chimneys of Westminster Palace. A paper on suspension bridges, contributed in 1867 to the Institution of Civil Engineers, was honoured with the Telford medal; and he delivered in 1869 a set of lectures on magnetism in the university of Cambridge, besides at sundry times numerous discourses to the general public. He failed in 1853 to obtain the office of superintendent of the Nautical Almanac, although 'willing to take it at a low rate for the addition to my salary.'
Airy was elected a fellow of the Royal Society on 21 Jan. 1836, frequently sat on the council, and was president 1872-73. He occupied the same post in the Royal Astronomical Society during five biennial periods, and presided over the British Association at its Ipswich meeting in 1851. He became a member of the Cambridge Philosophical Society in 1823, and later of the Institution of Civil Engineers, of the Royal Society of Edinburgh, of the Royal Irish Academy, and of several foreign scientific bodies. On 18 March 1872 he succeeded Sir John Herschel as one of eight foreign members of the French Institute ; he was presented in 1875 with the freedom of the city of London, was created D.C.L. of Oxford (20 June 1844), LL.D. of Cambridge (1862) and Edinburgh, and decided honorary fellow of Trinity College, Cambridge. The czar Nicholas sent him a gold medal specially struck; and among the orders conferred upon him were those of Pour le Mérite of Prussia, of the Legion of Honour, of the North Star of Sweden, of the Dannebrog, and of the Rose of Brazil. On 17 May 1871 he was appointed companion of the Bath, and, a year later (17 June 1872), was promoted to be knight commander. His wife died on 13 Aug. 1875, and on the ground of the lapse of her pension Airy obtained an augmentation of his salary to 1,200l. yearly.
Airy was an indefatigable traveller. In 1829 he inspected the observatories of Turin, Milan, Bologna, and Florence; in 1835 examined the Markree refractor in Ireland, and in 1848 elaborately tested the great Parsonstown reflector. In 1846 he visited Hansen at Gotha, Gauss at GÖttingen, and Caroline Lucretia Herschel [q.v.] at Hanover; in 1847 spent a month at Pulkowa with Otto Struve, and, returning by Berlin and Hamburg, saw Humboldt, Galle, Repsold, and Rtimker. He entered into correspondence with Leverrier in June 1816 about the still unseen planet Neptune, and on 9 July suggested to Professor Challis a plan of search. In the following year he escorted Leverrier to the meeting of the British Association at Oxford. His unjustifiable coldness to John Couch Adams [q.v. Suppl.] was doubtless due to the embarrassments that followed his accidental yet regrettable omission to pay due attention to the letter in which Adams communicated to him the progress of his Neptune investigation.
Airy resigned the office of astronomer royal on 15 Aug. 1881, and resided thenceforward, with his two unmarried daughters, at the White House, close to Greenwich Park, and at Playford, where he had bought a cottage in 1845. His main desire was to complete the 'Numerical Lunar Theory,' upon which he had been engaged from 1872. Printed in 1886, the colossal performance proved, however, to be undermined by unexplained errors. 'With painful alarm,' the aged author noted in the preface, 'I find that the equations are not satisfied, and that the discordance is large.' After two years of hopeless struggle, he desisted from efforts towards correction which have not been re-newed. He continued to enjoy excursions to Cumberland and Playford, but a fall on 11 Nov. 1891 produced an internal injury necessitating a surgical operation, which he survived only a few days. He died at the White House on 2 Jan. 1892, and was buried in Playford churchyard.
'He was of medium stature,' Mr. Wilfrid Airy writes, 'and not powerfully built.' 'The ruling feature of his character was order. From the time that he went up to Cambridge to the end of his life his system of order was strictly maintained.' He enforced it upon himself no less rigidly than upon his subordinates, and kept up at the Royal Observatory a cast-iron discipline, which powerfully contributed to the efficiency of his administration. He never destroyed a document, but devised an ingenious plan of easy reference to the huge bulk of his papers. In his decrepitude this methodical bent tyrannised over him, and 'he seemed more anxious to put letters into their proper place than to master their contents.' 'His nature was eminently practical, and his dislike of mere theoretical problems and investigations was proportionately great. He was continually at war with some of the resident Cambridge mathematicians on this subject. Year after year he criticised the Senate House papers and the Smith's Prize papers very severely, and conducted an interesting and acrimonious private correspondence with Professor Cayley on the same subject.' A very important feature of his investigations was their thoroughness. 'He was never satisfied with leaving a result as a barren mathematical expression. He would reduce it, if possible, to a practical and
