by George A. Wilkins
© Oxford University Press 2004 All rights reserved
Downing, Arthur Matthew Weld (1850-1917), mathematician and astronomer, was born on 13 April 1850 at Carlow, Ireland, the younger son of Arthur Matthew Downing (b. 1809/10), and his wife, Mary Weld. He was educated at Nutgrove, then a well-known school near Rathfarnham, co. Dublin, and at Trinity College, Dublin, which he entered in November 1866. He specialized in mathematics and graduated in 1871, in which year he won a scholarship in science. In the following year he was successful in an open competition for appointment as an assistant at the Royal Observatory, Greenwich, and he commenced his duties in January 1873.
Downing remained at the observatory for nineteen years, during which time he was concerned primarily with the accurate determination of the positions and motions of stars from very precise measurements made with a variety of astrometric telescopes. He observed regularly for most of this time, but his main concern was with the onerous computations that were required to derive the data published in the catalogues from, for example, the observed times and angular altitudes of the stars as they crossed the spider thread of the telescope. It was necessary to analyse the data to determine the errors of the measurements and to improve the mathematical models that related the telescope on the earth, as it rotated on its axis and revolved around the sun, to the reference frame of the star catalogue.
The principal products of this work were the published star catalogues and the improved accuracy of the determinations of Greenwich time, but Downing also wrote more than fifty scientific papers. The value of his work was recognized by the granting in 1893 of an honorary degree of DSc by Trinity College, Dublin, and by his election in 1896 as a fellow of the Royal Society.
On 1 January 1892 Downing took up the post of superintendent of the Nautical Almanac following the resignation of Dr J. Russell Hind. At that time the Nautical Almanac office was separate from the Greenwich observatory. Hind had been largely content to leave the almanac unchanged from year to year, but Downing introduced improvements, such as those suggested by the Royal Astronomical Society in 1891, as opportunities arose. He continued to make other investigations; he predicted, correctly, but too late for publication, that the Leonid meteor shower in 1899 would be very disappointing.
In the first edition of the Nautical Almanac and Astronomical Ephemeris for which he was responsible, that for 1896, Downing announced that its first part, which contained the data that were needed by navigators at sea for the determination of their positions, would be published separately so that seamen would not need to pay for, or carry, the high-precision data provided for the use of astronomers. In the preface to the edition for 1907 he announced that the tabulations of 'lunar distances', which had been the principal innovation in the first edition for 1767, had been omitted; the widespread use of accurate chronometers had made them unnecessary.
Downing was a major participant in the International Conference on Fundamental Stars that was held at the Paris observatory in 1896. The conference adopted several resolutions concerning the computation and publication of star positions and also led to the adoption for the British and American almanacs of new theories for the computation of the ephemerides of the planets. Downing was strongly criticized by some astronomers for introducing these changes in the edition for 1901 without formally consulting the Royal Astronomical Society, but his decisions were upheld. He retired from the post of superintendent on reaching the age of sixty.
In common with other astronomers at the Greenwich observatory, Downing took an active interest in the affairs of the Royal Astronomical Society and was one of its secretaries (1889-92); he subsequently served as a vice-president. He was one of the founder members of the British Astronomical Association, which was primarily for amateur astronomers, and he served as its president in 1893-5. He organized its first eclipse expedition to the Scandinavian Arctic in 1896 and contributed many articles and unsigned items to its Journal and other publications. Some of these would almost certainly have been prompted by the many enquiries that he dealt with in the Nautical Almanac office.
Downing was methodical and careful in all his work, and he was fair, courteous, and considerate in his relations with his staff. After his retirement he suffered increasingly from heart disease, and he died at 30 New Oxford Street, Bloomsbury, on 8 December 1917, leaving a widow, Ellen Jane Downing, and their only child, a married daughter. He was cremated on 13 December at Golders Green crematorium.
GEORGE A. WILKINS
Sources
W. F. D. [W. F. Dyson] and E. W. M. [E. W. Maunder], Monthly Notices of the Royal Astronomical Society, 78 (1917-18), 241-4
A. S. D. Maunder, Journal of the British Astronomical Association, 28 (1917-18), 67-9, 72-3
A. C. D. Crommelin, Nature, 100 (1917-18), 308-9
History of the Royal Astronomical Society, [1]: 1820-1920, ed. J. L. E. Dreyer and H. H. Turner (1923), 217-18
d. cert.
Boase, Mod. Eng. biog.
Boylan
Archives
CUL, archives of the Royal Greenwich Observatory
RAS, letters to Royal Astronomical Society
Wealth at death
£1584 4s. 6d.: probate, 1 Feb 1918, CGPLA Eng. & Wales
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