own observations in his books. One of these works is his Taḥdīd al-amākin (Determination of coordinates of cities), which he wrote as a prisoner on his journey in 1018 from Khwārizm to Ghazna. In this book, Bīrūnī mentions a lunar eclipse of 997 that he observed in Khwārizm, having arranged a simultaneous observation with Abū al-Wafā’ al-Būzjānī who was residing in Baghdad. Bīrūnī’s aim was to find the difference in longitude of the two cities. Bīrūnī’s The Chronology of the Ancient Nations, written in about 1000, is a mine of information on calendars used by the Persians, Sogdians, Kwārizmians, Jews, Syrians, Ḥarrānians, Arabs, and Greeks. This is still one of the most reliable sources on ancient and medieval chronology. Bīrūnī does not mention much about India, because at this time he was not yet well informed about the Indian calendar. In the second half of his life, Bīrūnī became more and more interested in Indian culture. This change may have been the result of his accompanying Sultan Mahmūd on several expeditions to India. By virtue of Bīrūnī’s service as an interrogator of Indian prisoners, among whom were learned scholars, he was able to accumulate much knowledge of Indian culture, especially that of the exact sciences written in Sanskrit. His studies on India resulted in his masterpiece called India, completed in 1030. With this book, Bīrūnī well deserves to be called “the first Indologist” in the modern sense of the word. One may characterize Bīrūnī’s attitude toward Indian culture as a mixture of sympathy and criticism; on the whole, he was fair and without prejudice. Because he was well acquainted with Greek science, Bīrūnī was able to compare Greek and Indian astronomy and make evaluative comments. The Indian astronomer whom he referred to most frequently was Brahmagupta. He even stated that he intended to translate Brahmagupta’s Brāhmasphuṭasiddhānta into Arabic; however, since he was unable to complete it, he instead provided a table of contents. Bīrūnī was most productive in the years around 1030, after Maḥmūd died and the throne passed on to his elder son Mas�ūd, to whom Bīrūnī dedicated his magnum opus on astronomy, al-Qānūn al-Mas�ūdī. The book consists of 11 treatises (maqālas), each containing several chapters (bābs); some chapters are further subdivided into sections ( faṣls). Treatise I is an introduction, dealing with the principles and basic concepts of astronomy as well as cosmology, time, and space. Treatise II deals with calendars, the three best known being the Hijra, Greek (i. e., Seleucid), and Persian. Treatise III is on trigonometry. Treatise IV takes up spherical astronomy. Treatise V discusses geodesy and mathematical geography. Treatise VI is on time differences, the solar motion, and the equation of time. Treatise VII deals with the lunar motion. Treatise VIII is on eclipses and crescent visibility. Treatise IX is on the fixed stars. Treatise X is on the planets. Treatise XI describes astrological operations. Al-Qānūn al-Mas�ūdī is primarily based on Ptolemy’s Almagest, but many new elements, of Indian, Iranian, and Arabic origin, are added. Bīrūnī also tried to improve Ptolemy’s astronomical parameters using the observations that were made by his predecessors and by himself. He refers to the elements of Indian calendar and chronology in Treatises I and II. In Treatise III, after explaining the chords according to Ptolemy, he offers a table of sines as well as a table of tangents (gnomon shadows). The 1,029 fixed stars are tabulated in Table IX.5.2 following the model of those in the Almagest (where the number is 1,022). To the longitude of the stars in the Almagest, Bīrūnī added 13° according to the increase from Ptolemy’s time due to the precession of equinoxes. The magnitudes of the stars are given in two columns, one based on the Almagest and the other from Ṣūfī’s book on 48 constellations. Bīrūnī’s planetary theory, which is found in Treatise X, is essentially the same as Ptolemy’s, with some modifications in the parameters. The last treatise is on the topic of astrology, which require highly advanced knowledge of mathematics; these include the equalization of the houses and the determination of the length of one’s life by means of the computation of an arc called tasyīr. Although al-Qānūn al-Mas�ūdī did not have much influence in medieval Europe, the book was well read in the eastern half of the Muslim world and indeed further east. One example of this is that a very peculiar irregularity in Mercury’s first equation table in the al-Qānūn can be attested to in the Chinese text Huihui li (composed in 1384). Another major work of Bīrūnī is on astrology: Kitāb al-tafhīm liawā’il ṣinā�at al-tanjīm. The Arabic manuscript in the British Museum was published with an English translation by R. R. Wright. The translation, however, was made from a Persian version. This book is divided into three parts with the subject areas being mathematics, astronomy, and astrology. Bīrūnī’s aim is very clearly stated by himself: “I have begun with geometry and proceeded to arithmetic and the science of numbers, then to the structure of the Universe, and finally to judicial astrology, for no one is worthy of the style and title of astrologer who is not thoroughly conversant with these four sciences.” It is undoubtedly because Bīrūnī and his work were not well known to medieval Europeans that his Latinized name survives in a modern French dictionary as “aliboron,” which means “stupid person” – clearly an inept description for this Islamic medieval polymath whose passion for knowledge was reflected in the scope and areas of interest he pursued. Michio Yano Selected References Al-Bīrūnī, Abū al-Rayhān Muhammad b. Ahmad (1954–1956). Al-Qānūn al-Masʕūdī. Hyderabad. (This book has been translated into Russian; for English readers, Kennedy prepared a very convenient table of contents with brief summaries in English.) Ali, Jamil (trans.) (1967). The Determination of the Coordinates of Cities: Al-Bīrūnī’s Tahdīd al-Amākin. Beirut: American University of Beirut. Barani, Syed Hasan (1951). “Muslim Researches in Geodesy.” In Al-Bīrūnī Commemoration Volume, A.H. 362–A.H. 1362. Calcutta: Iran Society, pp. 1–52. Boilot, D. J. (1955). “L’oeuvre d’al-Beruni, Essai bibliographique.” Mélange de l’Institut dominicain d’étude orientales 2: 161–256. Kennedy, E. S. (1970). “Al-Bīrūnī.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 2, pp. 147–158. New York: Charles Scribner’s Sons. ——— (1971). “Al-Bīrūnī’s Masudic Canon.” Al-Abhath 24: 59–81. (Reprinted in E. S. Kennedy, Colleagues, and Former Students, Studies in the Islamic Exact Sciences, edited by David A. King and Mary Helen Kennedy. Beirut: American University of Beirut, 1983, pp. 573–595. [Contains a convenient table of contents of the al-Qānūn al-Masʕūdī with brief summaries in English.]) Biṭrūjī ——— (1973). A Commentary Upon Bīrūnī’s Kitāb Tahdīd al-Amākin. Beirut: American University of Beirut. ——— (1976). The Exhaustive Treatise on Shadows by Abū al-Rayhān Muhammad b. Ahmad al-Bīrūnī, translation and commentary. 2 Vols. Aleppo: Institute for the History of Arabic Science. Sachau, C. Edward (1879). The Chronology of Ancient Nations. London. ——— (1910). Alberuni’s India. 2 Vols. Reissue of the 1888 edition. London. Samsó, Julio (1996). “Al-Bīrūnī’ in al-Andalus.” In From Baghdad to Barcelona: Essays on the History of the Islamic Exact Sciences in Honour of Prof. Juan Vernet, edited by Josep Casulleras and Julio Samsó. Vol. 2, pp. 583–612. Barcelona: Instituto “Millás Vallicrosa” de Historia de la Ciencia Árabe. Wright, R. Ramsey (1934). The Book of Instruction in the Elements of the Art of Astrology. London: Luzac and Co. Yano, Michio (2002). “The First Equation Table for Mercury in the Huihui li.” In History of Oriental Astronomy, edited by S. M. Razaullah Ansari, pp. 33–43. Dordrecht: Kluwer Academic Publishers. Biṭrūjī: Nūr al-Dīn Abū Isḥāq [Abū Ja�far]Ibrāhīm ibn Yūsuf al-Biṭrūjī Flourished Andalusia (Spain), 1185–1192 Biṭrūjī was a famous Andalusian (Arab) cosmologist who wrote an astronomical work that was quite influential in Latin Europe, where he was known as Alpetragius. Little is known of his life. He was probably a disciple of the philosopher Ibn Ṭufayl (died: 1185/1186), who was already dead when Biṭrūjī wrote his Kitāb fī al-hay’a. On the other hand, an anonymous treatise on tides (Escorial MS 1636, dated 1192) contains ideas seemingly borrowed from Biṭrūjī’s work. A more definitive guide to dating is Michael Scot, who finished his Latin translation of Biṭrūjī’s work in Toledo in 1217. His book was also translated into Hebrew by Mosheh ben Tibbon in 1259, and one of the manuscripts of this Hebrew translation states that he was a judge. A late 15th-century Moroccan source calls him faqīh (jurist). His name, al-Biṭrūjī, may be a corruption of al-Biṭrawshī, derived from Biṭrawsh, a village in Faḥṣ al-Ballūṭ (Cordova province). Biṭrūjī’s only extant work bears the title Kitāb [murta�ish] fī alhay’a (A [revolutionary] book on cosmology), which is extant in two Arabic manuscripts, the Latin translation of Scot, the Hebrew translation of ben Tibbon, and the Latin by Calo Calonymos (1286–circa 1328) from the Hebrew. A modern English translation and commentary can be found in Goldstein (1971). Biṭrūjī’s book is the final result of the efforts made by Andalusian Aristotelian philosophers of the 12th century (Ibn Bājja, Ibn Ṭufayl, Ibn Rushd, and Maimonides) to overcome the physical difficulties inherent in the geometrical models of Ptolemy’s Almagest and to describe the cosmos in agreement with Aristotelian or Neoplatonic physics. It is a book on hay’a (theoretical astronomy/cosmology). Earlier Andalusian work in this genre include two books by Qāsim ibn Muṭarrif al-Qaṭṭān (10th century), who followed the line of Ptolemy’s Planetary Hypotheses, and an anonymous Toledan author of the second half of the 11th century who seems to represent the earliest Andalusian attempt to criticize the Almagest from a physical point of view. Despite these precedents in the Islamic west, Biṭrūjī seems to be the first to present alternatives to Ptolemy’s models. His knowledge of the astronomical literature, though, was limited; he had probably read the Almagest, but he does not seem to have understood it completely. According to Biṭrūjī, Ptolemy was the archetypical mathematical astronomer who created imaginary models that were successful in their ability to predict planetary positions but were totally unreal. Besides Ptolemy, Biṭrūjī may have read Theon of Alexandria’s Commentary to the Almagest. He also was well acquainted with the treatise on the motion of the fixed stars by Zarqālī. Furthermore, he quotes Jābir ibn Aflaḥ’s Iṣlāḥ al-Majisṭī (Revision of the Almagest) regarding the problem of the order of the planets in the Solar System but rejects Jābir’s proposal to put both Mercury and Venus above the Sun, opting instead to make only Venus a superior planet. Jābir had argued that proposal on the basis of a lack of records of Mercury or Venus transits, but Biṭrūjī suggested that this might be because of both Mercury and Venus being self-luminous. Biṭrūjī presented the first non-Ptolemaic astronomical system after Ptolemy, although he admits that the results are only qualitative. As a follower of Aristotle, his system is homocentric, the celestial bodies being always kept at the same distance from the center of the Earth. Despite this, Biṭrūjī employs mathematical eccentrics and epicycles, which are placed on the surface of the corresponding sphere and in the area of the pole. Apparently, he has adapted ideas derived from Zarqālī’s trepidation models or perhaps from Eudoxus. One of the most original aspects of Biṭrūjī’s system is his proposal of a physical cause of celestial motions. Biṭrūjī uses the idea of impetus, originally put forth by John Philoponus (6th century) to deal with forced motion in the sublunar world, to account for the transmission of energy from a first mover that is placed in the ninth sphere. The motion of the ninth sphere, which rotates uniformly once every 24 hours, is transmitted to the inner spheres, and it becomes progressively slower as it approaches the Earth. The velocity of rotation of each sphere is used by Biṭrūjī to establish the order of the planets. It is noteworthy that Biṭrūjī is applying the same dynamics to the sublunar and the celestial worlds, contradicting the Aristotelian idea that there is a specific kind of dynamics for each world. Indeed, the force of the first mover reaches the sublunary world causing the rotation of comets in the upper atmosphere as well as the tides. Similar ideas can also be found in Ibn Rushd. Both Ibn Rushd and Biṭrūjī use another idea to explain this transmission of motion: the celestial spheres feel a “passion” or “desire” (shawq, desiderium) to imitate the sphere of the first mover, which is the most perfect one. Thus the spheres closer to the first mover are most like the ninth sphere and therefore move faster, while those farther away move slower. This use of shawq seems to derive from Neoplatonic notions developed by the philosopher Abū al-Barakāt al-Baghdādī (died: 1164), whose ideas may have been introduced into Andalusia by his disciple Abū Sa�d Isaac, the son of Abraham ibn �Ezra. Impetus and shawq were used by Biṭrūjī in his attempt to solve a puzzling problem: How can one explain that the unique first mover can produce both the daily east–west motion and the longitudinal (zodiacal) west–east motions in the planetary spheres? Biṭrūjī’s explanation is that the motions in longitude can be explained as a “delay” (taqṣīr, incurtatio) in the perfect daily motion being transmitted by the first mover; this delay becomes progressively more noticeable in the planetary spheres further away from the first mover. Biṭrūjī builds his geometrical models on this theoretical basis. Taqṣīr corresponds to the planetary motion in longitude while Biṭrūjī seems to identify shawq with the anomaly. In the case of the planets, B 133 134 B Bjerknes, Vilhelm Frimann Koren each one of them moves near the ecliptic but its motion is regulated by the pole of each planet, placed at a distance of 90° from the planet itself. This pole rotates on a small polar epicycle whose center moves, as a result of taqṣīr, on a polar deferent. This use of a type of deferent and epicycle (within the context of homocentric astronomy) allows Biṭrūjī to explain, in a way similar to Ptolemy, the irregularities of planetary motions (direct motion, station, retrogradation). The problem is that Biṭrūjī also tries to explain, using the motion in anomaly (rotation of the pole of the planet on the polar epicycle), the changes in planetary latitude. This, however, does not really work since the periods of recurrence in anomaly and in latitude are not the same. Other problems result due to Biṭrūjī’s ambiguity regarding the direction of motions and the fact that shawq does not diminish, as claimed, in the planetary spheres as they are further removed from the first mover. Thus, despite their ingenuity, Biṭrūjī’s models are unable to provide the predictive accuracy of Ptolemy’s models, and there are inconsistent aspects to them as well. In the case of the fixed stars, he proposes a model that results in a variable velocity in the precession of equinoxes, which echoes earlier Andalusian theories of the trepidation of the equinoxes. The geometrical model for the fixed stars is not easy to understand as preserved in the extant texts. A recent paper by J. L. Mancha (2004) gives a new and sophisticated interpretation, based on the Latin translation, which supports the hypothesis formulated by E. Kennedy in 1973 that Biṭrūjī’s homocentric system is an updating and reformulation of the system of Eudoxus. For the motion of the fixed stars the Zarqālian tradition would be combined with aspects of Eudoxus’s models, i. e., he uses a Eudoxan couple that results in a hippopede. With Mancha’s interpretation, Biṭrūjī’s model for the fixed stars makes sense, but we have the problem of establishing which sources available to the Andalusian cosmologist gave him information on Eudoxus’s models. Despite its scientific failings, the Kitāb fī al-hay’a was quite successful. The Latin translation by Michael Scot contributed to its European diffusion between the 13th and the 16th centuries. It was accepted in scholastic circles where it was considered a valid alternative to Ptolemy’s Almagest. The work was also known in the Islamic East, perhaps introduced in Egypt by Maimonides. The Damascene astronomer Ibn al-Shāṭir mentions a certain al-Majrīṭī as having presented non-Ptolemaic models; this may be a corruption of alBiṭrūjī’s name. Julio Samsó Alternate name Alpetragius Selected References Abattouy, Mohammed (2001). “Au dessus ou au-dessous du Soleil: Prolégomènes sur la position de Mercure et Vénus dans la tradition astronomique andalouse.” In Science et pensée scientifique en Occident Musulman au Moyen Age, edited by Bennacer El Bouazzati, pp. 19–42. Rabat: Faculty of Letters of Rabat. Avi-Yonah, Reuven S. (1985). “Ptolemy vs al-Bitrūjī: A Study of Scientific Decision-Making in the Middle Ages.” Archives internationales d’histoire des sciences 35: 124–147. Carmody, Francis J. (1952). Al-Bitrūjī: De motibus celorum. Critical edition of the Latin translation of Michael Scot. Berkeley: University of California Press. (See review by E. S. Kennedy in Speculum 29 (1954): 246–251.) Casulleras, Josep (1998). “The Contents of Qāsim ibn Mutarrif al-Qattān’s Kitāb al-hay’a.” In The Formation of al-Andalus, Part 2: Language, Religion, Culture and the Sciences, edited by Maribel Fierro and Julio Samsó, pp. 339–358. Aldershot: Ashgate. Cortabarría, Angel (1982). “Deux sources de S. Albert le Grand: Al-Bitruji et alBattani.” Mélanges de l’Institut dominicain d’etudes orientales 15: 31–52. Forcada, Miquel (1999). “La ciencia en Averroes.” In Averroes y los averroísmos: Actas del III Congreso Nacional de Filosofía Medieval. Zaragoza: Sociedad de Filosofía Medieval, pp. 49–102. Goldstein, Bernard R. (1971). Al-Bitrūjī: On the Principles of Astronomy. 2 Vols. New Haven: Yale University Press. (See the reviews by Kennedy and Lorch.) Kennedy, E. S. (1973). “Alpetragius’s Astronomy.” Journal for the History of Astronomy 4: 134–136. Lorch, Richard (1974). “Review of Al-Bitrūjī: On the Principles of Astronomy” by Bernard Goldstein. Archives internationales d’histoire des sciences 24: 173–175. Mancha, J. L. (2004). “Al-Bitrūjī’s Theory of the Motion of the Fixed Stars.” Archive for the History of the Exact Sciences 58: 143–182. Sabra, A. I. (1984). “The Andalusian Revolt against Ptolemaic Astronomy: Averroes and al-Bitrūjī.” In Transformation and Tradition in the Sciences, edited by Everett Mendelsohn, pp. 133–153. Cambridge: Cambridge University Press. (Reprinted in Sabra, Optics, Astronomy and Logic, XV. Aldershot: Ashgate, 1994.) Saliba, George (1994). A History of Arabic Astronomy: Planetary Theories during the Golden Age of Islam. New York: New York University Press. ——— (1999). “Critiques of Ptolemaic Astronomy in Islamic Spain.” Al-Qantara 20: 3–25. Samsó, Julio (1992). Las ciencias de los antiguos en al-Andalus. Madrid: Mapfre, pp. 330–356. ——— (1994). Islamic Astronomy and Medieval Spain. Aldershot: Variorum. Bjerknes, Vilhelm Frimann Koren Born Died Christiana (Oslo, Norway), 14 March 1862 Oslo, Norway, 9 April 1951 Norwegian mathematical physicist and geophysicist Vilhelm Bjerknes is best remembered for his work in meteorology, which, however, had considerable impact on planetary astronomy and the study of the atmospheres of other planets. Bjerknes’ father was Carl Bjerknes, the noted hydrodynamicist who studied under Dirichlet in Paris. His mother was Aletta Koren. Vilhelm was born in what is now Oslo but was then Christiana. (It was renamed Kristiana in 1877 and then Oslo in 1925.) He began undergraduate studies in 1880 at the University of Kristiana and was awarded a Master’s degree from there in 1888. All through this period he had collaborated with his father on hydrodynamical research, but, as his father became more reclusive in his later years, Vilhelm ended the collaboration after he received his Master’s degree. He was awarded a state scholarship that allowed him to travel to Paris in 1889 where he attended lectures by Jules Poincaré on electrodynamics. From 1890 to 1892, Bjerknes worked as an assistant to Heinrich Hertz in Bonn. Later in 1892, he returned to Norway to complete his doctoral thesis based on the work he had performed with Hertz in Bonn on electrical resistance in narrow frequency bands (something that would later become useful in the development of the radio). With his degree in hand, Bjerknes was given a lectureship at the Högskola (School of engineering) in Stockholm in 1893. Two years later he became professor of applied mechanics and mathematical physics at the University of Stockholm. On 2 November 1897, Bjerknes’ wife gave birth to their son Jacob who would later become famous for discovering the mechanism that controls cyclones. A trip to the United States in 1905 began 36 continuous years of funding from the Carnegie Foundation. Blaauw, Adriaan In 1907, Bjerknes returned to Kristiana to take up the post of chair of applied mechanics and mathematical physics. He was not to stay there for long, however. Just 5 years later the University of Leipzig offered him the chair of geophysics. He accepted this offer and took a number of his Kristiana collaborators with him, including his son Jacob, then aged 15. This post was followed in 1917 with an appointment as chair at the University of Bergen where he founded the Bergen Geophysical Institute. Nine years later he made his final move, returning once again to his alma mater, then known as the University of Oslo, to take up the chair he left in 1912. Bjerknes retired in 1932. Most of Bjerknes’ career was based on hydrodynamics in one form or another. He also was the first person to suggest that sunspots were the erupting ends of magnetic vortices that were caused by the Sun’s differential rotation. His work in meteorology produced a number of commonly known terms such as “cold front,” “warm front,” and “stationary front.” He is considered to be the father of modern numerical weather prediction. Bjerknes’ equations (and those produced by his assistants at Bergen) for vortices, which he originally derived from the vortex work of William Thomson (Lord Kelvin) and Hermann von Helmholtz, are so rigorous that modern computers still have difficulty solving them in reasonable timescales. Ian T. Durham Acknowledgment The author wishes to acknowledge Lori Laliberte of Simmons College for helping to compile some of this information. Selected References Bjerknes, V. (1926). “Solar Hydrodynamics.” Astrophysical Journal 64: 93–121. ——— (1937). “Application of Line Integral Theorems to the Hyrodynamics of Terrestrial and Cosmic Vortices.” Astrophysica norvegica 2: 263–339. Bjerknes, J. and C. L. Godske (1936). “On the Theory of Cyclone Formation at Extra-Tropical Fronts.” Astrophysica norvegica 1: 199–235. Friedman, R. M. (1993). Appropriating the Weather: Vilhelm Bjerknes and the Construction of a Modern Meteorology. Ithaca: Cornell University Press. Gold, E. (1951). “Vilhelm Friman Koren Bjerknes.” Obituary Notices of the Royal Society of London 7: 303–317. Blaauw, Adriaan Born Amsterdam, the Netherlands, 12 April 1914 Among many accomplishments, Blaauw is credited with two important ideas in the field of stellar dynamics: First, many clusters of hot, bright stars are unstable and currently dissipating, and so must be very young; second, hot, massive stars with large velocities relative to the disk of the galaxy (runaway stars) might be former members of binary systems whose companions exploded as supernovae, leaving them to move off in a straight line at the speeds they formerly had as orbital speeds. Both contributed to the establishment within astronomy of the principle that star formation is an ongoing process, at a time when this was not widely understood. Blaauw, the son of Cornelis Blaauw and Gesina Clasina Zwart, received his early education in Amsterdam, his bachelor’s and master’s degrees from the University of Leiden, and, in 1946, a Ph.D. (cum laude) from the University of Groningen. The latter was awarded for work on motions of stars in the Scorpio–Centaurus cluster with Pieter van Rhijn. Blaauw’s major professional positions have included: assistantship at the Kapteyn Institute (1938–45), lecturer at Leiden (1953/54), associate professor at the University of Chicago (1953–57), professor at the University of Groningen and director of the Kapteyn Institute (1957–69), director general of the European Southern Observatory (1970–74), professor at Leiden (1975–1981), and guest investigator at the University of Groningen (1981–). His contributions to the study of the structure of the Milky Way include the correct location of the center, based on data from radio astronomy as well as stellar motions, and tracing the local galactic rotation, also from combined observations. Blaauw has been on the forefront of international cooperation in astronomy, as one of the founders of the European Southern Observatory [ESO] and an early director of ESO, as first chair of the board of directors of the journal Astronomy and Astrophysics (which united six previously separate publications from four countries), and as President of the International Astronomical Union. While in this office, he shepherded the return of the People’s Republic of China to membership without loss of the astronomers from the Republic of China (Taiwan) under the rubric “one nation; two adhering organizations.” Blaauw is the recipient of many honors and awards from organizations in the United States, France, England, Scandinavia, Belgium, and Switzerland, as well as from the Netherlands. He is married to Alida Henderika van Muijlwijk; they have one son and three daughters. Eugene F. Milone Selected References Blaauw, A. (1939). “A Determination of the Longitude of the Vertex and the Ratio of the Axes of the Velocity-Ellipsoid from the Dispersions of the Proper Motions of Faint Stars Measured at the Radcliffe Observatory.” Bulletin of the Astronomical B 135 136 B Blackett, Patrick Maynard Stuart Institutes of the Netherlands 8: 305–312. (Dr. Blaauw’s first publication, which indicates what would be his abiding interest in galactic structure.) ——— (1946). “A Study of the Scorpio–Centaurus Cluster.” Publications of the Kapteyn Laboratory, no. 52. (Ph.D. thesis, under the direction of Pieter J. van Rhijn.) ——— (1952). “The Evolution of Expanding Stellar Associations; the Age and Origin of the Scorpio–Centaurus Group.” Bulletin of the Astronomical Institutes of the Netherlands 11: 414–419. ——— (1952). “The Velocity Distribution of the Interstellar Calcium Clouds.” Bulletin of the Astronomical Institutes of the Netherlands 11: 459–473. ——— (1956). “On the Luminosities, Motions, and Space Distribution of the Nearer Northern O-B5 Stars.” Astrophysical Journal 123: 408–439. ——— (1961). “On the Origin of O- and B-type Stars with High Velocities (The ‘Run-Away’ Stars), and Some Related Problems.” Bulletin of the Astronomical Institutes of the Netherlands 15: 265–290. ——— (1963). “The Calibration of Luminosity Criteria.” In Basic Astronomical Data, edited by K. Aa. Strand, pp. 383–420. Vol. 3 of Stars and Stellar Systems. Chicago: University of Chicago Press. ——— (1964). “The O Associations in the Solar Neighborhood.” Annual Review of Astronomy and Astrophysics 2: 213–246. ——— (1965). “The Concept of Stellar Populations.” In Galactic Structure, edited by Adriaan Blaauw and Maarten Schmidt, pp. 435–453. Vol. 5 of Stars and Stellar Systems. Chicago: University of Chicago Press. ——— (1980). “Jan H. Oort’s Work.” In Oort and the Universe, edited by Hugo van Woerden, Willem N. Brouw, and Henk C. van de Hulst, pp. 1–19. Dordrecht: D. Reidel. ——— (1985). “The Progenitors of the Local Pulsar Population.” In Birth and Evolution of Massive Stars and Stellar Groups, edited by W. Boland and H. van Woerden, pp. 211–224. Dordrecht: D. Reidel. ——— (1991). ESO’s Early History. Garching: European Southern Observatory. ——— (1991). “OB Associations and the Fossil Record of Star Formation.” In The Physics of Star Formation and Early Stellar Formation, edited by Charles J. Lada and Nikolaos D. Kylafis. Dordrecht: Kluwer Academic Publishers. ——— (1993). ”Massive Runaway Stars.” In Massive Stars: Their Lives in the Interstellar Medium, edited by Joseph P. Cassinelli and Edward B. Churchwell, p. 219. San Francisco: Astronomical Society of the Pacific. ——— (1995). “Stellar Evolution and the Population Concept after 1950: The Vatican Conference.” In Stellar Populations, edited by P. C. van der Kruit and G. Gilmore, pp. 39–48. IAU Symposium No. 164. Dordrecht: Kluwer (reprinted in 1999 in Astronomy and Astrophysics, 267, 45–54). Blaauw, A., C. S. Gum, J. L. Pawsey, and G. Westerhout (1959). “Definition of the New I. A.U. System of Galactic Coordinates.” Monthly Notices of the Royal Astronomical Society 119: 422–423. De Zeeuw, P. T. et al. (1999). “A Hipparcos Census of the Nearby OB Associations.” Astronomical Journal 117: 354–399. Struve, O. and A. Blaauw (1948). “The Radial Velocity of RR Lyrae.” Astrophysical Journal 108: 60–77. Blackett, Patrick Maynard Stuart Born Died London, England, 18 November 1897 London, England, 13 July 1974 British experimental physicist Patrick Blackett received the 1948 Nobel Prize in Physics for the discovery among cosmic-ray secondaries of the particle now called the muon, confirmation of the positron (discovered by Carl Anderson), and for the instrument development that made these possible. Blackett received his early education at Osborne and Dartmouth Naval Colleges, and was commissioned as a midshipman at the outbreak of World War I, though he had not yet completed his education. He participated in the battles of the Falkland Islands and Jutland, rising to the rank of lieutenant. Blackett had decided by the end of the war to resign his commission and briefly visited the laboratory of James Franck at Göttingen, but the Navy sent him and about 400 other young officers up to Cambridge University for a 6-month course to complete their formal education, and within a few weeks he decided to remain at Cambridge, completing first degrees in mathematics (part I of the tripos in 1919) and physics (part II of the tripos in natural sciences in 1921). Ernest Rutherford had then just arrived in Cambridge, and Blackett began work with him on the study of collision processes using a Wilson cloud chamber as a detector, obtaining unambiguous evidence both for the disintegration of atomic nuclei and for the buildup of a heavy nucleus from the lighter ones. G. P. S. (Beppo) Occhialini (a student of Enrico Fermi) then arrived in Cambridge, also for a short visit that extended for many years. Together they modified the cloud-chamber technique to improve by a very large factor its efficiency for detection of cosmic ray particles. Cloud chambers have a very low duty cycle, and the early ones, fired at random, often caught not even one cosmic-ray secondary particle. The improvement was a coincidence counter, above the chamber, which told the gas to expand, cool, and reveal particle tracks only when a particle had been seen coming. In 1933, Blackett became professor of physics at Birkbeck College, London, where the discovery of the particle with the same charge as an electron, but much larger mass (the muon) occurred. In 1937, he was appointed to the Langworthy Professorship at the University of Manchester, following William L. Bragg. As war approached, Blackett joined the Tizard committee, endorsing the majority report that Britain should develop Watson-Watt’s radar for defense against enemy aircraft, and, later, the Maud committee, from which his minority report urged Britain to join with the United States in the development of atomic weapons as was eventually done rather than proceeding alone. He moved quickly through a variety of wartime positions, finally becoming director of Naval Operations Research (1942–1945), supervising work on bombsights, radar, antisubmarine measures, and much else, including convoy sizes (which he concluded should be as large as possible, rather than being limited to 60 vessels at most). Blackett returned to Manchester in 1945, and implemented a large increase in the size of his department. He encouraged Bernard Lovell to set up trailers of ex-military radar equipment at Jodrell Bank, near Manchester, and made radio astronomy one of the subjects to be studied in his department. Later, he helped Lovell with plans for the construction of the 250-ft. steerable paraboloid and helped him through subsequent financial and political difficulties. In 1947, Blackett suggested that the Earth’s magnetic field was a fundamental property of a rotating body, and further suggested that the magnetic fields of rotating bodies (the Earth, the Sun, and the star 78 Virginis, the strong magnetic field of which had just been measured by Horace Babcock) were roughly proportional to their angular momenta. A critical test of the idea was the measurement of very weak magnetic fields suitable in rotating laboratory objects, and Blackett was able to show that the suggested relationship was wrong. He then turned to the measurement of very weak magnetic fields in Blagg, Mary Adela igneous rock (remanent fields) beginning in 1951. These paleomagnetic fields preserve the direction that the rocks had relative to the Earth’s magnetic field when they solidified. Blackett’s work showed that both the latitude of England and the orientation of the land had changed over the past 100 million years, and so provided some of the early evidence in favor of plate tectonics and continental drift. Blackett continued work in paleomagnetism as professor of physics at Imperial College, London from 1953, in particular encouraging the work of Keith Runcorn and providing support for a critical conference in London in 1964 in which supporters and opponents of ideas about paleomagneticism and plate tectonics presented their opposing views, and more believers left the conference than had arrived. His own work continued, for instance, to reveal the correlations between ancient climates and ancient latitudes determined from rock magnetic measurement. Blackett officially retired in 1965, being very soon thereafter elected president of the Royal Society (London) and appointed advisor to the new Ministry of Technology. Blackett received more than 20 honorary degrees and academy fellowships and prizes in addition to the Nobel Prize. He was invested with the British Order of Merit in 1967 and created a Life Peer (as Barson Blackett of Chelsea) in 1969. Roy H. Garstang Alternate name Baron Blackett of Chelsea Selected References Lovell, Bernard (1975). “Patrick Maynard Stuart Blackett, Baron Blackett, of Chelsea.” Biographical Memoirs of Fellows of the Royal Society 21: 1–115. ——— (1976). “Patrick Maynard Stuart Blackett, Baron Blackett, of Chelsea.” Quarterly Journal of the Royal Astronomical Society 17: 68–79. Nye, Mary Jo (2004). Blackett: Physics, War, and Politics in the Twentieth Century. Cambridge, Massachusetts: Harvard University Press. Blagg, Mary Adela Born Died Cheadle, Staffordshire, England, 17 May 1858 Cheadle, Staffordshire, England, 14 April 1944 British amateur astronomer, Mary Blagg, is best known for her work on lunar nomenclature and variable stars. The daughter of a solicitor, Charles Blagg, Mary was educated at home and at a private boarding school in London. Finding mathematics intriguing, she borrowed her brother’s schoolbooks to teach herself mathematical subjects. Even without a formal background, she became increasingly competent in mathematics and gained skills that prepared her to understand basic astronomy. However, it was not until she was middle aged that she became seriously involved with astronomy. Her interest developed after she attended lectures in Cheadle given by John Herschel’s grandson, astronomer Joseph Alfred Hardcastle (1868–1917). These University Extension Lectures encouraged Blagg to ponder the possibility of doing original work in astronomy. Although there is no evidence that Hardcastle convinced Blagg of the need to standardize lunar nomenclature, he did suggest selenography as an interesting field to study. When she became interested in the nomenclature problem, Blagg found that astronomers had already recognized the need for reform. The state of the subject was chaotic. For example, in some cases the same name denoted different formations, and in others different names were given to the same formation. After Samuel Saunder drew its attention to discrepancies, the Royal Astronomical Society became interested in a uniform nomenclature. Saunder involved Professor Herbert Turner in the problem. Turner represented the Royal Society before the International Association of Academies in Vienna in 1907. At that meeting, an international Lunar Nomenclature Committee was formed with Saunder as an active participant. Saunder, in turn, asked Blagg to assist him by collating the names given to lunar formations on existing maps of the Moon. In 1913, her Collated List was published under the auspices of the International Association of Academies. The organizational meeting of the International Astronomical Union [IAU] was held in Brussels in 1919. From this date, the IAU has been the arbiter of planetary and satellite nomenclature. Blagg’s interest in the Moon continued, and in 1920 she was appointed to the Lunar Commission of the IAU. The other members of the Lunar Commission were Guillaume Bigourdan, Karl H. Müller, William Pickering, and Pierre Puiseux, with Turner serving as chair. The Lunar Commission prepared a definitive list of names that, after it was published, became the standard authority on lunar nomenclature. The report of the committee, published as “Named Lunar Formations,” was the first systematic listing of lunar nomenclature and named Blagg and Müller as authors. Blagg also became interested in variable stars through Turner who had acquired a manuscript containing Joseph Baxendell’s raw data on variable stars. Turner called for skilled volunteers to assist him in analyzing these data. Blagg volunteered to help, and produced a series of ten papers jointly authored with Turner in the Monthly Notices of the Royal Astronomical Society (1912–1918). Turner reported that the task of editing these data fell almost entirely to Blagg. He stressed the difficulties of identification and praised her ability to analyze and interpret the ambiguities. Blagg’s experience with Baxendell’s data prepared her to study the eclipsing binary β Lyrae and the long period variables RT Cygni, V Cassiopeiae, and U Persei. She deduced new elements for these stars and harmonically analyzed the light curves obtained from the observations of other astronomers. Mary Blagg was an unassuming woman who never married and who was rarely seen at meetings. It was notable when she attended the IAU meeting at Cambridge in 1925 and even more so when she attended the meeting in Leiden in 1928. She spent much of her time in community service, including caring for Belgian refugee children during World War I. During the last 8 years of her life heart trouble reduced her to an invalid. Like several other British and American women astronomers of her time, Mary Blagg might have become a professional astronomer if the opportunity had presented itself. She managed to succeed in astronomy partially because she was willing to work under the direction of others and to undertake tedious problems rejected by male astronomers. Her skill and good judgment in approaching these problems assured that her contributions were more than mere fact collecting. The Royal Astronomical Society recognized B 137 138 B Blazhko, Sergei Nikolaevich Blagg’s importance and elected her a fellow in 1915. Following her death, the International Lunar Committee assigned the name Blagg to a small lunar crater. Marilyn Bailey Ogilvie Selected References Blagg, Mary A. (1913). Collated List of Lunar Formations Named or Lettered in the Maps of Neison, Schmidt, and Mädler. Compiled and Annotated for the Committee by Mary A. Blagg under the Direction of the Late S. A. Saunder. Edinburgh: Neill and Co. Blagg, Mary A. (ed.) (1924). “Baxendell’s Observations of β Lyrae.” Monthly Notices of the Royal Astronomical Society 84: 629–659. ——— (1925). “Observations of β Lyrae by Members of the B. A.A., 1906-1920.” Monthly Notices of the Royal Astronomical Society 85: 484–496. Blagg, Mary A. and Karl Müller (1935). Named Lunar Formations. London: Percy Lund, Humphries. Kidwell, Peggy Aldrich (1984). “Women Astronomers in Britain, 1780–1930.” Isis 75: 534–546. Ryves, P. M. (1945). “Mary Adela Blagg.” Monthly Notices of the Royal Astronomical Society 105: 65–66. Blanchinus, Francisco > Bianchini, Francesco Blazhko, Sergei Nikolaevich Born Died Despite the inhumanity of Stalin’s regime, Blazhko continued to maintain high moral standards and served as a role model for generations of his followers. Blazhko’s contribution to the investigation of different kinds of variable stars helped create a strong Moscow research program. He also enriched the important photographic glass library of the Moscow Observatory. Interested also in history of astronomy, Blazhko compiled a valuable history of a century of astronomy at the Moscow University from 1824 to 1920. Blazhko’s name was not widely recognized in the West apart from his effect, but he was well known to compatriots. He was a corresponding member of the Union of Soviet Socialist Republics Academy of Science (1929). For his textbooks, Blazhko was awarded the highest state trophy, the Stalin Prize (1952), which was later renamed the USSR State Prize. A crater 54 km in diameter on the farside of the Moon (latitude 31°.6 N, longitude 148°.0 W) is named in his honor. Alexander A. Gurshtein Selected References Anon. (1986). “Blazhko, Sergei Nikolaevich.” In Astronomy: Biograficheskii spravochnik (Astronomers: A biographical handbook), edited by I. G. Kolchinskii, A. A. Korsun’, and M. G. Rodriges, pp. 41–42. 2nd ed. Kiev: Naukova dumka. Blazhko, S. N. (1940). “The History of the Astronomical Observatory of Moscow University in Connection with Teaching at the University (1824–1920)” (in Russian). Uchenye zapiski MGU (Scientific Transactions of Moscow State University) 58: 5–106. ——— (1947). A Course of General Astronomy (in Russian). Moskow: Gos. izdetel’stvo technico-teoreticheskoi literatury. ——— (1948). A Course in Spherical Astronomy (in Russian). Moscow: Gos. izdetel’stvo technico-teoreticheskoi literatury. ——— (1951). A Course in Practical Astronomy (in Russian). 