Airy, Sir George Biddell

by Allan Chapman

© Oxford University Press 2004 All rights reserved

Airy, Sir George Biddell (1801-1892), astronomer, was born at Alnwick, Northumberland, on 27 July 1801, the eldest of the four children of William Airy (1749-1827), of Luddington in Lincolnshire. His mother, Ann Biddell (d. 1841), a woman of strong character and natural abilities, was the daughter of a well-to-do farmer from near Bury St Edmunds, Suffolk. The Airys were an old family claiming descent from Thomas Ayray (fl. c.1350), but which had fallen on hard times by the eighteenth century. William Airy was a man of extraordinary gifts, and memory, who had risen from being a farm labourer to collector of excise in Northumberland, whence he was transferred to Hereford in 1802, and to Essex in 1810. Three years later he lost his appointment and lapsed into poverty. These events deeply influenced his son, and it is likely that the concern with public accountability which was such a trait in the latter's career stemmed from it.

When he was ten years old Airy took first place in Byatt Walker's school at Colchester. From 1812 he spent his holidays at Playford, near Ipswich, with his uncle Arthur Biddell, a farmer and valuer, whose influence on his career proved decisive. In Biddell's library he was able to study optics, chemistry, and mechanics, and he met there Thomas Clarkson, Bernard Barton, William Cubitt, and Robert and James Ransome. From 1814 to 1819 Airy attended the grammar school at Colchester, where he was noted for his memory, repeating at one examination 1394 lines of Latin verse; in his teens he garnered much miscellaneous information from his father's books. On Clarkson's advice he was sent to Cambridge, and entered as a sizar of Trinity College in October 1819. In 1822 he took a scholarship, and in 1823 graduated as senior wrangler and first Smith's prizeman. On his election to a fellowship of his college in October 1824 he became assistant mathematical tutor. He delivered lectures, took pupils, and pursued original scientific investigation.

Teaching at Cambridge
Airy's Mathematical Tracts on Physical Astronomy was published in 1826, and it immediately became a textbook in the university. An essay on the wave theory of light was appended to the second edition in 1831. For his various optical researches, chiefly contained in papers laid before the Cambridge Philosophical Society, Airy received in 1831 the Copley medal from the Royal Society. He was admitted to membership of the Astronomical and Geological societies respectively in 1828 and 1829, and was awarded in 1833 the gold medal of the former body for his detection of the 'long inequality' in the orbits of Venus and the earth, communicated to the Royal Society on 24 November 1831. The Lalande prize followed in 1834, and on 9 January 1835 Airy was elected a correspondent of the Académie Royale des Sciences. But he was not elected FRS until 21 January 1836 (after becoming astronomer royal); he was then immediately taken on to the council. It is hard to explain his long-delayed election to the Royal Society, for he already enjoyed an international scientific reputation and had many close friends who were fellows. It is likely that the high cost of fellowship (£50) was the main obstacle, for Airy was always fastidious about money and perceived himself as a relatively poor man.

In the winter of 1823-4 Airy stayed in London with James South, met Sir Humphry Davy and John Herschel, and had his first experience of practical astronomy at South's large private observatory at Blackman Street, Southwark. During a walking tour in Derbyshire in July 1824 he proposed, after two days' acquaintance, to Richarda (1804-1875), the eldest daughter of the Revd Richard Smith, a former fellow of Trinity and incumbent of Edensor, near Chatsworth. Richarda was a great beauty, and Airy later recorded: 'Our eyes met ... and my fate was sealed ... I felt irresistibly that we must be united' ('Family history of G. B. Airy', Enid Airy MSS, 41). He was gently refused, pending the improvement of his permanent financial prospects. Thenceforth he concentrated his efforts upon securing a position in life and an income. In 1825 and 1826 he led reading parties to Keswick, Swansea, and Orléans, usually at a fee of about £42 per student; on the first occasion he saw much of the poets Southey and Wordsworth, and on the second made the acquaintance in Paris of Laplace, Arago, Pouillet, and Bouvard.

