The character of the position which he thus won was entirely congenial to him, his somewhat reserved nature and methodical habits finding satisfaction in the retired life and orderly routine of the Observatory. His mathematical tastes led him to find pleasure in computations, and during the greater part of his nineteen years at Greenwich the reductions of the Circle observations, and, later, those of the Altazimuth and Equatorial observations, were carried out by him or under his superintendence. For over ten years the care of the library and manuscripts was also in his hands, and for nearly the whole of his time at the Observatory he was one of the four regular observers with the Transit-Circle and Altazimuth.

A series of more than thirty papers followed, dealing with the comparison of star places in different catalogues, their correction for systematic errors, the computation of proper motions, and other inquiries important in fundamental astronomy. These won him a reputation as an able and conscientious worker in this essential but less popular side of the science ...

The association of observers, especially the possessors of small telescopes, for mutual help, and their organisation in the work of astronomical observation, the circulation of current astronomical information, and the encouragement of popular interest in astronomy.

Here began his real life-work, for which his natural bent, his education at Dublin, and his experience at Greenwich had admirably fitted him. The quiet, withdrawn, old-world corner of Gray's Inn, the responsible routine of the computations for the "Seaman's Bible," varying so little from one year to another, were exactly fitted to his temperament. Of undoubted ability, shrewd, determined, and far-seeing, and possessed of a great amount of energy, the Nautical Almanac was in safe keeping in his hands, and during the years he held the post his mental alertness suggested a number of alterations and improvements which he carried out most successfully. In particular he greatly increased the number of "Nautical Almanac Stars," earning thereby the gratitude alike of astronomers, seamen, and surveyors. Under his hand also additions were made to the section of planetary satellites, and physical ephemerides of the planets were introduced. On the other hand, he witnessed the demise of "lunar distances," that hoary method that had well served its day and generation.

Methodical himself in all his work, punctilious and careful, cautious and straightforward in all official matters, he set the highest value on the work of his staff, and as a trained, practical observer knew how to insist on the need for extreme accuracy throughout the various calculations. To his knowledge of mathematics he added decided skill in computation, but although he was less liable than most men to make mistakes, he in no case allowed himself to dispense with the most scrupulous revision of any work that he had in hand. His extensive command of dates and figures did not, however, always save him from an occasional blunder, and it was a joke against him that on one occasion he "dated a cheque two years ahead, the cheque coming back with a notification that it was post-dated. After all, it was a natural mistake for one to make whose main work was wholly devoted to events due to occur some years ahead.

In addition to his strictly official work, the queries that were showered upon him were many and varied, relating to chronology, the calendar, eclipses, astronomical constants, the construction of the Nautical Almanac, and kindred matters. One inquirer perhaps wanted to know the exact time of some full moon of a century ago; another, its age on the night of the Gunpowder Plot. Or such inquiries might be made of him as, "What was the time of high water at Dover when Julius Caesar landed in August 55 B.C.?" Every inquiry of a sensible character received prompt attention, and even faddists and cranks were kindly dealt with when their peculiarities were confined within certain prescribed limits.

An extensive piece of work which occupied seven years of his official life was his revision of Taylor's General Catalogue of 11,000 Stars for the Equinox, 1835.0, from Observations made at Madras Observatory, 1831 to 1842. This work was a natural sequel to the numerous and important contributions he had made in previous years to this branch of sidereal astronomy. In his preface he says "That his (Taylor's) work may now be rendered more useful to astronomy is the reward for which I hope in the publication of this revised edition," and that aim and hope illustrate the keynote of his character. He found the question of the expected reappearance of the Leonids an interesting and profitable study for several years, during which he collaborated with the late Dr Johnstone Stoney in an attempt to construct an ephemeris of the densest portion of the swarm. The calculations appertaining to this were made at H.M. Nautical Almanac Office under his superintendence, and went to show that the failure of the shower to reappear at the end of last century was probably due to the perturbations of the meteors by the action of Jupiter, Saturn, and Uranus, while the meteors were travelling at a great distance from the Sun. The main body of the swarm was thus made to pass at a distance of nearly $1\large\frac{3}{4}\normalsize$ millions of miles from the Earth's orbit.

Downing's term of office at Gray's Inn was marked by special efforts at cooperation between similar departments in other countries with the view of avoiding duplication of work, and led to the holding in Paris, in 1896 May, of an International Conference on Fundamental Stars, and the results of the Conference, the inauguration of which was due to him, were far-reaching.

In later years illness troubled Dr Downing considerably and appeared to intensify his natural reserve. He retired from the Nautical Almanac in 1910 on completing the sixtieth year of his age. It is the testimony of a member of his staff who was with him throughout the years of his Superintendency, that "he was at all times fair, courteous, and considerate; he always consulted the interests of his staff, and was in every worthy movement a sympathetic helper."

Vice-President of the Royal Astronomical Society. President of the British Astronomical Association. Superintendent of the Nature Almanac. Author of the following papers, among many others, which have appeared in the 'Monthly Notices' of the Royal Astronomical Society: - 'Proper Motions of Certain Stars in the Greenwich Seven Catalogue for 1860' (vol xl, p 85); 'The Greenwich Standard Right Ascensions' (vol xl, p 430); 'The Possible Ten-month Period of Variation in Latitude' (vol xl, p 430); 'On the NPD's of the Cape Catalogue for 1880, and on the Greenwich and Cape Mean Systems of North Polar Distances' (vol xlii, p 20); 'Discussion of the Observations of gamma Draconis, made with the Greenwich Reflex Zenith Tube, during the years 1857-1875' (vol xlii, p 326); 'On the relative Motion of the Components of 'p' Eridani (vol xliii, p 263); 'On the Orbit of gamma Coronae Australis' (vol xliii, p 368); 'On the Periodic Time of alpha Centauri' (vol xlv, p 151); 'A Comparison of the Star Places of the Argentine General Catalogue for 1875 with those of the Cape Catalogue, 1880' (vol xlvii, p 446); 'Positions for 1750 and Proper Motions of 154 Stars, S of -29 degrees dec, from a revision of Powalky's Reduction of the Star Places of Lacaille's Astronomiae Fundamenta' (vol xlviii, p 322); 'Discussion of Washington Observations of the Sun, 1875-1883' (vol xlix, p 431); 'Corrections to the Orbit of Juno' (vol 1, p 487); 'The Orbit of Flora, with corrections to Brunnow's Tafeln der Flora' (vol lii, p 585).

Reviewing Dr Downing's career as a whole, it might be summed up by saying that the talents he displayed were sober and solid rather than brilliant, but the useful work which he accomplished entitles him to an honourable place among professional astronomers.