3rd ed. Moscow: izdetel’stvo technico-teoreticheskoi literatury. Nicolaidis, E. (1984). Le développement de l’astronomie en U.S.S.R (1917–1935). Paris: Observatoire de Paris. Khotimsk near Mogilev, (Belarus), 17 November 1870 Moscow, (Russia), 11 February 1956 Soviet astronomer Sergei N. Blazhko was a noted observer and an acclaimed pedagogue, the author of three prominent textbooks in multiple editions. He was an 1892 graduate of the Moscow University, where he later taught throughout his life, and a disciple and follower of Vitold Tserasky. His name is now most often heard in connection with the Blazhko effect, an irregularity in the periods of RR Lyrae stars which is, in turn, periodic. The cause has not yet been firmly established. After the devastating period following the Bolshevik Revolution of 1917, Blazhko was a key figure within the Moscow University leadership of the Moscow Observatory, founded in 1895 under the directorship of Tserasky. Blazhko held a variety of positions at the Moscow University, including professor of astronomy (1918), deputy director of the Astronomical Observatory (1918–1920), director of the Observatory (1920–1931), chair of the Department of Astronomy (1931–1937), and chair of the Department of Astrometry (1937– 1953). Blazhko was an efficient observer and an authoritative expert on positional astronomy (astrometry) and astronomical instruments. A benevolent person and an excellent pedagogue, he had numerous disciples. Blazhko masterminded the conversion of the Moscow Observatory from a modest educational unit into a great scientific institution of worldwide significance (the Shternberg State Astronomical Institute, usually abbreviated as GAISh, or SAI). Bliss, Nathaniel Born Died Bisley, Gloucestershire, England, 28 November 1700 London, England, 2 September 1764 Nathaniel Bliss was a Savilian Professor of Geometry at Oxford and the fourth Astronomer Royal at the Greenwich Observatory. Bliss (named after his father, a Bisley gentleman) received his BA in 1720 and MA in 1723 from Pembroke College, Oxford. After taking holy orders, he became rector of Saint Ebbe’s Church in Oxford in 1736. He also married and had a son, John, in 1740. Bliss replaced Edmond Halley as Savilian Professor of Geometry upon the latter’s death in 1742, and in the same year became a Fellow of the Royal Society. Soon after his appointment at Oxford, Bliss began a correspondence with James Bradley, third Astronomer Royal. The correspondence began with discussion of the Jovian satellites and lasted for 20 years until Bradley’s death in 1762. Bliss also frequently visited Bradley at the Greenwich Observatory and even assisted him on several occasions. Bliss also worked for and with George Parker, second Earl of Macclesfield, on various astronomical problems. Macclesfield, a Fellow of the Royal Society from 1722 and its President from 1752 until his death in 1764, was an accomplished astronomer with his own observatory and Bobrovnikoff, Nicholas Theodore assistants. In 1744, Bliss sent Macclesfield a letter requesting that he observe a comet from his observatory at Shirburn Castle, while Bliss, at Greenwich Observatory, made his own meridian observations of the comet (C/1743 X1) approaching the Sun. On 6 June 1761, Bliss, following Bradley’s instructions, also observed the transit of Venus when Bradley was unable to do so because of his poor health. On the basis of his observations, Bliss calculated the Sun’s horizontal parallax to be 10″.3 (the modern figure is 8″.8) and Venus’ horizontal parallax as 36″.3. The results were published the following year in the Philosophical Transactions of the Royal Society. Bliss also reported to the Royal Society the observations of the same event made in Bologna by Italian astronomer, Eustachio Zanotti. Bliss’ appointment as Astronomer Royal in 1762 following Bradley’s death lasted until Bliss’ own death in 1764, marking the shortest term of any Astronomer Royal. Because of his brief 2-year tenure, Bliss left behind fewer observations and calculations than his predecessors. Moreover, his work at the observatory was occasionally interrupted because he had retained the Savilian Chair and continued teaching, thus splitting his time between Oxford and Greenwich. He seemed to have been more productive in astronomy before he became Astronomer Royal, although he did observe a solar eclipse in 1764, the results of which were published in the Philosophical Transactions. Bliss also converted John Flamsteed’s Sextant House into a small observatory specially designed to make room for a 40-in. movable quadrant, although the new observatory was completed only after his death. Bliss had a great interest in improving clocks. During Bliss’ tenure at Greenwich, Nevil Maskelyne and John Harrison participated in the second historic trial of Harrison’s marine chronometer number 4 in the West Indies. Maskelyne returned from this trip in 1764 to succeed Bliss as Astronomer Royal. After Bliss’ death, his widow initiated a continuation of his lectures by organizing a popular lecture of “Electrical Experiments for the Entertainment of Ladies and others” that was delivered at Oxford on 21 May 1765 by Thomas Hornsby, successor to Bradley as Savilian Professor of Astronomy. Furthermore, the Board of Longitude regarded Bliss’ work on the problem of longitude (made with his assistant, Charles Green, who had also served as Bradley’s assistant) as important and useful. Since it was considered private property, the Board purchased this work from Bliss’ widow and stored it in the Greenwich Observatory. In 1805, Abram Robertson, Savilian Professor of Geometry, appended Bliss and Green’s work (including transits of the Sun, planets, and fixed stars over the meridian; meridional distances of the fixed stars from the zenith; and apparent right ascensions of the planets) to the second volume of Bradley’s observations – the first volume had been edited by Hornsby in 1798 – entitled Astronomical observations made at the Royal Observatory at Greenwich from the Year MDCCL to the Year MDCCLXII. Voula Saridakis Selected References Carter, L. J. and A. T. Lawton (1985). “The Mystery of Bayer’s Uranometria.” Spaceflight 27: 117–128. Fauvel, John, Raymond Flood, and Robin Wilson (eds.) (2000). Oxford Figures: 800 Years of the Mathematical Sciences. Oxford: Oxford University Press. Forbes, Eric G. (1975). Greenwich Observatory. Vol. 1, Origins and Early History (1675–1835). London: Taylor and Francis. Gunther, R. T. (1937). Early Science in Oxford. Vol. 11, Oxford Colleges and Their Men of Science. Oxford: Oxford University Press. Howse, Derek (1975). Greenwich Observatory. Vol. 3, The Buildings and Instruments. London: Taylor and Francis. Lawton, A. T. and L. J. Carter (1985). “The Quest for Nathaniel Bliss.” Spaceflight 27: 275–282. Maunder, E. Walter (1900). The Royal Observatory Greenwich: A Glance at Its History and Work. London: Religious Tract Society. Bobrovnikoff, Nicholas Theodore Born Died Markova, Russia, 29 April 1896 Berkeley, California, USA, 21 March 1988 Cometary spectroscopist Nicholas Bobrovnikoff, the son of Theodore Basil and Helena (née Gavriloff) Bobrovnikoff, graduated from the Kharkov Gymnasium in 1914. As a youth, he had witnessed the appearance of comet 1P/Halley in 1910. Although wishing to become an astronomer, Bobrovnikoff enrolled as a student (1914–1917) at the Institute of Mining Engineers in Petrograd (now Saint Petersburg), and later studied at the University of Kharkov. He became a junior officer in the Russian Army and joined the White (anti-Bolshevik) Army in 1918. Severely wounded, recovered, and later ill with typhus, Bobrovnikoff was evacuated to Cyprus in 1920. After recuperating, he made his way to Prague, where he won a scholarship to Charles University (now the University of Prague), and resumed his studies of physics, mathematics, and astronomy, graduating in 1924. Through the efforts of Yerkes Observatory director Edwin Frost, Bobrovnikoff was admitted to the graduate program of the University of Chicago in September 1924. For his doctoral dissertation, Bobrovnikoff made a thorough analysis of the behavior of comet Halley and twenty seven other comets, observed as far back as 1908. He concentrated on the molecular bands and lines within the spectra of these comets, and interpreted their varied appearances as due to fluorescence caused by sunlight. Bobrovnikoff also identified some previously unknown spectral features associated with the comets. He was awarded his Ph.D. in 1927. Bobrovnikoff received a postdoctoral fellowship and spent the next two years at the Lick Observatory, where he had access to large numbers of plates and spectra taken of comet Halley. He borrowed others from the Mount Wilson Observatory. These observations allowed him to correlate the comet’s appearance, brightness, and spectral changes over the entire range of its visibility. Bobrovnikoff studied the development of cometary outbursts and argued for a “striking analogy” between their motions and the behaviors of gases seen in solar prominences. Bobrovnikoff had found evidence for what would later be termed the solar wind, whose outward flow bends the path of material expelled from comet nuclei. A National Research Council Fellowship at the University of California at Berkeley (1929/1930) enabled him to prepare his results for publication. Bobrovnikoff ’s landmark paper appeared in 1931. He became a naturalized citizen in 1930 and married Mildred Gwynne Sharrer; the couple later had three children. That same year, Bobrovnikoff was appointed an assistant professor at Ohio Wesleyan University, which housed a 69-in. reflector at its Perkins Observatory. There, he concentrated on the spectra of cool M-type stars, which display strong molecular bands. B 139 140 B Bochart de Saron [Bochart-Saron], Jean-Baptiste-Gaspard Bobrovnikoff succeeded Harlan Stetson as director of the Perkins Observatory (circa 1934–1952). To ease its financial situation, he negotiated an agreement by which its ownership was transferred to the Ohio State University. Bobrovnikoff continued research and teaching until his retirement in 1966. He coauthored a popular book, Astronomy Before the Telescope (1984). Bobrovnikoff lived to see comet Halley’s return to our skies during 1985/1986. Jordan D. Marché, II Selected References Bobrovnikoff, Nicholas T. (1931). “Halley’s Comet and Its Apparition of 1909– 1911.” Publications of the Lick Observatory 17, pt. 2: 309–482. Osterbrock, Donald E. (1986). “Nicholas T. Bobrovnikoff and the Scientific Study of Comet Halley 1910.” Mercury 15, no. 2: 46–50, 63. ——— (1997). Yerkes Observatory, 1892–1950: The Birth, Near Death, and Resurrection of a Scientific Research Institution. Chicago: University of Chicago Press, esp. pp. 73, 144–150. Osterbrock, Donald E., John R. Gustafson, and W. J. Shiloh Unruh (1988). Eye on the Sky: Lick Observatory’s First Century. Berkeley: University of California Press, esp. pp. 210–212. Bochart de Saron [Bochart-Saron], Jean-Baptiste-Gaspard Born Died in Saron (Champagne). He is best remembered for his work on cometary theory. A lifelong friend of Messier, Bochart calculated the orbits of the comets Messier observed. Bochart improved the numerical method to deduce orbits from a few points, a method established by the Jesuit astronomer Roger Boscovic. In May 1781, Bochart calculated the orbit of the purported “comet” discovered by William Herschel. After unsuccessful attempts to make the observations fit, he assumed an orbit with a radius of 12 AU, greater than any cometary orbit radius, which turned out to be the correct orbit for the planet Uranus, when computed later by Pierre-Simon de Laplace. Moreover, Bochart published, at his own expense, Laplace’s Théorie du mouvement elliptique et de la figure de la Terre. Bochart was a key participant in the Carte de France project. When public funding for the work ended after the Seven Years War, César Cassini de Thury encouraged private funding. Cassini approached Bochart to become codirector in the place of Charles Camus, when the latter died. Bochart also maintained a chemical laboratory and an engraving machine. Following the death and retirement of members of the Parlement de Paris, Bochart became its first president on 26 January 1789. In October 1790, while he was on a journey to Italy to prevent revolt against the new French authorities, the Parlement was dismissed; as a result of the protests of the dismissed members – Bochart included – they were imprisoned and condemned to the guillotine. Bochart was executed on 20 April 1794. Although not a first-rank astronomer, he was a talented, curious, and wealthy man, a generous patron, and host to many of his contemporaries. To them he was a pleasant and modest person, with scientific competence. Paris, France, 16 January 1730 Paris, France, 20 April 1794 Jean-Baptiste Bochart de Saron was a patron of the sciences, an optician and observer, and a talented mathematician who improved cometary orbit calculations. As Jean-Baptiste Bochart de Saron, father of Jean-Baptiste, died when his son was one, his mother, Marie-Anne Braïer, entrusted him to her brother-in-law, Elie Bochart, Canon of Notre-Dame. Bochart later entered the Jesuit College, Louis le Grand, where he learned the basic elements of letters and sciences. Although he had a great interest in mathematics, especially geometry, he pursued a law career and entered parlement on his 18th birthday, later being appointed a judge. He married Angélique-Françoise d’Aguesseau, and they had five children. His wife died in 1780. Bochart was admitted to the Académie royale des sciences, first as a surnuméraire on 5 June 1779, then as an honorary member in 1785. He served as the academy’s vice president (elected in 1782 and 1787) and as president (elected in 1783 and 1788). Bochart manufactured a variety of optical parts for telescopes, including a 30-in. speculum mirror instrument, used by Charles Messier from 1765. Jérôme Lalande claimed that this telescope was among the most efficient available in Paris at the time. Later, Bochart purchased instruments from the best Paris and London manufacturers, among them a 3.5-ft., 4.2-in. achromatic refractor by John and Peter Dollond. Further, clocks and instruments by Jesse Ramsden and others joined Bochart’s collection, one of the finest in Europe, which he lent to his friends Messier, Pierre Méchain, Guillaume Le Gentil de La Galaisière, Pierre Le Monnier, Jean-Baptiste Delambre, and A. P. du Séjour. Bochart carried out a few observations, sometimes with his scientific friends, from his Parisian residences and his country home Monique Gros Selected References Barbin, Pierre (1996). “Le dernier premier président du parlement de Paris en Champagne: Jean-Baptiste Gaspard Bochart et le château de Saron.” La vie en Champagne 5: 3–7. Bigourdan, Guillaume (1930). Histoire de l’astronomie d’observation et des observatoires en France. 2nd pt. Paris: Gauthiers-Villars et Cie. Cassini, Jean Dominique (1810). Mémoires pour servir à l’histoire des sciences et à celle de l’observatoire royal de Paris, suivis de la vie de J. D. Cassini par luimême, et des éloges de plusieurs académiciens morts pendant la révolution. Paris. Lalande, Joseph Jérome le François de (1803). Bibliographie astronomique avec l’histoire de l’astronomie depuis 1781 jusqu’ à 1802. Paris: 1803, Imprimerie de la République. (Reprint, Amsterdam: J. C. Gieben, 1970.) Bode, Johann Elert Born Died Hamburg, (Germany), 19 January 1747 Berlin, (Germany), 23 November 1826 Johann Bode directed the observatory of the Royal Academy of Sciences (Berlin), helped to publicize an important “law” regarding the planets’ distances from the Sun, and published an important reference work (the Astronomisches Jarhbuch) for more than 50 years. He was the son of Johann Jakob Bode and his wife Anna Margarete (née Kruse). Bode, Johann Elert Following a basic education at his father’s business school, Bode acquired an astronomical proficiency on his own, putting to good use the encouragement provided by several local citizens. On the strength of his early publications, he was offered an appointment (1772) at Berlin by Johann Lambert as calculator for the Astronomisches Jahrbuch, to be issued by the Royal Academy of Sciences. Following Lambert’s death in 1777, Bode took over as editor of the yearbook. In 1786, he became a full member of the academy (and professor), and in 1787, director of the Royal Observatory. After resigning from this position in 1825, Bode continued as editor of the Jahrbuch until his death. His successor in both positions was Johann Encke. After his arrival in Berlin, Bode was a cofounder (in 1773) of Gesellschaft Naturforschender Freunde zu Berlin (Society of Naturalist Friends). Although this learned body exists today, the initial prominence given to astronomy within its framework ended with his death. Bode was thrice married: in 1774 to Johanna Christiane Lange (died: 1782), in 1783 to Sophie Dorothea Lange (died: 1790), and in 1791 to Charlotte Wilhelmine Lehmann. He had eight children from these marriages. Bode’s name today is best remembered for the Titius–Bode law of planetary distances, which, during his lifetime, seemed to be confirmed in a rather spectacular way by the discoveries of Uranus and the asteroids. Bode publicized the mathematical relation first deduced by Wittenberg professor Johann Titius, describing the relative spacing of the planets’ orbits. Nonetheless, Bode’s influence on astronomy went far beyond the contribution to be expected from someone at a relatively minor observatory on the continent. Bode’s career marks the transition in astronomy from a “natural history survey of the heavens” to modern, precision astrometry. His numerous activities turn out, in retrospect, to mirror this change of methodology, effort, and priorities. The Berlin Astronomisches Jahrbuch, which began under Lambert’s supervision for the year 1776, followed the tradition established by the Connaissance des temps (from 1688) and the Nautical Almanac (established in 1766). Its final (184th) volume was published for the year 1959. Yet, organization and layout of the early ephemerides and related material look surprisingly modern. From the beginning, the Jahrbuch contained a second part designed as “a collection of the most recent observations, news, commentaries and papers.” In the absence of any periodicals devoted strictly to astronomical research, the Jahrbuch became an important archive journal serving the whole European astronomical community. It retained this function even after Baron János von Zach’s founding of the Monatliche Correspondenz in 1800. Only with the appearance of Heinrich Schumacher’s Astronomische Nachrichten (1821) did the need for publication of research papers in the Jahrbuch decline; the practice was discontinued by Bode’s successor, Encke. When Bode took over the observatory from his predecessor, Johann Bernoulli III, the facilities were in severe disarray. After bringing the instruments into working order and making arrangements for proper time determinations, he put his modest facilities to optimal use. Bode’s diligent astrometric observations spanned 4 decades. A major accomplishment was the measurement of several thousand uncataloged star positions plotted for his monumental sky atlas, Uranographia (1801). This atlas was the last to follow the tradition of depicting beautifully engraved constellation figures. At the same time, it was the first to include the vast number of double stars, clusters, and nebulae cataloged by William Herschel. In addition to the responsibilities of the Academy (and its observatory) for calendrical matters, Bode’s major concern was public time service. He took special care to provide the public with an accurate clock placed on the outer wall of the observatory building. Berlin later became one of the first European capitals to adopt mean solar time as a public standard. The position of the observatory director entailed other tasks related to the academy (and government) on practical matters. Bode calibrated new instruments for the Prussian geodetic service and advised on the acquisition of instruments for the new observatory established at Königsberg in 1811. Bode likewise advocated the search for a “missing” planet between Mars and Jupiter that was fulfilled by accidental discovery of the first asteroid. Having taken part in preparations for the systematic search, Bode was one of the men first informed by Giuseppe Piazzi of the discovery (and subsequent loss) of (1) Ceres. His most significant contribution was the rapid dissemination of this information to the right people, leading to the celebrated orbital calculations performed by Carl Gauss and the subsequent recovery of the object by Zach and Heinrich Olbers. Bode’s activities as writer, editor, translator, and lecturer also merit special mention. His (nontechnical) Anleitung zur Kenntniss des gestirnten Himmels (Introduction to the Knowledge of the Starry Heavens, 1768) remained, with frequent updates, a standard text for a full century. Bode’s 1782 German edition of John Flamsteed’s Star Atlas was aimed at the professional user. His 1780 edition of Bernard de Fontenelle’s 1686 Entretiens (with his own commentary) passed through several editions. Bode’s lectures at the Academy, as B 141 142 B Boëthius, Anicius Manlius Torquatus Severinus well as for learned societies, covered subjects of general interest. His notes on new discoveries were published in the daily newspaper (Vossische Zeitung). Elected already in 1789 to membership in the Royal Society (London), Bode was a member of numerous foreign academies (Saint Petersburg, Stockholm, Göttingen, Copenhagen, Moscow, and Verona). He was awarded an honorary doctorate from the University of Breslau in 1817. A knight of the Prussian Red Eagle Order, on the 50th anniversary of his work with the Berlin Academy (1822), Bode was awarded the Russian Saint Anne Order. Bode’s life and work cover a critical period of transition in the history of science. His most visible contribution to the development of modern astronomy was perhaps his Jahrbuch. By compiling and disseminating astronomical news and discoveries, and aiding the emerging cooperation of European astronomers, he laid the groundwork for the activities of his successors, especially Encke. Bode’s writings and his lectures served to establish astronomy as a meaningful part of the early metropolitan culture in Berlin. Wolfgang Kokott Selected References Encke, Johann Franz (1827). “Gedaechtnissrede auf Johann Elert Bode.” Abhandlungen, Akademie der Wissenschaften. Berlin. Kokott, Wolfgang (2002). “Bode’s Astronomisches Jahrbuch als internationales Archivjournal.” In Astronomie von Olbers bis Schwarzschild, edited by Wolfgang R. Dick, pp. 142–157. Acta Historica Astronomiae, Vol. 14. Frankfurt am Main: Harri Deutsch. Schwemin, Friedhelm (1982). “Johann Elert Bode: Skizze zu Leben und Werk.” Sitzungsberichte Gesellschaft Naturforschender Freunde zu Berlin, n.s., 22: 99–117. ——— (1985). “Johann Elert Bode, der bedeutende Berliner Astronom.” Mitteilungen Verein für die Geschichte Berlins 81: 282–287. Sticker, Bernhard (1970). “Bode, Johann Elert.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 2, pp. 220–221. New York: Charles Scribner’s Sons. Boëthius, Anicius Manlius Torquatus Severinus Born Died probably Rome, (Italy), circa 480 in the ager Calventianus (near or in present-day Pavia, Italy), 524–526 As the West lost contact with Byzantium, Boëthius’s writings became one of the few surviving links between Western scholars and Hellenistic scholarship. His writings on logic, arithmetic, and music became standard texts and, along with his other writings, were copied and translated all over Europe. A few decades after Roman Italy had come under Gothic rule, Boëthius was born into the gens Anicii: a powerful, wealthy, aristocratic, Catholic family. His father – who had been Prefect of Rome, Praetorian Prefect, and Consul – died when Boëthius was young, so Boëthius was raised by his eminent kinsman Symmachus. Symmachus saw to Boëthius’s education in the Greek-patterned enkuklios paideia, an “all-encompassing learning.” Boëthius’s learnedness and natural talent elevated him through the ranks of public office, eventually to consulship under the Ostrogoth Theodoric in 510. Boëthius attained his highest rank, Master of the Offices, in 522, but from this height he fell: Accused of treason, he was impoverished and imprisoned near Pavia. He remained there while his trial proceeded at Rome. Boëthius, though absent, was found guilty. Boëthius’s epitaph records imply that he died by the sword, but the Chronica Theodoriciana records an end more painful: Torturers tightened a cord around Boëthius’s forehead “so tightly that his eyes cracked in their sockets, and finally, while under torture, he was beaten to death with a cudgel.” After Boëthius, Mastership of the Offices went to another kinsman, Cassiodorus, whose writings provide some of the earliest extant records of Boëthius’s life. Cassiodorus notes that Boëthius was skilled in both Latin and Greek, that his finest work was in logic, and that in the mathematical disciplines “he either equaled or surpassed the ancient authors.” One of Cassiodorus’s tasks was to draft letters for Theodoric, and through some of these we see the esteem in which Boëthius had previously been held, and for which he had been elevated to such high rank. Especially respected was Boëthius’s part in making Greek learning accessible to the Latin world. Theodoric noted Boëthius’s practical side: the application of theory to produce toys, urban fortifications, what seems to be a fire-driven organ, and an orrery that demonstrated how lunar phases are produced. Theodoric acknowledged the usefulness of Boëthius’s mathematics in coinage reform and, to demonstrate the royal endorsement of higher learning, Theodoric asked Boëthius to apply his astronomical skills to building a grand sundial (at public expense), augmented by a water clock for times when the Sun did not shine. Boëthius planned to translate as much of Aristotle’s and Plato’s works as possible, to show that the two philosophers fundamentally agreed with each other, and to write commentaries on all of their works. This ambition went unfulfilled, at least partly because Greek texts were by this time scarcely available in the Latin West. Still, Boëthius did manage to translate nearly all of Aristotle’s logical works, and he is credited with four theological works of his own, plus introductions to the four recognized mathematical disciplines: arithmetic, music, astronomy, and geometry. His introductions to arithmetic and music are extant: On Arithmetic is an expanded Bohlin, Karl Petrus Teodor translation of the arithmetic by Nicomachus of Gerasa, much clarified and somewhat restructured; On Music is drawn from both Nicomachus and Ptolemy, set amidst the Pythagorean music of the spheres. Boëthius’s theoretical tendencies are particularly evident in the musical treatise, so much so that Guido d’Arezzo, an 11th-century musical theorist, complained that it was “useful to only philosophers.” But Boëthius’s music is not only mathematics: It also covers music therapy, detailing the psychological effects of the Greek modes, and a physical theory of sound, attributing musical pitch to the frequency at which a string vibrates and strikes the surrounding air. As for the texts on geometry and astronomy, we do not know whether Boëthius really wrote them. Their existence is testified in the 10th century by the mathematician Gerbert d’Aurillac, who reports having seen them at Bobbio. The astronomy, he says, filled eight books; the finely illustrated geometry two. But neither work has survived. Boëthius’s passion for mathematics is lengthily explained in the Consolation of Philosophy – written during the year or so awaiting execution – where Lady Philosophy, visiting Boëthius in his prison cell, persuades him that such learning leads to God and happiness. The Consolation is richly spiced with numerous astronomical snippets describing a Neoplatonist cosmos (geocentric celestial spheres governed by God who created them after ideal forms and maintains them in harmony), but these are generally allegorical and without much detail. Boëthius’s second commentary on Aristotle’s On Interpretation shows that he gave much reign to stellar influences on animals and humans, greatly constricting the scope for free will. He wrote in several places that studying philosophy naturally led him to work on understanding the heavenly motions. But little further evidence about Boëthius’s astronomy is available: the orrery, water clock, and sundial mentioned by Theodoric. Some centuries after his death, Boëthius’s remains were transferred to Pavia, where they now lie in the Church of San Pietro in Ciel d’Oro, under an epitaph composed by Gerbert. In 1883 he was beatified, and his cultus officially confirmed. Boëthius translated and wrote commentaries on all but one of Aristotle’s logical treatises (Topica, De interpretatione, Categoriae, Analytica priora, Analytica posteriora, and De sophistici elenchis) and Porphyry’s Isagoge. This group of translations served as a standard logical textbook through the Middle Ages. Alistair Kwan Selected References Bower, Calvin M. (trans.) and Claude V. Palisca (ed.) (1989). Fundamentals of Music, by Boethius. New Haven: Yale University Press. (Translation of De institutione musica.) Cassiodorus, Flavius Magnus Aurelius (1992). Variae, translated with notes and introduction by S. J. B Barnish. Liverpool: Liverpool University Press. Chadwick, Henry (1981). Boethius: The Consolations of Music, Logic, Theology and Philosophy, by Boethius. Oxford: Clarendon Press. Gibson, Margaret (ed.) (1981). Boëthius. Oxford: Basil Blackwell. Masi, Michael (1983). The Boethian Number Theory: A Translation of the De institutione arithmetica. Amsterdam: Rodopi. Stewart, H. F., E. K. Rand, and S. J. Tester (trans.) (1973). The Theological Tractates; The Consolation of Philosophy, by Boethius. Loeb Classical Library, no. 74. Cambridge, Massachusetts: Harvard University Press. Strump, Eleonore (trans.) (1978). Boethius’s De topicis differentiis. Ithaca: Cornell University Press. ——— (1988). Boethius’s In Ciceronis Topica. Ithaca, New York: Cornell University Press. Boguslawsky, Palon [Palm] Heinrich Ludwig von Born Died 1789 1851 Former military officer Palm Boguslawsky was director of the Breslau Observatory and an authority on the planet Uranus. Oddly, he does not appear in Arthur Alexander’s The Planet Uranus (New York: American Elsevier, 1965). Boguslawsky’s successor at Breslau was Johann Galle. Selected Reference von Boguslawsky, M. (1884). “Auszug auseinem Schreiben des Herrn Professors Boguslawsky, Directors der Breslauer Sternwarte, an den Hérausgeber.” Astronomische Nachrichten 21: 253. Bohlin, Karl Petrus Teodor Born Died Stockholm, Sweden, 30 October 1860 Ytterenhorna, Sweden, 25 May 1939 Karl Bohlin was a theoretical astronomer, known primarily for work on the orbits of asteroids and other three-body problems. Bohlin obtained a doctor’s degree from Uppsala University in 1886. From 1886 to 1891, he taught at the Uppsala University and the Technical University in Stockholm, and was assistant director of the Stockholm Observatory. From 1891 to 1893, he was employed at the Rechen-Institut at the Berlin Observatory and in 1893/1894 at the Pulkovo Observatory to work on the orbit of comet 2P/Encke (named for Johann Encke). Bohlin was appointed director of the Stockholm Observatory in 1897 and served until his retirement in 1927. He helped found the Swedish Astronomical Society in 1919 and was its first chairman until 1926. Bohlin primarily was a theoretician in celestial mechanics. He is known for his development of group perturbations of asteroids and work on the three-body problem. He measured and analyzed positions of planets, their satellites, and comets. He was probably the first to call attention to the asymmetric distribution of globular clusters and, assuming that they are centered on the galactic center, in 1909 he computed its longitude in excellent agreement with the current value. He also studied variable stars with a new reflector that he obtained for the Stockholm Observatory in time for the solar eclipse of 1914. Helmut A. Abt B 143 144 B Bohr, Niels Henrik David Selected Reference Lindblad, Bertil (1939). “Obituary.” (in Swedish). Popular astronomisk tidsskrift 20: 136. Bohr, Niels Henrik David Born Died Copenhagen, Denmark, 7 October 1885 Copenhagen, Denmark, 18 November 1962 Danish theoretical physicist Niels Bohr provided the first quantum mechanical description of atomic structure that was able to account reasonably well for the observed wavelengths of features emitted and absorbed by atoms in the laboratory and in stars. He received the 1922 Nobel Prize in Physics for this work. Bohr was born to Christian and Ellen Adler Bohr. He had an older sister, Jenny, and younger brother, Harald, a successful mathematician and Niels’s closest friend throughout his life. Christian Bohr was a university professor and physiologist. Just after Niels’s birth, Christian was appointed a professor of physiology at the University of Copenhagen, replacing Peter Panum, and the Bohrs took up residence in Panum’s professorial house. In 1891, Niels entered the Grammelholms School where his brother was also educated. Niels remained at Grammelholms until his graduation in 1903. He was a good student, though never at the very top in his class. It may be surprising to note that he excelled most at sport, being particularly adept at soccer, though it was his brother Harald who won a silver medal in soccer for Denmark in the 1908 Olympic Games in London. In the final 2 years at Grammelholms Bohr specialized in mathematics and physics where he began to show a particular aptitude, reportedly finding errors in the textbooks. In 1903, Bohr enrolled at the University of Copenhagen studying physics as his major subject and mathematics, chemistry, and astronomy as his minor subjects. In 1906, he published the only paper describing experiments he carried out himself (in his father’s physiology laboratory as there was no physics laboratory at the university). The paper won the Gold Medal of the Royal Danish Academy of Sciences and Letters. It was an analysis of the vibrations of water jets as a means of determining surface tension and built on the work of Lord Rayleigh. It also provided him with a basis for his later work on the liquid-drop model of the nucleus. Bohr received his master’s in 1909 and his doctorate in 1911. Both degrees focused on the electron theory of metals and were purely classical in their approach. It was the limitations of the classical laws in describing the phenomenon that made him realize that there must be some radically different way of describing atomic processes. Bohr’s doctoral dissertation was dedicated to the memory of his father who had died just months earlier. In 1910, Bohr met Margrethe Nørlund. The two were married in August of 1912 and had a very close relationship. They had six sons, two of whom died in childhood. His son Aage (born: 1922) received the 1975 Nobel Prize in Physics for work on the structure of the nuclei of atoms, which had some conceptual similarities to his father’s work on the behavior of electrons around those nuclei. In 1911, Niels Bohr made his first visit to Britain and the Cavendish Laboratory, then headed by the esteemed J. J. Thomson, discoverer of the electron. Bohr had hoped to interest Thomson in his work but was unsuccessful. However, he did meet and impress Ernest Rutherford with whom he developed a 25-year friendship. It was Rutherford who brought Bohr to the University of Manchester (then called Victoria University) and who showed that most of the mass of an atom resides in the nucleus. This was to be a major point in Bohr’s development of his atomic model. He remained in Manchester for the year, returning to Copenhagen in July 1912 with his atomic model partly developed. He finally completed work on his atomic model in 1913. The key issues of the Bohr model were, first, that an electron could exist only in certain orbits around the nucleus, each with a definite energy, and would emit or absorb radiation (light) only in transitions between orbits; and, second, that there would also be an atomic analog to the ellipticity of planet orbits and that electron orbits with different deviations from circles would have slightly different energies, making atomic spectra more complex than with just the basic circular orbits. These ideas were largely superseded in the period after 1925 when quantum mechanics came to be expressed in the more complex mathematics of differential equations and matrices. Also in 1913, Bohr was appointed docent at the University of Copenhagen. The post did not afford him the freedom to explore mathematical physics as deeply as he wished, and Bohr wrote to the university petitioning them to create a professorship in theoretical physics. The university dragged its heels, and in 1914 Bohr accepted an offer to return to Manchester. Due to World War I, his stay in Manchester lasted longer than he anticipated but, finally, in 1916 the University of Copenhagen created the Chair of Theoretical Physics, and Bohr returned to Denmark to take up the post. It was the first time at the university that theoretical physics was recognized as a worthwhile discipline in its own right. It was then that he made yet another lifelong friend in Hendrik Kramers, who had come to Copenhagen in 1918 to escape the ravages of war and to study under Bohr. The two would collaborate on numerous scientific and social issues over the next 40 years. In 1917, Bohr was elected to the Royal Danish Academy of Sciences and Letters and soon began, eventually with Kramers’s aid, to plan the development of the Institute for Theoretical Physics (later the Niels Bohr Institute). Modern quantum mechanics was born around 1925, and in 1927 Bohr published his first work on complementarity. This led to a long, public debate between Bohr and Albert Einstein over the philosophical foundations of quantum theory. In 1926, Bohr was elected a fellow of the Royal Society, and he received the Society’s Copley Medal in 1938. In 1932, the Bohrs moved from their house at the institute to a mansion at Carlsberg donated to the Royal Danish Academy of Sciences and Letters by the Carlsberg Foundation, which had supplied Bohr with research funding in prior years. The academy, of which he was president for many years, offered the home to Bohr for the remainder of his life. In 1937, Bohr and his family toured a number of countries where he gave lectures and, while in Britain, spoke at Rutherford’s funeral. On returning to Denmark, the looming war brought great changes in Bohr’s life. Though raised a Christian, his mother was Jewish and the Nazi occupation of Denmark in 1940 made his life difficult. It was not made easier by a visit in autumn 1941 from Bok, Bart Jan Werner Heisenberg, who had been a close colleague and friend before the German occupation of Denmark, which put them firmly on opposite sides of World War II. Precisely what happened during that visit has been explored at great length in both history books and a somewhat fictionalized play called Copenhagen. In 1943, encouraged by the British government, Bohr and his family escaped to Sweden in a fishing boat. From Sweden he flew to Britain where he began work developing a nuclear fission bomb. After a few months, the entire British team was sent to Los Alamos in the United States to collaborate on the Manhattan Project where Bohr was officially referred to as “Dr. Baker.” Almost immediately, however, he became concerned with the social and political implications of the bomb, writing a letter in 1944 to President Roosevelt and Prime Minister Churchill urging them to promote international cooperation. Later, in 1957, Bohr received the first United States Atoms for Peace Award and continued throughout the remainder of his life, often in conjunction with his old friend Kramers who was chair of the United Nations committee on nuclear policy, to argue for nuclear arms control. In the autumn of 1945, Bohr returned to Copenhagen where he regained his post and his home in Carlsberg. Much of his time over the next decade was spent planning the Danish Atomic Energy Commission’s research establishment at Risø. At the beginning of the 1960s, he and members of his institute began planning for a meeting in 1963 to celebrate the 50th anniversary of the publication of his original papers on atomic theory. Unfortunately, Bohr died a year before of a heart attack, leaving a legacy as one of history’s greatest physicists. On an astronomical note, there is a crater on the Moon named for him. Bok, Bart Jan Born Died Hoorn, the Netherlands, 28 April 1906 Tucson, Arizona, USA, 5 August 1983 Ian T. Durham Selected References Bohr, Niels (1972–). Collected Works, edited by L. Rosenfeld and others. Amsterdam: North-Holland. ——— (1987). The Philosophical Writings of Neils Bohr. Vol. 1, Atomic Theory and the Description of Nature. Woodbridge, Connecticut: Ox Bow. Carroll, Bradley W. and Ostlie, Dale A. (1996). An Introduction to Modern Astrophysics. Reading, Massachusetts: Addison Wesley Longman. French, A. P. and P. J. Kennedy (eds.) (1985). Niels Bohr: A Centenary Volume. Cambridge, Massachusetts: Harvard University Press. Kragh, Helge (1999). Quantum Generations: A History of Physics in the Twentieth Century. Princeton, New Jersey: Princeton University Press. Mitra, A. N. et al. (eds.) (1985). Niels Bohr: A Profile. New Delhi: Indian National Science Academy. Moore, Ruth E. (1967). Niels Bohr: The Man and the Scientist. London: Hodder and Stoughton. ——— (1966). Niels Bohr: The Man, His Science, and the World They Changed. Cambridge, Massachusetts: Harvard University Press. Pais, Abraham (1985). “Niels Bohr and the Development of Physics.” In A Tribute to Niels Bohr: Special Colloquim Held at CERN on 6 May 1985, pp. 85–117. Geneva: CERN. ——— (1991). Niels Bohr’s Times, In Physics, Philosophy, and Polity. Oxford: Clarendon Press. ——— (2000). “Niels Bohr: The Man and His Science.” In The Genius of Science, pp. 6–29. Oxford: Oxford University Press. Pauli, Wolfgang (ed.) (1955). Niels Bohr and the Development of Physics. New York: McGraw-Hill. (Reissue, Oxford: Pergamon Press, 1962.) Whittaker, Sir Edmund (1953). A History of the Theories of Aether and Electricity. Vol. 2, The Modern Theories. New York: Harper. Bart Bok was the son of Sergeant Major Jan Bok (Royal Dutch Army) and Gesina Annetta (née van der Lee) Bok. Bart Bok's name is associated with the Bok globules, small, dark, gas clouds, many of which are forming-or about to form-new stars. He was also one of Harvard's early champions of star formation as an important, on-going process, at a time when Jesse Greenstein and others were not so sure. He attended primary school in Hoorn and secondary school in The Hague. Bok entered Leiden University in 1924; two of his classmates were Gerard Kuiper and Pieter Theodorus Oosterhoff. Upon graduation in 1927, Bok was accepted by Groningen University, where he pursued a doctorate in astronomy under Piet van Rhijn. He studied the η Carinae region for his dissertation; his Ph.D. was awarded in 1933. In 1929, Bok married astronomer Priscilla Fairfield; the couple raised two children. He became an American citizen in 1938. The majority of Bok’s career was spent at Harvard University; he received the Robert Wheeler Wilson Fellowship (1929–1933) while still a graduate student. In succession, Bok was appointed assistant professor (1933–1939), associate professor (1939–1947), and the Robert Wheeler Wilson Professor of Astronomy (1947–1957). For six of those years, Bok was also associate director of the Harvard College Observatory (1946–1952). An astronomical leader on two continents from 1957 to 1966 Bok was professor and head of the department of astronomy at the Australian National University and director of its Mount B 145 146 B Bok, Bart Jan Stromlo Observatory. He thereupon returned to the United States as professor and head of the astronomy department at the University of Arizona and director of its Steward Observatory (1966–1970). During his Harvard years, Bok established a network of colleagues who were engaged with him on a program to determine the interstellar extinction rate at low galactic latitudes. Three of these “star counters” were Sidney W. McCuskey (Case Institute of Technology); Robert H. Baker (University of Illinois); and Edwin C. Carpenter (University of Arizona). Bok made annual “inspection trips” to cheer on his troops and to discuss their preliminary results. It was this activity that first led Bok and his wife to consider the University of Arizona and its Steward Observatory as the final “resting place” in their professional careers. In the early 1940s, Bok led the way for an astrophysical observatory to be built in Mexico. A 26/31-in. Schmidt telescope was established at the Observatorio Astrofísico de Tonantzintla with assistance from astronomers at the Mexican National University. The facility was opened in 1942 and first directed by Luis Erro. In 1950, Bok repeated the exercise by establishing a 24/32 in. Schmidt telescope, the so-called “Armagh–Dunsink–Harvard Telescope,” at Harvard’s Boyden Station in South Africa. There, Bok was able to collect a large number of plates for his enduring study of interstellar extinction in the galactic plane. In 1944, Hendrik C. van de Hulst, a research student at Leiden Observatory in the Netherlands, predicted the existence of a spectral line of cold, neutral, hydrogen due to an atomic hyperfine transition at the 21-cm wavelength. For his 1950 doctoral dissertation, Harvard physics graduate student Harold I. Ewen, working with Edward Durall, observationally confirmed Van de Hulst’s prediction. Typically, Bok was the first American astronomer to seize upon this opportunity. In 1952, he rustled up the funds necessary to build a 24-ft steerable antenna at Harvard’s Oak Ridge Station. With receivers built especially for the 21-cm/1420 MHz-radiation, he began a series of studies on the occurrence of neutral hydrogen in the plane of our Galaxy. A number of young radio astronomers emerged with new doctorates from this work, among them were Nannie Lou Dieter, Frank D. Drake, and David L. Heeschen. Not all senior American astronomers, however, were of the opinion that radio astronomy was worth the effort. Bok was often advised to get on with doing useful, i. e., optical, research. But he persisted. In Australia, Bok encouraged collaborative efforts between the radio astronomers at the Commonwealth Scientific and Industrial Research Organization [CSIRO] and the optical astronomers at Mount Stromlo. Always a champion of research on the Magellanic Clouds, Bok collaborated with the Swedish government to have