Chairs at Cambridge
On 7 December 1826 Airy was elected Lucasian professor of mathematics at Cambridge, but the emoluments of the office--£99 per annum, with £100 as ex officio member of the board of longitude--only slightly exceeded those of his relinquished college tutorship. Airy was anxious to obtain a chair in so far as it offered release from his bachelor fellowship, with the prospect of making a sufficient income to marry. He renewed the prestige of the Lucasian chair by his ardour for the promotion of experimental physics in the university. In his lectures on light he first drew attention to the defect of vision subsequently called 'astigmatism', from which he personally suffered. As a deeply practical man, Airy went on to develop an early form of spectacles with which to correct this condition. A trip to Dublin in 1827 in quest of the vacant post of astronomer royal in Ireland was fruitless. But on 6 February 1828, and after an adroit act of brinkmanship with the Cambridge University senate, he succeeded Robert Woodhouse as Plumian professor of astronomy and director of the newly established Cambridge University observatory, with the salary increased from £300 to £500 per annum. He now had an income and a residence that was sufficient to persuade Revd Smith of his ability to maintain his daughter, and Airy married Richarda Smith on 24 March 1830. At the Cambridge observatory he introduced an improved system of meridian observations, afterwards continued at Greenwich and partially adopted abroad, and set the example of thoroughly reducing them before publication.

In addition to superintending the erection of the meridian instruments at Cambridge, Airy devised the equatorial mount for the Cauchoix 12 inch object glass, which was presented in 1833 to the observatory by the duke of Northumberland--the famous Northumberland refractor. In February 1835 Sir Robert Peel offered Airy a civil-list pension of £300 a year, which, by his request, was settled on his wife. And on 18 June that year he accepted the post of astronomer royal, for which Lord Melbourne designated him in succession to John Pond, after much negotiation. Airy insisted that the salary should be increased from £600 to £800 per annum.

Astronomer royal
Airy's tenure of the office of astronomer royal lasted forty-six years, and was marked by extraordinary energy. Although he bargained hard for his salaries, he gave total and devoted service in return, seeing himself as a thoroughly professional scientist. He completely re-equipped the Royal Greenwich Observatory with instruments designed by himself. The erection in 1847 of an altazimuth instrument for observing the position of the moon in every part of the sky proved of great importance for the correction of lunar tables. A new meridian transit circle of unprecedented optical power and mechanical stability was mounted in 1851, and a reflex zenith tube replaced Troughton's zenith sector in the same year.

Airy saw the 'staple and standard' work of the Greenwich observatory as the construction of critically accurate tables and maps of stellar and planetary positions. These tables, recorded to fractions of a single second of arc, could then be used by the Royal Navy and by other scientific bodies involved in navigation or astronomical research. But by 1859 other branches of astronomy, requiring great telescopic power rather than just positional measurement, were becoming important in international astronomy, and in that year Airy inaugurated the installation of a 13 inch aperture equatorial refracting telescope, with optics by Merz of Munich, to give Greenwich an enhanced capacity in physical astronomy. While Airy believed that 'by both reason and tradition' Greenwich was a meridian observatory, he was assiduous in keeping up to date. In 1838 he created at Greenwich a magnetic and meteorological department, where from 1848 he employed Brooke's system of photographic registration, as superior to the earlier and immensely tedious method of manual recording. From 1854 the meridian transit of stars was recorded electrically, thereby greatly reducing the personal errors of the individual astronomers who made the observations, and from the same time the observatory began to send electrical signals down the commercial telegraph network to broadcast Greenwich mean time signals across Britain. Spectroscopic observations were organized in 1868, and the prismatic mapping of solar prominences began in 1874. The Kew photoheliograph began a daily record of sunspots in 1873. One of Airy's abiding precepts was that an astronomical observation that had not been mathematically reduced was useless, and when he came into office at Greenwich he resolved to reduce and publish the backlog of outstanding lunar and planetary observations made at the observatory between 1750 and 1830. For this he received the gold medal of the Royal Astronomical Society in 1846 and a testimonial in 1848. The resulting body of published data would provide an invaluable source for researches into celestial mechanics.

