by H. Spencer Jones, rev. Isobel Falconer
© Oxford University Press 2004 All rights reserved
Brown, Ernest William (1866-1938), mathematician and astronomer, was born on 29 November 1866 at Hull, the second child and elder son of William Brown, farmer, and later a lumber merchant of Hull, and his wife, Emma Martin. Educated at the Hull and East Riding College, he entered Christ's College, Cambridge, as a scholar in 1884. He was sixth wrangler in the mathematical tripos of 1887 and was elected a fellow of Christ's in 1889. At the suggestion of George Darwin he took up in 1888 the study of the American astronomer George William Hill's papers on the lunar theory. This led him to what was to prove his life's work: for the next twenty years he gave little thought to other research and it remained his favourite subject during the thirty years that came after. In 1891 he went to the United States of America as professor of applied mathematics at Haverford College, Pennsylvania; in 1907 he was appointed professor of mathematics at Yale University, retiring in 1932, on account of ill health, with the title of emeritus professor. He retained his connection with Cambridge and with Christ's College, spending a part of almost every summer there. He was elected an honorary fellow of Christ's in 1911.
In 1896 Brown published An Introductory Treatise on the Lunar Theory, containing a critical examination of the various methods of predicting the motion of the moon. His own theory was a development of Hill's method. The main results were published in five parts in the Memoirs of the Royal Astronomical Society between 1897 and 1908. For an essay on the direct planetary perturbations of the moon he was awarded, in 1907, the Adams prize of the University of Cambridge. The heavy task of reducing the theory to tables was begun in 1908, the numerical values of the constants used in the tables being obtained from comparison of the theory with the Greenwich observations of the moon (some 20,000 in number) from 1750 to 1900. His monumental Tables of the Motion of the Moon in three volumes were published in 1919, and were for many years employed to calculate the moon's place in the Nautical Almanac.
The completeness and accuracy of Brown's theory enabled one of the most pressing problems in gravitational astronomy to be decided. Comparison between the moon's observed positions and the earlier theory of Petrus Andreas Hansen had shown large fluctuations, which could not be explained by any known gravitational cause but which might have arisen from errors or incompleteness in the theory. Comparison with Brown's Tables soon showed that the moon's observed positions were not accurately represented by the theory. Brown suggested that the cause was a variable rate of rotation of the earth and obtained evidence in support of this view, which has since been conclusively established. In order to improve the observed positions of the moon, he organized a worldwide programme for the observation and reduction of occultations of stars by the moon. In his later years he made significant contributions to various problems in celestial mechanics, mainly concerned with planetary theory.
Brown was elected FRS in 1898. He was awarded the gold medal of the Royal Astronomical Society in 1907; the Pontecoulant prize of the Paris Academy of Sciences in 1909; a royal medal of the Royal Society in 1914; the Bruce medal of the Astronomical Society of the Pacific in 1920; and the Watson medal of the National Academy of Sciences, Washington, in 1937. He received honorary degrees from the universities of Adelaide (1914), Yale (1933), Columbia (1934), and McGill (1936). He never married. He died at Yale observatory, New Haven, Connecticut, on 22 July 1938.
H. SPENCER JONES, rev. ISOBEL FALCONER
Sources
C. G. Darwin, Obits. FRS, 3 (1939-41), 19-22
private information (1949)
personal knowledge (1949)
election certificate, RS
CGPLA Eng. & Wales (1938)
Likenesses
Moull & Fox, photograph, RS
Phillips, photograph, RS
photograph, repro. in Darwin, Obits. FRS, facing p. 19
Wealth at death
£787 13s. 0d.: administration with will, 20 Dec 1938, CGPLA Eng. & Wales
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