yet another Schmidt telescope installed at Mount Stromlo. There, Uppsala University detailed one of their staff astronomers, Bengt E. Westerlund, as a resident observer. Bok also led the charge to find a site for a modern, large (4-m class) reflector, to replace the aging 74-in. telescope at Mount Stromlo. This resulted in the establishment of a facility at Siding Springs, starting with a 1-m Ritchey–Crétien reflector and, after Bok’s departure for Arizona, the 3.5-m Anglo–Australian Telescope. After accepting the post at the University of Arizona, Bok was able to obtain a grant from the United States National Science Foundation to change the complexion of the university’s small Steward Observatory. The grant amounted to $2.6 million, and Bok’s solution was to build and equip the largest telescope he could get for that amount of money. By these means, the Observatory’s 90-in. reflecting telescope was acquired. When Bok arrived in 1966, the scientific staff at the observatory consisted of five astronomers, five graduate students, one secretary, one machinist, and one staff photographer. After Bok retired in June 1970, the count was 15 astronomers, more than a dozen graduate students, 12 undergraduate students, four secretaries, and 14 technical support personnel (including the same staff photographer). On 28 April 1996, which would have been Bok’s 90th birthday, the 90-in. reflector was renamed the Bart J. Bok Telescope. Bok belonged to many professional organizations and received numerous awards. He was a member of the American Association for the Advancement of Science, vice president (1970–1971) and president (1971–1972) of the American Astronomical Society, board member of the Astronomical Society of the Pacific, member of the National Academy of Sciences and the Royal Astronomical Society, and vice president of the International Astronomical Union (1970–1974). He received the Bruce Gold Medal of the Astronomical Society of the Pacific (1977), the Jansky Prize of the National Radio Astronomy Observatory (1972), the Henry Norris Russell Lectureship of the American Astronomical Society (1982), and the Klumpke–Roberts Award of the Astronomical Society of the Pacific (1982). Bok’s own enthusiasm for his subject was infectious and always invigorating. Moreover, this enthusiasm carried over into “Town and Gown” situations. He was always willing to talk to the public about astronomy. His lectures, given during the Steward Observatory public evening series, were always delivered to standing-roomonly audiences. A bout with polio in 1939 left Bart with a withered right arm and unfit for military service during World War II. However, he and Harvard colleague Frances Woodworth Wright wrote a book together, Basic Marine Navigation, intended for use by the United States armed forces, especially for the Navy’s V-12 program. Wright eventually turned that enterprise into a book of her own, with Bok’s blessing, entitled Celestial Navigation. The 1947 paper announcing the first set of Bok globules was coauthored by Edith F. Reilly, who also had a physical handicap and was only briefly part of the astronomical community. Bok’s life was filled with writing projects, not only for scientific research publications, but also for public information and consumption. Raymond E. White Selected References Bok, Bart Jan and Priscilla Fairfield Bok. The Milky Way. Philadelphia: Blakiston, 1941, 1945. (Reprinted, Cambridge, Massachusetts: Harvard University Press, 1957, 1974, 1981.) Bok, Bart Jan and Frances Woodworth Wright (1944). Basic Marine Navigation. Boston: Houghton Mifflin. (Reprint, 1952.) Graham, J. A., C. M. Wade, and R. M. Price (1994). “Bart J. Bok.” Biographical Memoirs, National Academy of Sciences 64: 73–97. Levy, David H. (1993). The Man Who Sold The Milky Way: A Biography of Bart Bok. Tucson: University of Arizona Press. White, Raymond E. (1983). “Bart J. Bok (1906–83): A Personal Memoir from a ‘Grandson.’” Sky & Telescope 66, no. 4: 303–306. Bond, George Phillips Bond, George Phillips Born Died Dorchester, Massachusetts, USA, 20 May 1825 Cambridge, Massachusetts, USA, 17 February 1865 As the second director of the Harvard College Observatory, George Bond’s tenure, from 1859 to 1865, was tragically short. However, in his career Bond managed to make significant contributions to astronomical science in his comet and nebula observations as well as through his early experimental work in astronomical photography. As the son of the first Harvard director, William Bond, he served for years as his father’s assistant, and was appointed director of the observatory shortly after his father’s death. While George Bond’s career must be seen in the context of his father’s, he was clearly more highly trained and mathematically proficient. He directed the observatory at a time when its role and the climate of science in America were both changing. George Bond was born in Dorchester and moved to Cambridge when his father assumed directorship of the Harvard Observatory in 1839. Unlike his father, who was financially unable to complete his public education, George received a fine education. He attended the then famous Hopkins Classical preparatory school in Cambridge and graduated from Harvard University in 1845. By all accounts he was a serious and dedicated student who excelled in mathematics. He also had a strong interest in natural history and is said to have considered a career in this field. However, the death of his older brother William compelled him to take up the role of his father’s assistant. George’s astronomical career began while he was still a student. As early as 1842 he is reported making observations in the small observatory used before the 15-in. “great refractor” was installed. Not long after graduation George was hired as the observatory’s assistant observer. Despite being offered other positions, he remained in this post until his father died in 1859. Much of George Bond’s observing career centered on the study of comets. Between 1845 and 1851, at a time when finding comets was a major mark of an observer’s skill, he made independent discoveries of 10 comets, of which one actually bears his name (C/1850 Q1). His monograph on comet C/1855 L1 (Donati), “Account of the Great Comet of 1858,” was probably his most important scientific contribution. It was widely praised and resulted in his being awarded the Royal Astronomical Society Gold Medal in 1865. Bond was the first American to receive this award. Because George and his father worked closely together over a period of many years, and because of the son’s deference to his father’s reputation, it is difficult to parse the achievements of the two men. They collaborated on several visual studies, including sunspots (from 1847 to 1849), Saturn (1847–1856), and Jupiter (1847– 1849). The two also collaborated on studies of the Andromeda and Orion nebulas and the Hercules cluster. In 1848, they codiscovered Saturn’s eighth moon Hyperion. George is generally credited with being the codiscoverer, with William Rutter Dawes, of the faint inner or crépe ring of Saturn. The two Bonds also collaborated (along with Boston photographer John Adams Whipple) in early attempts to photograph the heavens. From 1849 to 1851 they experimented with daguerreotypes. In 1850, the three succeeded in recording the first image of a star (Vega or α Lyrae) on a daguerreotype. In 1851, using short exposures and at a separate photographic focus, they succeeded in taking a series of beautifully clear images of the Moon. George Bond displayed these daguerreotypes to great effect when he visited Europe in 1851. Beginning in 1857 the younger Bond, working with Whipple and his partner James Wallace Black, took a series of between 200 and 300 collodion photographs through the large telescope. The more sensitive film and longer exposures, achieved with the telescope’s improved clock-drive, allowed them to photograph stars as faint as 6th magnitude. As part of this work, Bond made preliminary stellar and photometric measurements. The difficulties of working with collodion films made such work impractical at the time, but Bond clearly showed the possibilities of the new technology. As his father’s assistant, George Bond participated fully in the observatory’s longitude work. He directed the United States Coast Survey Chronometric Expeditions (1849–1855) and made the data reductions that led to the most accurate determinations of American longitude to date. He also was a key participant in the work to develop a telegraphic method of determining longitude (what came to be called the American method). In 1851, George was chosen to take the longitude instruments developed by the Bonds to London, where they were demonstrated and exhibited at the Crystal Palace Exhibition. The instruments were awarded a Council Medal, the exhibition’s highest award. By the 1850s, George Bond had developed a reputation as a firstrate astronomer, and the Harvard Observatory had become the de facto national observatory for many. In 1856, he was offered the prestigious position of chief astronomer of the Northwest Boundary Survey, charged with establishing the American–Canadian border. Although he declined the offer, it indicates the high regard in which he was held. Unlike his father, who pursued his entire career with little controversy, George Bond was unable to avoid professional disputes. The most serious was with fellow Harvard astronomer Benjamin Peirce, who first quarreled with Bond over their articles on the structure of Saturn’s rings. Peirce’s hostility became resentful and openly critical when he was denied the position of observatory director after William Bond’s death. Within a month of being named director George wrote to Peirce, offering a reconciliation and access to the observatory. Peirce never responded. Bond believed that his later failure to be elected to the National Academy of Sciences was at least partly due to Peirce’s influence. In 1857 Otto Wilhelm Struve, sharply criticized the Observatory’s work on the Orion nebula. Rising to what he perceived as a criticism of the observatory as well as his father, George became determined to produce a definitive study of the nebula and spent the winters of 1857, 1858, and 1859 making detailed observations. He had to postpone the project to finish his work on Donati’s comet, but in the last days of his life he worked diligently, but unsuccessfully, to finish it. Bond’s work on the Orion nebula was completed and published by Truman Safford before the latter accepted the directorship of the Dearborn Observatory when it first opened. After several years of delicate health, William Bond died. Tragically, the death of George’s father and his appointment as observatory director also coincided with the death of George’s wife, Harvard librarian Harriet (née Harris) Bond, who died in December 1858. At about the same time, Bond experienced the first symptoms B 147 148 B Bond, William Cranch indicating that he had contracted tuberculosis. Despite heroic efforts to keep working, George Bond’s remaining years were characterized by generally declining health and energy. Bond took over the observatory at a time when its role was changing, a factor making his directorship even more complicated in the face of the adverse influences of his personal and health problems. Much of the longitude and other practical work that had for many years provided the main grist of the observatory workload was no longer a priority or was being provided by other sources. Federal contracts and income ended by 1862, and by then the Civil War was draining resources of all kinds. In 1863, Bond wrote to a colleague that all but one of his assistants had either enlisted or been drafted into the Union Army. Despite these problems, Bond gamely tried to improve the observatory. Determined to acquire a larger telescope, he first attempted to buy the exquisite 18½-in. refracting telescope lens produced by Alvan Clark & Sons for the University of Mississippi. When the Civil War broke out and the university lost its ability to pay for the lens, Bond negotiated to purchase the lens, but the Clarks eventually sold it to the Chicago Astronomical Society for use at the Dearborn Observatory. Bond made a second trip to Europe in 1863 in search of a new larger instrument, but nothing came of it. George Phillips Bond made his last astronomical observation on 24 August 1864. His strength continued to fade until he finally died. Steven Turner Selected References Baker, Daniel W. (1890). History of the Harvard College Observatory During the Period 1840–1890. Cambridge, Massachusetts. Bond, George Phillips (1862). “Account of the Great Comet of 1858.” Annals of the Astronomical Observatory of Harvard College 3. ——— (1867). “Observations upon the Great Nebula of Orion.” Annals of the Astronomical Observatory of Harvard College 5. Hoffleit, Dorrit (1950). Some Firsts in Astronomical Photography. Cambridge, Massachusetts: Harvard College Observatory. Holden, Edward S. (1897). Memorials of William Cranch Bond and of his son George Phillips Bond. San Francisco: C. A. Murdock and Co. Stephens, Carlene E. (1987). “Partners in Time: William Bond and Son of Boston and the Harvard College Observatory.” Harvard Library Bulletin 35, no. 4: 351–384. ——— (1990). “Astronomy as Public Utility: The Bond Years at the Harvard College Observatory.” Journal for the History of Astronomy 21: 21–36. Bond, William Cranch Born Died Falmouth (Portland), Maine, USA, 9 September 1789 Cambridge, Massachusetts, USA, 29 January 1859 As the first director of the Harvard College Observatory, from 1839 to 1859, William Bond was one of the major figures in antebellum American astronomy. His work as an astronomer was more closely linked to institution building, his business, and to the needs of commerce than it was to the basic observational or theoretical astronomical work of his times. Biographies of his life have generally focused on his rise from humble beginnings, his remarkable mechanical abilities, and his role in establishing the Harvard College Observatory. Recent research has centered more on his work as a provider of precise time and position measurements to the developing nation and his role in the scientific network that developed around Cambridge during his lifetime. Financial hardship soon caused his family to move to Boston, Massachusetts, where his father, William, started a watch and jewelry business. As a boy Bond showed great mechanical aptitude, building a weight-driven chronometer at age ten and a fine wooden quadrant at age 16. In 1812, he completed what was reputed to be the first seagoing chronometer made in America. Under his direction the Bond firm expanded into the important marine chronometer trade and later provided precision astronomical regulators to American customers. The nature of both enterprises meant that the firm engaged in extensive trade with British suppliers and customers. As a young man William showed an intense interest in astronomy, which he attributed to seeing the solar eclipse of 1806. Despite being largely self-taught and lacking proper instruments, he was the first American to observe and track the comet of 1811(C/1811 F1). This brought him to the attention of Harvard professor John Farrar and later the famed Nathaniel Bowditch, both of whom encouraged and assisted Bond. In 1815, upon learning that Bond was planning to travel to England, Farrar was instrumental in having the college ask Bond to visit Greenwich Observatory and the London instrument makers. For the college this was a preliminary step in the eventual construction of an observatory. For Bond, who met not only the Royal Astronomer John Pond and William Herschel, but also a host of other luminaries of British astronomy, it must have been a powerful formative experience. Indeed, Bond’s passion for astronomy was so great that he converted the parlor of his home in Dorchester into a transit room, Bond, William Cranch installing a massive granite pier in the center of the room and a meridian opening in the ceiling. With this and a growing collection of other instruments he used his private observatory to pursue a regular observing program, determining (among other things) his precise longitude. He also used his observatory to support his business. Beginning in 1834, he had a series of contracts with the United States Navy to rate and maintain ships’ chronometers, and in 1838 he received an appointment from the federal government to assist the Wilkes expedition, providing meteorological, magnetic, and astronomical observations. Bond brought this practical approach to astronomy with him when in 1839 he accepted Harvard College president Josiah Quincy’s invitation to become the school’s astronomer. Harvard’s choice of Bond was a logical one; he already was known to be a first-rate observer, and his ongoing work on the Wilkes expedition was sure to bring prestige to the college. As a bonus, Bond brought all his instruments with him, and these were much superior to the few telescopes then owned by the college. Bond received no salary until 1846 but was provided living quarters and space for his instruments. The great comet of 1843 (C/1843 D1) drew the attention of many Americans to the heavens. In Cambridge, reports that Bond’s instruments were inadequate to chart the orbit of the comet soon led to a spontaneous public campaign that raised $20,000 to purchase a proper telescope. On his own, businessman David Sears donated another $5,000 for a stone pier. By 1847, the great 15-in. Merz and Mahler refractor – the great equatorial – was in place and ready to use. In less than 7 years Bond had taken Harvard College from astronomical obscurity to possession of a telescope equal in size to any in the world. The uses that Bond made of this new instrument and the other resources at his disposal reflect his background as a “mechanic” and his belief that science should be “useful.” While it is often difficult to separate his work from that of his son and collaborator, George Bond, certain broad statements can be made: First, that although he was a diligent and accomplished observer, his main contributions to astronomy were his technical innovations. Second, that while other astronomers, like Harvard’s professor of mathematics and astronomy Benjamin Peirce, may have advocated a program of theoretical research, William Bond chose to devote large amounts of the observatory’s resources to purely practical interests. Nonetheless, under his direction the Harvard College Observatory succeeded on many levels. From 1847 to 1856 William Bond and his son made an extended study of Saturn. In 1848, they discovered Saturn’s moon Hyperion and later made detailed observations of the faint ring structures. The Bonds also made visual studies of other planets and, particularly, the nebulae in Andromeda and Orion. Between 1847 and 1849 they used a smaller refractor to make a series of nearly 250 sunspot drawings. In 1849, William was elected a Foreign Associate of the Royal Astronomical Society. William Bond also made significant improvements to the large telescope itself: first with an ingenious observer’s chair and then in 1857 with a much improved clock drive, designed by the Bonds and manufactured by the Cambridge telescope maker Alvan Clark. With much assistance from his son George and Boston photographer John Adams Whipple, William also pioneered the application of photography to astronomy. In July 1850 they took the first successful picture of a star, a daguerreotype of Vega (α Lyrae). After the new drive was installed, they experimented extensively with the newly developed wet-plate collodion process, eventually taking between 200 and 300 photographs of the heavens. Concurrent with his work as an observer, William Bond also continued to accept assignments from federal agencies. In the mid1840s, following the lead of other national observatories, he began to ship chronometers between Cambridge and Liverpool with the goal of precisely determining the longitude of the observatory. In 1849, Alexander Bache, head of the United States Coast Survey, gave formal sponsorship for this project, and the Bonds transported groups of chronometers across the Atlantic in a series of trials that finally ended in 1855. Eventually Cambridge’s position was so precisely determined that it became the reference point for the United States Topographical Engineers and the de facto American meridian. Also in the 1840s, Bond and his sons George and Richard became key players in the American efforts to determine longitude telegraphically. They were instrumental in the development of a workable break-circuit device to automatically transmit time signals over the telegraph and also developed the drum chronograph, which was later widely used in American observatories. Despite priority disputes, the Bonds exhibited the “American Method” of determining longitude at the 1851 London Crystal Palace Exhibition. They received a Council Medal, the exhibition’s highest award. Under Bond, work at the observatory overlapped with the activities of his business. In 1851, he installed the world’s first telegraphic time service in the observatory, providing astronomically derived signals to keep the railroads safely on time – and indirectly providing standardized time to large parts of the northeastern United States. The signals were supplied through the Bond & Sons firm, which also supplied timekeepers to the railroads. Although clearly serving a commercial purpose, under Bond the observatory provided this service without compensation. Bond saw it as part of the observatory’s mission to be “useful.” Later in the century, selling time became a significant source of revenue for many American observatories. Bond’s last few years were characterized by delicate health, and many of his duties were assumed by his son George. Of his other assistants, Truman Safford, Asaph Hall, and William Rogers were later ranked among the country’s most talented astronomers. His son George, a talented astronomer in his own right, succeeded him as director of the Harvard College Observatory. Steven Turner Selected References Baker, Daniel W. (1890). History of the Harvard College Observatory During the Period 1840–1890. Cambridge, Massachusetts. Bond, William Cranch (1856). “History and Description of the Astronomical Observatory of Harvard College.” Annals of the Astronomical Observatory of Harvard College 1. Holden, Edward S. (1897). Memorials of William Cranch Bond and of his son George Phillips Bond. San Francisco: C.A. Murdock and Co. Stephens, Carlene E. (1987). “Partners in Time: William Bond and Son of Boston and the Harvard College Observatory.” Harvard Library Bulletin 35, no. 4: 351–384. ——— (1989). “The Most Reliable Time”: William Bond, the New England Railroads, and Time Awareness in 19th-Century America.” Technology and Culture 30: 1–24. ——— (1990). “Astronomy as Public Utility: The Bond Years at the Harvard College Observatory.” Journal for the History of Astronomy 21: 21–36. B 149 150 B Borda, Jean-Charles de Borda, Jean-Charles de Born Died Dax, (Landes), France, 4 May 1733 Paris, France, 19 February 1799 Jean-Charles de Borda was a positional astronomer, instrument designer, and one of the founders of the metric system. Borda was born in a noble family, son of Jean-Antoine de Borda and JeanneMarie Thérèse de Lacroix. He began his education at the Jesuit school La Flèche, and later entered the light cavalry and then the Academy of Engineers of Mézières. His scientific curiosity made him eligible for the Paris Academy of Sciences in 1756. Borda’s first publications in the annals of the academy deal with a subject not directly related to astronomy: the resistance of fluids. In 1769, due to Aymar Joseph de Roquefeuil’s insistence, the Marine Academy was created, and Borda was elected a member and professor of mathematics. There, he developed a great deal of his astronomical knowledge. In 1771, Borda embarked on the frigate La Flore, destined for America. He was accompanied by the astronomer Alexandre Pingré, with the goal to study the behavior of chronometers and to determine their utility when using the lunar-distances method to determine longitude at sea. The simplified method, which Borda tested on this trip and was published in two volumes with tables in 1778, became common practice in the French navy. Simplified versions of the method were also published in the Connaissance des temps in the years 1779, 1780, and 1787. Borda specialized in positional astronomy to be used in navigation and astronomical instrumentation, and in this field he accomplished his best work. Other trips to America and Africa sealed his fame as a sailor and as an educated scientist. He was named captain, and was captured during combat by the British in 1782 and in 1784. With his health too weak for life at sea, Borda was named superintendent of construction of the school of naval engineers. In 1795, at its creation, he was also selected a member of the Bureau of Longitudes. From 1778 Borda perfected an instrument adumbrated by Tobias Mayer in 1752, which he named the “repeating circle” or “astronomical circle.” Borda’s circle competed with the traditional quadrant used for astronomical measurements both at sea and on land, and its superiority was manifested in the operation of the geodesic union of the observatories in Greenwich and Paris, which took place in 1787. Under his direction, the artist E. Lenoir made a great number of instruments of various dimensions. In 1801, the Spanish astronomer and mariner José de Mendoza introduced new improvements that led to the instrument’s definitive shape for use in navigation and in terrestrial operations. Borda also calculated, in subsequent years, numerous trigonometric sexagesimal and centesimal tables for better use of the instrument. As an expert observer and a careful experimenter, Borda’s name was associated from the very beginning with the activity that would be the most important of his later years: the work on the basis of a new system of weights and measures promoted by revolutionary France. It was his initiative, on record in the Procès verbaux de l’Académie des sciences, to create a commission that drew up the definitive project. Indeed, on 16 February 1791, the academy selected him along with Pierre de Laplace, J. A. Condorcet, Joseph Lagrange, and Gaspard Monge to propose a new model of measurements founded on the length of a terrestrial meridian. The report on 19 March 1791 constituted without a doubt the origin of the decimal metric system, which became the international system of weights and measures. In his work to define the metric system, Borda displayed an unwearied activity up until his death. He was in charge along with C. A. de Coulomb of measuring the length of the pendulum that marked seconds at the 45° parallel. Borda verified the rules used to measure the geodesic bases and to determine the model kilogram. He supervised the construction of repeating circles, which Jean Delambre and Pierre Méchain used in their measurements. On 5 July 1795, Borda presented his Rapport sur la vérification du mètre qui doit server d’étalon pour la fabrication des unités républicaines, which introduced the provisional meter, and was part of all the commissions that determined the definitive meter. In the middle of these efforts to officially approve this new measurement, Borda died. Antonio Ten Translated by: Claudia Netz Selected References Mascart, J. (1919). La vie et les travaux du Chevalier Jean Charles de Borda. Lyons: Annales de l’Université de Lyon. (For an almost complete bibliography of Borda’s works.) Ten, Antonio E. (1996). Medir el metro: La historia de la prolongación del arco de meridiano Dunkerque–Barcelona, base del Sistema Métrico Decimal. Valencia: Instituto de Estudios Documentales e Históricos sobre la Ciencia, Universitat de València. Borelli, Giovanni Francesco Antonio Alfonso Born Died Naples, (Italy), January 1608 Rome, (Italy), 31 December 1679 Giovanni Borelli was an early Italian Copernican, experimenter, and observer. Christened on 28 January 1608 in Naples, he was born to Miguel Alfonso, an itinerant soldier in the occupying Spanish army, and Laura Porrello (also called Borrelli in some records), a native of Naples. Giovanni and his brother Filippo later took the name Borelli, although why is unknown. The brothers met the controversial philosopher Tommaso Campanella around 1626 and both became his students. Filippo, who fled to Paris in 1634 with Campanella, edited the latter’s works and appears to have returned to Italy and entered the Dominican order, taking the name Tommaso. After 1628, Giovanni Borelli went instead to Rome, where he studied under Benedetto Castelli, who held Borelli in high esteem. In 1635, Castelli recommended Borelli to fill the vacant mathematics chair in Messina and later, in 1640, recommended him, unsuccessfully, to Galileo Galilei for a similar chair at Pisa, one he eventually gained in 1656. Borelli began his career in Messina inauspiciously, it appears, being at first a very unsuccessful lecturer, but improved considerably in time and attracted wide student interest. He also became Boskovic, Rudjer [Roger] J. central to the intellectual life of the university despite his lack of published output. In 1642, the Senate of Messina enjoined Borelli to travel through Italy recruiting talented faculty for the university, a journey that brought him into contact with many of the leading lights of the Italian scientific community and broadly established his reputation and broadened his own education. He remained in Messina until 1656, publishing several works in mathematics and displaying a growing expertise in theoretical medicine but not evincing any special interest in either physics or astronomy. However, his Copernican interests were becoming known, because in 1650 he was passed over in a bid for the chair of mathematics in Bologna, which was given to Giovanni Cassini; his philosophical position may have been a factor. Eventually, in 1656, Borelli managed to succeed to the chair of mathematics at Pisa previously occupied by Galilei and Castelli, relocating to Tuscany and beginning the most intellectually productive period of his life. The Medicis, who controlled the university and the city, were deeply affected by and sympathetic to the Galilean scientific program, especially the princes Leopold and Ferdinand who were the founders of the Accademia del Cimento. This was a group of dedicated empiricists that included Vincenzo Viviani, the last pupil of Galilei, Carlo Rinaldi, and the Danish philosopher Nicholas Steno. After his arrival in Pisa, Borelli became central to its activities, and was perhaps its most visible, and contentious, member; it lasted from 1657 through 1667. Although publishing anonymously, like the later Bourbaki collaboration whose members published only as a collective, it is clear that much of the work of the Accademia was Borelli’s. The works of the Accademia, finally collected and published in 1667 as the Saggi di naturali esperienze fatte nell’accademia del cimento, not only ranged over a broad experimental territory, mainly pneumatics, thermal physics, and fluids, but also included astronomy. For instance, following Christiaan Huygens’ announcement of the discovery of a ring system around Saturn in 1660, Borelli conducted what may be the first experimental study of observer effects. He constructed a scale model of Saturn with an inclined ring that was observed at a distance with the unaided eye and lenses to simulate the planet’s angular diameter and approximate illumination, showing that the model reproduced the explanation. At a distance of 23 m, the appearance to the unaided eye in daylight illumination was a sphere flanked by two stars; at 75 m with a small telescope it displayed the rings and shadow clearly as Huygens had described. This also explained the results obtained by Galilei and others with more imperfect telescopes. Finally, uninformed observers of the Accademia were asked to sketch the appearance, foreshadowing an experiment conducted at the start of the 20th century by Simon Newcomb for the Martian canals. Borelli displayed a lively interest in astronomy during his years in Tuscany. In an interesting prediction for the lunar eclipse of 16 June 1666, Borelli calculated that atmospheric refraction would permit the simultaneous observation of the Moon in eclipse, which occurred at sunset, and the rising Sun; an expedition organized by the Accademia to the island of Georgina in the Tyrrhenian Sea confirmed this and determined an atmospheric refraction of nearly 1°. A similar prediction for Venus, that on 21 and 22 April 1662 it would be both the morning and evening star, was not confirmed because of the weather and was not attempted again. Borelli also engaged in observations of comets C/1664 W1 and C/1665 F1. He demonstrated that the motion followed a curved orbit akin to a parabola, and that the comet’s lack of parallax placed it above the Moon. Both were clearly Copernican results and sufficiently sensitive that the work, Del movimento della cometa apparsa nel mesi di dicembre 1665, was published in Pisa under a pseudonym, Pier Maria Mutoli. Borelli also established an observatory in San Miniato, near Florence, during the summer of 1665. The next year saw publication of his Theoricae mediceorum planetarum ex causis physicis deductae, his most important work in astronomy in which he sought to explain the elliptical orbital motion of the Jovian moons through a combination of centripetal tendencies because of the ponderous nature of the satellites’ rotationally driven torques – much as Johannes Kepler had done for the planets driven by the solar rays and/or magnetic field – and centrifugal forces. In this work, he failed to appreciate the role of inertia requiring active tangential driving by the central body, but anticipated the importance of radial equilibrium between the gravitating tendency of the body and its centrifugal deviation. In 1667, Borelli returned to Messina to renew his appointment as professor of mathematics, also taking an active role in scientific academies in Naples and Rome. He ultimately fled to Rome in 1672 with a prise on his head – as Campanella had so many years before – following a political dispute with the ruling Spanish government in Messina. Borelli received the patronage of Queen Christina of Sweden, whose connections with René Descartes are well known, and who supported publication of his final work on anatomy and musculature. Suffering serious financial difficulties in his last years, Borelli lodged with the order of Casa di San Pantaleo in Rome after 1677, teaching at their school, and died there. Borelli also had an international reputation as an important telescope maker. In his later years, his advice was sought by Jean Cassini, then director of the Paris Observatory, and Jean Picard. John Flamsteed procured a 90-ft focal length lens from him for the newly founded Royal Observatory at Greenwich in 1675. Steven N. Shore Selected References Koyré, A. (1973). The Astronomical Revolution. Ithaca, New York: Cornell University Press. Middleton, W. E. Knowles (1971). The Experimenters: A Study of the Accademia del Cimento. Baltimore: Johns Hopkins University Press. Settle, Thomas B. (1970). “Borelli, Giovanni Alfonso.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 2, pp. 306–314. New York: Charles Scribner’s Sons. Boskovic, Rudjer [Roger] J. Born Died Ragusa (Dubrovnik, Croatia), 18 May 1711 Milan, (Italy), 13 February 1787 The polymathic Jesuit Rudjer Boskovic contributed to practical and theoretical mathematics, optics, and astronomy. He was born to Nikola Boskovic, a merchant, and Paula Bettera. After his early B 151 152 B Boskovic, Rudjer [Roger] J. education at the Jesuit school in Ragusa, Boskovic entered the Jesuits in 1725 and then studied at the Collegium Romanum. He advanced quickly in his studies. He was made professor of mathematics at the Collegium Romanum in 1740 before he was ordained and even before he finished his course of theology. In 1759, Boskovic left Rome for Paris, to the Academy of Sciences, of which he was a corresponding member. After staying there for half a year, he traveled first to London, where he met many scientific and philosophical noteworthies before continuing to tour Europe and returning to Italy in 1763. Boskovic became professor of mathematics in Pavia, where he focused on optics and also led efforts to build the Brera Observatory in Milan (though his plans were not fully carried out). In 1770, he moved to the Scuole Palatine in Milan, but trouble led to his resignation of his professorship in 1772. When Pope Clement XIV banned the Jesuit order the following year, Boskovic moved to Paris, where he again concentrated on optics and astronomy as captain of optics in the French navy. In 1782, he returned to Italy, eventually settling down in Milan, where he worked at the Brera Observatory until his death. Boskovic argued against blind loyalty to Aristotelian physics and did not suffer fools gladly. This characteristic led to many disputes and contributed to many of his political difficulties. In his early days, Boskovic was not allowed to teach openly the Copernican system as a fact. Out of respect for the Roman Inquisition, Boskovic taught it as a mathematical hypothesis and mentioned the need to satisfy censors in order to acquire the imprimatur, but urged its acceptance nonetheless. His influence helped minimize the hostility of Catholic churchmen to the Copernican system, and he convinced Pope Benedict XIV to remove De Revolutionibus from the Index of Forbidden Books. Boskovic demonstrated considerable practical and theoretical talent. He was commissioned to repair the fissures in Saint Peter’s dome as well as in other cathedral domes, to direct the drainage of the Pontine marshes, and to survey the meridian of the Papal states. His practical inventions include the ring micrometer, which enabled him to determine the relative positions of two heavenly bodies. Boskovic was the first to apply probability to the theory of errors, as was later acknowledged by Pierre de Laplace and Carl Gauss. His ideas also led to methods developed by Laplace and Gauss to compute the orbits of comets and asteroids. In his analysis of the vis viva controversy, about which he concluded that it was a verbal rather than a philosophical problem, Boskovic also first expressed his atomic theory based on a universal force law describing both attractive and repulsive regions; he developed the details of this theory in his Theoria Philosophiae Naturalis. Boskovic’s interest in astronomy led him to a complete study of optics, optical instruments, and the theoretical foundations and instrumental practice of observational astronomy. He formulated a general photometric law of illumination, developed a law of light emission, and worked for the improvement of lenses and optical devices. His Dioptrics addresses many principles of telescopic observation, including achromatic lenses and the importance of eyepieces; it also offers an impressive example of Boskovic’s accuracy in measuring the reflection and dispersion of light using his own invention, the vitrometer. Boskovic’s astronomical efforts yielded many other results as well, including methods to determine the Sun’s rotation, details of the transit of Mercury, and observations of the aurora. In 1753, he refuted Leonhard Euler’s analysis of the lunar atmosphere, arguing that it was, at best, far less dense than supposed. In 1766, Boskovic communicated to Joseph de Lalande a method of measuring the speed of starlight by use of a telescope filled with water to discover whether light travels with the same velocity in air and in water. In 1770, as the first director of the Brera Observatory, he made preparations to carry out this experiment, but could not do so before his removal. Boskovic was a correspondent for the Royal Society of London and a frequent contributor to the Jesuit periodical Mémoires des Trévoux. He regularly encouraged international scientific cooperation. He helped convince the Royal Society to form an expedition to observe the 1761 transit of Venus, but was unable to participate in the observations himself. The Royal Society subsequently invited Boskovic to lead a trip to California to observe the 1769 transit of Venus, but this was canceled for political reasons. Boskovic lived a long, fruitful life in which he explored diverse interests. Eastern European and Russian scientists have long shown a strong interest in his work; more recently, Western scientists have become better acquainted with his contributions, yielding a host of recent books and articles. His legacy has been preserved in the special Boskovic Archives in the Rare Books Library at the University of California in Berkeley. The nearly 200 items housed there include many of his 66 scientific treatises and over 2,000 letters of correspondence with other mathematicians, including Laplace, Jean D’Alembert, Daniel Bernoulli, Euler, and Joseph Lagrange. Various symposia have been held on the anniversaries of Boskovic’s publications, birth, and death. A lunar crater also honors him. Joseph F. MacDonnell Selected References Anon. Philosophical Transactions of the Royal Society of London. (Articles by Boskovic or concerning his work are found in Vol. 1, pp. 394–396, 120–123; Vol. 2, pp. 693–698; Vol. 5, pp. 2023; Vol. 6, pp. 3061–3063; Vol. 8, pp. 6033–6036; Vol. 9, pp. 219–222; Vol. 11, pp. 611; Vol. 13, pp. 244–258; Vol. 14, pp. 721–726; Vol. 16, pp. 314–323.) Boskovic, R. J. (1739). De novo telescopii usu ad objecta coelestia determinanda. Rome. ——— (1758). Philosophiae naturalis theoria. Rome. ——— (1767). Dissertationes quinque ad dioptricam. ——— (1770). Voyage astronomique et geographique dans l’etat de l’eglise. Paris. ——— (1785). Opera pertinentia ad Opticam et Astronomiam. Bassani. (Contains five volumes of diverse and original material. Vols. 1 and 2: Theory of astronomical refractors, spherical and chromatic aberration; Vol. 3: Orbits of comets; Vol. 4: Geodesy and trigonometry; Vol. 5: Diverse topics – Saturn’s rings, sunspots, and the determination of longitude.) De Morgan, A. (1862). Contents of the Correspondence of the 17th and 18th century. London. Macan, Ivan, ed. (1987). The Philosophy of Science of Ruder Boskovic: Proceedings of the Symposium of the Institute of Philosophy and Theology, S. J. Zagreb: Jumena. Rigaud, Stephan Jordan (ed.) (1841). Correspondence of Scientific Men of the Seventeenth Century. 2 Vols. (Reprint, Hildesheim, Germany: Georg Olms, 1965.) Sommervogel, Carlos (1890–1960). Bibliothèque de la Compagnie de Jésus. 