Expeditions
Airy observed the total solar eclipse of 8 July 1842 from Mount Superga, near Turin, and it was this eclipse which provided astronomers with the decisive confirmation of the existence of the solar prominences. Airy also observed the total eclipse of 28 July 1851 from Göteborg in Sweden. He then visited Uppsala, was received in audience by King Oscar at Stockholm, and on the return journey inspected the pumping engines at Haarlem. For the eclipse of 18 July 1860 in Spain he organized a cosmopolitan expedition, which he conveyed to Bilbao and Santander in the troopship Himalaya, placed at his disposal by the Admiralty.

In the autumn of 1854 Airy superintended an elaborate series of pendulum experiments for the purpose of measuring the increase of gravity with descent below the earth's surface. Similar attempts made by him in the Dolcoath mine, Cornwall, in 1826 and 1828, with the co-operation of William Whewell and Richard Sheepshanks, had been accidentally frustrated. He now renewed them in the Harton colliery, near South Shields, at a depth of 1260 feet. Although his value for 'G', the gravitational constant, was excessive, Airy used telegraphic apparatus to obtain a consistent time signal between the pendulums at the top and bottom of Harton pit.

The preparations for the observations of the transit of Venus in 1874 were laborious; Airy had control of the various British expeditions, and he provided twenty-three telescopes and undertook the preliminary work at the Greenwich observatory and the subsequent reduction of the vast mass of collected data. The volume embodying them was issued in 1881.

Greenwich meridian
Airy was always assiduous in maintaining the primacy of the Greenwich observatory in matters pertaining to navigation. In 1838, the same year as he set up a magnetic department, he commenced a series of experiments to study the influence of the hulls of iron ships upon their compasses, and the system of correction which he devised remained in use for decades thereafter. He was keen to determine the longitudes of as many places as possible with reference to the Greenwich meridian. At first he used chronometers, and by the mid-1850s was employing the instantaneous signals of the electric telegraph to relate to Greenwich not only important maritime places in the British Isles, such as Valentia in western Ireland, but the state observatories of Paris, Brussels, Vienna, Washington, and elsewhere. The primacy of the Greenwich meridian which developed from Airy's astronomical and geodetic work played a major part in its being accepted in 1884 as the international zero longitude and prime meridian of the world.

Adviser to government
His extraordinary industry and capacity for business enabled Airy to accomplish a wide range of official tasks. Indeed, he became something of a universal adviser to the government on matters involving physical science. These included the weights and measures commission (1838-42), of which he was chairman, and the tidal harbours commission. He was actively involved in the improvement of lighthouses, and advised and sometimes trained the officers who surveyed the Maine, New Brunswick, and Oregon boundaries. In 1845 his work on the railway gauge commission helped to provide the evidence from which parliament decided upon the 'standard gauge' of 4 feet 81Ú2 inches for future British railways. He settled the provisions for the sale of gas, reduced the tidal observations of Ireland and India, and was consulted on the launch of the steamship Great Eastern, Charles Babbage's calculating engine, the smoky chimneys of the palace of Westminster, the design of Big Ben, and the laying of the Atlantic telegraph cable. Airy's work on the stresses within beams still has a major place in modern civil engineering design, and his paper on suspension bridges to the Institution of Civil Engineers in 1867 gained him the Telford medal. One of his few failures came in 1850, when he was refused the superintendentship of the Nautical Almanac, in spite of being 'willing to take it at a low rate for the addition to my salary' of astronomer royal. The job went to his former assistant, John Russell Hind. Airy was constantly active as a lecturer and an author. His published works, including books, official reports, major research papers, authoritative encyclopaedia chapters, and high-quality articles for The Athenaeum and other magazines, exceeded 500 items.

Honours and awards
Airy was president of the Royal Society during 1872-3. He presided over the Royal Astronomical Society for four terms, and 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. In 1875 he was proud to be presented with the freedom of the City of London. He was created a DCL of Oxford on 20 June 1844 (though he refused to pay the fee of 6 guineas) and an LLD of Cambridge (1862) and Edinburgh, and was elected honorary fellow of Trinity College, Cambridge. Tsar Nicholas sent him a gold medal specially struck, and the foreign honours conferred upon him included the order of merit of Prussia, the Légion d'honneur, the North Star of Sweden, the Dannebrog, and 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 knight commander. But these honours came only after Airy had turned down three previous offers of a knighthood, in 1835 (on the grounds that he was too poor), in 1847, and in 1863 (because a £30 fee was involved).

