Downing, Arthur Matthew Weld
Born Carlow, Ireland, 13 April 1850
Died London, England, 8 December 1917
As an astronomer whose entire career was at the Royal Greenwich Observatory and the Nautical Almanac Office of Great Britain, Downing was concerned with the precise position and motion of astronomical objects. Those who knew him well remarked that his “reserved nature and methodical habits” made him an ideal person for the work that occupied him in these positions.
Downing, the younger son of Arthur Matthew Downing and Mary (Weld) Downing, was born about 90 km southwest of Dublin; attended Nutgrove, a well-known school nearby; and went to Trinity College, Dublin, where he received his B.A. degree in 1871. Subsequently, his alma mater awarded him an M.A. in 1881, and an honorary D.Sc. in 1893.
After graduating at the top of his year in mathematics, Downing was successful in an open competition for the position of assistant at the Royal Observatory, Greenwich. He began his duties there in January 1873 and after rising to the position of first-class assistant and superintendent of computations, remained there until the end of 1891. His work aided in understanding the contribution of various instrumental and human factors to minute errors in the cataloged positions of the stars, the Sun, and the Moon.
During his Greenwich years, Downing’s publications covered such topics as the radii of Venus and Mars, errors in transit times of the Sun and stars, proper motion, observations of the 1878 transit of Mercury, and discussion of the orbits of some visual binary stars and asteroids. In a dozen papers, he compared star catalogs, mainly those made at southern hemisphere observatories.
With such a background, Downing was a logical choice to succeed John Hind as the superintendent of the Nautical Almanac at the end of 1891. Right away, he began to introduce changes, though always with care and circumspection. Even in the first Nautical Almanacfor which he was responsible, for the year 1896, he introduced several innovations. The data that was most required by ship masters was published separately in a low-cost volume. In the complete almanac, which included data of importance to astronomers, the general constants were revised necessitating a great deal of computation. As well, occultation data was presented in a form conducive to easy calculation for any point on Earth. From 1892 to 1910, Downing frequently published papers in the Monthly Notices of the Royal Astronomical Societyrelevant to his work at the Nautical Almanac Office, comparing and correcting star catalogs and tables of the Sun, Moon, and planets.
Downing also promoted the idea of co-operation with other national almanacs and began collaborating with Simon Newcomb , his American counterpart, in 1893. According to Newcomb, Downing took the initiative in 1895 of “proposing an international conference of the directors of the four leading ephemerides, to agree upon a uniform system of data for all computations pertaining to the fixed stars.” This was held in Paris in May, 1896.
Perhaps Downing’s best known papers were written in 1899 in collaboration with George Stoney who had been investigating the Leonid meteor shower since 1896. The Leonids had been spectacular in 1833 and 1866, and were expected to give a repeat performance in November 1899. Together, Stoney and Downing studied the perturbations of the swarm of particles orbiting the Sun which gives rise to these famous meteor showers. The computations took account of the attraction of Mars, Jupiter, Saturn, and Uranus, and were carried out under Downing’s supervision by staff of the Nautical Almanac Office with financial support from the Royal Society. Stoney and Downing found that the cloud of particles was greatly lengthened along its orbit, with the main part likely to miss the Earth. Similar results were independently arrived at in Germany by Adolf Berberich. The renowned astrophotographer, Isaac Roberts , used an ephemeris produced by Stoney and Downing to attempt several times to photograph the particle cloud in space, but was always unsuccessful, and the Leonid showers in 1899 and 1900 were very sparse. Though Stoney’s and Downing’s original paper was presented to the Royal Society on 2 March 1899, it was never published there, perhaps, because it could not appear in a timely fashion. It was, however, published in three other international journals and gained widespread attention.
Subsequently, Downing alone wrote a somewhat similar paper, “The Perturbations of the Bielid Meteors,” which was published in Proceedings A of the Royal Societyin 1905. In it, he predicted that the main concentration of meteoric particles would not intersect the Earth, and in fact, the Bielid shower proved to be disappointing, just as the Leonids were 5 or 6 years earlier.
Downing apparently left the British Isles on only three occasions. Besides the conference in Paris already mentioned, he also traveled to the continent to observe two solar eclipses, the first in Norway in August 1896, accompanied by his daughter, Mabel. Perhaps stung by the poor weather he experienced on that occasion, he determined to help those planning an expedition to India in 1898. He asked Indian meteorologists about the weather prospects for the solar eclipse there in January 1898 and in March 1897 presented a paper to the Royal Astronomical Society (RAS) on cloud statistics for the path of totality – an early example of systematic meteorological records being used to select appropriate sites in advance. When he traveled to his second total solar eclipse in Spain in 1900, this time accompanied by wife, Ellen Jane, his experience was perfect.
In 1877, Downing became a Fellow of the RAS and served on its council for most of his career, including a term as Secretary from 1889 to 1892. Besides his frequent contributions to the Society’s Monthly Notices, he also contributed articles to The Observatorymagazine and from 1885 through 1887 served as one of its editors. Downing was an 1890 founding member of the British Astronomical Association, whose members were mainly amateur aficionados. He took on many duties in the association, contributing to its Journaland serving as its President from 1892 to 1894. In 1896, he received his greatest honor – fellowship in the Royal Society.
After retirement from the Almanac office on his sixtieth birthday, Downing lived quietly in Lewisham, very near Greenwich and his former home in Blackheath. He died in London, from angina, 7 years later.
Downing’s role at Greenwich can be followed through annual Reports of the Astronomer Royal to the Board of Visitorsand summaries of these reports published in the Astronomical Register.Hundreds of Downing’s letters are in the Archives of the RAS and in the Archives of the Royal Greenwich Observatory, Cambridge University Library.
- George A. Wilkins, “Downing, Arthur Matthew Weld,” Oxford Dictionary of National Biography, Oxford University Press, 2004.Google Scholar
- McKenna, Susan M. P. “Downing, Arthur Matthew Weld,” in Gillispie, C. G. (ed.) Dictionary of Scientific Biography4, 175–77 and republished online in Complete Dictionary of Scientific Biography.Gale, 2008.Google Scholar
- Newcomb, Simon. The Reminiscences of an Astronomer. Boston: Houghton Mifflin, 1903, 229–31.Google Scholar