12 Vols. Brussels: Société Belge de Libraire. (108 entries.) Whyte, Lancelot Law (1961). Roger Joseph Boskovic. New York: Fordham Press. Boss, Lewis Boss, Benjamin Born Died Albany, New York, USA, 9 January 1880 Albany, New York, USA, 17 October 1970 American astronomer Benjamin Boss was noted for his star catalogs and for work in astrometry, the precise determination of stellar positions and motions. Son of the astronomer Lewis Boss, the director of the Dudley Observatory in Albany, New York, Benjamin was educated at the Albany Academy. He was awarded his bachelor’s degree from Harvard University in 1901, returning to Dudley as an assistant astronomer. In 1905, Benjamin Boss took a position at the United States Naval Observatory, Washington, and from 1906 to 1908 he ran its observing station at Tatuila, Samoa. While in the South Pacific, Boss organized an expedition to Flint Island to observe the 1908 total eclipse of the Sun. Thereafter, Boss returned to Dudley Observatory, where he was appointed secretary, Department of Meridian Astronomy, Carnegie Institution, Washington, serving in this post until 1912. The department was affiliated to Dudley Observatory, the latter institution carrying on star cataloging work financed by Andrew Carnegie. In 1912, Benjamin Boss was named acting director of Dudley Observatory, taking over from his late father; in 1915 he became director of both Dudley Observatory and the Department of Meridian Astrometry. In that same year, Boss began serving as editor of the Astronomical Journal, a position he held until 1941 when Dudley turned this publication over to the American Astronomical Society. (The Astronomical Journal, founded in 1849 by Benjamin Gould, is the oldest American periodical devoted to reporting astronomical research.) Boss made valuable contributions early in his career to the study of the motions of stars in the Milky Way Galaxy. Nineteenthcentury astronomers had generally supposed that stellar motions were essentially random (apart from systematic streaming due to the motion of the Solar System). Work around 1900 by Jacobus Kapteyn, Arthur Eddington, Frank Dyson, and Karl Schwarzschild revealed definite systematic motions that we now attribute to the rotation of the galactic disk within a nonrotating stellar halo. Kapteyn described the phenomenon as star streams, Schwarzschild as a velocity ellipsoid. Both the Bosses initially opposed the idea, though the elder Boss had actually discovered one systematic motion (that of the stars of the Hyades cluster, from which their distances can be determined), and his 1910 catalog had data later used to support star streams in general. The younger Boss soon changed his mind when he himself found asymmetries in the motions of the stars with the largest apparent motions on the sky (the ones that do not share disk rotation) and recognized several additional moving groups of stars like the Hyades but more distant. Benjamin Boss spent the vast majority of his professional career reducing data for and compiling the massive General Catalogue of 33,341 Stars for the Epoch 1950.0, which was published by the Carnegie Institution in 1937. Lewis Boss had first conceived of this project in the 1880s. The General Catalogue incorporated data from two earlier Dudley catalogs of southern and northern stars and 238 other star catalogs dating back to 1755. In addition to selecting data critically, the younger Boss developed sophisticated methods for giving more weight to more reliable data and taking systematic errors into account. He and his staff put almost three decades (1910–1937) and 300–700 “computer years” of effort into the General Catalogue, which remained unrivaled in its number of accurate positions and proper motions well into the 20th century. It was one of the first star catalogs keypunched into machine-readable format. (The Dudley Observatory “computers” differed from the women who did data analysis and processing at Harvard, Lick, Yerkes, and Mount Wilson observatories in being almost exclusively women who had only a high-school education at best, while the other observatories tended to employ women who had received college degrees.) Boss retired from the directorship in 1956. Peter Wlasuk Selected References Anon. (18 October 1970). “Obituary.” New York Times: 42. Boss, Benjamin (1910). “Systematic Proper-Motions of Stars of Type B.” Astronomical Journal 26: 163–166. ——— (1911). “Community of Motion among Several Stars of Large ProperMotion.” Astronomical Journal 27: 33–37. ——— (1912). “Systematic Motions of the Stars Arranged According to Type.” Astronomical Journal 27: 83–94. Boss, Lewis (1908). “Convergent of a Moving Cluster in Taurus.”: 42 Astronomical Journal 26: 31–36. Wise, George (2004). Civic Astronomy: A History of the Dudley Observatory. Chap. 5. Dordrecht: Kluwer Academic Publishers. Boss, Lewis Born Died Providence, Rhode Island, USA, 26 October 1846 Albany, New York, USA, 5 October 1912 Astrometrist Lewis Boss directed the Dudley Observatory (Albany, New York), was responsible for the production of four independent star catalogs, and edited the Astronomical Journal. Boss, son of Samuel P. and Lucinda (née Joslin) Boss, was educated at Dartmouth College and received his A.B. in 1870. Boss’s formal training in astronomy was limited to a single course taken under Charles Young. Yet, he learned to use astronomical instruments and to reduce his observations through visits made to the Dartmouth College Observatory. Boss deepened his interest in astronomical matters while working as a clerk in the government land office at Washington, DC. Concurrently, he secured the loan of various instruments from the United States Naval Observatory. In 1871, Boss married Helen Hutchinson; the couple had four children. One of them was the astronomer Benjamin Boss. In 1872, Boss joined the United States Northern Boundary Commission survey of the 49th parallel (separating Canada and the United States) as assistant astronomer. He was charged with establishing the latitudes of stations from which surveyors operated. Boss B 153 154 B Bouguer, Pierre of the Royal Astronomical Society (1905), the Lalande Prize of the French Académie des sciences (1911), and membership in the National Academy of Sciences. Boss’s papers are preserved at the Dudley Observatory Archives, Schenectady, New York. Richard Baum Selected References Boss, Benjamin (1912). “Lewis Boss.” Astronomical Journal 27: 131–132. ——— (1920). “Biographical Memoir of Lewis Boss.” Biographical Memoirs, National Academy of Sciences 9: 239–260. Carter, Merri Sue (1999). “Boss, Lewis.” In American National Biography, edited by John A. Garraty and Mark C. Carnes. Vol. 3, pp. 223–224. New York: Oxford University Press. Turner, H. H. (1905). “Address Delivered by the President, H. H. Turner, on Presenting the Gold Medal of the Society to Professor Lewis Boss.” Monthly Notices of the Royal Astronomical Society 65: 412–425. Warner, Deborah Jean (1970). “Boss, Lewis.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 2, pp. 332–333. New York: Charles Scribner’s Sons. Bouguer, Pierre improved contemporary latitude determinations by eliminating systematic errors caused by faulty observations and methods of reduction. From these labors, Boss compiled a catalog (1878) of the declinations and proper motions of 500 stars that was adopted by the American Ephemeris in 1883. Appointed director of the Dudley Observatory in 1876, Boss remained in that position for the rest of his life. A major project during his tenure was the observation and reduction of star positions for a zone (+1° to +5° declination) of the Astronomische Gesellschaft Katalog. Boss kept his probable errors well within the limits expected for this catalog. A comparison of his results with earlier observations induced the Carnegie Institution of Washington to appoint Boss as the head of its department of meridian astrometry in 1906. Boss’s work led to numerous scientific papers and four other important star catalogs. These are Boss’s Preliminary General Catalogue (1910); the San Luis Catalogue (1928), based on observations by Boss and his son, Benjamin, with the Dudley Observatory’s meridian circle temporarily sited in Argentina; the Albany Catalogue (1931); and the General Catalogue (1937), which contains positional data and proper motions of 33,342 stars brighter than 7.0 magnitude. Boss also determined the orbits of several comets, observed the total solar eclipse of 29 July 1878, and headed the government expedition to Santiago, Chile, to photograph the 1882 transit of Venus. In 1893, he moved the Dudley Observatory to a more favorable location at Albany, New York. Four years later, he became associate editor, and in 1909 editor, of the Astronomical Journal. During his lifetime, Boss received honorary doctorates from Union College, Syracuse University, and Dartmouth College. For his “long-continued work on the positions and proper motions of fundamental stars,” Boss was awarded the Gold Medal Born Died Le Croisic, (Loire-Atlantique), France, February 1698 Paris, France, 15 August 1758 Pierre Bouguer was the inventor of the photometer, the heliometer, and the metacenter. He was also an hydrographer, an astronomer, and the father of naval architecture. Bouguer was one of three children of Jan Bouguer and Marie Françoise Josseau; he was baptized on 10 February 1698. His father was a navigator, but lost a leg in battle and received the certificate of Maîtrise d’hydrographe. In June 1691, Jan Bouguer took charge of the new École d’hydrographie in Le Croisic. In the year Pierre was born, Jan published a navigation treatise. Pierre was among his father’s pupils at the school. When his father died in 1714, Bouguer was a student in the Jesuit school in Vannes. He applied to succeed his father, went to Brest, and successfully passed the examination to become the Maître d’hydrographie du Roy at Le Croisic. The research he performed alongside his teaching was noticed, and in 1730 Bouguer was called to Le Havre, then the most important harbor on the English Channel. At Bouguer’s request, his Le Croisic post was given to his brother Jean. In 1727, Bouguer was awarded a special prize, given by the Académie royale des sciences, for the best way to mast ships. In 1729 and 1731 he obtained similar prizes for determining the altitude of celestial bodies at sea and for the art of determining the orientation of the compass. At the same time he published his Essai d’optique sur la gradation de la lumière. All of this brought Bouguer to the attention of the Parisian scientists: In 1731, while still residing in Le Havre, he became an associate geometer of the academy, and soon a full member. Bouguer was selected to be part of the expedition to travel close to the Equator (Peru) to decide between Isaac Newton and Giovanni Boulliau, Ismaël and Jacques Cassini, on the Earth’s shape. He embarked at La Rochelle in May 1735 having with him, among other instruments, an octant newly made for navigational aids from John Hadley’s design. This expedition, under Louis Godin, would take 10 years. Accompanying Bouguer were also Charles La Condamine and two Spanish officers, Jorge Juan and Antonio de Ulloa. This trip had important consequences for Bouguer and his scientific work. Four of the men returned to France, with results favoring Newton, while Godin pursued a career in Spain, dying there. The quality of the data, much better than that of the Lapland expedition under Pierre de Maupertuis, allowed Jean-Baptiste Delambre and Pierre Méchain to employ it for their determination of the length of the meter in 1799. The measurements were made according to the Toise du Pérou they brought with them in Equador. Difficulties between Bouguer and La Condamine resulted in several publications, by Bouguer in 1744 and in 1746 (later in 1754) followed by La Condamine in 1751. In his free time, Bouguer pursued ideas he had during the expedition. He had previously studied refraction, publishing a memoir in 1729. He completed this work in 1737, leaving his name on Bouguer’s law, considered valid for a half-century. Bouguer developed force de la lumière, the subject now known as photometry. His Essai d’optique sur la gradation de la lumière was published in 1729, but the photometer (he called it a lucimètre) came 10 years later. From this work came two of Bouguer’s laws, one being related to the degree of illumination variations, the other one linked to the logarithmic scale, leading to the droite de Bouguer. His Traité d’optique sur la gradation de la lumière, in its definitive form, was posthumously published by his friend Nicolas de La Caille in 1760. In 1747/1748 Bouguer designed a new instrument that he called an héliomètre to measure diameters of the Sun and of the Moon, experimenting with it during the following year. The more successful idea of John Dollond in England (1753), of making a two-part achromatic objective instead of two full lenses set close together by Bouguer, was more efficient. Nonetheless, the great success of the heliometer was the first measurement of an accurate stellar parallax by Friedrich Bessel, in 1838. From the Peruvian expedition, Bouguer also brought back results on the deflection of the plumb line, mostly influenced by the mountains; he mentioned it in 1754 and in 1756, resulting in the adoption of the term Bouguer anomaly, a phenomenon studied by others later. Bouguer also pursued studies on the Earth’s rotation. As an hydrographer, he carried out research into naval science, leading to a number of publications including De la mâture des vaisseaux … (1727), Traité du navire, de sa construction et de ses mouvements (1746), Nouveau traité de navigation … (1753), and De la manœuvre des vaisseaux … (1757). The most important was the 1746 volume, recounting Bouguer’s travels on the Atlantic and to Peru, as well as developing a number of important ideas about shipbuilding. Shipbuilding at the time was in the hands of marine carpenters, who kept their methods secret. In dealing with the stability of a ship, Bouguer posited the notion of the métacentre, a theoretical point situated above the center of buoyancy. So long as the metacenter is also above the ship’s center of gravity, buoyancy can restore equilibrium; if the metacenter is below the center of gravity, capsizing can occur. The book was translated into English, appearing as A Treatise on Ship-building and Navigation … . Suzanne Débarbat Selected References Anon. (2001). Tricentenaire de la naissance de Pierre Bouguer 1698–1998: Célébration Bureau des longitudes sous le patronage de l’Académie des sciences (Paris, 16 juin 1998). Paris: l’Académie des sciences. Fauque, D. (2001). “Du bon usage de l’éloge: Cas de celui de Pierre Bouguer.” Revue d’histoire des sciences 54, no. 3: 351–382. Lamontagne, R. (1964). La vie et l’œuvre de Pierre Bouguer. Montréal et Paris: Presses de l’Université de Montréal and Presses Universitaires de France. Boulliau, Ismaël Born Died Loudun, (Vienne), France, 28 September 1605 Paris, France, 25 November 1694 An early Copernican and Keplerian, Ismaël Boulliau was the most noted astronomer of his generation. The first surviving child of Calvinist parents, Ismael Boulliau (1583–1625), a notary and city official, and Susanna Motet (1582–1634), Boulliau began his studies in humanities at Loudun and after taking a law degree at Poitiers, he completed his studies in philosophy at Paris. Following his father’s death in 1625, Boulliau converted to Catholicism and moved permanently to Paris in 1632. During the next 30 years Boulliau enjoyed the patronage of the family De Thou and assisted the brothers Dupuy at the Bibliothèque du roi, home of the famous Cabinet Dupuy. Here Boulliau made lifelong friends with Pierre Gassendi and Marin Mersenne, met with René Descartes, Gilles Roberval, and Blaise Pascal, and established long-term relationships with learned B 155 156 B Boulliau, Ismaël visitors – among them Johannes Hevelius, Henry Oldenburg, and Christiaan Huygens – many becoming major correspondents. Although he published numerous books and traveled widely in Holland, Germany, Poland, Italy, and the Levant Boulliau’s reputation as astronomer, mathematician, and classical scholar was largely due to his correspondence network. A pivotal figure in the Republic of Letters, Boulliau extended the humanist tradition of intelligencer to the New Science. His correspondence network, which rivaled the combined efforts of Mersenne and Oldenburg, tells us much about the New Science – much about the reception of Nicolaus Copernicus, Johannes Kepler, Galileo Galilei, Descartes and much about the complex communities that gave science shape. Boulliau inherited an interest in astronomy from his father. Good evidence suggests Boulliau made astronomical observations by the age of 12, became enamored with astrology in adolescence, and by age 20 converted to Copernicanism. Mersenne proclaimed that Boulliau, by age 30, was “one of the most excellent astronomers of the century.” When Boulliau reached the age of 45, Gassendi bestowed upon him the singular title “premiere astronomer of the century.” Nominated astronomus profundæ indaginis by Giovanni Riccioli in 1651, Boulliau enjoyed a remarkable reputation throughout his career. Since that time, however, his contributions have been viewed more critically. While he acknowledged Boulliau’s historical importance, Jean-Baptiste Delambre, for example, dismissed Boulliau’s planetary theory as ingenious but useless, concluding that it was a “retrograde step” for science. Similar views – still linked to the “retrograde” metaphor – have appeared in more recent works. From the beginning of his career Boulliau sought to reform and restore astronomy. This meant improving astronomical tables and perfecting the principles of planetary motion. Despite his much-discussed Platonism, Boulliau believed this reformation required fresh – not necessarily new – observations. Boulliau began by applying his skills as a classical scholar, by unearthing ancient observations of the Egyptians, Babylonians, Greeks, and others. His strategy–at once historical, empirical, and mathematical – was to establish a long base line of observations, and from these “general circumstances” of planetary motion, to determine their mean motions, thus exposing their deepest uniformities and most subtle inequalities. In addition to his historical studies, Boulliau was a dedicated observer, maintaining detailed records from 1623 to 1687. Over the course of his career, Boulliau owned several of the best telescopes in Europe. More valuable than “diamonds and rubies,” they included an 11-ft. telescope, given to him by the Grand Duke of Tuscany in 1651, and later, thanks to friends, he obtained lenses from Huygens (a 22-ft. in 1659), T. L. Burattini (10- and 12-ft. in 1666), and Giuseppe Campani (1670). Active for over 60 years, Boulliau’s long-term interests, beyond the usual concern for eclipses and conjunctions, focused on the variable star Mira Ceti and lunar libration – Boulliau called the Moon’s second (synodic) inequality “evection,” a term still in use. Although he was not a first-rate observer, Boulliau was unrivaled in the Republic of Letters for coordinating astronomical observations, communicating data, and comparing results. Despite his passion for observation, Boulliau is best remembered as a theorist. An outspoken Copernican and critical student of Kepler, Boulliau’s first book in astronomy aimed to supply new arguments for the motion of the Earth based on “Astronomy, Geometry, and Optics” and not “physical conjecture.” Although his Philolaus (Amsterdam, 1639) was published anonymously, the author was never in doubt, as Boulliau’s manuscript (De motu telluris, 1634) had circulated privately in the years immediately following Galilei’s condemnation. When the book finally appeared, it exerted an immense influence, spawning controversy across Europe that ranged from praise and envy to anger and rage. Boulliau’s magnum opus appeared 6 years later. Arguably the most important work on planetary systems between Kepler and Isaac Newton, the Astronomia philolaïca (Paris, 1645) clearly extended awareness of planetary ellipses. Here Boulliau offered an entirely new cosmology, a “newer than new” alternative to Kepler’s Astronomia nova. Boulliau began by attacking Kepler’s cosmology at its very foundation, systematically undermining the physical principles on which Kepler based his calculations. Boulliau concluded that Kepler’s celestial physics and calculational procedures were conjectural and cumbersome, unworthy of Kepler’s genius. Critical of Kepler’s assumptions and conclusions, Boulliau embraced elliptical orbits but insisted they could not be demonstrated by calculation alone. In place of Kepler’s anima mortrix and “celestial figments,” Boulliau argued it was simpler to assume that planets were self-moved, that their motion, imparted at creation, was conserved. In place of Kepler’s indirect “a-geometrical methods” Boulliau proposed direct calculation based on mean motion. Boulliau’s solution to the “problem of the planets” was the conical hypothesis (1645). Because circles and ellipses are conic sections, Boulliau imagined that the planets moved along the surface of an oblique cone, each revolving in an elliptical orbit around the Sun located at the lower focus. By construction, the axis of the cone bisected the base, which at once defined the upper (empty) focus of the ellipse as well as an infinite number of circles parallel to the base. The position of a planet on the ellipse at any given time (Kepler’s problem) was thus defined by an intersecting circle, and hence, at any given instant, the motion of the planet was uniform and circular around its center (Plato’s Dictum). Where Kepler invoked a complex interplay of forces, Boulliau explained elliptical motion by reason of geometry; the planets naturally accelerated or decelerated due to the differing size of circles. Where Kepler employed indirect trial-and-error methods based on physics, Boulliau provided direct procedures based on geometrical principles. In context, Boulliau’s conical hypothesis was elegant and practical. Kepler’s construction – by contrast – was ingenious but useless. The foundations of Boulliau’s cosmology, however, were soon called into question – the result was the “Boulliau–Ward debate.” Prompted by Sir Paul Neile, Seth Ward published several treatises (1653; 1656) attacking Boulliau. Here Ward claimed to offer not only a more accurate alternative to the conical hypothesis (the “simple elliptical” model) but also to demonstrate that the two models were geometrically equivalent. Boulliau responded with his Astronomia philolaica fundamenta clarius explicata (Paris, 1657). After acknowledging his error, noted earlier in his Philolaic Tables (1645), Boulliau shrewdly turned the tables against Ward. The real error, Boulliau maintained, belonged to Ward, who erroneously identified the conical hypothesis with his “simple elliptical” alternative, that is, an ellipse where the empty (nonsolar) focus served as an equant point. The two hypotheses were not, in fact, observationally equivalent. If Ward’s model were applied to the planet Mars, it would result in a maximum error of almost 8′ in heliocentric longitude, not the 2.5′ calculated from the conical hypothesis. Ward failed to note Bouvard, Alexis the difference; Delambre, a century later, repeated the error. Boulliau then supplied a more refined model, the “modified elliptical” hypothesis. Boulliau compared the new model with Kepler’s calculations (using the same Tychonic data) and found it more accurate, having reduced the error to less than 50 arc seconds, clearly within the limits of observational error. If the issue was empirical accuracy and ease of calculation, Boulliau had clearly won the day. Boulliau’s reputation reached its zenith during the 1660s in England. Cited in learned works and the popular press, Boulliau’s name was widely linked to mathematical models and various astronomical tables. But his vision of a New Cosmology was lost. During this time Boulliau’s Philolaic Tables were widely copied, adapted, or imitated. In England, Jeremy Shakerley, among others, believed they were more accurate than Kepler’s, while in Italy, Riccioli demonstrated the claim for Saturn, Jupiter, and Mercury. Boulliau’s modified elliptical hypothesis also received accolades. Although he had proposed his own method, Nicolaus Kauffman (Mercator) continued to praise Boulliau’s model, claiming it could hardly be improved for accuracy. Not least, the “Ornament of the Century” offered praise. In his Principia (1687, Bk. III) Newton claimed that Kepler and Boulliau “above all others” had determined the periodic times of the planets with greatest accuracy. As the century drew to a close, Boulliau’s reputation – by all appearances – had yet to undergo its “retrograde” phase. Back at the Paris École des mines, Bour presented two theses on 3 December 1855. One concerned the three-body problem, the other the theory of attraction. In 1859, he became a lecturer on descriptive geometry in Paris, a post he held until the next year when he became a professor at the École des mines. Then in 1861, he became a professor of mechanics at the École Polytechnique. In 1862, Bour was a candidate for membership in the Academy of Sciences, but he lost to Pierre-Ossian Bonnet. In 1858, the prize question in mathematics for the Academy of Sciences concerned the differential equations resulting when any surface is pressed against a given surface. Of five papers submitted, the judges agreed that three provided adequate solutions, but Bour was awarded the prize for his masterful analysis of the case where the given surface was itself a solid of revolution. The judges hoped that he would generalize his analysis but unfortunately Bour could not extend the work, dying of an incurable disease. Christian Nitschelm Selected Reference Taton, René (1970). “Bour, Edmond.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 2, pp. 350–351. New York: Charles Scribner’s Sons. Robert Alan Hatch Selected References Hatch, Robert A. (1982). The Collection Boulliau (FF.13019–13059): An Inventory. Philadelphia: American Philosophical Society. ——— (1994). “Coherence, Correspondence and Choice: Gassendi and Boulliau on Light and Vision.” In Quadricentenaire de la naissance de Pierre Gassendi (1592–1992). Vol. 2, pp. 365–385. Digne-les-Bains: Société scientifique et littéraire. Koyré, Alexandre (1955). “A Documentary History of the Problem of Fall from Kepler to Newton.” Transactions of the American Philosophical Society, n.s., 45, pt. 4. Wilson, Curtis A. (1970). “From Kepler’s Laws, So-called, to Universal Gravitation: Empirical Factors.” Archive for the History of Exact Sciences 6: 89–170. Bour, Edmond Born Died Gray, Haute-Saône, France, 19 May 1832 Paris, France, 9 March 1866 Edmond Bour was a professor and mathematician who contributed to celestial mechanics. Bour, the son of Joseph Bour and Gabrielle Jeunet, entered the École Polytechnique in 1850, graduating first in his class in 1852. He then moved to the École des mines. On 5 March 1855, Bour presented “On the Integration of Differential Equations of Analytical Mechanics” to the Academy of Sciences; a shortened version of the work appeared in J. Liouville’s Journal of Pure and Applied Mathematics. In July of that year, he was appointed professor of mechanics and mining at the École des mines at Saint-Étienne. Bouvard, Alexis Born Died Contamines, (Haute-Savoie), France, 27 June 1767 Paris, France, 7 June 1843 Alexis Bouvard was a French astronomer who first suggested that perturbations to Uranus’ motion might be caused by an unseen planet. Bouvard was a penniless rural youth who, in 1785, made his way to Paris where he took mathematics lessons to be able to make a living as a calculator. He attended free courses at the Collège de France. His passion for astronomy was ignited by visits to the Paris Observatory, where he was soon admitted as a student-astronomer in 1793. Within 2 years, he was promoted to astronomer. Bouvard met Pierre de Laplace in 1794 just as the Mécanique céleste was being composed. Laplace gave him the task of doing the detailed calculations for the work. With Laplace as patron, Bouvard gained a position at the Bureau des longitudes in 1794. He spent the rest of his career there, providing tables for Connaissance des temps and the Annuaire of the bureau. At the observatory, he was an indefatigable observer, discovering comets in C/1797 P1, C/1798 X1, C/1801 N1 (discovered a night earlier by Jean Pons), and C/1805 U1. When comet 2P/1818 W1 appeared, he calculated an orbit for the bureau and realized it was the same as that for the comet of 1805, later to be called comet 2P/Encke. During this period he also worked on lunar theory, which garnered a prize from the Institut de France in 1800. In 1808, Bouvard published his Tables astronomiques, which provided tables for the orbits of Jupiter and Saturn. When revising the work (for publication in 1821), Bouvard wanted to include tables for Uranus. Even though he had a few prediscovery sightings, mostly thanks to the work of Pierre le Monnier, Bouvard could not B 157 158 B Bowditch, Nathaniel fit an orbit using Laplace’s methods, so based his tables on postdiscovery positions. Within a few years, it was clear that Bouvard’s tables were not predicting accurate locations. He believed that there must be a perturbing body. He asked his nephew, Eugène Bouvard, then a student-astronomer at the Paris Observatory, to follow up on this idea, but the latter resigned in 1842 and Bouvard himself was dead the next year. It was, however, the mismatch of Bouvard’s predictions and actual observations of Uranus that led John Adams and Urbain Le Verrier to predict the position of Neptune in 1846. Bouvard was elected to the Académie des sciences in 1803, and the Royal Society of London named him a fellow in 1826. Richard A. Jarrell Selected Reference Alexander, A. F. O’D. (1970). “Bouvard, Alexis.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillespie. Vol. 2, pp. 359–360. New York: Charles Scribner’s Sons. Bowditch, Nathaniel Born Died Salem, Massachusetts, (USA), 26 March 1773 Boston, Massachusetts, USA, 16 March 1838 Nathaniel Bowditch was already well recognized for his original contributions to astronomy when he translated, corrected, and annotated the first four volumes of Pierre de Laplace’s Méchanique céleste. His translation, published and distributed at his own expense, provided a foundation for American physical astronomy in the 19th century. The fourth of seven children of Habakkuk and Mary (née Ingersoll) Bowditch, Nathaniel’s formal education stopped at the age of 10 when straitened financial conditions of the family forced him to go to work in his father’s cooperage. By 1785, Bowditch had learned the rudiments of accounting and entered a 9-year contract of indentured service as a clerk with a ship’s chandler. Living and working in the chandlery, he benefited from access to the owner’s extensive library, from which he continued to educate himself, learning Latin and mathematics while working as a clerk. He also benefited from a peculiar set of circumstances: In 1780, the Pilgrim, a privateer based at Beverly, Massachusetts, captured a ship whose cargo included the scientific library of the Irish chemist Richard Kirwan. Among the 115 books captured were works of Isaac Newton, Daniel Bernoulli, Johann Bernoulli (III), and Jacob Bernoulli, and E. Chambers’s Cyclopedia; Or an Universal Dictionary of the Arts and Sciences. The Pilgrim arrived in Salem in 1781 and auctioned its cargo; the books were bought by a local apothecary who intended to use the pages for wrapping paper. This dreadful fate was avoided when a group of citizens raised funds to buy the books and donate them to the newly founded Salem Philosophical Society. This gave Salem the best scientific library north of Philadelphia. The books were housed in the home of Reverend John Prince, who allowed the 18-year-old Bowditch to access the library in 1791. In 1793, Bowditch discovered an error in Newton’s Principia. After completing his contractual service at the chandlery, Bowditch assisted with a survey of Salem and taught himself the mathematics and practice of navigation. Soon thereafter, Bowditch traded the sedentary life ashore for the life at sea, making one voyage as a clerk and then three voyages as a supercargo between 1795 and 1799. Between his first and second voyages in March 1798, Bowditch married Elizabeth Boardman; she died 7 months later while he was at sea. On his first voyage, Bowditch was also the second mate of the crew with responsibility for navigation. As he checked through the available reference tables in the 13th English edition of John Hamilton Moore’s The Practical Navigator, he discovered mistakes in the tables that could result in serious navigation errors. Furthermore, the tables were incomplete, and Bowditch designed additional tables that would simplify calculations and make the volume easier to use at sea. It was also on this first voyage that Bowditch conceived of a simplified but more accurate procedure for determining the local time from the Moon, the navigational technique known as “method of lunars.” He began using this technique and found it gave more accurate results. The method of lunars allowed mariners to determine their longitude by observing the position of the Moon to determine the local time. Though accurate marine chronometers had been built by John Harrison between 1735 and 1759, they were as yet too expensive for use by merchant sailors, who relied instead on observations of celestial phenomena (such as the position of the Moon) in order to determine local time. At the end of his first voyage, Bowditch provided a list of these errors to Edmund M. Blunt, the distributor of Moore’s Practical Navigator. He advised Blunt of his ideas to correct and supplement both the tables and the text of the Practical Navigator and provided him with a tabulation of some of the errors he had already discovered. Blunt was enthusiastic, and they agreed to undertake the creation of a new practical navigator. Blunt published a new edition, titled The American Practical Navigator, in 1799 with Bowditch’s first round of corrections. On his second voyage Bowditch continued to find errors, and a second corrected edition of the American Practical Navigator was published. After the third voyage, Bowditch was ready with his completely revised edition including the new method of lunars, many supplemental tables, and other innovations, which Blunt published in 1802 as The New American Practical Navigator with Bowditch as the author. In total, Bowditch had compiled a list of over 8,000 errors in the tables of Moore’s The Practical Navigator. It is small wonder that “the Bowditch” as it came to be known, developed a reputation for its reliability and was the standard reference for navigators for more than a century. In 1800, Bowditch married a cousin, Mary Ingersoll, who was 8 years younger. They had eight children. In 1802, Bowditch became part owner and master of a merchant ship. His fifth voyage, to Sumatra in November 1803 (during which Bowditch read the first volume of Laplace’s monumental Méchanique céleste), would be Bowditch’s last trip. He gave up the sea to become an insurance executive at the Essex Fire and Marine Insurance Company in Salem. His mathematical experience served Bowditch well in this new environment in which actuarial skills were highly valued and profitable. He was elected president of the firm in 1804. In the early morning of 14 December 1807, a meteor streaked across the skies of New England. Bowditch compiled the observations of many individuals who had seen the meteor and estimated the meteor to have traveled at 3 miles/s along a path 18 miles high. Bowen, Ira Sprague Bowditch also published papers on the oblateness of the Earth, the orbits of comets, errors in solar tables, and the motion of a pendulum suspended from two points. Bowditch was the first to investigate the curves traced out by such a pendulum, which are now well known as the Lissajous curves of acoustics and electronics. These papers established Bowditch as one of the preeminent figures in American science, and earned him recognition by European scientific societies. In 1818, he was elected a fellow of the Royal Society of London; in 1829 Bowditch was the first American to be elected a foreign associate of the Royal Astronomical Society. Harvard offered Bowditch its chair of mathematics and physics in 1806; West Point made a similar offer, as did the University of Virginia (1818). Bowditch declined them all – an academic position would have necessitated too great a cut in salary. But it would have been nearly impossible for Bowditch – a prominent Federalist and scholar – to avoid a connection with Harvard, a prominent school supported by many Federalists. In 1810, he became one of the university’s overseers, and in June 1826, one of its trustees. At that point, Harvard was in dire financial straits. An internal audit ordered by Bowditch turned up a number of accounting irregularities. Bowditch forced many changes in the name of fiscal responsibility, which brought him into conflict with Harvard’s president, John Kirkland. In one noteworthy encounter, Kirkland defended the competence of a mathematics professor about to be dismissed. Bowditch’s assessment was that “Peirce of the sophomore class” was a better mathematician than the professor. The Peirce involved was none other than Benjamin Peirce, who would himself become a professor at Harvard in 1833, and go on to help establish the Harvard Observatory. When Kirkland eventually resigned, the students – with whom Kirkland was very popular – lambasted Bowditch. Bowditch’s best-known work is a translation of Laplace’s monumental Méchanique céleste into English. But Bowditch did much more than translate Laplace: He added a great deal of commentary to make the work more comprehensible, filling details dismissed by Laplace with a glib “It is easy to see …” He corrected many mistakes in Laplace’s work, and provided citations to the sources that Laplace had relied upon but had failed to credit. Bowditch’s effort was similar to that of Mary Somerville’s The Mechanism of the Heavens but was more comprehensive. The publication of the translation was delayed by many years due to a lack of funding. Though the American Academy of Arts and Sciences offered to pay for the publication by soliciting private donations, Bowditch refused to accept their offer, and eventually paid for publication at his own expense. This cost was nearly $12,000 – a third of his personal fortune. The first four volumes would appear in 1829, 1832, 1834, and 1839. Bowditch died of cancer partway through the translation of the fifth volume. Jeff Suzuki Selected References Albree, Joe (1992). “Salem’s Bowditch.” Mathematical Intelligencer 14, no. 1: 58–60. Berry, Robert Elton (1941). Yankee Stargazer. McGraw-Hill. Bowditch, Nathaniel Ingersoll (1840). Memoir of Nathaniel Bowditch … Originally prefixed to the Fourth Volume of the Mécanique céleste. 2nd ed. Boston: Charles C. Little and James Brown, Publishers. Rothenberg, Marc (1999). “Bowditch, Nathaniel.” In American National Biography, edited by John A. Garraty and Mark C. Carnes. Vol. 3, pp. 270–272. New York: Oxford University Press. Bowen, Ira Sprague Born Died Seneca Falls, New York, USA, 21 December 1898 Los Angeles, California, USA, 6 February 1973 American spectroscopist Ira Bowen is eponymized in the Bowen fluorescence mechanism, which accounts for the anomalously large strength of a few emission features of oxygen and nitrogen in gaseous nebulae. His most important contribution was the recognition that certain other lines in these nebular spectra were produced by improbable transitions (but different ones) also of oxygen and nitrogen, rather than by a hypothetical “nebulium.” Ira Bowen was the son of Philinda Sprague and James Bowen (Pastor of the local Wesleyan Methodist Church) and educated at Houghton Seminary and Oberlin College (A.B.: 1916; Sc.D.: 1948). He began graduate work at the University of Chicago, where he was strongly influenced by Albert Michelson and Robert Millikan, the latter in effect taking Bowen with him to the California Institute of Technology as an instructor in 1921, his graduate work unfinished. Bowen received a Caltech Ph.D. in 1926 for work in vacuum ultraviolet spectroscopy. He also contributed to high-altitude measurements of cosmic rays. Caltech appointed Bowen to its faculty as soon as he ceased to be a graduate student (assistant professorship, 1926; associate professorship, 1928; and full professorship, 1931), and the work for which he is remembered was done there. In 1946, the trustees of the Carnegie Institution of Washington appointed Bowen director of Mount Wilson Observatory as successor to Walter Adams – an unusual choice, given his background in laboratory spectroscopy. With the establishment of Palomar Mountain Observatory in 1948, and with its headquarters in the same Pasadena building, he became director of both, eventually under the name Hale Observatories (named for George Hale). Bowen retired in 1964, having held firm throughout to the rule that women astronomers could not be assigned observing time at either place, leaving it to his successor (Horace Babcock) to welcome the first official women observers. Soon after taking up his assistant professorship, Bowen solved a 60-year-old conundrum. William Huggins had been the first astronomer to look at the spectra of a large number of diffuse nebulae and found that some of them emitted only discrete wavelengths and so must consist largely of ionized gas. He was able to identify hydrogen, and at one time thought that the bright pair of green lines at 5007 Å and 4959 Å was produced by nitrogen. When much larger collections of laboratory spectra of many elements provided no identification, Huggins coined the name “nebulium” (by analogy with Norman Lockyer’s “helium” for the element producing particular features in the solar spectrum). The main part of the periodic table was closed with hafnium (1923) and rhenium (1925), and they were not the cause either, leading contemporary astronomers to the conclusion that the green lines must come from some familiar element, but under very nonterrestrial conditions, for instance extreme low density, according to Henry Norris Russell and others. Bowen had read about this puzzle, and knew enough both about ultraviolet spectra of atoms and about early quantum mechanics to be able to conclude in 1927 that the “nebulium” lines were emission from twice-ionized oxygen raised into an excited state by collisions B 159 160 B Bower, Ernest Clare with other atoms and deexciting only after a very long time, because the transition required the outgoing light particle (photon) to carry an unlikely (though not impossible) amount of angular momentum. These transitions and the lines they produce are called “forbidden,” though in fact they are only disfavored, so that a laboratory sample of gas is never large enough to radiate a detectable amount of the line before the atoms get deexcited by other collisions. Bowen and other investigators subsequently identified forbidden (in this sense) lines of singly ionized and neutral oxygen, ionized nitrogen, ionized sulfur, and several ionization states of neon and argon in the spectra of planetary nebulae and supernova remnants like the Crab Nebula. In 1938, Bowen visited Lick Observatory, obtaining a number of spectra of planetary nebulae in cooperation with Arthur Wyse, using a new spectrograph of his own design. A few permitted lines of twice-ionized oxygen seemed to be relatively much stronger than they were in the laboratory, as were two lines of doubly ionized nitrogen. Bowen was able to explain these anomalies as being due to strong lines of hydrogen and helium exciting the O[III] and N[III] atoms to levels that would otherwise only be sparsely populated. Thus, the lines emitted when the atoms fell back out of these particular levels were unusually strong. This is Bowen fluorescence, and there are other examples elsewhere in astronomical spectroscopy. In the 1930s, Bowen played a major role in the optical design of the 200-in. telescope on Palomar Mountain as well as other optical equipment. Bowen built a novel device, called an image slicer, which placed the spectra of successive strips across an extended object sideby-side upon the photographic plate. This invention enormously increased the efficiency of observations of gaseous nebulae. As director of the Mount Wilson Observatory from 1946 to 1948, and of the combined Mount Wilson and Palomar observatories from 1948 to 1964, he directed the completion of the 200-in. Hale telescope and 48-in. Schmidt telescope and designed many of their instruments. Bowen also initiated baking photographic plates to improve their sensitivity. During World War II he was in charge of photographic work on the rocket project at the Jet Propulsion Laboratory. Bowen received many honors. He was a Gold Medallist (1966) and Halley Lecturer of the Royal Astronomical Society and an H. N. Russell Lecturer (1964) of the American Astronomical Society. Also, he received the Ives Medal (Optical Society of America, 1952), Draper Medal (National Academy of Sciences, 1942), Potts Medal (Franklin Institute), Rumford Prize (American Academy of Arts and Sciences, 1949), and the Bruce Medal (Astronomical Society of the Pacific, 1957). He was a member of the National Academies of Sciences of the USA, of Sweden, and of India and received honorary degrees from Oberlin College, Lund University, and Princeton University. A lunar crater is named for him. Ira Bowen and Mary Jane Howard were married in 1929; they had no children. Most of Bowen’s papers (1916–1961) are at the California Institute of Technology (Huntington Library and Caltech Archives). These include manuscript articles and speeches, and biographical material. The Center for History of Physics at the American Institute of Physics has a manuscript autobiography, some correspondence, and an oral history interview of Bowen. Y. P. Varshni Selected References Aller, Lawrence H. (1974). “Ira Sprague Bowen.” Quarterly Journal of the Royal Astronomical Society 15: 193–195. Babcock, Horace W. (1982). “Ira Sprague Bowen.” Biographical Memoirs, National Academy of Sciences 53: 83–119. Bowen, I. S. (1927). “The Origin of the Chief Nebular Lines.” Publications of the Astronomical Society of the Pacific 39: 295–297. ——— (1927). “The Origin of the Nebulium Spectrum.” Nature 120: 473. Greenstein, Jesse L. (1973). “Ira Sprague Bowen.” Mercury 2, no. 3: 3–5. Wilson, O. C. (1973). “Ira Sprague Bowen (1898–1973).” Sky & Telescope 45, no. 4: 212–214. Bower, Ernest Clare Born Died 1890 1964 American astronomer Ernest Bower calculated one of the first independent orbits of Pluto, shortly after that planet’s 1930 discovery by Lowell Observatory’s Clyde Tombaugh. Selected Reference Weintraub, David A. (2006). Is Pluto a planet?: A Historical Journey through the Solar System. Princeton University Press. Boyer, Charles Born Died Toulouse, Haute-Garonne, France, 28 July 1911 Toulouse, Haute-Garonne, France, 21 August 1989 The French magistrate Charles Boyer, observing Venus from 1957 to 1960 at Brazzaville, French Congo (now Corgo, former Zaire), took sequences of photographic plates with ultraviolet [UV] filters. He noted a 4-day recurrence in the apparition of dark features. The data was complemented by observations with astronomer Henri Camichel at Pic du Midi Observatory. A 4-day retrograde rotation of the upper Venusian atmosphere was demonstrated. The discovery was later confirmed by the Soviet Venera 8 entry probe, which, in 1972, detected directly a westward 100 m/s wind at an altitude of 55 km. It was also confirmed by the American Mariner 10 craft, which, in February 1974, took a movie of several days duration in UV light during approach, showing the planetary atmosphere turning in 4 days retrograde. Boyer was elected to International Astronomical Union Commission 16 on the Physical Study of Planets and Satellites. Audouin Dollfus Selected References Rösch, Jean (1990). “Charles Boyer (1911–1989) et la rotation de Vénus.” L’Astronomie 104: 216–219. Sheehan, William and Thomas Dobbins (1999). “Charles Boyer and the Clouds of Venus.” Sky and Telescope 97, no. 6: 56–60. Bradley, James Bradley, James Born Died Sherbourne, Gloucestershire, England, March 1693 Chalford, Gloucestershire, England, 13 July 1762 James Bradley discovered the aberration of starlight. He was the third son of William Bradley and Jane Pound. On 25 June 1744, at age 51, Bradley married Susannah Peach of Chalford, Gloucestershire, England, from whom he had a daughter in 1745. His wife died in 1757. Bradley attended the Northleach Grammar School. He received his B.A. in 1714 and M.A. in 1717 from Balliol College, Oxford. Bradley was awarded an honorary D.D. degree by Oxford in 1742 upon his appointment as Astronomer Royal. In 1718, he was elected a fellow of the Royal Society at the recommendation of Astronomer Royal Edmond Halley. He was also given membership in national academies of science in Berlin, Paris, Bologna, and Saint Petersburg. Bradley was ordained in 1719 and became vicar of the congregation at Bridstow, Monmouthshire. Bradley learned astronomy from his uncle, Reverend James Pound, rector at Wanstead, Essex, near London, with whom Bradley frequently stayed. Young Bradley adored his uncle James, who helped support him financially, nursed him through smallpox in 1717, and ultimately fostered his love of astronomy. By the time Bradley was in his 20s, he and his uncle had formed a for-hire observing partnership. So respected were their skills that both Isaac Newton and Halley entrusted them on multiple occasions with observing projects. Working together, Bradley and Pound determined the positions of stars and nebulae, observed eclipses of Jupiter’s satellites, and measured the diameter of Venus (with a 212-ft.-long telescope) and also the parallax of Mars. Bradley himself calculated the orbits of two comets. Bradley resigned his vicarage in Bridstow in 1721 upon his appointment as Savilian Professor of Astronomy at Oxford, a position for which he was recommended by Newton. Given his modest annual salary of £140, Bradley could not afford to live at the university. Instead, he moved in with Pound in Wanstead and visited the Oxford campus only to deliver the required lectures. In 1724, following the death of his beloved uncle, Bradley began to observe with Samuel Molyneux, a wealthy amateur astronomer and member of Parliament from Kew, outside London. Having read of Robert Hooke’s failed attempt to detect the annual parallax of the star γ Draconis in 1669, Molyneux asked Bradley to collaborate with him in a renewed effort utilizing a high-precision zenith telescope made by England’s foremost instrument maker George Graham. (Detection of stellar parallax would provide observational evidence of the Copernican theory of the cosmos, wherein the Earth’s orbital motion creates an annual oscillation of the stars; by this time, the Copernican theory already had a strong theoretical and mathematical foundation.) The telescope was fixed vertically to the face of a chimney in Molyneux’s mansion bordering Kew Green. To accommodate its 24-ft.-long tube, holes were cut through the roof and between floors. The Kew telescope was found to be exquisitely sensitive to environmental influences: The combined body heat of three people standing nearby disturbed the air enough to set the instrument’s plumb line swaying. Cobwebs had to be regularly cleared from the plumb line, lest they shift the zero mark from which all measurements were gauged. Nevertheless, Bradley determined that the telescope was capable of measuring star positions with better than 1˝ accuracy. Over 80 position measurements of γ Draconis were obtained by Bradley and Molyneux over a 2-year period commencing 3 December 1725. The observations confirmed that γ Draconis exhibits an annual 20˝ oscillation from its nominal position in the sky. However, Bradley and Molyneux noted that the timing of the oscillatory movement is 3 months out of phase with that expected for a parallax shift, and the degree of movement itself is far larger than they had anticipated. In August 1727, Bradley installed a smaller, wider-field version of the Kew telescope in the house of his late uncle, in Wanstead, and continued the zenith observations of γ Draconis and other stars on his own. Even after his aunt sold the house in 1732, the new owner, Elizabeth Williams, permitted him free access to his now famous telescope. (Molyneux died unexpectedly in 1728 at age 39.) Bradley reportedly realized the true cause of γ Draconis’s annual oscillation in the autumn of 1728 during a sailing cruise on the Thames. He noted how the wind vane on the boat’s mast shifted its orientation with the boat’s motion, even when the wind direction had not changed – i. e., the vane’s orientation was influenced not only by the wind but also by the movement of the boat. Similarly, Bradley reasoned, the apparent direction from which a star’s light reaches the observer is altered by the forward movement of the Earth; thus the position of the star seems to oscillate as the Earth circles the Sun. This phenomenon is known as the aberration of light. From his observations, Bradley computed the speed of light: 295,000 km/s (183,000 miles/s), which is within 2% of the modern value. Bradley also established an upper limit to the annual parallaxes of the stars he had observed: Were any parallax as large as 1˝, he would have observed it with the Wanstead telescope. Thus he estimated that even the nearest stars must lie at least 400,000 times farther than the Sun. B 161 162 B Bradwardine, Thomas Continuing his zenith observations for another 20 years, Bradley detected a further oscillation of star positions, by as much as 9″. This he attributed to a periodic nodding motion of the Earth’s axis (nutation) stimulated by the Moon’s gravitational pull. For this discovery, the Royal Society of London awarded him the Copley Medal in 1748. In 1742, Bradley succeeded Halley as England’s third Astronomer Royal and director of the Royal Observatory at Greenwich, a post he would hold for the next 20 years. Despite his ascendance, Bradley maintained his propriety: He refused the king’s offer of the vicarage of Greenwich, together with its significant stipend, explaining that he could not in good conscience accept a job to which he would devote less than his full measure. Bradley found Halley’s Greenwich instruments to be in disrepair. He restored them and embarked on an ambitious observing program to measure the positions of stars and determine the precise means to correct such measurements for the effects of atmospheric refraction. In 1749, he persuaded government officials to provide a grant of £1,000 with which he upgraded the Royal Observatory’s equipment, including two quadrants and a transit instrument by Bird, a precision clock by Graham, and a micrometer. Between 1748 and 1762, Bradley and his assistants carried out more than 60,000 individual observations of stars. He also accurately determined the latitude of Greenwich and carried out a detailed assessment of Tobias Mayer’s lunar tables for determining longitude at sea. In 1818, German astronomer Friedrich Bessel united Bradley’s observations with his own to produce a fundamental catalog of 3,222 stars with positions accurate for the year 1755. The Bradley– Bessel compilation formed the starting point for determining the proper motions of these stars. By setting a new standard of precision in observation, Bradley can rightly be dubbed the founder of highprecision positional astronomy. Alan W. Hirshfeld Selected References Anon. (1963). “James Bradley, 1693–1762 – Bicentenary Contributions.” Quarterly Journal of the Royal Astronomical Society 4. (Includes a series of papers commemorating the bicentenary of Bradley’s death: W. H. McCrea, “James Bradley 1693–1762,” pp. 38–40; W. H. Mcrea, “The Significance of the Discovery of Aberration,” pp. 41–43; D. E. Blackwell, “The Discovery of Stellar Aberration,” pp. 44–46; and Sir Richard Woolley, “James Bradley, Third Astronomer Royal,” pp. 47–52.) Bradley, James (1728). “A Letter … giving an Account of a new discovered Motion of the Fix’d Stars.” Philosophical Transactions 35: 637–661. ——— (1748). “A Letter … concerning an apparent Motion observed in some of the fixed Stars.” Philosophical Transactions 45: 1–43. ——— (1798–1805). Astronomical Observations Made at the Royal Observatory at Greenwich From the Year 1750 to the Year 1762 by the Rev. James Bradley, D. D., Astronomer Royal, Oxford: Oxford University Press. (Most of Bradley’s Greenwich observations were published posthumously in two volumes, including a positional catalog of stars, edited by Hornsby, under the title.) ——— (1832). Miscellaneous Works and Correspondence of the Rev. James Bradley, edited by S. P. Rigaud. Oxford: Oxford University Press. Chapman, Allan (1990). Dividing the Circle: The Development of Critical Angular Measurement in Astronomy, 1500-1850. New York: Ellis Horwood. Clerke, Agnes M. (1902). A Popular History of Astronomy during the Nineteenth Century. 4th ed. London: Adam and Charles Black. Hoskin, Michael (1982). Stellar Astronomy. Chalfont St. Giles, England: Science History Publications. King, Henry C. (1955). The History of the Telescope, New York: Dover Publications. (Bradley’s zenith telescopes are discussed herein; his second instrument is on display at the Royal Greenwich Observatory.) Stewart, Albert B. (1964). “The Discovery of Stellar Aberration.” Scientific American 210, no. 3: 100–108. (Especially informative.) Thomson, Thomas (1812). History of the Royal Society. London. (Thomson tells of Bradley’s serendipitous sailing cruise during which he worked out the essentials of stellar aberration.) Turner, Herbert Hall (1963). Astronomical Discovery. Berkeley: University of California Press. Bradwardine, Thomas Born Died England, circa 1290 London, England, 26 August 1349 Thomas Bradwardine is chiefly known for his writings on mathematics, but may also have produced astronomical tables. Bradwardine enters the historical record in 1321 as a fellow of Balliol College, Oxford. Two years later he migrated to Merton College, where he remained until 1335. Bradwardine became chancellor of Saint Paul’s Cathedral, London, in 1337, and sometime thereafter he became chaplain to Edward III. Bradwardine preached that the English victories in the Hundred Years’ War came from God’s will rather than through the influence of celestial bodies. His theological masterwork, De causa Dei, emphasized divine action throughout creation. Bradwardine was elected archbishop of Canterbury in 1348, but King Edward quashed the election on a technicality. He received the royal assent in the following year and was consecrated archbishop on 10 July 1349, only to die of the plague 6 weeks later. At Oxford, Bradwardine chiefly lectured and wrote on mathematical subjects, and produced the textbooks De arithmetica speculativa and De geometria speculativa. Composed in 1328, his De proportionibus gave an innovative treatment of velocity in terms of proportions between force and resistance; it helped shape late medieval and early modern approaches to kinematics. Bradwardine’s philosophical works include De continuo, addressing the continuous or discontinuous nature of matter, and Insolubilia, concerning logical paradoxes. Bradwardine may have compiled astronomical tables for calculating the positions of planets, but this has not been established for certain. It is certain that Bradwardine had an interest in astronomy and astrology. The astronomers John Maudith, Simon Bredon, and William Rede were his colleagues. Bradwardine himself owned astronomical works in manuscript. A theme in his later theological writings was the futility of astrological prediction. Keith Snedegar Selected References Emden, A. B. (1957–1959). A Biographical Register of the University of Oxford. Vol. 1, pp. 244–246. Oxford: Oxford University Press. North, J. D. (1992). “Natural Philosophy in Late Medieval Oxford” and “Astronomy and Mathematics.” In The History of the University of Oxford. Vol. 2, Late Medieval Oxford, edited by J. I. Catto and Ralph Evans, pp. 65–102, 103–174. Oxford: Clarendon Press. Brahe, Tycho [Tyge] Ottesen Brahe, Tycho [Tyge] Ottesen Born Died Knudstrup, Scania, (Sweden), 14 December 1546 Prague, (Czech Republic), 24 October 1601 Author of the Tychonic system, the great observer Tycho Brahe was raised as an only child at the home of his father’s brother Jørgen Brahe, who had decided that Tycho was to have an education in law. The fields of astronomy and chemistry were not considered suitable backgrounds for the life of a nobleman. Twelve-year-old Brahe came to the University of Copenhagen and started a study and travel period that was to last for the next 12 years. He possibly observed that a solar eclipse event predicted for 1560 actually took place at the predicted time. This may have led him to begin studying astronomy on his own. In 1562, Brahe traveled to the University of Leipzig, where he added the study of astronomy to his study of the law, and bought astronomy books and instruments. He studied with critical eyes and soon saw that only direct observation of the sky could resolve the contradictory ideas in all the learned books. In 1563, Saturn and Jupiter were in a position close to each other, and Brahe found that the ancient Alphonsine tables gave the date with an error of one entire month, whereas the new Prutenic method, calculated according to the theories of Nicolaus Copernicus, only had an error of a few days. Subsequently, Brahe devoted his life to a renovation of astronomy based on more trustworthy observations. His first instrument, an approximately 3-ft. long Jacob’s staff, was not perfect, but, regardless, he calculated a correction table so that the results were usable. In 1565, Brahe started on his second study trip, to Wittenberg and Rostock, Germany. It was here that during a dueling match he lost part of his nose; ever after he had to use a prosthesis. Brahe now openly studied alchemy and astrology in addition to routinely making astronomical observations. In 1568, he enrolled at the University of Basel with the intention of settling down at a later date in this town or its vicinity. Now at the age of 22, Brahe had acquired all the knowledge of chemistry and astronomy of his times. He spent most of 1569 and 1570 in Augsburg, Germany, as an astronomy assistant to the mayor of the town. Brahe was in charge of the construction of a quadrant with a radius of 19 ft., intended to be capable of measuring every arc minute. However, his experience was that an instrument that heavy and clumsy could not yield the expected measuring accuracy. Brahe also constructed the shell of a wooden sphere with a diameter of 5 ft. Ten years later he had ensured that this globe retained its rounded form, and was marked with poles and divided into circles for reading and recalculation of celestial coordinates. After another 15 years of work, Brahe had the surface marked accurately with definite positions for 1,000 fixed stars, and this celestial globe stood as an impressive monument to his life’s work. The globe traveled with Brahe to Bohemia and was later brought home to Denmark, as a war treasure, to Round Tower (in Copenhagen) where it burned in 1728. After the death of his father in 1571, Brahe moved into the home of Steen Bille at the estate of Herrevad (in Denmark), and delved more heavily into the study of alchemy. But on 11 November 1572, in the constellation of Cassiopeia, he spotted a great wonder: a new star that we know today as a supernova. Brahe measured the star’s (SN B Cas) distance from the so called fixed stars in the vicinity, and he recorded how its brightness gradually diminished. He proved that the star was situated farther from the Earth and the Moon than could be explained away as an atmospheric phenomenon; rather it must belong among the fixed stars. But this meant that the star would have appeared (in an Aristotelian view of the sky) in the region of unchangeability. That prevailing thesis had to subside in light of what this 26-year-old, well-educated astronomer had seen in the sky. Brahe’s first book, De Nova Stella, was published in 1573. Only after his death was Brahe’s comprehensive astronomical work about the new star, Astronomiae Instauratae Progymnasmata, published in three volumes. The first volume included Brahe’s new theories about the Sun and the Moon, as well as his revised star catalog. The second volume was about the new star, and the third volume was a critical review of the works of others about the new star. With publication of De Nova Stella, Brahe’s position as an astronomer had been firmly established within the learned society of Europe. The problem now was finding a suitable way of life for this nobleman researcher. In the fall of 1574, he lectured in Copenhagen about the movements of the heavenly bodies according to Copernicus’ theories, but related them to a stationary Earth. In this way Brahe avoided an open conflict between traditional cosmology and the Copernican astronomy. For most of 1575, Brahe was traveling and preparing for his emigration to Basel. First he visited Landgrave William IV of Hesse in Kassel, who himself was an astronomer. They embarked on a friendship that can be traced in many letters containing astronomical themes. In 1596, Brahe published his correspondence with B 163 164 B Brahe, Tycho [Tyge] Ottesen colleagues from Kassel as the first, and only, volume of his Epistolae Astronomicae. King Frederick II of Denmark offered Brahe the island of Hven, situated between Scania and Zealand and, in addition, the means for the construction of a suitable residence and observatory. Brahe agreed to the king’s wishes, being attracted to the idea of a lone island that would be a haven free from the disturbance of visitors. On 8 August 1576, the cornerstone was laid for Uraniborg, built in gothic renaissance style. So from the date of his 30th birthday on 14 December 1576, Brahe could engage in routine observations and began 20 years of happy work. Uraniborg was not finished until 1580, by which time it was equipped with a laboratory basement, residence, library, and observatory. In 1584, Brahe had Stjerneborg (a sort of star castle) built, with five cupolas over corresponding vaults where the larger instruments would have a permanent place protected against the wind. The island of Hven became the home of an exemplary research institution where Brahe developed instruments, carried out a vast number of observations and calculation programs, and finished his work in the form of scientific publications. At Hven everything was in a class by itself, including the expenses. Apart from the island being free of cost for his lifetime, a separate building subsidy, and an annual cash payment, Brahe could also enjoy the income from several personal endowments. His activities cost the crown between 1% and 2% of its total annual revenue. In return Brahe delivered to the king an annual almanac and, in addition, he constructed horoscopes, issued prescriptions, and prepared medications. The endowments came with some obligations from which Brahe tried to withdraw, but for a long time most of the resulting conflicts found a reasonable solution. However, when Christian IV took over from his father (in 1596), he wished to save expenses on research grants. Brahe misjudged the importance of his scientific reputation in comparison to the grudges that his arrogance had caused. In April of 1597, he left Hven to take up residence first in Copenhagen, then in Rostock, and finally from October 1597 at the Wandesburg Castle near Hamburg. His attempts at a reinstatement of his former privileges were in vain, as Christian IV wanted to set his own terms for his mathematician. Early in 1598, Brahe printed a small edition of his Astronomiae Instauratae Mechanica with pictures and descriptions of his most important instruments, as well as a short survey of the theoretical results of his work. Moreover, his star catalog from Progymnasmata was extended and copied in a number of exemplars with the title Stellarum Inerrantium Restitution. These two publications were sent to a number of colleagues and princes. After an invitation from Emperor Rudolph II, Brahe traveled to Prague, arriving in June of 1599. Not until late in 1600 did he succeed in getting all of his instruments moved to join him. Frequent relocations and economical problems hindered a sensible work schedule. It was a disappointment to Brahe that the institution from Hven did not take root in Bohemia. However, this move became very important in the history of astronomy, because it was in Prague that Brahe gained the assistance of Johannes Kepler, who was to be his scientific heir. Brahe had developed instruments of various types, including the sextant for the measurement of visual angles in random planes, quadrants for altitude measurement, and armillary spheres erected for the measurement of coordinates in relation to the ecliptic or the celestial equator. He constructed new and more accurate sights, and he equipped his measuring areas with transverse lines for more precise reading than previously available. After 10 years at Hven, Brahe was satisfied with his instruments, whose resolving accuracy had been increased to about 1′. Brahe was already dead when Galileo Galilei first directed telescopes toward the heavens, and yet another two generations were to pass before telescopes were equipped with the crosshairs and micrometer that could match Brahe’s naked-eye instruments. Brahe had found it necessary to take into consideration the previously unrecognized effects of atmospheric refraction. He investigated these and then constructed tables of their influence. Only one astronomical parameter, the all-too-large solar parallax of 3′, did Brahe adopt from his predecessors. This is the reason his refraction tables are not correct. Even so, in his day and age they represented progress. Brahe observed more frequently and routinely than any other early astronomer. His results were collected and were easily accessible for later developments. Among the theoretical results was his star catalog, the first real improvement in this area since ancient times. Brahe found it necessary to work on a revision of the theories of the “wandering stars” by pinpointing more accurate positions of the “fixed” reference points. He calculated better solar tables, and his theory of the movement of the Moon included descriptions of four previously unobserved irregularities, which he partly derived using the hypothetical-deductive method. Brahe did not manage to develop complete planetary theories, but was the first one to know that the nodal line of each planetary orbit moves with its own rate of slow rotation. Brahe observed seven comets, and wrote his main astronomical work De Mundi Aetherei Recentioribus Phaenomenis about the first and the largest of these. This was printed at Hven in 1588. He proved that comets move among the planets much farther away than the Moon, and thus were no more mere atmospheric phenomena than was the new supernova. This enabled him to strike a further blow against the Aristotelian cosmology, disproving the existence of hard, impenetrable planetary spheres. In describing the structure of the Universe, Brahe had only a few dubious observations to build upon. Before 1588, he still considered the possibility of proving the view of Copernicus, and he was reluctant to bring arguments against the idea of a moving Earth. Yet, this idea appeared unreasonable to him. It conflicted with several Biblical passages, and the thought of the Universe having a wide empty space of no use between the outer planet of Saturn and the fixed stars seemed absurd. Therefore Brahe formulated his own compromise: The Sun and Moon circle around the unmoving Earth at the center of the Universe, and the five other planets circle around the Sun as a second but moveable center. Brahe had worked on this Tychonic System since 1578 and published it within his work about the comets. Oddly enough he used thereafter arguments against the Earth’s movement, copied out of the Aristotelian philosophy that his own work had helped to break down. Nevertheless, Brahe could not be an orthodox believer in the Aristotelian philosophy; he preferred Pythagorean and Platonic arguments about harmony and symmetry connected with religious and astrological considerations. Connected to this train of thought, all movements in the sky should be described by circular components of motion. Brahe stuck to this principle and did not live to see Kepler’s theory of elliptical planetary orbits set into the Copernican Universe. Kristian Peder Moesgaard Translated by: Inger Kirsten Lutz and Gene M. Lutz Brandes, Heinrich Wilhelm Selected References Christianson, John Robert (2000). On Tycho’s Island: Tycho Brahe and His Assistants, 1570-1601. Cambridge: Cambridge University Press. Christianson, John Robert et al. (eds.) (2002). Tycho Brahe and Prague: Crossroads of European Science. Acta Historica Astronomiae, Vol. 16. Frankfurt am Main: Deutsch. Dreyer, J. L. E. (1963). Tycho Brahe: A Picture of Scientific Life and Work in the Sixteenth Century. New York: Dover. ——— (ed.) (1913–1929). Tychonis Brahe Dani opera omnia. 15 Vols. Copenhagen. Gade, John Allyne (1947). The Life and Times of Tycho Brahe. New York: Greenwood. Gingerich, Owen and James R. Voelkel (1998). “Tycho Brahe’s Copernican Campaign.” Journal for the History of Astronomy 29: 1–34. Hellman, C. Doris (1975). “Kepler and Tycho Brahe.” Vistas in Astronomy 18: 223–230. Mosley, Adam, Nicholas Jardine and Karin Tybjerg (2003). “Epistolary Culture, Editorial Practices, and the Propriety of Tycho’s Astronomical Letters.” Journal for the History of Astronomy 34: 421–451. Rosen, Edward (1986). Three Imperial Mathematicians: Kepler Trapped between Tycho Brahe and Ursus. New York: Abaris Books. Thoren, Victor E. (1990). The Lord of Uraniborg: A Biography of Tycho Brahe. Cambridge: Cambridge University Press. Thykier, Claus (1992). “Tycho Brahe’s Empiric Methods, His Instruments, His Sudden Escape from Denmark, and a New Theory about His Death.” Meteoritics 27: 297. (Paper abstract.) Vinter Hansen, Julie M. (1946). “Tycho Brahe Statue on Hven.” Publications of the Astronomical Society of the Pacific 58: 351. Wesley, Walter G. (1979). “Tycho Brahe’s Solar Observations.” Journal for the History of Astronomy 10: 96–101. West, Richard M. (1997). “Tycho and his Observatory as Sources of Inspiration to Modern Astronomy.” In Optical Telescopes of Today and Tomorrow, edited by Arne L. Ardeberg, pp. 774–783. Bellingham, Washington: Society of Photo-optical Instrumental Engineers. Brahmagupta Born Died Bhillamāla (Bhinmal, Rajasthan, India), 598 after 665 Brahmagupta was an Indian (Hindu) astronomer. He probably lived at Bhillamāla (modern Bhinmal in the southwest of Rajasthan). His father was Jiṣṇu, and Brahmagupta was sometimes called Jiṣṇu-suta (son of Jiṣṇu). Brahmagupta was a follower (and possibly the founder) of the Brāhma School, one of four principal schools of classical astronomy (from late 5th to 12th centuries) active in that period. Brahmagupta composed two principal works, namely, the Brāhmasphuṭasiddhānta in 628 (precise treatise of the Brāhma school), and the Khaṇḍakhādyaka in 665. In the Brāhmasphuṭasiddhānta, Brahmagupta criticized Āryabhaṭa I, the founder of the Ārya School. But in his Khaṇḍakhādyaka, Brahmagupta accepted the system of the Ārdharātrika School, another school founded by Āryabhaṭa I. Brahmagupta was a contemporary of another Indian astronomer, Bhāskara I, but it is not known whether they knew each other. Brahmagupta composed the Brāhmasphuṭasiddhānta when he was 30 years old. He states that his work is an improved version of the astronomical system described by Brahman. If this were true, then the Brāhma School, whose name is a derivative of Brahman, might have existed before Brahmagupta. The Brāhmasphuṭasiddhānta, whose author and date are not definitely known, is the earliest extant work of the Brāhma School. It consists of 24 chapters (and in some editions has an added chapter of versified tables). In classical Hindu astronomy, both geocentric epicyclic and eccentric systems are used to calculate the positions of the planets. In the Brāhmasphuṭasiddhānta, the method used is one of successive approximations (except for the case of Mars). This tells us that the Indian model of planetary motion was not a simple imitation of the Greek geometrical model. Thirty-seven years later, Brahmagupta composed the Khaṇḍakhādyaka. In its first part, the Pūrvakhaṇḍakhādyaka, he followed the Ārdharātrika School, while in the second part, the Uttarakhaṇḍakhādyaka, he presented his own improved system. Here, Brahmagupta did not use the method of successive approximations to calculate planetary positions. He used several mathematical devices, including a second-order interpolation, for his astronomical calculations. The Brāhma School promoted by Brahmagupta was followed by Śrīpati in his Siddhāntaśekhara and by Bhāskara II in his Siddhāntaśiromaṇi. Brahmagupta’s astronomy was transmitted to Arabia in the latter half of the 8th century. Brahmagupta was well known to al-Bīrūnī and mentioned in his India. Selected References Chattopadhyay, Anjana (2002). “Brahmagupta.” In Biographical Dictionary of Indian Scientists: From Ancient to Contemporary, pp. 236–237. New Delhi: Rupa. Chatterjee, Bina (ed. and trans.) (1980). The Khandakhādyak (an Astronomical Treatise) of Brahmagupta with the Commentary of Bhattotpala. 2 Vols. New Delhi, India: privately published. Dikshita, Sankara Balakrshna (1969). Bhāratīya Jyotish Śāstra (History of Indian Astronomy), translated by Raghunath Vinayak Vaidya. Delhi: Manager of Publications (Government of India). Pingree, David (1970). “Brahmagupta.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 2, pp. 416–418. New York: Charles Scribner’s Sons. ——— (1978). “History of Mathematical Astronomy in India.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 15 (Suppl. 1), pp. 533–633. New York: Charles Scribner’s Sons. Brandes, Heinrich Wilhelm Born Died Groden near Cuxhaven, (Niedersachsen, Germany), 22 July 1777 Leipzig, (Germany), 17 May 1834 Heinrich Brandes was a pioneer in the study of meteors. He was a son of Albert Georg Brandes, a Protestant minister. Following grammar-school education, he studied science and mathematics at Göttingen with A. G. Kaestner and G. C. Lichtenberg. After 10 years of work as a dike official, Brandes was appointed in 1811 professor of mathematics at Breslau University . In 1826, he succeeded L. W. Gilbert in the chair of physics at Leipzig. Brandes B 165 166 B Brashear, John Alfred was married, and his son, Carl Wilhelm Theodor, was a lecturer at Leipzig. In 1798, Brandes and his fellow student Johann Benzenberg performed a series of observations to determine the altitude (and velocity) of meteors by triangulation. This work, locating these objects in the upper atmosphere rather than the troposphere, eventually led to the discovery of their interplanetary nature. Later, at Breslau, Brandes organized a regional network of observers with the aim of collecting data on a larger scale. He was the first to note seasonal variations of meteor frequency. Following Denison Olmstead’s pioneering investigations of the Leonids, Brandes recognized the Perseids as still another periodic meteor stream. Brandes’ special ability in the field of mathematical physics resulted in a wide range of contributions to contemporary science. Beside the mathematical method developed for reduction of the meteor observations (later improved on by Heinrich Olbers), his contributions to the theory of cometary tails, atmospheric refraction, atmospheric physics in general, and several aspects of contemporary mechanics deserve special mention. Beside numerous technical and popular publications, Brandes’ work as a coeditor of the monumental Gehler’s Physikalisches Woerterbuch – with a large score of contributions of his own on astronomical as well as other topics – was of special value in his time. Wolfgang Kokott Selected References Bruhns, K. (1876). “Brandes: Heinrich Wilhelm.” In Allgemeine Deutsche Biographie. Vol. 3, pp. 242–243. Leipzig: Dunker and Humblot. Poggendorff, J. C. (1863). “Brandes.” In Biographisch-literarisches Handwörterbuch. Vol. 1, cols. 278–279. Leipzig. Brashear, John Alfred Born Died Brownsville, Pennsylvania, USA, 24 November 1840 Pittsburgh, Pennsylvania, USA, 8 April 1920 John Brashear, a mechanical genius, manufactured many customized astronomical instruments for the scientific community as well as supplying substantial numbers of excellent smaller telescopes to the commercial market. Many of these smaller instruments, as well as the larger observatory grade instruments, are still in use. Brashear invented an improved and widely applied process for silvering mirrors which carries his name. He also acted as a civic leader and representative of astronomy. His support was crucial to the development of the Allegheny Observatory. Brashear was the son of a skilled saddle maker, Basil Brown Brashear, and a schoolteacher, Julia (née Smith). When John was 9 years old, his grandfather took him to look through the telescope of a friend, Squire Wampler. Brashear’s first look at the Moon and the rings of Saturn was through a lens made by Wampler. The flint element of the lens was crafted from glass that Wampler found among the debris of glassworks destroyed in 1845 by the great Pittsburgh fire. Brashear was so impressed by those sights that the study of the stars became his primary interest. However, as both his education and his means were meager, so also were his opportunities for employment or further education limited. When the Civil War broke out, Brashear’s father enlisted in the Union Army, so Brashear went to work in the steel mills of Pittsburgh’s South Side to help support his family. He earned only $10 per week, but Brashear learned well and became one of the most skilled millwrights in the city. In 1862, Brashear married Phoebe Stewart. After his career at the mill and his marriage had stabilized, he decided to pursue his nascent interest in astronomy. He did so at first with a small and inexpensive refracting telescope mounted on a wooden tripod, but this soon proved inadequate and Brashear undertook to construct his own telescope. His initial efforts at building a telescope, though time consuming and sometimes disappointing, eventually changed his life. In 1872, in a workshop behind his home and with the assistance of Phoebe, Brashear started grinding and polishing a lens for a telescope, even though he had never read a book on astronomy or physics. After 2 years, the 5-in. lens was finished. Brashear held it to the light; it slipped and broke into two pieces, a major disappointment to Brashear and his wife. An English friend, who was visiting at the time of the accident, replaced the glass, since the Brashears had no money to buy one. However, it took 2 months for the replacement glass to be shipped from England. The telescope was completed after 3 more years of work. Soon people from the South Side neighborhood were looking through Brashear’s new telescope. Brashear showed his telescope lens to Samuel Langley, director of the Allegheny Observatory in nearby Allegheny City, now the north side of Pittsburgh. Impressed with Brashear’s work, Langley suggested that Brashear try building a reflecting telescope. Brashear obtained directions on mirror making from Henry Draper, and a procedure for silvering the mirror from a British Bredikhin, Fyodor Aleksandrovich scientific magazine, The English Mechanic and World of Science. However, a year later, the nearly finished mirror shattered as he attempted to silver it. This second disappointment was devastating. At Phoebe’s urging, however, Brashear started another mirror and succeeded by devising his own method for silvering the mirror. He was now at a crossroad. From one advertisement in an 1879 issue of Scientific American, “Silvered-glass specula, diagonals and eye-pieces made for amateurs desiring to construct their own telescopes,” Brashear received hundreds of orders. In response and in a manner that became typical of Brashear, in 1880 he sent detailed descriptions, formulae, and drawings of his work to The English Mechanic. His silvering method, later known as Brashear’s process, quickly became the preferred method of silvering mirrors. After suffering a nervous breakdown in early 1881 from hard work in the mill, along with the many hours spent working in his optical shop, Brashear considered leaving the secure living as a millwright, to become a full-time optical worker. In July 1881, Brashear received an important commission from Langley to silver a heliostat mirror for an expedition to further study the selective absorption of the Earth’s atmosphere from the summit of Mount Whitney, California. He still had a mortgage on his home and a family to support. The wealthy Pittsburgh philanthropist William Thaw, Langley’s long-time benefactor, came to Brashear’s assistance. In addition to financing the enlargement and better equipping of Brashear’s workshop, Thaw paid off Brashear’s mortgage. In 1886, Thaw provided Brashear with an even larger and better-equipped workshop, and a larger home, both near the Allegheny Observatory – all at no lease cost. This unique lease arrangement was continued by Thaw’s heirs until Brashear’s death, and provided Brashear a release for full-time employment in optics. After Thaw placed Brashear on a firm financial footing in 1881, Brashear made lenses and mirrors for telescopes and spectroscopes, both large and small, for people and organizations throughout the world. Scientists from all over sought his expertise in solving problems. Where adequate equipment did not exist, Brashear designed the equipment needed and instructed the buyer on using it. When Brashear constructed the Greenwich Observatory’s spectroscope, for example, it was so advanced that no one at the observatory could assemble it. Through a lengthy correspondence, Brashear explained the assembly and its alignment to the observatory staff. Brashear produced telescopic and spectroscopic optics, and other scientific apparatus, of previously unsurpassed precision. At a time when scientific research was at its technical limits, Brashear optics and equipment greatly extended that reach. Among the major achievements of the firm are 18 or more refracting telescopes with apertures from 12 in. to 30 in., four reflecting telescopes with apertures in the range of 30 in. to 72 in., and numerous spectroscopes and spectrographs for large telescope installations. The most noteworthy of the latter instruments was the Mills spectrograph designed by William Campbell for stellar radial-velocity measurements at the Lick Observatory. Brashear was also responsible for the manufacture of numerous optical flats, and for mirrors later ruled to produce concave gratings for spectrographs. Highly specialized optical systems were produced for the International Bureau in Paris for standardizing the length of a meter in terms of the wavelength of light, and for Albert Michelson’s first large interferometer. Brashear also produced much of Langley’s experimental aerodynamics equipment beginning in March 1887. He keenly felt Langley’s disappointment in 1903 when his experimental man-carrying airplane failed, just months before the success of the Wright Brothers. By 1898, when James Keeler left the Allegheny Observatory to direct the Lick Observatory, Brashear had become a muchrespected public figure in Pittsburgh. He served as acting director of the Allegheny Observatory from 1898 to 1900, and from 1901 to 1904 he served as acting chancellor of the Western University of Pennsylvania, now the University of Pittsburgh. In both cases, Brashear refused a permanent appointment. His acceptance of these senior positions, even on a temporary basis, was made possible by the employment of James McDowell, his son-in-law who was a very capable manager of the firm in Brashear’s absence. While continuing to provide precision optics and instruments to the scientific community, Brashear also raised funds for relocating the Allegheny Observatory building beyond the smog and development of industrial Pittsburgh. Consistent with his dream of bringing the heavens to the common man, Brashear insisted that the new Allegheny Observatory include a public lecture hall and public use of the original 13-in. Fitz-Clark refractor telescope. Popularly known as Uncle John in Pittsburgh, because of his many educational and philanthropic efforts, Brashear was appointed a trustee of the Carnegie Institute (Museums of Natural History and of Art and The Music Hall) in Pittsburgh, and to the committee that designed the Carnegie Technical Schools (now the Carnegie Mellon University.) He was actively involved in various other philanthropic efforts. As a result of his philanthropy and civic dedication, as well as his scientific enterprise, Brashear received a number of honorary degrees. Glenn A. Walsh Selected References Brashear, John A. (1925). John A. Brashear: The Autobiography of A Man Who Loved the Stars, edited by W. Lucien Scaife. Boston: Houghton Mifflin. (Reprinted in several editions, including a 1988 edition by the University of Pittsburgh Press, which omits Chapters 19 and 20 from the original edition.) Elkus, Leonore R. (1981). Famous Men and Women of Pittsburgh. Pittsburgh: Pittsburgh History and Landmarks Foundation. Fried, Bart (1993). “Tracking ‘Uncle John’s’ Telescopes-Identifying and Dating Instruments made by John Brashear.” Rittenhouse 7, no. 26: 49–55. Schlesinger, Frank (1920). “John Alfred Brashear, 1840–1920.” Popular Astronomy 28: 373–379. Bredikhin, Fyodor Aleksandrovich Born Died Nikolaev, (Ukraine), 26 November/8 December 1831 Saint Petersburg, Russia, 1/14 May 1904 Comets, and especially the nature of their tails, were Fyodor Bredikhin’s major preoccupation throughout his entire scientific career. After graduation in 1855 from Moscow University, Bredikhin conducted his postgraduate study there, also working at the Moscow B 167 168 B Bredon, Simon Observatory. In 1862 he defended his master’s thesis, On the Tails of Comets, and in 1864 his doctoral dissertation, Perturbations of Comets that do not Depend on the Gravitational Attraction of Planets. The same year Bredikhin was appointed professor at Moscow University and in 1873 became director of the university’s observatory. He then succeeded Otto Wilhelm Struve, the first director of the Pulkovo Observatory, in 1890. Bredikhin retired from his observatory post in 1895, for health reasons. Bredikhin held memberships in the Russian Astronomical Society, Deutsche Akademie der Naturforscher Leopoldina in Halle (1883), the Royal Astronomical Society (1884), the Italian Society of Spectroscopists (1889), and the Bureau des longitudes in Paris (1894). In 1892, the University of Padua awarded him an honorary doctorate. Beginning with his first paper on the subject, “Quelques mots sur les queues des comètes” (1861), Bredikhin carried out extensive observational and theoretical studies of comets. His work on the subject continued after his retirement and culminated in the so called mechanical theory aimed at explaining the peculiar shape of cometary tails. They are typically directed toward the Sun near the nucleus but then curve away from it, forming multiple jets, as if they were repelled by the Sun. Bredikhin classified cometary tails into three types depending on the magnitude of this effective repulsive force. Although his theory was later abandoned, some aspects of his classification are still valid. Bredikhin’s other projects ranged from gravimetry to astrophysical spectroscopy to observations of meteor showers and the zodiacal light. His studies of the solar corona resulted in a theory that noted a connection between coronal streamers and chromospheric filaments and the lack of a direct connection between such streamers and sunspots. textbook on arithmetic. He wrote theorica planetarum and at least began a commentary on Ptolemy’s Almagest; the first three books (of 13) are extant in manuscript. One of the few observational astronomers of the Middle Ages, Bredon recorded a Venus–Regulus appulse and a lunar occultation of Aldebaran in 1347. The purpose of these observations was to determine the amount of precession that had occurred between Ptolemy’s time and the 14th century. Bredon had a keen interest in astrology; comparing Latin translations of Ptolemy’s Quadripartitum, he produced his own version of this text. He also aided his Merton College colleague John Ashenden in the composition of an astrological Summa. Bredon’s later career was that of a physician to high nobility: Joanna Queen of Scotland, Richard Earl of Arundel, and Elizabeth Lady Clare were among his patients. He may well have been the exemplar for Geoffrey Chaucer’s “doctour of phisik.” Upon his death, Bredon left 23 scientific books and an astrolabe to Merton College. Keith Snedegar Selected Reference Snedegar, K. V. (1999).“The Works and Days of Simon Bredon, a Fourteenthcentury Astronomer and Physician.” In Between Demonstration and Imagination: Essays in the History of Science and Philosophy Presented to John D. North, edited by Lodi Nauta and Arjo Vanderjagt, pp. 285–309. Dordrecht: Kluwer Academic Publishers. Bremiker, Carl Yuri V. Balashov Selected References Bredikhin, Fyodor Aleksandrovich (1862). O khvostakh komet (On the tails of comets). Moscow. (This classic work was later reprinted in Russian, with a 2nd ed. edited by K. D. Pokrovsky, Moscow: Gostekhteorizdat, 1934.) ——— (1954). Etyudy a meteorakh (Essays on meteors), edited by S. V. Orlov. Moscow: USSR Academy of Sciences Press. (His works on meteors were reprinted in the Russian series The Classics of Science, with an article and commentary by A. D. Dubyago.) Nevskaya, N. I. (1964). Fedor Aleksandrovich Bredikhin (1831–1904). Moscow: Nauka. (Probably the best scientific biography of Bredikhin, with a comprehensive bibliography of all his works and over 250 secondary sources.) Bredon, Simon Born Died England, circa 1310 England, 1372 Simon Bredon observed planetary motions to investigate precession. Bredon was a fellow of Merton College, Oxford, between 1330 and 1341, where he lectured on mathematical subjects and wrote a Born Died Hagen near, Hanover, (Germany), 23 February 1804 Berlin, Germany, 26 March 1877 Carl Bremiker published convenient mathematical tables arranged to simplify and speed astronomical calculations, and edited several journals over an extended period. Bremiker, the son of a manufacturer, Johann Carl Bremiker, was educated as a surveyor. Employed by the Rhinish–Westphalian survey immediately after he completed his training, Bremiker went to Berlin in 1835 to pursue mathematical and astronomical studies at the university. His calculation of an expected reappearance of Encke’s comet (2P/Encke) was so accurate that Johann Encke himself commented that Bremiker’s work could not have been improved upon. As a mathematician and astronomer at the Berlin Observatory, Bremiker helped prepare the Berliner astronomische Jahrbuch. Between 1839 and 1858, Bremiker was intimately involved with the observation and calculation of five hours – 6, 9, 13, 17 and 21 – for the Berliner academischen Sternkarten, a valuable catalog and atlas created as a cooperative effort by several observatories. His completed, but as yet unapproved, chart for hour 21 was used by Johann Galle for his discovery of the planet Neptune near the position predicted by Urbain Le Verrier in 1846. In his announcement letter to Le Verrier, Galle described Bremiker’s chart as excellent for this purpose. Brenner, Leo From 1850 to 1877, Bremiker served as editor of the Nautische Jahrbuch. He was appointed a departmental director at the Royal Prussian Geodetical Institute in 1868. Perhaps the greatest service to astronomy Bremiker performed was his efforts to simplify and improve the logarithm tables of Baron Georg von Vega. Bremiker’s seven-place Logarithmischtrigonometriche Handbuch (1856) was arranged more conveniently for complex astronomical calculations and went through 40 editions before the advent of mechanical calculators. As a practical astronomer, Bremiker observed from his own residence with a small telescope, discovering a comet, C/1840 U1, on 26 October 1840. In 1842, Bremiker married a tailor’s daughter, Ida Alwine Steuber; they had one son. Thomas R. Williams Selected References Anon. (1878). “Carl Bremiker.” Monthly Notices of the Royal Astronomical Society 38: 151–152. Clerke, Agnes M. (1893). A Popular History of Astronomy during the Nineteenth Century. London: Adam and Charles Black. Grosser, Morton (1962). The Discovery of Neptune. Cambridge, Massachusetts: Harvard University Press. Milkutat, Ernst (1955). “Bremiker, Carl.” In Neue deutsche Biographie. Vol. 2, p. 582. Berlin: Duncker and Humboldt. Brenner, Leo Born Died Trieste, (Italy), 1855 possibly Berlin, Germany, 1928 “Leo Brenner” was the pseudonym adopted by Spiridion Gopčević, a Serbian journalist, novelist, playwright, dabbler in the tumultuous politics of the Balkans, and one of the strangest characters ever to appear on the astronomical scene. He wrote several influential books and a host of articles that championed a variety of conflicting causes, including Serbian nationalism, Albanian independence, and a defense of the Hapsburg Monarchy. Gopčević’s frequent changes of political allegiance reflect his volatile temperament and a proclivity to alienate his associates. After marrying into wealth, Gopčević assumed the name Leo Brenner and took up astronomy at the age of 35. In 1894, he established the “Manora Observatory” on the Dalmatian island of Lošinj, located in the northern Adriatic Sea off the coast of present-day Croatia. Lošinj was then an outpost of the Hapsburg’s Austro–Hungarian Empire. Equipped with a fine 7-in. refractor and aided by excellent seeing that resulted from the modest diurnal temperature variation characteristic of the island’s delightful climate, Brenner issued a torrent of observational reports and quickly gained a measure of respect among lunar and planetary specialists, notably Philipp Fauth and Percival Lowell, who both visited Lošinj during the late 1890s. The reception of Brenner’s 1897 monograph describing his observations of Jupiter was typical of that enjoyed by his early work. The review in the British journal The Observatory was especially generous in its praise: “A really magnificent memoir . . . The feature which entitles the work to be called ‘magnificent’ consists of a series of very finely tinted charts. Concerning these it is safe to say that nothing equal to them in point of finish and quality of details has hitherto appeared.” Brenner’s popular books on observational astronomy, Spaziergaenge durch das Himmelszelt (1898) and Beobachtungs-Objecte fuer Amateur-Astronomen (1902), were also well received. However, Brenner’s success was destined to be short lived. According to the Austrian historian Martin Stangl, Brenner was driven by “a nearly pathological craving for fame and recognition” combined with an “overestimation of the possible.” Brenner’s renderings of Mars featured a canal network even more intricate than Lowell’s. He also imagined that he could glimpse oceans through transient clearings in the cloud canopy of Venus and proclaimed the discovery of a laughably precise but wildly inaccurate axial rotation period of 23 h 57 min 36.27728 s, rather like a geologist estimating the age of the Earth to the nearest minute. Spurious rotation periods for Mercury and Uranus soon followed, as well as a claim that he had resolved the M31 nebula (the Andromeda galaxy) into stars, a feat well beyond the grasp of his modest instrument. Stangl does note, however, that modern planetary observations have, in certain respects, shown features that are remarkably similar to some of Brenner’s observations that were criticized severely in his time. When his observations were greeted with skepticism, Brenner retaliated by making scurrilous ad hominem attacks on his critics. Several influential figures became targets, notably the popular French astronomer Camille Flammarion and his highly respected assistant Eugène Antoniadi. Brenner even fell out with Lowell, and habitually heaped sarcasm and abuse on the staff and equipment of the Vienna Observatory. His reputation was all but destroyed as a result of this conduct, and he was soon regarded as a pariah by the astronomical establishment. As Brenner’s claims grew ever more incredible, many even began to suspect that his observations were outright forgeries. In 1898, the editor of the Astronomische Nachrichten, Heinrich Kreutz, refused to accept any more of Brenner’s submissions. Brenner coped with this rebuff by establishing his own monthly journal, Astronomische Rundschau, which served as a vehicle for self-promotion and allowed him to conduct personal vendettas against the growing ranks of astronomers who dared to disagree with him. It occasionally featured counterfeit endorsements of Brenner’s work by various luminaries. Many of the articles in the Astronomische Rundschau written by well-known figures like Simon Newcomb, Thomas See, and Edward Barnard were simply pirated from other journals. In 1909, Brenner abruptly revealed his true identity to the readers of the Astronomische Rundschau and announced that he would cease to publish the journal, sell his observatory and library, and abandon astronomy. His fate in the years that followed is mysterious. Philipp Fauth, who remained fond of Brenner, recorded in his letters that Brenner had committed suicide, though the year and circumstances of his death are disputed to this day. Thomas A. Dobbins and William Sheehan Alternate name Gopčević, Spiridion B 169 170 B Brinkley, John Selected References Ashbrook, Joseph (1978). “The Curious Career of Leo Brenner.” Sky & Telescope 56, no. 6: 515–516. Fauth, Hermann (1993). Philipp Fauth – Leben und Werk. From the autobiographical notes assembled by Hermann Fauth and edited by Freddy Litten. Munich: Institut für Geschichte der Naturwissenschaften. Heim, Michael (1966). Spiridion Gopcevic: Leben und Werk. Wiesbaden: Otto Harrassowitz Verlag. Stangl, Martin (1995). “The Forgotten Legacy of Leo Brenner.” Sky & Telescope 90, no. 2: 100–102. In 1814, Brinkley published a new theory of astronomical refraction, along with tables for its calculation, and published a catalog of 47 fundamental stars. He also made contributions to the determination of the obliquity of the ecliptic, the precession of equinoxes, and the constants of aberration and lunar nutation. His textbook, Elements of Astronomy, was first published in 1813 and went through numerous editions to become a standard reference work. Mary Croarken Selected References Anon. (November 1835). “Dr. Brinkley, Bishop of Cloyne.” Gentleman’s Magazine 4: 547. Anon. (1836). “Dr. Brinkley.” Memoirs of the Royal Astronomical Society 9: 281–282. Brinkley, John Born Died Woodbridge, Suffolk, England, January 1767 Dublin, Ireland, 14 September 1835 John Brinkley was an observational astronomer, mathematician, and director of the Dunsink Observatory. The illegitimate son of Sarah Brinkley, a butcher’s daughter from Woodbridge in Suffolk, he attended a school in Benhall before going to Caius College, Cambridge. There he graduated as senior wrangler in 1788 and was the first Smith Prize winner in 1788. Brinkley was a fellow of Caius College (1788–1792) and was awarded an M.A. from Cambridge in 1791 and a D.D. from Dublin in 1806. He took holy orders while a fellow at Cambridge. Brinkley had to work his way through university. One of his summer vacation jobs was as an assistant at the Royal Observatory, Greenwich, while Nevil Maskelyne was Astronomer Royal. Brinkley stayed at the observatory from 23 June to 9 November 1787, and again from 27 January to 28 March 1788, before returning to Cambridge to complete his studies. In 1790, Maskelyne recommended him for the post of professor of astronomy at Dublin. Two years later, Brinkley was appointed Andrews Professor of Astronomy and director of Dunsink Observatory. Later that year he was given the title Astronomer Royal for Ireland. He was elected fellow of the Royal Society in 1803, was president of the Royal Irish Academy (1822–1835), and was president of the Royal Astronomical Society (1825–1827 and 1831–1833). In 1826 he was appointed Bishop of Cloyne. When Brinkley arrived in 1792, Dunsink Observatory contained only a transit instrument and was awaiting the arrival of an 8-ft. altitude-and-azimuth circle that had been ordered from Ramsden but which did not arrive until 1808. In the meantime, Brinkley made many contributions to mathematics, publishing in the Transactions of the Royal Irish Academy and the Philosophical Transactions of the Royal Society of London. In 1808, Brinkley began to become more interested in practical astronomy and by 1810 reported the discovery of an annual parallax for α Lyrae of 2.52″, which he followed in 1814 by announcing similar results for other stars. Brinkley’s results were disputed by John Pond, Maskelyne’s successor as Astronomer Royal. But while their disagreement on the issue went on for some years, it was always conducted with moderation and politeness. Brinkley was awarded the Copley Medal by the Royal Society for his work on stellar parallax, but he ultimately was proved wrong, and the incident brought about recognition for the need for a closer scrutiny of instrumental defects. Brisbane, Thomas Makdougall Born Died Brisbane House, (Strathclyde), Scotland, 23 July 1773 Brisbane House, (Strathclyde), Scotland, 27 January 1860 Thomas Brisbane’s contribution to science was primarily as a patron. Brisbane established three private observatories, at Brisbane House in Scotland (1808), at Parramatta near Sydney, Australia (1822), and at Makerstoun in Scotland (1826). As a Southern Hemisphere observatory, the modest establishment at Parramatta made a valuable contribution to mapping the southern skies. In addition to astronomical work at Makerstoun, a program of magnetic observations begun in 1841 was of lasting scientific value. The eldest son of Thomas Brisbane and Eleanor (née Bruce), Brisbane was educated by tutors at home, at an academy at Kensington, and at Edinburgh University. His military career began in 1789 as an ensign in the 38th regiment in Ireland. Brisbane was promoted several times in successive years and saw action in Flanders under the Duke of York. He went to the West Indies in 1795 as major in the 53rd regiment. Although Brisbane developed a taste for mathematics and astronomy at the University of Edinburgh, it was an incident in 1795 that triggered his lifelong engagement with practical astronomy. The ship on which he was traveling to the West Indies was very nearly wrecked due to a miscalculation of longitude. Brisbane acquired his first instruments and soon taught himself nautical astronomy. The tropical conditions in the West Indies wore down Brisbane’s health, and he returned home in 1803 as a lieutenant colonel. When he was unable to join the 69th regiment in India in 1805, Brisbane went on half pay for some years. While in semiretirement from the army in 1808, Brisbane built an observatory at Brisbane House, borrowing against his future inheritance to equip it with fine instruments. His efforts and investment made the Brisbane House Observatory much superior to the only other Scottish observatory, at Garnet Hill, the Royal Observatory in Edinburgh not being founded until 1818. Brisbane returned to active service in 1812, seeing action in Spain and the south of France during the Peninsular War. The following year he went to Canada as a major general and assumed command of Peninsular veterans at the battle of Plattsburg, Brooks, William Robert New York. Following the battle of Waterloo in 1815, Brisbane was part of the army of occupation in France. In 1819, Brisbane married Anna Maria Makdougall, heiress of Sir Henry Hay Makdougall. Under the terms of the marriage settlement, Brisbane adopted the middle name Makdougall in 1826. Their four children predeceased them both. After some years largely spent in Scotland, Brisbane returned to public life in a civil position. Aware that Southern Hemisphere astronomy offered great opportunities for scientific discovery by building on the work of Edmond Halley and Nicholas de La Caille, Brisbane sought an appointment as Governor of New South Wales and made plans for his second observatory. With news of his appointment in 1821 he purchased instruments by Troughton and Reichenbach to equip an observatory and employed the established astronomer Karl Rümker as assistant and the mechanically minded fellow Scot James Dunlop as second assistant. At the time Brisbane built the observatory at Parramatta in 1822, plans for an official British observatory had settled on Cape Town. However, it was some years before the South African observatory was fully operational. Therefore, Brisbane’s private establishment was able to contribute novel observations to European scientific periodicals. Brisbane himself observed the solstices in 1823 as well as an inferior conjunction of Venus. More significant was Dunlop’s rediscovery of Encke’s comet (2P/Encke) on 2 June 1822, based on Rümker’s calculations. This was only the second time that the return of a comet had been predicted and observed, Halley’s comet (IP/ Halley) being the first in December 1758. In 1823 Rümker left Parramatta, but the lessexperienced Dunlop remained as the principal observer. Brisbane was an active participant in the work of the observatory for the first year, but then the demands of his official duties forced him to leave the astronomical work substantially to Rümker and Dunlop. Brisbane held the post as Governor of New South Wales for 4 years. During that period, his administration is credited with a number of reforms that were important to the rapid evolution of the new colony, including more effective applications of convict labor, enhanced surveying and sale of government lands, inauguration of free immigration on a large scale, and the encouragement of new crops. During those 4 years, the area of cleared land was doubled, and the export of wool quintupled. In spite of these successes, however, Brisbane’s administration was staffed with contentious individuals appointed by the Crown, and their reports to London carried considerable negative weight. In consequence, and in spite of substantial progress being made in the colony, Brisbane was not favorably regarded in London and was recalled in December 1825. Brisbane turned over the records for the stellar observations made at Parramatta between 1822 and 1826 to William Richardson at the Greenwich Observatory in 1830. The objective of Brisbane’s observing program had been to compile a catalog of all stars brighter than the eighth magnitude from the zenith at Parramatta to the South Celestial Pole. From these observations, Richardson compiled the Parramatta Catalogue of 7385 stars for the equinox of 1825. On his retirement to Scotland, Brisbane took up residence at Makerstoun near Kelso on the Tweed River. There he established his third astronomical observatory, where he took an active part in the observations himself for some 20 years. The particular importance of the Makerstoun Observatory rests on its role as a magnetic observatory under the direction of John Allen Broun. After 1841, the observatory took part in the international program established by Carl Gauss. Despite the effect of active military service on his health and the anxieties of colonial administration, Brisbane lived for nearly 35 years after his retirement, dying at the age of 87. Brisbane was elected a fellow of the Royal Societies of London (1810) and Edinburgh (1811). In 1833 he succeeded Sir Walter Scott as president of the latter, an office he held until his death. An early member of the Astronomical Society of London, later the Royal Astronomical Society [RAS], he was one of its vice presidents in 1827. The RAS awarded Brisbane its Gold Medal in 1828 for his contribution to Southern Hemisphere astronomy. Brisbane was knighted [KCB] with other Peninsula War generals in 1814, and was awarded honorary degrees by the universities of Edinburgh (1823), Oxford (1832), and Cambridge (1833). Broader public recognition came with the award of a baronetcy (1836) and the GCB (1837). The Edinburgh Royal Society awarded him its Keith Medal in 1848 in recognition of the valuable work of the magnetic observatory. Julian Holland Selected References Brisbane, Thomas M. (1860). Reminiscences of General Sir Thomas Makdougall Brisbane: of Brisbane and Makerstoun, Bart, edited by W. Tasker. Edinburgh. Heydon, J. D. (1966). “Brisbane, Sir Thomas Makdougal (1773–1860).” In Australian Dictionary of Biography. Vol. 1, 1788–1850, pp. 151–155. Melbourne: Melbourne University Press. Liston, C. A. (1980). “New South Wales Under Governor Brisbane, 1821–1825.” Ph.D. diss., University of Sydney. Mennel, Phillip (1892). “Brisbane, General Sir Thos. Makdougal.” In The Dictionary of Australasian Biography. London: Hutchinson and Co., pp. 56–57. Morrison-Low, Alison (2004). “The Soldier-Astronomer in Scotland: Sir Thomas Makdougall Brisbane's Scientific Work in the Northern Hemisphere.” In Historical Records of Australian Science. Vol. 15, pp. 151–176. Richardson, William (1835). A Catalogue of 7385 Stars Chiefly in the Southern Hemisphere. London. Saunders, Shirley (1990). “Astronomy in Colonial New South Wales: 1788 to 1858.” Ph.D. diss., University of Sydney. (Provides a substantial modern appraisal of the work of Parramatta Observatory.) ——— (2004). “Sir Thomas Brisbane's Legacy to Colonial Science: Colonial Astronomy at the Parramatta Observatory, 1822–1848.” In Historical Records of Australian Science. Vol. 15, pp. 177–209. Stephens, Henry Morse and Agnes M. Clerke (1885). “Brisbane, Sir Thomas Makdougall. ” In Dictionary of National Biography, edited by Sir Leslie Stephen and Sir Sidney Lee. Vol. 2, pp. 1261–1264. London: Oxford University Press. Sweetman, John and Anita McConnell (2004).“Brisbane, Sir Thomas Makdougall, baronet (1773–1860).” In Oxford Dictionary of National Biography. Brooks, William Robert Born Died Maidstone, Kent, England, 11 June 1844 Geneva, New York, USA, 3 May 1921 An American astronomer known for his work as a discoverer of comets, William Brooks was the son of a Baptist minister, Reverend William Brooks, and Caroline (née Wickings) Brooks. When still a small boy William accompanied his family on a voyage to Australia, during which his interest in astronomy was piqued by watching the ship’s captain make latitude and longitude determinations. At the B 171 172 B Brorsen, Theodor Johann Christian Ambders age of 13 he immigrated with his family to Marion, New York, USA The bright and graceful comet C/1858 L1 (Donati) of 1858, which he viewed through a homemade spyglass, fascinated Brooks shortly thereafter but did not lead to his active involvement in astronomy at that time. After his marriage to Mary E. Smith of Edwardsburg, Michigan, in 1870, Brooks settled at Phelps, in the Finger Lakes district of upstate New York, where he worked as a photographer. In his spare time, Brooks built the Red House Observatory (actually no more than a small observing platform built in an apple orchard on his property), and from that vantage point searched for comets with several portable telescopes, including a homebuilt 5-in. reflector. He found his first comet in 1881 (72P/1881 T1), though a delay in the announcement led to the comet’s becoming generally known as Denning’s comet. (It was then lost until a rediscovery by S. Fujikawa in 1978.) Brooks’s next comet was discovered in 1883 (C/1883 D1); he found no less than three in the single year 1886. In 1888, Brooks was invited to Geneva, New York, to take charge of an observatory built by William Smith, a wealthy nurseryman who also emigrated from England. Built on the site of Smith’s mansion, the observatory consisted of a two-story tower with a dome, designed by Warner and Swasey, housing a superb shortfocus 10.5-in. Clacey refractor. In addition to receiving the keys to the observatory, Brooks and his family were quartered comfortably in a large Victorian brick house on the premises. In addition to his role as director of the observatory, Brooks served as a professor of astronomy at Hobart College from 1900, and at William Smith College as well. Brooks remained single-minded in the pursuit of comets, and became the most prolific visual discoverer of comets in America, second on the all-time list only to Jean Pons of the Marseilles Observatory. To the 11 comets he had found at Phelps, he added 15 more at Geneva between 1888 and 1905. The record is the more remarkable in that he had to carry out his comet seeking, as he wrote: neglect; its astronomical work had ended with the career of the director. William Sheehan Selected References Anon. (1907 ). “Brooks, William Robert.” In National Cyclopaedia Of American Biography. Vol. 5, pp. 197–198. New York: James T. White and Co. Anon. (1922). “William R. Brooks.” Monthly Notices of the Royal Astronomical Society 82: 246–247. Bortle, John E. (1991). “The King of Comet Finders.” Sky & Telescope 81, no. 5: 476–477. Swift, Lewis (1887). History and work of the Warner Observatory, Rochester, New York. Rochester, New York: Democrat and Chronicle Book and Job Print. Brorsen, Theodor Johann Christian Ambders Born Died Nordborg, Denmark, 29 July 1819 Nordborg, Denmark, 31 March 1895 in the few intervals between other duties, among which is the entertainment of visitors, the Observatory being freely open to the public on every clear night. This explains why most of my Geneva comets have been discovered in the morning sky. Brooks discovered his last comet, C/1911 O1, in July 1911. It turned out to be his best. Brightening rapidly as it approached the Sun and the Earth, by mid-October it loomed in the northeastern sky after evening twilight, reaching second magnitude with a bluish-white tail extending 30° and putting on a display little inferior to that put on by Halley’s comet a year earlier. Over his lifetime, Brooks independently discovered 31 comets, 21 of which bear his name in the historical records. For his comet discoveries in 1883, 1885, 1886, and 1887, Brooks was awarded the Warner Prize eight times. (Lewis Swift designated the recipients of the Warner Cash Prize for new comet discoveries, acting as a proxy for H. H. Warner, a patent-medicine vendor and astronomical patron at Rochester, New York.) A few years before his death, Smith willed his mansion, observatory, and the observatory director’s Victorian residence to Hobart College (later Hobart and William Smith Colleges). After Brooks's death, his daughter bought the “director’s house” from Hobart. She lived there until 1954, but the observatory fell into Theodor Brorsen is best known for his discovery of five comets; he also dedicated himself to observation of the zodiacal light and the counterglow or gegenschein. Brorsen was the son of ship captain Christian August Brorsen and his wife Annette Margrethe Gerhardine (née Schumacher), a granddaughter of a local official. At the age of seven, Brorsen entered a Protestant school in Christiansfeld. His secondary education was obtained at the Latin school in Flensburg. Brouwer, Dirk Originally a student of law, he visited the Berlin Observatory (then directed by Johann Encke) and enrolled in some astronomy and mathematics courses. Brorsen’s studies were continued at the universities of Kiel and Heidelberg. While a student, Brorsen discovered two comets with a small telescope at the Kiel Observatory, on 26 February and 30 April 1846 (5D/1846 D2 and C/1846 J1). His third comet, 23P/1847 O1 (Brorsen–Metcalf), was discovered on 20 July 1847 at the Altona Observatory near Hamburg, where he was appointed after completing his studies. Founded by Danish King Frederik VI in 1816, that observatory became fully operational in 1821 and was directed by Heinrich Schumacher, the founding editor of the journal, Astronomische Nachrichten. Soon, Brorsen received other invitations. He declined a position as observer at Rundetaarn Observatory in Copenhagen, but accepted an invitation from English banker and Hamburg shipowner John Parish in 1847 to work at his private observatory at Senftenberg Castle in northeastern Bohemia. Parish’s observatory had been founded in 1844. Brorsen and Parish began to rebuild the observatory with Schumacher’s advice. The new observatory consisted of a meridian room and a dome housing an equatorially mounted refracting telescope. It became the best-equipped observatory in Bohemia, being larger than the main Prague Observatory at Clementinum College. During his stay in Bohemia, Brorsen became a member of the “Lotos,” a German association of natural scientists founded in Prague. Both Brorsen and Parish maintained an active scientific correspondence with astronomers in Germany and elsewhere. About 40 of Brorsen’s observational and theoretical papers were published in the Astronomische Nachrichten. They were concerned mainly with comets, the zodiacal light, and the positions of minor planets. Brorsen had only a single, healthy eye; the other was damaged while playing with a sword during his youth. He liked to observe faint, diffuse objects; he discovered five comets and two galactic nebulae. While in Senftenberg, he regularly observed the zodiacal light and was the first to study thoroughly the spot of light termed the gegenschein. Brorsen believed that the latter was a “cometary tail” of the Earth, directed away from the Sun. After John Parish’s death in 1858, the heir, Georg Parish, returned from the United States. He introduced severe economic measures for the entire Senftenberg properties, and the observatory was declared a frivolity. Brorsen would have liked to continue his observations, even without receiving a salary, but the new owner had no understanding of science. The observatory was dismantled and the instruments were sold to observatories at Vienna, Madrid, and Tübingen. Unemployed, Brorsen moved to a small house and lived with his Czech housekeeper in Senftenberg; he never married. During those years, he devoted himself to other scientific interests, including geology, mineralogy, paleontology, and botany. In 1870, Brorsen returned to Als and never resumed astronomical observations. Brorsen was awarded a Gold Medal by Christian VIII, King of Denmark, in 1846. This medal is displayed in the Brorsen exhibition at the Museum in Sonderborg (Als). Minor planet (3979) bears his name. Martin Solc Selected References Anon. (1995). “Danish astronomer Theodor J. Ch. A. Brorsen” (in Czech). In Proceedings of the Conference Held on the 100th Anniversary of Brorsen’s Death. Kralove: Astronomical Society of Hradec. Kreil, K. (1845). “Nachrichten über die Sternwarte des Herrn Barons v. Senftenberg.” Astronomische Nachrichten 23: 129–134. Mortensen, Harald (1944). “Astronomen Theodor Brorsen” (in Danish). In Astronomisk Tidskrift (Saertryck ur Astronomiska Saellkapet Tycho Brahe). Arsbok, pp. 79–83. Petersen, Hertha Raben (1986). Theodor Brorsen, Astronom (in Danish). Nordborg: H. C. Lorenzens. Brouwer, Dirk Born Died Rotterdam, the Netherlands, 1 September 1902 New Haven, Connecticut, USA, 31 January 1966 Dutch–American Dirk Brouwer made significant contributions to the field of celestial mechanics (understanding the orbits of natural and artificial bodies) and pioneered the use of digital computers to solve problems with unprecedented accuracy. The son of Martinus and Louisa (Née Van Wamelen) Brouwer, Dirk graduated from high school in Rotterdam and attended the University of Leiden, studying mathematics and astronomy. He received his doctorate in 1927 under the guidance of Willem de Sitter, while serving as an assistant at the Leiden Observatory. Thereupon, he received a oneyear fellowship from the International Education Board to study at the University of California at Berkeley and Yale University. Brouwer remained at Yale for the rest of his life, starting as a research assistant to Ernest Brown in 1928, being named an assistant professor in 1933, and in 1941 becoming a full professor, chairman of the Department of Astronomy, editor of the Astronomical Journal, and director of the Yale Observatory. In 1944, Brouwer was named Munson Professor of Natural Philosophy and Astronomy, in 1951 became a fellow of the National Academy of Sciences, and in 1955 received the Gold Medal of the Royal Astronomical Society. In 1966, he received the Bruce Medal of the Astronomical Society of the Pacific. Brouwer superintended the transfer of the Yale Southern Station from South Africa to Australia, occasionally working at both sites. His best-known Ph.D. students are Raynor Duncombe (who moved into aerospace engineering) and William Klepzinsky, and Yale produced a number of other outstanding students and young researchers in celestial mechanics during his tenure there. Brouwer’s work on celestial mechanics (or dynamical astronomy, as it was then known) began with his work at Leiden, where he published papers on the orbits of the satellites of Jupiter and the mass of Titan. He next collaborated with Brown at Yale to determine variations in the Moon’s orbit caused by random variations in the Earth’s rotation rate. Brouwer determined that these fluctuations were from disturbances in the interior of the Earth and coined the phrase “ephemeris time” for a time independent of those fluctuations. On realizing that some errors in the predicted and observed positions of the Moon were due to incorrectly located reference stars, not errors in his theory, Brouwer studied asteroids to provide B 173 174 B Brown, Ernest William an independent astronomical measuring stick. This led to the study of the origin of asteroids, and he made contributions to the understanding of the Hirayama families of asteroids and the existence of the Kirkwood gaps in the asteroid belt. In collaboration with Wallace Eckert at International Business Machines and Gerald Clemence, Director of the Nautical Almanac Office of the US Naval Observatory, Brouwer pioneered the application of computers to solve orbital problems and to efficiently compile star charts from raw data. The most impressive result of this collaboration was the publication in 1951 of the coordinates of the five outer planets from 1653 to 2060, a calculation of unprecedented magnitude and accuracy, and a standard still referred to today. Brouwer and Eckert’s computationally simple and efficient methods of differential corrections of orbits of planets and satellites were adopted throughout the world. Brouwer’s work on methods of integrations and analysis of the accumulation of errors was also important to the field. Celestial mechanics experienced a resurgence of interest following the launch of Sputnik in 1957. To meet the growing demand, Brouwer sponsored Summer Institutes in Dynamical Astronomy [SIDA] and in 1961 wrote the highly regarded Methods of Celestial Mechanics with Clemence. Brouwer also made significant advances in orbit calculations of artificial satellites, including algorithms that took into account the oblateness of the Earth and atmospheric drag effects on computing the motion of artificial satellites. The American Astronautical Society and the Society's Division on Dynamical Astronomy each sponsor a Dirk Brouwer Award. He further has been memorialized by having a crater on the Moon and a minor planet (1746) named for him. Brouwer’s papers are housed at the Yale Observatory Archives. Michael Fosmire Selected References Clemence, G. M. (1970). “Dirk Brouwer.” Biographical Memoirs, National Academy of Sciences 41: 69–87. Henyey, L. G. (1966). “Posthumous Award of the Bruce Gold Medal.” Publications of the Astronomical Society of the Pacific 78: 195–198. Hoffleit, Dorrit (1992). Astronomy at Yale, 1701–1968. Memoirs of the Connecticut Academy of Arts and Sciences, Vol. 23. New Haven: Connecticut Academy of Arts and Sciences. Brown, Ernest William Born Died Hull, England, 29 November 1866 New Haven, Connecticut, USA, 22 July 1938 Ernest Brown is chiefly remembered for his outstanding work in celestial mechanics, more specifically his meticulous researches into the complex intricacies of lunar theory. He was the only surviving son of wealthy farmers William and Emma Martin Brown; he had two sisters, and a brother who died in infancy. Educated at East Riding College, Hull, Brown quickly showed an aptitude for mathematics, and in 1884 won a scholarship to Christ’s College, Cambridge. There he studied under George Darwin, with whom he developed a friendship that lasted until the latter’s death in 1912. Indeed it was Darwin who urged him to study George Hill’s papers on the theory of the Moon. That was in the summer of 1888. Brown had by then spent a year in postgraduate study at Cambridge. The suggestion set the pattern of his scientific career. For the next 20 years little else occupied his professional mind, and though in the remaining 30 years his interests broadened to embrace independent problems – including the stellar version of the three-body problem, the numerical verification of solar perturbations in the Moon’s motion, the motion of bodies near Lagrangian points, and the general theory of the Trojan group of asteroids – lunar theory by far remained his favorite subject. He rarely ventured outside the realm of celestial mechanics. Brown received his B.A. as sixth wrangler in 1887. He became a fellow of Christ’s College in 1889; that same year on 11 January he was elected a fellow of the Royal Astronomical Society. Brown obtained his M.A. in 1891. That year, he left his native shores for the United States to take up an appointment as instructor of mathematics in Haverford College; 2 years later, he became professor of mathematics. Distance however, could not diminish Brown’s strong affection for his old alma mater, and part of almost every summer he returned to Cambridge, frequently staying at the Darwin residence, even long after Darwin’s death. Brown received his D.Sc. in 1897, and became an honorary fellow of Christ’s College (1911). He was elected a fellow of the Royal Society (1897), and awarded its Royal Medal in 1914. Other honors Brown received include the Gold Medal of the Royal Astronomical Society (1907), the Pontécoulant Prize of the Paris Academy of Sciences (1910), and the Bruce Medal of the Astronomical Society of the Pacific (1920). The Watson Medal of the United States National Academy of Sciences (1937), an institution of which he was elected a member once he became an American citizen, was one of his more cherished awards, possibly because it did not specifically relate to his work on lunar theory but rather to his contributions to other aspects of celestial mechanics. Brown did not intend to develop a completely new lunar theory when he started his investigation of the Moon’s motion. Rather, it evolved as he became more familiar with the whole field and familiarized himself with the various methods available for use in its study. Systematic development began in 1895, with the results published in five parts in the Memoirs of the Royal Astronomical Society (1897–1908). Brown always gave Hill his full and proper share of the credit for his solution of the main problem, but though he followed Hill’s example, and assumed the Sun, the Earth, and the Moon to be of spherical form, with the center of the Earth–Moon system performing an elliptical orbit around the Sun, “it would be unfair … to consider his work merely a routine application of Hill’s methods” (Brouwer, “Obituary,” 302). The objective was no less than a new determination of each coefficient in longitude and in latitude with greater completeness and accuracy than his predecessors had found. Among the few lunar motions that had evaded elucidation was the comparatively large fluctuation in mean longitude. Simon Newcomb had attributed the discrepancy to irregularities in the rate of rotation of the Earth. If that were so, Brown argued, similar fluctuations should be present in the observed mean longitude of other bodies in the Solar System. His investigation of transits of Brown, Robert Hanbury Mercury seemed to verify the supposition, but not enough to convince him of its reality. Brown devoted much thought to the problem; in 1926, after rejecting several possibilities, he concurred with Newcomb, attributing the apparent discrepancy to irregular variations in the Earth’s rate of rotation. The construction of new tables of the Moon’s motion, rendered with the incomparable assistance of Henry B. Hedrick, followed directly on completion of the theory. In 1907, Brown became professor of mathematics at the Yale University, where he was, in succession, Sterling Professor of Mathematics (1921–1931), the first Josiah Willard Gibbs Professor of Mathematics (1931/1932), and professor emeritus. Brown reached an agreement with Yale to undertake the cost of production of his tables. Tables of the Motion of the Moon, printed by Cambridge University Press, appeared in three volumes from Yale University Press in 1919. They contained 660 pages of tables and text, with explanations of their use. Although they included nearly five times more terms than Peter Hansen had used in his tables, they were more convenient to use, and in 1923 were incorporated into most national ephemerides for the calculation of the Moon’s place. As a young man Brown was a keen mountaineer, and traveled extensively. He was an accomplished pianist, and fond of music. He read widely, but as he got older developed a taste for detective stories. Brown never married, and made his home with his unmarried sister, who sadly predeceased him by about 2 years. Long-standing bronchial troubles precipitated early retirement in 1932, and shadowed his last 6 years. Richard Baum Selected References Brouwer, Dirk (1939). “Ernest William Brown.” Monthly Notices of the Royal Astronomical Society 99: 300–307. Brown, Ernest W. (1899). “Theory of the Motion of the Moon.” Pt 1–5. Memoirs of the Royal Astronomical Society 53: 39–116, 163–202; 54 (1904): 1–63; 57 (1908): 51–145; 59 (1910): 1–103. ——— (1914). “Cosmical Physic.” Nature 94: 184–190. ——— (1919). Tables of the Motion of the Moon. 3 Vols. New Haven: Yale University Press. Brown, Ernest W. and Clarence A. Shook (1933). Planetary Theory. Cambridge: University Press. Schlesinger, Frank and Dirk Brouwer (1941). “Biographical Memoir of Ernest William Brown.” Biographical Memoirs, National Academy of Sciences 21: 243–273. Brown, Robert Hanbury Born Died Aruvankadu, (Tamil Nadu, India), 31 August 1916 Andover, Hampshire, England, 16 January 2002 British radio astronomer R. Hanbury Brown is best known for the invention and development, with Robert Twiss, of optical intensity interferometry. He was named after a grandfather, who worked on irrigation with the Royal Engineers in Egypt and India, where his father, also a soldier, was born and stationed at the time of the astronomer’s birth. Later in his life, the surname was sometimes rendered as Hanbury Brown, and he was generally called Hanbury. Brown was educated at Tonbridge School and took a first class degree in electrical engineering at Brighton Technical College in 1935. He went on to Imperial College, London, intending to work toward a Ph.D. Instead, Brown became involved almost immediately with the London University Air Squadron and the Air Ministry, where he was put to work on the pioneering research on radar then under way under Robert Watson-Watt. He also helped develop beacons for aircraft and ground stations to distinguish friendly from unfriendly aircraft, which were used in the allied invasion of Europe in 1944. Brown was seconded to the United States Naval Research lab (1942–1945), working on similar projects there. He continued to work with Watson-Watt as a consultant until 1949, when he joined Bernard Lovell at the Jodrell Bank radio observatory of University of Manchester, intending again to work toward a Ph.D. but again being diverted. Brown was appointed a senior lecturer at the university in 1953, a reader in 1955, and to a professorship of radio astronomy in 1960, from which he resigned in 1963 following a move to Australia. He married Heather Chesterton, and they had three children. When Brown went to Manchester University’s Jodrell Bank in 1949 the only radio telescope there was Lovell’s handmade 66-m dish, which could only point to the zenith. Brown, along with a graduate student, Cyril Hazard, modified the telescope so that it could be moved to other altitudes on the meridian. Their results with this crude arrangement were an important practical demonstration of the need for a large, steerable radio telescope, which was eventually completed at Jodrell Bank in 1957. Working at a wavelength of 1.89 m, Brown and Hazard, in 1950, showed conclusively that M31 emitted radio waves. It was the first of many extra-galactic radio sources that they identified and mapped. The pair also confirmed the earlier work of Grote Reber, detecting emission from the Milky Way and from a few discrete sources, though at better resolution than had been possible earlier. At the time, it was not known if radio sources such as those in Cygnus and Cassiopeia were starlike. There had been a few successful demonstrations of stellar diameters at optical wavelengths by Albert Michelson and Francis Pease in the 1920s using an interferometer. But because radio wavelengths are much longer, a comparable radio interferometer would have had to be immense. So Brown set out to devise a different type and, together with mathematician Richard Twiss, invented a device that he called an intensity interferometer. In all interferometers, waves from a source fall on two or more receivers the separation of which can be varied. In the traditional design, the phase relationship between these collected waves must be preserved up to the point where they are added, implying that the receivers must be physically connected and that the difference in path lengths to the point of combination must be known very accurately. In the intensity interferometer this phase preservation is not necessary since the radiation is collected at two separate receivers and transmitted by phone or radio link to an electronic device where only the fluctuation in power from each receiver is correlated. The intensity interferometer had the unexpected advantage of being unaffected by atmospheric scintillations, too. With the first intensity interferometer, built by two of Brown’s research students, Roger C. Jennison and M. K. Das Gupta, the angular diameters of the radio sources Cygnus A (Cyg A) and Cassiopeia A (Cas A) were actually measured to be B 175 176 B Brück, Hermann Alexander arc minutes in size, thus proving that they were not starlike. This result did not entirely resolve the issue of whether most sources were galaxies (expected to be extended) or associated with stars (expected to be compact). In fact Cas A is a supernova remnant and Cyg A an active galaxy. Since these sources were much larger than expected, it happened that other radio astronomers were simultaneously obtaining the same measurements using traditional interferometric techniques with only moderate antenna separation. As it turned out, mainly due to the development of highly accurate frequency standards, the traditional amplitude interferometer, rather than the intensity interferometer, became the instrument of choice in radio astronomy. But the intensity interferometer’s immunity from atmospheric scintillation convinced Brown and Twiss that if they could adapt it to optical wavelengths, it would overcome one of the major problems that had prevented Michelson and Pease from making further progress in the 1920s. Since separate detectors were used, it moreover avoided the need for extreme mechanical stability. However, many physicists were skeptical that the principle was sound, and a great deal of time and effort went into proving that it was – even when the results came in, proving that the method worked. Brown and Twiss had their first success in this connection in 1956 when they measured the angular diameter of Sirius at optical wavelengths as 7.1 milli-arcseconds, an achievement that required only 18 h of actual observing but 5 months to accumulate in the poor English climate (an important factor in Brown’s move to Australia). Even more important was the willingness of the School of Physics at the University of Sydney to share with the University of Manchester in the large expense by installing and maintaining the equipment at Narrabri, a site some 500 km outside the city. As a result, Brown moved to a professorship at the University of Sydney, retiring into a fellowship in 1981, and returning with Heather to England in 1989. Though the skies were wonderfully dark, there were huge problems in getting the intensity interferometer up and running in the remote Australian bush. There were two multiple mirror telescopes 6.5 m in diameter mounted on carriages that could be moved around a circular track 188 m in diameter. Brown’s persistence paid off over the course of 7 years (1965–1972); he and his coworkers measured the angular diameters of 32 main sequence stars ranging from spectral types O through F. This information was a key in determining the stars’ effective temperatures from observation, which could then be compared with theoretical studies of stellar structure and atmospheres. The interferometer was further used to investigate the binary parameters of Spica; limb darkening in Sirius; a possible corona around Rigel; emission regions surrounding the Wolf–Rayet star, γ Velorum; the effect of rotation on the shape of Altair; and finally in a search for gamma ray sources. Brown did consider designing a larger intensity interferometer, but concluded that recent optical and electronic developments would enable the traditional type of interferometer to be modified to work more efficiently. He and his group worked in the laboratory to develop such a new instrument beginning in 1975, and the new Sydney University Stellar Interferometer [SUSI] came into service in the early 1980s. During his years in Australia, Brown welcomed thousands of visitors to the Narrabri Observatory, but he wished to convey more adequately to the public what astronomers were doing and why. This prompted him to write Man and the Stars (Oxford University Press, 1978) and, after retirement The Wisdom of Science: Its Relevance to Culture and Religion (Cambridge University Press, 1986). Boffin, a Personal Story of the Early Days of Radar, Radio Astronomy and Quantum Optics (Adam Hilger, Bristol, 1991) is his own account of his career. Very appropriately, Brown received the Albert Michelson Medal of the Franklin Institute in recognition of his measurements of angular diameters of stars. He received an Eddington Medal and was foreign associate of the Royal Astronomical Society (London) and a fellow and Hughes Medalist of the Royal Society (London), as well as recipient of honors from the Australia Academy of Science and from the Australian government. Brown served as president of the International Astronomical Union from 1982 to 1985 and presided at the General Assembly held in 1985 in India (Delhi) where he was born. Peter Broughton Alternate name Hanbury Brown, Robert Selected References Anon. (1985). Photons, Galaxies, and Stars: Selected Papers of R. Hanbury Brown. Bangalore: Indian Academy of Sciences. (Includes some of his most important papers, four of his lectures, and a brief biographical sketch.) Bedding, T. R., A. J. Booth, and J. Davis (eds.) (1997). Fundamental Stellar Properties. IAU Symposium No. 189. Dordrecht: Kluwer Academic Publishers. (Dedicated to Brown on the occasion of his 80th birthday.) Brown, R. Hanbury (1974). The Intensity Interferometer. London: Taylor and Francis. (Brown summarized the history, theory, practice, and application of his invention herein.) Carpenter, Jill (2001). “Robert Hanbury Brown.” In Notable Scientists from 1900 to the Present. Vol. 1, pp. 310–312. Farmington Hills, Michigan: Gale Group. (A sketch of his life and work which includes a list of many of his awards.) Davies, Rodney (2002). “Robert Hanbury Brown 1916–2002.” Astronomy and Geophysics 43, no. 3: 35–36. Davis, John and Sir Bernard Lovell (2003). “Robert Hanbury Brown.” Biographical Memoirs of Fellows of the Royal Society 49: 83–106. Brück, Hermann Alexander Born Died Berlin, Germany, 15 August 1905 Edinburgh, Scotland, 4 March 2000 Hermann Brück was a distinguished astronomer responsible for the resurgence of interest in astronomy in post-war Ireland and for raising the Royal Observatory Edinburgh [ROE] to an internationally recognized research center. He served as Astronomer Royal for Scotland from 1957 to his retirement in 1975. Brück was the only child of Hermann Heinrich Brück, an officer in the Prussian army who was killed in action during the battle of Lodz in 1914, and his wife Margaret. Educated at the Kaiserin Augusta Gymnasium, Charlottenburg, famed for its teaching of Greek, Latin, and mathematics, Brück matriculated at Kiel University in 1924. After a period there and at Bonn University, he moved to Munich. He studied there under the eminent physicist Arnold Sommerfeld and in 1928 gained his doctorate, which concerned the Brudzewski, Albertus de wave mechanics of crystals. Brück fondly remembered this period, as a student of theoretical physics, throughout his career and long life. He followed his friend Albrecht Unsöld into the field of astronomical spectroscopy by securing a post at the Potsdam Astrophysical Observatory. In 1935, Brück converted to Catholicism and with the threat of Nazism, fled Germany a year later, taking refuge with Jesuits in Italy along with his first wife Irma Waitzfelder (whom he married in Rome and who died in 1950). Brück’s faith would remain an integral part of his persona, and he was a long-standing member and councillor of the Pontifical Academy of Sciences. For his services to the Roman Catholic Church, when Brück was 90, Pope John Paul II conferred on him the Knight Grand Cross of the Order of Saint Gregory the Great. After a year at the Vatican Observatory, Brück came almost penniless to England in 1937 and secured a position at Cambridge. Here he worked under Sir Arthur Eddington, working on telecommunications though maintaining his interest in solar physics, and eventually progressing to the position of John Couch Adams Astronomer. In 1946, Brück was made assistant director of the Cambridge Observatory. In 1947, the Irish Prime Minister, Eamon de Valera, invited Brück to become director of the Dunsink Observatory (near Dublin) and professor of astronomy at the Dublin Institute for Advanced Studies. Here Brück joined a distinguished group of scientists (among them was his friend, Nobel laureate Erwin Schrödinger) and began the task of revitalizing Dunsink, which had fallen into disuse since the founding of the Irish State. The hosting of the International Astronomical Union’s [IAU] triennial Assembly in Dublin in 1955 evidenced the success of Brück’s initiative in reestablishing Irish astronomy. Among the exhibits were the photoelectric photometer developed by M. J. Smith, who had been Brück’s student in Cambridge, and the ultraviolet solar work that formed part of the Utrecht atlas. Another Nobel laureate, Sir Edward Appleton, principal of Edinburgh University, offered Brück further challenges when, in 1957, Appleton appointed him professor of astronomy and Astronomer Royal for Scotland. Here Brück was to initiate the development of innovative instruments for automated scanning of spectra, for measuring star and galaxy images, and for remote operation of telescopes, which led to the ROE operating the UK Schmidt telescope in Australia and the UK infrared telescope in Hawaii. In 1965, Brück first proposed that a large telescope be built in the Northern Hemisphere, but outside Britain. Site testing was carried out under ROE management, and the final outcome was the observatory at La Palma. These and other programs were to put the ROE at the forefront of the technological revolution embracing astronomy in the 1960s. Brück was an excellent educator and took great enjoyment and pride from his public lectures. One of his most memorable lectures, on the life and work of Angelo Secchi, was the opening address at the IAU Colloquium 47 in Rome in 1978. Brück also expanded the astronomy teaching at Edinburgh and introduced a new honors degree in astrophysics starting in 1967. Brück remained at Edinburgh until his retirement in 1975 when his attentions turned to the history of astronomy. With his second wife, Mary Conway, an astronomer herself whom he had married in 1951, Brück wrote the definitive work on the life of Charles Smyth, Astronomer Royal for Scotland between 1845 and 1888. Another book charted the history of astronomy in Edinburgh. Brück was made a CBE in 1966 for his work at Edinburgh and received honorary degrees from the National University of Ireland and the University of Saint Andrews. He was a member of the Royal Irish Academy and a fellow of the Royal Society of Edinburgh. Alastair G. Gunn Selected References Brand, Peter (2000). “Hermann Alexander Brück CBE, 1905–2000.” Astronomy and Geophysics 41, no. 6: 35. Brück, Hermann A. (1983). The Story of Astronomy in Edinburgh from Its Beginnings until 1975. Edinburgh: Edinburgh University Press. ——— (2000). “Recollections of Life as a Student and a Young Astronomer in Germany in the 1920s.” Journal for Astronomical History and Heritage 3, no. 2: 115–129. Brück, Hermann A. and Mary T. Brück (1988). The Peripatetic Astronomer: The Life of Charles Piazzi Smyth. Bristol: Adam Hilger. Brück, Hermann A., G. V. Coyne, and M. S. Longair (eds.) (1982). Astrophysical Cosmology. Vatican City: Pontifical Academy of Sciences. Brudzewski, Albertus de Born Died Brudzewo, Poland, 1446 Vilnius, (Lithuania), 1497 Albert Brudzewski lectured on planetary motions at the University of Cracow, where Nicolaus Copernicus may have studied with him. Brudzewski studied in Cracow, where he received his bachelor’s degree in 1470 and his master’s in 1474. Soon after, he was granted a professorship at that university, a position in which he regularly gave lectures on various subjects in physics and astronomy. Subsequently, he changed to theology, obtained his baccalaureate in 1490, and went to Vilnius as secretary for Prince Alexander of Lithuania, who later became the King of Poland. Brudzewski was a methodical, skillful, and effective lecturer. The humanist Philipp Callimachus wrote in a letter: “Everything created by the keen perceptions of Euclides and Ptolemaeus, [Brudzewski] made a part of his intellectual property. All that remained deeply hidden to lay eyes, he knew how to set before the eyes of his pupils” (Prowe, p. 144). He succeeded in molding countless young masters, who became instructors in the arts departments of Cracow’s Faculty of Arts, and whose intellectual focal point was occupied by Brudzewski himself. Because of him the University of Cracow at this time enjoyed a Europe-wide reputation for excellence in the study of mathematics. This renown was also based on the fact that Brudzewski introduced what was then the best theory of planetary motion, the one formulated by Georg Peurbach, into the academic curriculum at Cracow. He lectured on arithmetic, Peurbach’s planetary theory, Māshā’allāh ibn Atharī’s works, optics, several of Aristotle’s writings, the heavens, meteorology, etc. It can be assumed that Copernicus must have entered into Brudzewski’s readings as part of his studies in Cracow, especially B 177 178 B Bruhns, Karl [Carl] Christian the commentary on Aristotle. In addition to this, it is possible that Copernicus might have had personal contact with this scholar, who, in addition to his mathematical treatment of the movement of stars, also undertook observation of the heavens using such instruments as the astrolabe. However, there is no indication that Brudzewski ever derived any doubts about his geocentric world system from Copernicus’ views. Brudzewski belonged to that group of scholars who were affiliated with philosophical nominalism but who stood in the humanist camp. His duties at the University of Cracow allied him with the advocates of realism who were defending scholasticism and who had, at that time, won a temporary measure of influence. Of Brudzewski’s work, only the commentary on Peurbach’s theory of the planets appeared in print. It is likely that this work, which was published in 1494 and 1495 in Milan, was originally conceived as a textbook for his lectures conducted in 1482. Numerous other works on both astronomy and astrology are held in the University of Cracow’s library. Jürgen Hamel Alternate names Albertus Blar de Brudzewo Albert Brudzewski Selected References Albertus de Brudzewo (1495 and 1495). Commentarius in theoricas planetarum Georgii Purbachii. Mailand: U. Scinzenzeller. Birkenmajer, Ludwig Antoni (1924). Stromata Copernicana. Cracow, pp. 83–103. Prowe, Leopold (1883). Nicolaus Coppernicus. Vol. 1. Berlin. Bruhns, Karl [Carl] Christian Born Died Plön, (Schleswig-Holstein, Germany), 22 November 1830 Leipzig, Germany, 25 July 1881 Karl Bruhns was a German astronomer and professor who discovered six comets, established an observatory at Leipzig, and made important contributions in advancing meteorology in Germany by introducing a weather prediction service. Bruhns began his career in Berlin as a fitter and mechanic at Siemens & Halske, having been trained as a locksmith, but his primary interest was in astronomy. A professor at Altona recognized his exceptional mathematical skills and recommended him to Johann Encke, director of the Berlin Observatory. Following a year-long apprenticeship to Encke, Bruhns was appointed in 1852 as second assistant. He advanced to first assistant in 1854, replacing Franz Brünnow when he was recruited as director of the Detroit Observatory at the University of Michigan. By 1856, Bruhns fulfilled university requirements for a doctoral degree with his thesis De planetis minoribus inter Jovem et Martem circa solem versantibus. In 1859, while Bruhns was lecturing at Berlin and also privately, he proposed the construction of a new observatory at Leipzig. The original observatory, located in the tower of an old castle, was dilapidated, and the instruments outmoded. Under his supervision, work commenced in May 1860 on the new observatory, located at the outskirts of town. Bruhns served as the inaugural director, continuing until his death. He was an extraordinary instructor, serving as assistant professor of astronomy at the University of Leipzig beginning in 1861, with promotion to full professor in 1868. An 8-in. equatorial refractor by Pistor & Martins of Berlin, with a Steinheil objective, was added to supplement the observatory’s original Fraunhofer refractor and transit circle by Jesse Ramsden. The Leipzig Observatory was destroyed during World War II. Bruhns had a great interest in meteorology, and organized a meteorological service in Saxony, Germany, in 1863, and a weather prediction service in 1878. He was the discoverer of five new comets (C/1853 R1, C/1855 V1, C/1858 K1, C/1862 X1, and C/1864 Y1) and recovered two comets (5D/Brorsen in 1857 and 4P/Faye in 1858). Among his other contributions, he prepared ephemerides for numerous comets and asteroids, and he observed the solar eclipses of 1867 and 1868 and the transit of Mercury in 1868. Bruhns contributed to American journals including the Astronomical Journal and Astronomical Notices. He paid tribute to his mentors by writing full-length biographies of Encke (1869) and Alexander von Humboldt (1872). In 1989, Bruhns was honored with the naming of a new minor planet, (5127) Bruhns, discovered by E. W. Elst. Patricia S. Whitesell Selected References Anon. (1873). American Cyclopaedia: A Popular Dictionary of General Knowledge. Vol. 2, p. 355. New York: Appleton and Co. Brünnow, Franz Friedrich Ernst Anon. (1995). Deutsche biographische Enzyklopädie. Vol. 2, p. 163. Munich: K. G. Saur. Freiesleben, H. C. (1970). “Bruhns, Karl Christian.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 2, pp. 532–533. New York: Charles Scribner’s Sons. Brünnow, Franz Friedrich Ernst Born Died Berlin, (Germany), 18 November 1821 Heidelberg, Germany, 20 August 1891 Franz Friedrich Ernst Brünnow, a German-born and -trained astronomer, was the first European astronomer to be appointed director of an American observatory. He introduced American students to German astronomical methods, which stressed spherical and observational astronomy. Following a brief but distinguished career as director of the University of Michigan’s Detroit Observatory from 1854 to 1863, Brünnow served as Astronomer Royal of Ireland and director of the Dunsink Observatory until 1874. The son of Johann, a German privy councillor of state, and Wilhelmine (née Weppler), Brünnow attended the Friedrich-Wilhelm Gymnasium in Trier, Germany, and the University of Berlin, where he studied mathematics, astronomy, and physics. In 1843, upon completion of his thesis, De Attractione Moleculari, Brünnow was awarded a Ph.D. degree. As director of the private Bilk Observatory at Düsseldorf, Germany (1847–1851), he wrote an important paper on comet 122P/De Vico, for which he received the Amsterdam Academy’s Gold Medal. In 1851, Brünnow replaced Johann Galle as first assistant to Johann Encke at the Berlin Observatory, when Galle was appointed director of the Breslau Observatory. Brünnow was trained by Encke as one of a distinguished group of young astronomers that included Galle, Carl Bremiker, and Heinrich d’Arrest. Brünnow was present in the Berlin Observatory on 23 September 1846 when Galle discovered Neptune based on predictions by French astronomer Urbain Le Verrier. Brünnow met University of Michigan president Henry Philip Tappan when Tappan visited Berlin to purchase instruments for his new campus observatory. Under Tappan’s agreement with Encke, Brünnow superintended the construction of a Pistor & Martins meridian circle, and a Christian F. Tiede astronomical clock, both in Berlin shops, to ensure their accuracy before shipment to America. In 1854, Tappan appointed Brünnow as the inaugural director of the Detroit Observatory. Actually located at the University of Michigan in Ann Arbor, the observatory was named to honor its primary benefactors from Detroit. In 1857, Brünnow married Tappan’s only daughter, Rebecca Lloyd. As the first faculty member at the University of Michigan to hold the Ph.D. degree, and the first astronomer to introduce German astronomical methods at an American university, Brünnow’s contribution to American higher education in astronomy has been likened in significance to that of Louis Agassiz in natural history. Ann Arbor soon became regarded as the place to study astronomy in America. Brünnow’s students in what came to be known as the “Ann Arbor school” of astronomy included Cleveland Abbe, Asaph Hall, and James Watson. High standards and ideals, extremely hard work, and amazing perseverance characterized Brünnow’s academic career. The telescopes under his charge at Michigan, including a 6-in. Pistor & Martins meridian circle and 12 5/8-in. Henry Fitz refractor, lent themselves to the study of double stars, an obsession with Brünnow, and to studies of the motion of asteroids. Brünnow published several asteroid studies, including “The General Perturbations and Elliptical Elements of Vesta” and “Tables of Victoria” (1858) as well as an orbit for the double star 85 Pegasi. In collaboration with astronomer Christian Heinrich Peters of the Litchfield Observatory at Hamilton College in upstate New York, Brünnow established the longitude of the Detroit Observatory in 1861. The astronomical clocks at the two observatories were connected by telegraph to precisely determine the difference in longitude between them. Brünnow then collaborated with the US Lake Survey, based in Detroit, to determine the longitude of an established benchmark in Detroit. That point became the fundamental reference point for all positional determinations made by the Lake Survey in the Great Lakes region. The University of Michigan’s first scholarly journal, Astronomical Notices, was created by Brünnow in 1858 and published until 1862. The journal announced discoveries and research findings made at the Detroit Observatory, and published contributions from other notable astronomers. Astronomical Notices was created when Benjamin Gould barred Brünnow from publishing in the Astronomical Journal, which Gould founded and edited. Gould was embroiled in an expansive controversy that ultimately ended in his removal as director of the Dudley Observatory in Albany, New York. Brünnow, who was among the scientists to criticize Gould’s development of the observatory, was asked to replace Gould in 1859 as an interim director to establish normal observatory operations. Brünnow quickly succeeded in setting up the Dudley Observatory’s fine new telescopes, which he found in their shipping crates when he arrived. He also established a time service for Albany and made longitude determinations. When Ormsby Mitchel, the second permanent director of the Dudley Observatory, arrived in Albany in 1860, he and Brünnow clashed. With the added pressure of an urgent call from University of Michigan trustees to return to Ann Arbor, Brünnow resigned from the Dudley Observatory to return to his position as director of the Detroit Observatory. Shortly after the controversial dismissal of Tappan as president of the University of Michigan in 1863, Brünnow resigned his position as professor of astronomy and director of the Detroit Observatory. The entire family departed for Europe and never returned to the United States. Although Brünnow spent only 9 years in America, he left his mark in the history of American astronomy, and is considered one of the best among a small number of astronomers functioning in America in the mid-19th century. Brünnow’s most important work, Lehrbuch der spärischen Astronomie (Handbook of spherical astronomy), was first published in Berlin in 1851. This text established Brünnow as an astronomer of international renown. After leaving the Detroit Observatory, Brünnow translated the text into English in 1865; translations were later published in Spanish, French, Russian, and Italian. In 1865, Brünnow was appointed Astronomer Royal of Ireland, Andrews Professor of Astronomy in the University of Dublin, and director of the Dunsink Observatory. At Dunsink, he replaced B 179 180 B Bruno, Giordano outdated Ramsden transit instruments with a fine Pistor & Martins meridian circle. With that instrument, he then continued the research program on stellar parallax that had been developed by several of his predecessor directors at Dunsink. Brünnow published the parallax results in his Astronomical Observations (1870) and Researches Made at Dunsink (1873). In 1871, Brünnow collaborated with John Stubbs of Trinity College to expand and update a classic text titled Brinkley’s Astronomy. In 1869, Brünnow was elected a fellow of the Royal Astronomical Society. Failing eyesight forced Brünnow to resign in 1874. He retired to Basel then moved in 1880 to Vevey, Switzerland, to be with the Tappans, settling finally in Heidelberg, Germany, in 1889 to be with his son Rudolph after the Tappans’ deaths in 1881 and 1884. Brünnow’s poor eyesight precluded any scientific work, so he occupied himself through his considerable musical talent. He once remarked that, had he not pursued astronomy, he ought to have devoted himself entirely to music. Brünnow was making preparations for a trip to Switzerland when he suddenly became ill and died. His death was unexpected, although he had been seriously ill several months earlier. The Brünnows had one son, Rudolph Ernst Brünnow, born in Ann Arbor, who became a distinguished scholar as a professor of Assyriology at the University of Heidelberg, Germany, and later at Princeton University. Patricia S. Whitesell Selected References Anon. Papers of Franz F. E. Brünnow. Bentley Historical Library, University of Michigan, Ann Arbor, Michigan. Anon. (1892). “Franz Friedrich Ernst Brünnow.” Monthly Notices of the Royal Astronomical Society 52: 230–233. James, Mary Ann (1987). Elites in Conflict: The Antebellum Clash over the Dudley Observatory. New Brunswick, New Jersey: Rutgers University Press. Plotkin, Howard (1980). “Henry Tappan, Franz Brünnow and the Founding of the Ann Arbor School of Astronomers, 1852–1863.” Annals of Science 37: 287–302. Shaw, Wilfred B. (1951). The University of Michigan: An Encyclopedic Survey. Vol. 2, pp. 442–447. Ann Arbor: University of Michigan Press. Wayman, Patrick A. (1987). Dunsink Observatory, 1785–1985: A Bicentennial History. Dublin: Royal Dublin Society. Whitesell, Patricia S. (1998). A Creation of His Own: Tappan’s Detroit Observatory. Ann Arbor: Bentley Historical Library, University of Michigan. ——— (2000). “Nineteenth-Century Longitude Determinations in the Great Lakes Region: Government–University Collaborations.” Journal of Astronomical History and Heritage 3: 131–157. Bruno, Giordano Born Died Nola, (Campania, Italy), 1548 Rome, (Italy), 19 February 1600 Although not an astronomer in any technical sense, Giordano Bruno has a place in the history of cosmology because of his outspoken if confused espousal of Copernicanism, and his imaginative pantheistic application of certain aspects of atomism to the cosmos as a whole. He was the first to affirm that stars are suns, and he asserted an infinity of suns accompanied by an infinity of inhabited earths within an infinite Universe. Bruno was baptized Filippo, but at the age of 15 or 16 he joined the Dominican order and took the name Giordano. He became a priest in the early 1570s and spent some years in Rome teaching the “art of memory,” of which he was a master, to students who included Pope Pius V. After being accused of heresy, Bruno left Rome in 1576 and began 15 years of wandering, spending a year or two in each place he visited and everywhere encountering (or positively inspiring) hostility against his aggressively expressed unorthodox views, mainly on points of religion. In Calvinist Geneva he was threatened with execution in 1579. He moved to Toulouse, where he received a doctorate in theology, then on to Paris in 1581, and to London and Oxford in 1583. But in Oxford, Bruno stirred up more trouble and offense, in response to which he returned to London, where he lived at the house of the French ambassador. During this residency he composed and published his purportedly pro-Copernican dialogue La cena de le Ceneri (Ash Wednesday Supper), which contains praise for Queen Elizabeth and ridicule of Oxford, where reigns “a constellation of pedantry, ostentation, ignorance, and presumption” (Opere It., p. 176). In 1585, Bruno returned to Paris and a year later moved on to Wittenberg, but had to leave again in 1588, this time for Prague. In 1589 he moved on to Helmstedt, and in 1590 to Frankfurt. Then he made the fatal mistake of returning to Italy. For a while, during 1591, he was in Padua, hoping to be offered that university’s chair of mathematics, a position in fact filled a year later by Galileo Galilei. Late in 1591, Bruno moved to Venice as the guest of a nobleman named Mocenigo, who within a year denounced him as a heretic. So began his incarceration and interrogation by the Inquisition, first in Venice and then, from February Bunsen, Robert Wilhelm Eberhard 1593, in Rome, where, after a long imprisonment, the unrepentant Bruno was burnt at the stake. Because of this “martyrdom” to the Inquisition, Bruno has achieved iconic status among many interpreters of the history of science. The loss of thorough records for the period of his final imprisonment has left the field open to speculation concerning the nature of the charges levied against him. What is clear to serious scholars, however, is that Bruno was not a martyr for Copernicanism, despite the continued mythmaking of some popular accounts. The Catholic Church took no official position on Nicolaus Copernicus until 1616, 16 years after Bruno’s death, when De revolutionibus was placed on the Index librorum prohibitorum. Moreover, any reader of The Ash Wednesday Supper can see how egregiously Bruno mangled Copernicus’s theory. In short, if Bruno’s fiery execution is no proof that he was a bad theologian, neither does it constitute proof that he was a good scientist. Debates continue concerning Bruno’s true significance. The dominant current in his thought was Hermeticism, a mystical, ultimately pantheistic amalgam of ideas based on the supposedly Mosaic-era writings of Hermes Trismegistus. Bruno uses pantheism’s identification of God and cosmos to undermine Aristotle’s doctrine of the finitude of the Universe, for: it is fitting that an inaccessible divine countenance should have an infinite likeness with infinite parts – such as those countless worlds I have postulated . … There must be innumerable individuals such as those great creatures are (of which our earth is one – the divine mother who gave birth to us, nourishes us, and will finally receive us again into herself ). [And] to encompass these innumerable creatures requires an infinite space (Opere It., p. 312; Danielson, p. 142). Bruno’s pantheistic presumption that life is present everywhere in the Universe, combined with his affection for atomism, led him directly to postulate a homogeneous cosmos with stars and earths distributed throughout empty space, and accordingly with no more cosmic center and no more crystalline spheres: This entire fantasy of star- and fire-bearing orbs, of axes, of deferent circles, of cranking epicycles – along with plenty of other monstrous notions – is founded merely on the illusory notion that, as it appears, the earth is in the midpoint and center of the universe, while everything else circles about this fixed stationary earth . … [But] this appearance is the same for those who dwell on the moon and on the other stars sharing the same space, be they earths or suns” (Opere It., p. 344; Danielson p. 143). Bruno’s cosmology, therefore, while it can sound as if it anticipates the homogeneous absolute space of Isaac Newton, springs from pantheistic assumptions and in fact obviates the need for a mechanical celestial physics. The animated nature of the heavenly spheres is for Bruno sufficient explanation for their behavior. For example, “the moon (which is another earth) moves by her own force through the air about the sun” (ibid.). At the same time, such bold speculation about other earths and suns, even if it was purely imaginative, helped to stir the minds of real scientists like Johannes Kepler, John Wilkins, and Christiaan Huygens, whose thoughts of extraterrestrial life were further stimulated by the advent of technology that Bruno never dreamt of: the telescope. Kepler called Bruno’s infinitization of the cosmos “that dreadful philosophy.” But Bruno did not need to be scientifically acceptable to be scientifically significant. Dennis Danielson Selected References Bruno, Giordano (1888). Le opere italiane di Giordano Bruno. Göttingen: Dieterichsche Universitätsbuchhandlung. ——— (1975). The Ash Wednesday Supper, translated with an introduction and notes by Stanley L. Jaki. The Hague: Mouton. (Contains a useful introduction.) ——— (1980). Opere Latine. Turin: Unione tipografico-editrice torinese. Danielson, Dennis (ed.) (2000). The Book of the Cosmos: Imagining the Universe from Heraclitus to Hawking. Cambridge, Massachusetts: Perseus, especially Chap. 23, “Innumerable Suns, and an Infinite Number of Stars” (an excerpt from De l’infinito universo et Mondi), pp. 140–144. Gatti, Hilary (1999). Giordano Bruno and Renaissance Science. Ithaca, New York: Cornell University Press. (A high-quality scholarly book with useful bibliography.) McMullin, Ernan (1986). “Giordano Bruno at Oxford.” Isis 77: 85–94. ——— (1987). “Bruno and Copernicus.” Isis 78: 55–74. (Helpful in clarifying the specific astronomical relationship of Bruno to the teaching of De revolutionibus.) Michel, Paul Henri (1973). The Cosmology of Giordano Bruno, translated by R. E. W. Maddison. Ithaca, New York: Cornell University Press. Singer, Dorothea Waley (1968). Giordano Bruno: His Life and Thought (with a translation of On the infinite universe and worlds). New York: Greenwood. White, Michael (2002). The Pope and the Heretic: The True Story of Giordano Bruno, the Man Who Dared to Defy the Roman Inquisition. New York: William Morrow. (A partisan popularization typical of its genre and with no concern for accuracy or balance.) Yates, Frances A. (1964). Giordano Bruno and the Hermetic Tradition. (Reprint, Chicago: University of Chicago Press, 1991.) (The most influential study of Bruno of the late-20th century.) Bunsen, Robert Wilhelm Eberhard Born Died Göttingen, (Germany), 31 March 1811 Heidelberg, Germany, 16 August 1899 Robert Bunsen’s enduring astronomical fame derives not from the Bunsen burner but from his contribution to the development of spectroscopy, the fundamental tool underlying virtually all of the discoveries of modern astronomy. Bunsen’s father, Christian Bunsen, was a professor of modern languages at the University of Göttingen. His mother was the daughter of a British–Hanoverian officer. He was the youngest of four sons. After graduation from the Gymnasium at Holzminden, Bunsen studied chemistry at Göttingen, obtaining the doctorate at the age of 19. From 1830 to 1833, he traveled extensively, aided in part by a grant from the government of Hanover, and established scientific contacts that he would nurture for decades. His experiences included visits to factories, tours, and periods of study at laboratories of leading German and Parisian chemists, field trips with geologists, and exposure to geological collections. B 181 182 B Bunsen, Robert Wilhelm Eberhard In 1833, Bunsen became a Privatdozent (lecturer) at the University of Göttingen. After a brief stint teaching at the Polytechnic School in Kassel from 1836 to 1838, he would affiliate with German university culture for the rest of his working career as a professor of chemistry at Marburg (1838–1852) and Heidelberg (1852–1889). A lifelong bachelor, Bunsen centered his life around his laboratory and his students. He traveled widely alone and with friends. His professional colleagues honored his scientific achievements with election to the Chemical Society of London (1842), and appointments as corresponding member of the Paris Académie des sciences (1853) and later as foreign member (1882) and as foreign fellow of the Royal Society of London (1858). Bunsen received the Copley Medal of the Royal Society of London (1860), the first Davy Medal (1877), and the Albert Medal of the English Society of Arts (1898) in recognition of his scientific contributions to industrial technology. Bunsen researched primarily in the areas of inorganic and analytical chemistry. He also did important work in organic chemistry in the 1830s and 1840s, maintained an interest in geological research throughout his working life, and applied his scientific expertise to improve blast-furnace efficiency and galvanic currents in batteries. Bunsen’s dramatic impact on astronomy stemmed from his essential contributions to the fledgling science of spectroscopy in the late 1850s and early 1860s. In 1859, his Heidelberg physicist colleague Gustav Kirchhoff explained the phenomenon of dark lines in the solar spectrum as absorptions of light of the same wavelengths that materials in the path of the light emit when heated or sparked. The two men recognized that analyses of emission and absorption spectra could indicate compositions of terrestrial and celestial substances. It was now possible to determine what the Sun and stars were made of with the same accuracy as chemical analyses would provided. Bunsen and Kirchhoff found that the study of light emitted by substances required a high-temperature, nonluminous flame. In the 1850s, Bunsen had improved earlier burner designs by Ami Argand and Michael Faraday to devise a means of premixing the gas and air before combustion that produced a flame of minimal colorization. The Bunsen burner was actually constructed by Peter Desaga, a technician at the University of Heidelberg, based on Bunsen’s idea. It proved to be an effective tool for exposing the characteristic colors of light emitted by substances. Together with Kirchhoff, Bunsen invented the spectroscope in 1859. The first model was little more than a prism within a cigar box into and out of which protruded ends of two old telescopes. The men observed colors emitted by various materials placed in the flame of the Bunsen burner and then dispersed through the prism. They were able to identify those colors characteristic of known chemical elements and to affiliate other colors with previously unknown elements. Using the spectroscope, they discovered cesium (1860) and rubidium (1861). Only trace amounts of elements in small samples were necessary for spectral identification. For example, cesium was detected in a few drops of the alkaline residue from an analysis of mineral water; 40 tons of mineral water later was required to yield the several grams of cesium chloride necessary to determine the physical and chemical properties of the new element. A succession of elemental discoveries enabled by the spectroscope ensued over the next two decades, including the controversial claim in 1868 by Norman Lockyer and Edward Frankland of a new element in the Sun’s chromosphere that Lockyer dubbed “helium.” The line in the solar spectrum that supported this claim had been observed independently by Pierre Janssen and Lockyer in 1868. This remained the only evidence for the element helium until William Ramsay and his coworkers isolated it from various minerals and mineral waters in the 1890s and determined its physical and chemical properties. Meanwhile, the rapid exploitation of photography to record spectra permanently for study and comparison opened up unprecedented opportunities for astronomers to determine the material constituents of the Sun and stars in the late 1800s. Robert K. DeKosky Selected References Curtin, Theodore (1961). “Robert Bunsen.” In Great Chemists, edited by Eduard Farber, pp. 575–581. New York: Interscience Publishers. (Brief biography by a former student.) Ostwald, Wilhelm (1905). Manner der Wissenschaft – R.W. Bunsen. Leipzig: Verlag von Wilhelm Weicher, pp. 13–22. Schacher, Susan G. (1970). “Bunsen, Robert Wilhelm Eberhard.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 2, pp. 586–590. New York: Charles Scribner’s Sons. (An authoritative sketch that includes primary and secondary references – including biographical materials written in German.) Weeks, Mary Elvira (1956). Discovery of the Elements, edited by Henry M. Leicester. 6th ed. Easton, Pennsylvania: Journal of Chemical Education, p. 626. (For an English translation of the Ostwald biography.) Burckhardt, Johann Karl [Jean-Charles] Buot [Buhot], Jacques Born Died L’Aigle, (Orne), France, before 1623 Paris, France, January 1678 Jacques Buot was an engineer, mathematician, astronomer, and physicist. Little is known about the life of Buot. He was probably a gunsmith in L’ Aigle, before moving to Paris on the advice of Pierre Petit, the civil engineer in charge of the French fortifications, and of Jean Balesdens, secretary and friend of Chancellor Séguier. Buot was described as Mathématicien (1647), Ingénieur ordinaire du Roi living in Paris at the Tuileries (1648) and staying at Montmor’s mansion (1649), Cosmographe, ingénieur ordinaire du roi et maître aux mathématiques de Monseigneur le Dauphin (1670, according to contemporary manuscripts drawn up by solicitors or Roman Catholic priests), and finally Ingénieur du Roi, professeur de mathématiques des Pages de la Grande Écurie. Buot was one of the original seven members of an assembly of “mathematicians,” which was to become part of the Académie royale des sciences. He had been chosen in about May 1666 by J. B. Colbert together with Pierre de Carcavi, Christiaan Huygens, Gilles Personne de Roberval, Bernard Frénicle de Bessy, Adrien Auzout and Jean Picard. The appointment brought with it a salary of 1,200 livres per year. Although M. J. A. Condorcet gave Buot’s death year as 1675, Buot was alive in December 1677 but very ill; Philippe de la Hire was appointed to the academy in his stead on 26 January 1678, so we know that Buot was dead by then. Except for correspondence with advocates like Petit and Balesdens, the first mention of Buot occurs in 1647 when he published his Usage de la roue de proportion …, avec un traité d’arithmétique, dedicated to Chancellor Séguier. This publication shows that Buot could rank with Edmond Gunter and Blaise Pascal as one of the first inventors of calculating machines. As a mathematician, Buot left several memoirs in the Procès verbaux of the academy on the “Limaçon de Mr Pascal,” a treatise about “les lieux géométriques,” and answers to several geometrical questions. As a physicist Buot was involved in many mechanical experiments including studies of the strength and expansion of metals like copper, iron and steel, studies of samples of magnetic materials, and experiments on forces such as gravity, the so-called centrifugal force, friction, and capillarity. The academy often requested his expert advice on tests of metals, alloys, solders, or object-glasses, to check on the correctness of maps, to provide instructions for the making of celestial globes, and to prepare reports such as those on lifting appliances and, not surprisingly, on the efficiency of different guns. In June 1675, he was asked to draw up a descriptive catalog of the instruments held by the academy. Together with François Blondel and Picard, he was an executor of the will of Roberval. The first mention of Buot as an astronomer occurred in the Astronomica Physica, published by J.-B. du Hamel in 1660, where observations of the solar eclipse of 8 April 1652 made by Buot, Petit, J. A. Le Tenneur, and Auzout in Paris are reported. In the Journal des Sçavans, of 26 January 1665, Buot’s Carte du Ciel, made by order of the king, is described. This map showed the constellations through which passed the orbit of comet C/1665 F1. Buot’s own observations of the comet were included with the map. Other achievements appeared in the Procès verbaux of the academy (with a gap between 1670 and 1674): a memoir on the projection of topographical maps in 1666; observations of the elevation of the celestial pole made at the end of 1666 by means of a sextant with a radius of 6 ft.; and a method for finding the positions of the fixed stars in 1667. From 1666 onward Buot took part in the routine operations of the academy. These included the observation of the solar eclipse of 2 July 1666 made by Buot, Huygens, Carcavi, Roberval, Auzout, and Frénicle from Colbert’s house, where the academy met; the marking of a meridian line on a stone at Paris Observatory on 21 June 1667 (the day of the summer solstice); and the observation of Saturn on 16 July 1667, from which he calculated the inclination of the planet’s ring to the ecliptic as 31° 38′ 35″ (correcting Huygens’s 1659 value), and that of 15 August 1667 carried out with Huygens, Picard, and Jean Richer from which he calculated the value of 32° 0′, and 9° 32′ 50″ for the inclination to the Equator. The Journal des Sçavans of 21 March 1672 reported the observation of a “great permanent spot” on Jupiter, which Jean Dominique Cassini had observed in 1665, but had not seen since the beginning of 1666. The reappearance of the same spot on 19 January 1672 and Cassini’s calculations to predict its position for 3 March motivated the academy to ask Buot and Edme Mariotte to assist Cassini at the Paris Observatory. Their observations confirmed the period of Jupiter’s rotation as 9 h and 56 min. In 1667 Buot invented the Équerre azimutale, precisely described and illustrated in the first volume of the Machines et inventions approuvées par l’Académie royale des sciences (not printed until 1735). Made of copper, the instrument enabled an observer to lay out an accurate meridian line without exact knowledge of the time of local noon. Claude Antoine Couplet, also ingénieur ordinaire du Roi et professeur royal de mathématiques des Pages de sa Grande Écurie and former student of Buot (and who married Buot’s stepdaughter Marie Baillot), assisted in the construction of the instrument. Françoise Launay Selected References Condorcet, M. J. A. Éloges des Académiciens de l’Académie Royale des Sciences morts depuis 1666 jusqu’en 1699. Paris, 1773. Facsimile. Paris: Foundation Singer-Polignac, 1968. Du Hamel, J. -B. (1660). Astronomia physica. Paris: Lamy. Guiffrey, J. (1881). Comptes des bâtiments du Roi. Vol. 1. Paris. Scheler, L. (1951). “Blaise Pascal, Jacques Buot et la machine à calculer.” Bulletin du bibliophile: 186–195. Sturdy, David J. (1995). Science and Social Status: The Members of the Académie des Sciences, 1666–1750. Woodbridge, England: Boydell Press. Burckhardt, Johann Karl [Jean-Charles] Born Died Leipzig, (Germany), 30 April 1773 Paris, France, 21 June 1825 Johann Karl Burckhardt (known in France as Jean-Charles) is best known for his contributions to Joseph-Jérôme Lalande’s catalog of 50,000 stars and for carrying out calculations based upon Pierre de Laplace’s theories for the ephemerides of the B 183 184 B Bürgi, Jost [Joost, Jobst] Bureau des longitudes. Burckhardt studied mathematics in Germany and applied his knowledge to eclipse computations and to longitude determinations using lunar occultations. When Baron János von Zach was in search of an astronomer for his Gotha Observatory (Seeberg), Burckhardt was recommended to him, and he was hired to work on practical astronomy and to observe star transits. In France, Lalande had undertaken a similar search for the Observatoire de l’École militaire, of which he was director. In August 1797, Zach requested Lalande to have Brurkhardt placed at the Collège de France, his pension being paid by the Duchesse de Gotha. Burckhardt arrived in Paris at the end of 1797. As a linguist, he was eager to study current astronomical publications in their original form. He translated the first two volumes of Laplace’s Mécanique céleste while reading the proofs; he also added some notes and double-checked the calculations, made by Alexis Bouvard. On various occasions Lalande praised Burckhardt for being a tireless observer, rapid calculator, and a translator making French science known in Germany. In Paris, Burckhardt worked for both the Observatoire de l’École militaire, where he resided, and the Bureau des longitudes. He published, in 1817, Table des diviseurs de tous les nombres du premier million ... avec les nombres premiers qui s’y trouvent. At the observatory of the École militaire, he actively participated in finalizing the catalog to which Lalande’s nephew, Michel Lefrançois and his wife, Amélie Harlay (one of the very few women astronomers of the time), were already engaged. The observations went up to 1 April 1801. In the same period, Burckhardt established a quick method for calculating the orbit of a comet given limited data, a method applied successfully to the orbit of the first asteroid discovered, by Giuseppe Piazzi, on 1 January 1801. In 1808, Burckhardt took an interest in the force de la lumière, as it was named by Pierre Bouguer, and he designed an instrument combining a heliometer with a photometer. The Bureau des longitudes appointed him as astronome adjoint upon his naturalization in 1799. At the Bureau, Burckhardt worked out lunar tables, employing more than 4,000 observations. A commission, comprised of Bouvard, Jean-Baptiste Delambre, and Laplace, examined the results in 1811, and Laplace found that their errors were smaller than those of J. T. Bürg; they were soon in use for French ephemerides. Burckhardt himself participated in later commissions as an expert on instruments (including comparisons for meters and kilograms in the new metric decimal system of weights and measures), to the reception of manuscripts from Delambre, Pierre Méchain, and Lefrançois related to the measurements of the Méridienne de France, and to examine the sector employed by Pierre de Maupertuis when in Lapland. Later, in 1819, with Bouvard and Francois Arago, he tested one of Lerebours’ refractors, having a focal length of 6 m and an aperture of 20 cm. At that time Arago wanted such a powerful instrument for the Paris Observatory, though he would not be successful for 25 years. Burckhardt published a number of papers, including one on Piazzi’s discovery. By 1817, he became a full member of the Bureau des longitudes. From 1804, he had been a member of the astronomical section in the first class of the Institut de France, which had replaced the old Académie royale des sciences. Solange Grillot Selected References Bigourdan, G. (1887). “Histoire des observatoires de l’école militaire.” Bulletin astronomique 4: 497–504. Lalande, J. (1970). Bibliographie astronomique avec l’histoire de l’astronomie de 1781 jusqu’à 1803. Paris: Imprimerie de la République, 1803. Facsimile, Amsterdam: J. C. Gieben. Bürgi, Jost [Joost, Jobst] Born Died Lichtensteig, St. Gallen, Switzerland, 28 February 1552 Kassel, (Hessen Germany), 31 January 1632 Jost Bürgi was a clock maker, astronomer, and applied mathematician. His father was probably a fitter. Very little seems to be known about his life before 1579. It is probable that Bürgi obtained much of his knowledge in Strassburg, one of his teachers being the Swiss mathematician Konrad Dasypodius. An indication that he did not get a systematic education is the fact that Bürgi did not know Latin, the scientific language of his time. Nevertheless, he made lasting scientific contributions that prompted some biographers to call him the “Swiss Archimedes.” Bürgi was married first to the daughter of David Bramer, then in 1611, married Catharina Braun. Bürgi developed a theory of logarithms independently of his Scottish contemporary John Napier. Napier’s logarithms were published in 1614; Burgi’s were published in 1620. The objective of both approaches was to simplify mathematical calculations. While Napier’s approach was algebraic, Bürgi’s point of view was geometric. It is believed that Bürgi created a table of logarithms before Napier by several years, but did not publish it until later in his book Tafeln arithmetischer und geometrischer Zahlenfolgen mit einer gründlichen Erlüterungen, wie sie zu verstehen sind und gebraucht werden können. Indications that Bürgi knew about logarithms earlier in 1588 can be obtained from a letter of the astronomer Nicholaus Bär (Raimarus Ursus), who explains that Bürgi had a method to simplify his calculations using logarithms. Logarithms paved the way for slide rules because the identity log(a·b) = log(a) + log(b) allows one to compute the product of two numbers a and b as an addition. Bürgi also computed sinetables. These tables, called Canon Sinuum, seem however to have been lost. The sinetables were used in a method called prosthaphaeresis, known to many astronomers in the 16th century. In this method, trigonometric formulas like sin(x) sin(y) = [cos(x−y) − cos(x+y)]/2 are used to reduce multiplication to addition. Bürgi is considered as one of the inventors of that method; other identities were used by Ursus, Johannes Werner, and Paul Wittich. Another indication that Bürgi’s discovery of logarithms was independent of Napier’s is the fact that Johannes Kepler, who admired Bürgi as a mathematician, states in the introduction to his Rudolphine Tables (1627):“… the accents in calculation led Justus Byrgius on the way to these very logarithms many years before Napier’s system appeared; but being an indolent man, and very uncommunicative, instead of rearing up his child for the public benefit he deserted it in the birth.” Although the two discoveries are today believed to be independent, Napier definitely enjoyed the right of priority in publication. Buridan, John Both methods were mainly computational. It seems that the first clear and theoretical exposition of the equation log(x y) = log(x) + log(y) can be found in Kepler’s Chilias logarithmorum. In 1579, Bürgi entered the employ of Landgrave Wilhelm IV of Hesse-Kassel, observing with the court-mathematician Christoph Rothmann at the excellent Kassel Observatory. Some denote it as the first stationary observatory in Europe. Bürgi, who also knew Tycho Brahe and who was a friend of Kepler, made many instruments for the observatory. One of the instruments was the “reduction compass,” another being the “triangularization instrument,” both of which had military applications. Bürgi’s famous celestial globe from 1594 can be seen on some Swiss stamps. Bürgi is credited with the invention of the minute hand on clocks in 1577. His invention was part of a clock he constructed for Brahe, who needed precise time for observing. Bürgi is also known in the history of time measurement for a clock he made in 1585 that would run for 3 months. He introduced the idea of adding an independent system to the traditional wheel-train, which was wound in short periods by the mainspring, giving a more constant flow to the escapement. This was later perfected, leading eventually to an autonomy of several months. In 1604, Bürgi became court watchmaker to Emperor Rudolf II. He returned to Kassel the year before his death. Oliver Knill Selected References Gingerich, Owen (1980). “Jost Bürgi at Kassel.” Journal for the History of Astronomy 11: 212–213. Gronau, D. (1987). “Johannes Kepler und die Logarithmen.” Reports of the Mathematical Statistical Section of the Research Society Joanneum: 284. Nový, Luboš (1970). “Bürgi, Joost.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 2, pp. 602–603. New York: Charles Scribner’s Sons. Thoren, Victor E. (1988). “Prosthaphaeresis Revisited.” Historia Mathematica 15: 32–39. Buridan, John Born Died Diocese of Arras, Picardy, France, circa 1300 1358–1361 John Buridan was one of the most influential philosophers of his time, who, after William Ockham, was primarily responsible for the emergence of the nominalist via moderna, the “modern way” of dealing with theoretical matters. He also contributed the idea of impetus to account for motion. We know relatively little about Buridan’s life. He was born around 1300 in the diocese of Arras, in Picardy, and completed his early education in the College of Cardinal Lemoine, where he may have been a recipient of a stipend for needy students. He obtained his license to teach, sometime after 1320 at the Arts Faculty of the University of Paris, where he taught for the rest of his life as Master of Arts. Buridan was twice elected rector of the University of Paris, in 1327/1328 and 1340, and became a highly respected, influential public figure. He was unusually well-off for a university professor, drawing income from at least three benefices. His students, radiating from Paris to the newly established universities of Europe, widely disseminated his nominalist doctrine. Buridan may have died in the plague of 1358, but he certainly did not live after 1361, when one of his benefices went to another person. In accordance with the requirements of philosophy teaching of the time, Buridan’s works – besides some independent treatises in logic (in particular, the Treatise on Consequences, and the monumental Summulae de Dialectica) – primarily consist of commentaries on Aristotle’s works, ranging from logic to metaphysics, natural philosophy, ethics, and politics. The question format, raising and thoroughly discussing major problems in connection with Aristotle’s text, allowed Buridan to develop a comprehensive nominalist philosophical system, putting to consistent use the analytic conceptual tools he worked out in his logical treatises. These conceptual tools allowed him to provide meticulous analyses of the technical language of Aristotelian science, and to tackle traditional scientific problems in innovative ways. Thus, for instance, he presented an analysis of time as being simply the number of the revolutions of the sphere of the fixed stars connoted in various ways by our concepts. This of course does not mean that time is a matter of subjective experience, since the revolutions of the outermost sphere are real regardless of whether there is a human mind to count them. Still, this number is only time if it is connoted by appropriate temporal concepts: As Buridan put it, were there no human minds forming concepts with such a connotation, the thing that is time would still exist, but it would not be time. But Buridan’s most lasting contribution to physics in general, and to astronomy in particular, was his theory of impetus, which had a significant role in eventually dismantling the Aristotelian paradigm. Buridan primarily introduced the notion of impetus to account for the motion of projectiles. The commonly accepted principle held that whatever is in motion needs a mover to sustain its motion. On the basis of this assumption, the question of what moves projectiles, such as an arrow when it is no longer moved by the bowstring, naturally emerged. Aristotle’s reply, that it is the air set in motion by the original mover, was heavily criticized by Buridan on the basis of careful observation, further analysis – if the air moves the projectile, what moves the air – as well as the analogous consideration of other types of motion, such as the ongoing rotation of a spinning wheel, which certainly cannot be explained by the motion of the surrounding air. Similar considerations apply to large bodies set in motion but no longer moved, such as a ship, which is very hard to stop, yet it is obviously not moved by the surrounding air. Accordingly, Buridan assumed that these motions must be explained by an impressed force, the impetus, which is left behind in the moving body by the mover. This force is directly proportional to the heaviness of the moved body and its speed; it is decreased by resistance, and increased by the ongoing activity of the mover, but remains the same if the body once set in motion is left alone. Thus, Buridan’s theory correctly predicted that a body set in motion but left alone will exhibit what modern physics would describe as inertial motion. Accordingly, contrary to Aristotle, Buridan should not find the hypothesis of the Earth’s daily rotation absurd, since, for example, by his theory’s predictions the alleged absurdity of an arrow shot directly upward never falling back in the B 185 186 B Burnham, Sherburne Wesley same place should not follow. However, when he actually analyzed this problem, he found Aristotle’s example about the arrow “more demonstrative” than the arguments of those who were willing to maintain the hypothesis of the rotation of the Earth. Apparently, in this argument Buridan simply failed to take into account the “lateral impetus” the arrow already has on account of the Earth’s movement, which, however, would have to be taken into account based on his principles. On the basis of the same principles, Buridan was able to account for the acceleration of falling bodies in terms of the growing intensity of their impetus. However, he was also committed to assigning greater acceleration to heavier bodies. But in general, Buridan’s theory remained on the level of qualitative explanation, without enabling predictions of quantifiable results that could be tested by measurements in experiments. Nevertheless, Buridan’s theory still had the tremendous significance of providing a unified explanation for the phenomena of very different motions that had been classified differently in the traditional Aristotelian system. It was precisely this unifying perspective of Buridan’s theory that enabled him to treat celestial motions and sublunary motions in accordance with the same mechanical principles. Accordingly, in his questions on Aristotle’s Physics, Buridan argued that, since we have no Biblical reason to assume the existence of the celestial intelligences (angels) traditionally assigned to move the heavenly spheres, celestial motions could be explained by an initial impetus given to these spheres by God, since they have no other natural inclination, and there is no resistance to their rotation. Buridan did not mention that this solution immediately invalidated the Aristotelian argument for the existence of a presently existing and active prime mover, that is, God. But he certainly was aware that these speculations took him dangerously close to questions to be determined in the Faculty of Theology. So he immediately remarked that he did not want to assert this position, but rather left the determination of the issue to theologians. These speculations once and for all opened up the possibility of a unified mechanics, based on the same principles for earthly and celestial motions. Perhaps this was the most important “change in perspective” in medieval astronomy provided by Buridan’s theory, pointing in the direction of early modern celestial mechanics. Grant, E. (1978). “Scientific Thought in Fourteenth-Century Paris: Jean Buridan and Nicole Oresme.” In Machaut’s World: Science and Art in the Fourteenth Century, edited by M. P. Cosman and Chandler, pp. 105–124. Annals of the New York Academy of Sciences, Vol. 314. New York: New York Academy of Sciences. Maier, Anneliese (1955). Metaphysische Hintergründe der spätscholastischen Naturphilosophie. Rome: Edizioni di Storia e Letteratura. Michael, B. (1985). Johannes Buridan: Studien zu seinem Leben, seinen Werken und zur Rezeption seiner Theorien im Europa des späten Mittelalters. Inaugural-Dissertation. 2 Vols. Berlin: Freien Universität Berlin. Thijssen, J. M. M. H. and J. Zupko (eds.) (2001). The Metaphysics and Natural Philosophy of John Buridan. Leiden: Brill. Burnham, Sherburne Wesley Born Died Thetford, Vermont, USA, 12 December 1838 Chicago, Illinois, USA, 11 March 1921 Gyula Klima Selected References Buridan, J. (1509). Quaestiones amper octo Physicorum libros Aristotelis. Paris. (Reprinted in Kommentar zur Aristotelischen Physik. Frankfurt Main, Minerva: 1964.) ——— (1942). Quaestiones super libros quattuor De caelo et mundo, edited by E. A. Moody. Cambridge, Massachusetts: Medieval Academy of America. ——— (2001). Summulae de dialectica. An annotated translation with a philosophical introduction by G. Klima. New Haven: Yale University Press. Clagett, Marshall (1951). “John Buridan, Questions on the Eight Books of the Physics of Aristotle.” In The Science of Mechanics in the Middle Ages, pp. 532–540. Madison: University of Wisconsin Press. (Book VIII, Question 12.) Crombie, A. C. (1959). Science in the Later Middle Ages and Early Modern Times: XIII–XVII Centuries. Vol. 2, Medieval and Early Modern Science. New York: Anchor. Ehrle, F. (1925). “Der Sentenzenkommentar Peters von Candia, des Pisaner Papstes Alexanders V.” Franziskanische Studien 9. Sherburne Burnham, the leading discoverer, observer, and cataloger of double stars in the late 19th and early 20th centuries, was the son of Roswell O. and Marinda (née Foote) Burnham. Educated only in the local district school and the Thetford Academy, Burnham received no formal postsecondary education. For most of his life, Burnham was an amateur astronomer in the sense that he did not earn his living by his astronomical work. After completing his schooling, he acquired knowledge of shorthand and was employed by a stenographic recording firm in New York City. That employment apparently Burnham, Sherburne Wesley involved a trip to Europe, for while in London in 1861, Burnham acquired his first telescope, a 3-in. refractor on a simple tripod. During the US Civil War, Burnham was an official reporter with the Union troops in New Orleans. Burnham’s interest in astronomy was sparked by the chance purchase of a book, L. Burritt’s Geography of the Heavens, while he was still serving in New Orleans. In 1866, Burnham moved to Chicago and became a court reporter, having already exchanged the 3-in. refractor for a 3.75-in. equatorially mounted Fitz refractor. A second book acquired for his early astronomical library, a copy of Reverend Thomas Webb’s Celestial Objects for Common Telescopes, apparently stimulated Burnham’s interest in double stars. The inadequacies of the Fitz telescope soon became evident to him. In 1869, Burnham commissioned a 6-in. refractor from Alvan Clark & Sons. He specified that Alvan Clark should take whatever time was necessary to make a telescope with “definition as perfect as they could make it” for his use in studying double stars, but otherwise left the details of the telescope design to Clark. With this instrument, delivered by Clark in 1870, Burnham discovered 451 previously unknown visual binary stars. All his subsequent discoveries were also made with instruments made by the Clarks. From 1876 to 1884, Burnham had access to the 18.5-in. refractor of the Dearborn Observatory. Although he continued to earn his living by his work in the courts, Burnham served as the acting director of the Dearborn Observatory from 20 September 1876 until 11 April 1877. An unfortunate dispute with the observatory board of directors cut short what might otherwise have been a beneficial arrangement for the observatory. Burnham eventually continued to use the Dearborn refractor for his double-star observations and, as Philip Fox pointed out in his history of the Dearborn Observatory, Burnham’s 413 double-star discoveries constitute the only evidence of productive scientific use of this telescope prior to the arrival of George Hough as the Dearborn Observatory director in 1879. Burnham was also associated with the then new Washburn Observatory of the University of Wisconsin. Edward Holden, later to become director of the Lick Observatory, was the Washburn director at the time. In 1881, Holden induced Burnham, who was by then quite famous for his work in double-star astronomy, to come to Madison and work as a professional astronomer. Burnham remained in Madison for a year, during which time he observed with the Washburn Clark 15.5-in. refractor and, to his later regret, sold his own 6-in. Clark refractor to the observatory. Burnham apparently decided he was not yet ready for a change of profession and returned to his regular employment as a court recorder in Chicago. In 1888, Holden offered Burnham a position at the newly opened Lick Observatory. Burnham accepted that position with alacrity even though it probably meant a considerable reduction in salary. Burnham had already observed from Mount Hamilton on two earlier occasions. In 1879, he conducted a site evaluation for the Lick Trustees with his 6-in. Clark refractor. He returned to Mount Hamilton in 1881 to observe the transit of Mercury. Thus, Burnham was well aware of the superior atmospheric conditions that favored astronomical observation from Mount Hamilton. By 1892, however, as Edwin Frost delicately phrased it, “internal conditions developed at the observatory which were not agreeable to Mr. Burnham.” Holden’s acrimonious disputes with Burnham, and with other astronomers at the Mount Hamilton, are well documented in the history of the Lick Observatory. Burnham resigned and returned to Chicago to become clerk for the US District Court, a position he held until 1902. Until 1897, Burnham could make only occasional visits to the Dearborn Observatory, but he continued to work on the computation of orbits and the preparation of a general catalog of double stars. In 1897, George Hale appointed Burnham professor of practical astronomy at the University of Chicago, in anticipation of the installation of the 40-in. refractor. Beginning in October of that year, Burnham was assigned two nights a week on the 40-in. refractor. Because of his court duties, those two nights were of Saturday and Sunday. Burnham would arrive on Saturday afternoon, get what sleep he could on Sunday, and return to Chicago by the early-morning train on Monday. At this stage, he gave up searching for new pairs, and concentrated on measuring those already known. In the course of a good night, he could measure 100 pairs. In this last period, he also used the telescope to measure proper motions. His last observation with the 40-in. refractor was made on the night of 13 May 1914. Burnham must have been gifted with extraordinarily good eyesight. He could recognize doubles that had eluded detection by others, and he could make measurements of high precision, even of pairs that were difficult to resolve. Burnham’s best measures were probably the finest made before the advent of speckle interferometry. Up to the time of his observations, it was generally believed that others, principally Friedrich, Gustav, Karl, and Otto Wilhelm Struve, had already discovered most of the existing double stars. By discovering approximately 1,300 new pairs, Burnham showed that many more remained to be discovered and ushered in a new era of double-star astronomy. The importance of Burnham’s discoveries resides not only in their quantity, but also in the fact that most of the Burnham double stars are of shorter periods. The shorter periods facilitated computation of more orbits than had previously been known. This, in turn, contributed substantially to our early understanding of the masses of stars. In 1900, Burnham dedicated a catalog of his own discoveries to the Hungarian–Italian amateur and observer of double stars, Baron Ercole Dembowski, who helped and encouraged Burnham by measuring many new pairs before Burnham himself was equipped to do so. Later, Burnham also prepared and published a two-volume catalog of all known double stars in the northern sky, which immediately became a standard reference work. Even after Robert Aitken published a revised version in 1932, Burnham’s catalog continues to be a useful reference work. Burnham also devised an improved method of illuminating the cross-wires of a filar micrometer, which was adopted by many other observers. Burnham married Mary Cleland in 1868, and they had three sons (Augustus, Raymond, and Harold) and three daughters (Marion, Lida, and Grace). Later in life, he was awarded an honorary A.M. by Yale University in 1878 and an honorary Sc.D. by Northwestern University in 1915. Burnham received the Gold Medal of the Royal Astronomical Society in 1894 and was elected an associate of that Society in 1898. He was awarded the Lalande Prize of the Paris Academy of Sciences in 1904. He was an associate fellow of the American Academy of Arts and Sciences. Burnham’s two great hobbies were photography and bowling. He often took photographs of others but apparently disliked having his own taken; a photograph of Burnham is a rarity. Many people who knew him because of one or the other of these hobbies were unaware of his singular achievements as an astronomical observer. Alan H. Batten B 187 188 B Burrau, Carl Selected References Abney, William de Wiveleslie (1894). “Address Delivered by the President, Captain W. de W. Abney … on presenting the Gold Medal to Professor S. W. Burnham.” Monthly Notices of the Royal Astronomical Society 54: 277–283. Barnard, Edward Emerson (1921). “Sherburne Wesley Burnham.” Popular Astronomy 29: 309–324. Burnham, Sherburne Wesley (1900). “A General Catalogue of 1290 Double Stars Discovered from 1871 to 1899: Introduction.” Publications of the Yerkes Observatory of the University of Chicago 1: vii–xxvii. ——— (1906). A General Catalogue of Double Stars within 121° of the North Pole. Carnegie Institution of Washington Publication No. 5. Washington, DC: Carnegie Institution of Washington. ——— (1913). Measures of Proper Motions Made with the 40-inch Refractor of the Yerkes Observatory in the Years 1907 to 1912. Carnegie Institution of Washington Publication No. 168. Washington, DC: Carnegie Institution of Washington. Fox, Philip (1915). “General Account of the Dearborn Observatory.” Annals of the Dearborn Observatory of Northwestern University 1: 1–20, esp. 8. Frost, Edwin Brant (1921). “Sherburne Wesley Burnham, 1838–1921.” Astrophysical Journal 54: 1–8. Jackson, John (1922). “Sherburne Wesley Burnham.” Monthly Notices of the Royal Astronomical Society 82: 258–263. Burrau, Carl Born Died Helsingör (Elsinore), Denmark, 29 July 1867 Copenhagen, Denmark, 8 October 1944 In collaboration with Svante Strömgren, Danish mathematician Carl Burrau investigated a three-body problem in which two of the masses are equal and revolve about each other in circular orbits. His collaboration with Törvald Thiele on the three-body problem, and their method of numerical transformations for this work, is frequently known as the Thiele–Burrau method. Selected Reference Valtonen, M. J., Mikkola, S., and Pietilä, H. (1995). “Burrau’s Three-Body Problem in the Post-Newtonian Approximation.” Monthly Notices of the Royal Astronomical Soceity. 273: 751. Būzjānī: Abū al-Wafā’ Muḥammad ibn Muḥammad ibn Yaḥyā al-Būzjānī Born Died Būzjān (Būzhgān, Khurāsān, Iran), 10 June 940 Baghdad, (Iraq), 997 or 998 Būzjānī was one of the leading astronomers and mathematicians of the Middle Ages, with significant contributions in observational astronomy. His achievements in trigonometry paved the way for more precise astronomical calculations. Būzjānī was born in Būzjān, in the region of Nīshāpūr. The town is now a deserted land in the vicinity of the small town of Torbat-i Jām, located today in the Iranian province of Khurāsān. He was from an educated and well-established family. He is said to have studied arithmetic under both his paternal and maternal uncles. Būzjānī flourished in an age of great political upheavals. The Būyids (945 to 1055), a family originally from the highlands of Daylam in northern Iran, had built a new dynasty that soon extended its rule over Iraq, the heart of the �Abbāsid caliphate, reducing the caliph’s rule to a mere formality. Under the Būyids, who were great patrons of science and the arts, many scientists and scholars were attracted to Baghdad to enjoy the benefits of the new rulers’ patronage. The change in the political climate had brought with it a great cultural revival in the eastern Islamic lands promoting literary, scientific, and philosophical activities on a grand scale. At the age of 20, Būzjānī moved to Baghdad, the capital of the � Abbāsid caliphate, where he soon rose to prominence as a leading astronomer and mathematician at the Būyid court, conducting observations and research in the Bāb al-Tibn observatory. The decade following 975 seems to have been his most active years in astronomy, during which he is said to have conducted most of his observations. Later, to comply with the wishes of Sharaf al-Dawla, the Būyid Amīr (Regent), who was himself a learned man with keen interest in astronomy, Būzjānī became actively involved in the construction of a new observatory in Baghdad. His collaborator was Kūhī, another celebrated astronomer from the northern part of Iran who at the time was unrivaled in making astronomical instruments. The astronomical work of Būzjānī and his colleagues in Baghdad mark the revival of the “Baghdad school,” a tradition with much vitality in the preceding century. Bīrūnī, the renowned astronomer and scientist living in Kath (in central Asia), tells us of his correspondence with Būzjānī, who was in Baghdad. This correspondence, and the exchange of astronomical data and measurements between them, signifies not only their mutual recognition as the leading astronomers of the time, but also the vigor with which astronomical observations were carried out in those days. According to Bīrūnī, in 997 the two astronomers prearranged to make a joint astronomical observation of a lunar eclipse to establish the difference in local time between their respective localities. The result showed a difference of approximately 1 hour between the two longitudes – very close to present-day calculations. In addition to this, Bīrūnī makes numerous references to Būzjānī’s measurements in his various works. Būzjānī’s principal astronomical work, and his sole extant writing on the subject, is Kitāb al-Majisṭī. The book consists of three chapters: trigonometry, application of spherical trigonometry to astronomy, and planetary theory. An incomplete manuscript of this work exists in the Bibliothèque nationale, Paris. A misinterpretation of a part of this book led Louis A. Sedillot (the French scientist) to claim that credit for discovering the variation (the third inequality) of the Moon’s motion belonged to Būzjānī, and not to Tycho Brahe. This gave rise to a long-lived debate in the French Academy of Science from 1837 to 1872. The case was finally resolved by Carra de Vaux, the prominent historian of science in Islam, who, after a thorough study of the manuscript in 1893, reasserted Brahe’s right to this discovery. Although Būzjānī’s al-Majisṭī – at least judging from the extant portion – did not introduce considerable theoretical novelties, it did Byrd, Mary Emma contain observational data that were used by many later astronomers. More importantly, its section on trigonometry was a comprehensive study of the subject, introducing proofs in a masterly way for the most important relations in both plane and spherical trigonometry. Būzjānī’s approach, at least in some instances, bears a striking resemblance to modern presentations. In al-Majisṭī, Būzjānī introduced for the first time the tangent function and hence facilitated the solutions to problems of the spherical right-angled triangle in his astronomical calculations. He also devised a new method for constructing the sine tables, which made his tables for sin 30′ more precise than those of his predecessors. This was an important advance, since the precision of astronomical calculations depends upon the precision of the sine tables. The sine table in Būzjānī’s Almagest was compiled at 15′ intervals and given to four sexagesimal places. In the sixth chapter of al-Majisṭī, Būzjānī defines the terms tangent, cotangent, sine, sine of the complement (cosine), secant and cosecant, establishing all the elementary relations between them. Then assuming the radius of the (trigonometric) circle R = 1, he deduces that the tangent will be equal to the ratio of the sine to the sine of complement, and the inverse for the cotangent (identical to our present terminology). Later, Bīrūnī, inspired by Būzjānī and for simplification, uses this norm of R = 1 instead of R = 60 which was up until then commonly used in compiling the tables. Būzjānī’s contributions to mathematics cover both theoretical and practical aspects of the science. His practical textbook on geometry, A Book on Those Geometric Constructions Which Are Necessary for a Craftsman, is unparalleled among the geometrical works of its kind written in the Islamic world. Būzjānī wrote a practical textbook on arithmetic as well. The book is entitled Book on What Is Necessary from the Science of Arithmetic for Scribes and Businessmen. This is apparently the first and only place where negative numbers have been employed in medieval Islamic texts. On the basis of works attributed to him, Būzjānī seems to have been a prolific scholar. He is said to have written 22 books and treatises. These include works on astronomy, arithmetic, and geometry, as well as translations and commentaries on the algebraic works of past masters like Diophantus and Khwārizmī, and a commentary on Euclid’s Elements. Of all these works, however, only eight (as far as we know) have survived. Of his astronomical works, references were made to a Zīj al-wāḍiḥ, an influential work that is no longer extant. Historical evidence, as well as the judgments of Būzjānī’s colleagues and generations of scholars who came after him, all attest to the fact that he was one of the greatest astronomers of his age. He was also said to have been a man with great moral virtues who dedicated his life to astronomy and mathematics. His endeavors in the domain of science did not die with him. In fact, the data Būzjānī had gathered from his observations were used by astronomers centuries after him. Furthermore, the science of trigonometry as it is today is much indebted to him for his work. In his honor and to his memory, a crater on the Moon has been named for Būzjānī. Behnaz Hashemipour Selected References al-Qiftī, Jamāl al-Dīn (1903). Ta’rīkh al-hukamā’, edited by J. Lippert. Leipzig: Theodor Weicher. Carra de Vaux (May–June 1892). “L’Almageste d’Abū’l Wéfā Alboūzdjānī.” Journal asiatique, 8th ser., 19: 408–471. Debarnot, Marie-Thérèse (1996). “Trigonometry.” In Encyclopedia of the History of Arabic Science, edited by Roshdi Rashed. Vol. 2, pp. 495–538. London: Routledge. Ghorbani, A. and M. A. Sheykhan (1992). Buzdjānī Nāmeh: The Biography and a Survey of Buzdjānī’s Mathematical Works. Tehran: Enqelab-e Eslami Publishing and Educational Organization. Gupta, R. C. (1992). “Abū al-Wafā’ and His Indian Rule about Regular Polygons.” Ganita Bhāratī 14: 57–61. Ibn al-Nadīm (1970). The Fihrist of al-Nadīm: A Tenth-Century Survey of Muslim Culture, edited and translated by Bayard Dodge. 2 Vols., Vol. 1, p. 83. New York: Columbia University Press. Kennedy, E. S. (1984). “Applied Mathematics in the Tenth Century: Abu’lWafā’ Calculates the Distance Baghdad–Mecca.” Historia Mathematica 11: 193–206. Kennedy, E. S. and Mustafa Mawaldi (1979). “Abū al-Wafā’ and the Heron Theorems.” Journal of the History of Arabic Science 3: 19–30. Kraemer, Joel L. (1992). Humanism in the Renaissance of Islam: The Cultural Revival During the Buyid Age. 2nd rev. ed. Leiden: E. J. Brill. Medovoi, M. I. (1960). “On the Arithmetic Treatise of Abū’l-Wafā’.” Studies in the History of Mathematics 13: 253–324. Pingree, David (1983). “Abu’l- Wafā’.” In Encyclopaedia Iranica, edited by Ehsan Yarshater. Vol. 1, pp. 392–394. London: Routledge and Kegan Paul. Saidan, Ahmad S. (1974). “The Arithmetic of Abū’l-Wafā’.” Isis 65: 367–375. Sesiano, Jacques (1998). “Le traité d’Abū’l-Wafā’ sur les carrés magiques.” Geschichte der Arabisch-Islamischen Wissenschaften 12: 121–244. Suter, H. (1960). “Abu ‘l-Wafā’ al-Būzadjānī.” In Encyclopaedia of Islam. 2nd ed. Vol. 1, p. 159. Leiden: E. J. Brill. Youschkevitch, A. P. (1970). “Abū’l-Wafā’ al-Būzjānī.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 1, pp. 39–43. New York: Charles Scribner’s Sons. Byrd, Mary Emma Born Died Le Roy, Michigan, USA, 15 November 1849 Lawrence, Kansas, USA, 30 July 1934 Mary Byrd directed the Smith College Observatory, determined the positions of comets by photographic astrometry, and pioneered the development of laboratory teaching methods in descriptive astronomy. Byrd’s father was an itinerant Congregational minister, the Reverend John Huntington Byrd; her mother was Elizabeth Adelaide Low. After age six, Byrd grew up in Kansas and later attended Oberlin College and the University of Michigan, where she earned an A.B. degree (1878). After four years as a teacher and a high-school principal, Byrd spent a year as a voluntary assistant at the Harvard College Observatory, under Edward Pickering. Between 1883 and 1887, she taught mathematics and astronomy at Carleton College, Northfield, Minnesota, and operated its time service under the supervision of William Payne. Byrd later earned her Ph.D. in astronomy at Carleton (1904). Like many women who chose to pursue a scientific career in that era, Byrd never married. In 1887, Byrd accepted the directorship of the Smith College Observatory, Northampton, Massachusetts. For nineteen years, she trained young women in science and developed laboratory methods of teaching descriptive astronomy (as opposed to B 189 190 B Byrd, Mary Emma standard lecture/recitation procedures). These were highlighted in Byrd’s Laboratory Manual of Astronomy (1899) and her First Observations in Astronomy (1913). An astute observer of changing educational practices and the declining influence of the liberal arts college’s classical curriculum, Byrd sought to place her subject on the same level as the new experimental subjects of physics and chemistry within the nation’s emergent research universities. Her own astronomical research concerned the photographic determination of the positions of comets. Collapse of the mental discipline model of pedagogy and the reduction of astronomy from a college prerequisite to an elective subject carried important implications for astronomy instructors in the years after 1900. Recognizing that a crucial link in the cycle of astronomy teaching and learning had been severed and must be reforged, Byrd looked to the nation’s normal schools as the place from which to recruit astronomy-literate teachers. She wrote prolifically to try and bridge apparent gaps in the pedagogical literature. Byrd abruptly resigned her position in 1906 after she learned that Smith College had agreed to accept financial support from Andrew Carnegie. Believing that such a decision severely compromised her institution’s freedom of expression, she undertook this action as a public protest. She was succeeded by Harriet Bigelow. Byrd was briefly associated with the Normal College of the City of New York (now Hunter College) but subsequently removed to her parents’ farm in Lawrence, Kansas. Nonetheless, she remained active in pedagogical reforms through the 1920s. Byrd was a member of the American Astronomical Society, the Astronomical Society of the Pacific, and the British Astronomical Association. Jordan D. Marché, II Selected References Bailey, Martha J. (1994). “Byrd, Mary Emma.” In American Women in Science: A Biographical Dictionary. Denver: ABC-CLIO, p. 46. Hoblit, Louise Barber (1934). “Mary E. Byrd.” Popular Astronomy 42: 496–498. Lankford, John (1997). American Astronomy: Community, Careers, and Power, 1859–1940. Chicago: University of Chicago Press, esp. pp. 318–319, 332. Marché II, Jordan D. (2002). “Mental Discipline, Curricular Reform, and the Decline of U. S. Astronomy Education, 1893–1920.” Astronomy Education Review 1: 58–75.