Airy was an indefatigable traveller. In 1829 he inspected the observatories of Turin, Milan, Bologna, and Florence. In 1835 he examined the new 13.3 inch refractor at Markree, co. Sligo, and in 1848 elaborately tested the great Birr Castle reflector, also in Ireland. In 1846 he visited Hans Pieter Hansen at Gotha, Johann Gauss at Göttingen, and Caroline Lucretia Herschel at Hanover; in 1847 he spent a month at Pulkovo, St Petersburg, with Otto Struve, and, returning by Berlin and Hamburg, saw Alexander von Humboldt, Johann Galle, Adolf Repsold, and Carl Rumker. He entered into correspondence with Jean J. U. Le Verrier in June 1846 about the still unseen planet Neptune, and on 9 July suggested to Professor James Challis at Cambridge a plan of search. It is unfortunate, however, that Airy became posterity's scapegoat for Britain's failure to discover Neptune in 1845 on the basis of John Couch Adams's calculations, a year before its actual discovery in Berlin using Le Verrier's co-ordinates. But it must not be forgotten that Adams failed to supply Airy with adequate data in 1845, and did not reply to Airy's letters requesting them.

Retirement
Airy resigned the office of astronomer royal on 15 August 1881, and resided thereafter with his two unmarried daughters at the White House, Croom's Hill, close to Greenwich Park, and at Playford, where he had bought a cottage in 1845. His wife had died on 13 August 1875, after several years of illness following a stroke. On the lapse of her civil-list pension Airy's salary was augmented to £1200 per annum. His main desire in retirement was to complete the 'numerical lunar theory', upon which he had been engaged from 1872. Although it was printed in 1886, the work was soon after recognized by Airy to be seriously flawed, so 'that the equations are not satisfied'. He continued to enjoy excursions to Cumberland and Playford, but a fall on 11 November 1891 produced an internal injury necessitating a surgical operation, which he survived only a few days. He died at the White House on 2 January 1892, and was buried on 7 January alongside his wife and three deceased children in Playford churchyard. Six children survived him.

In appearance, Airy was of medium stature and, while not powerfully built, possessed great powers of endurance. Even his infirmities became subjects for investigation, however; in Philosophical Transactions of the Royal Society (1870) Airy and his son Hubert, a physician, wrote one of the clinically definitive papers on migraine. The image of Airy which has come down from his Autobiography (1896), and from the reminiscences of some of his contemporaries, is that of a stern workaholic. An acquaintance with Greenwich observatory archives and with private family papers, however, adds depth to this two-dimensional view. His love of poetry, literature, and landscape, and his sustained romantic devotion to his wife, Richarda, indicate a remarkable warmth. The formality of letters to colleagues and even friends contrasts very markedly with those that were intended for members of his family. Although he derived obvious professional satisfaction from the efficient running of the Greenwich observatory, he kept strict office hours, and preferred to devote the remaining time not to learned societies or to clubs, but to family activities.

ALLAN CHAPMAN

Sources  
G. B. Airy, Autobiography of Sir George Biddell Airy, ed. W. Airy (1896)
E. J. R. [E. J. Routh], PRS, 51 (1892), i-xii
H. H. T. [H. H. Turner], Monthly Notices of the Royal Astronomical Society, 52 (1891-2), 212-29
The Times (5 Jan 1892)
East Anglian Daily Times (11 Jan 1892)
Suffolk Chronicle (9 Jan 1892)
Daily Times (5 Jan 1892)
PICE, 108 (1891-2), 391-4
Airy MSS, CUL, Royal Greenwich Observatory papers, RGO6
Enid Airy MSS, priv. coll.
Milne-Read MSS, priv. coll.
private information (2004)
d. cert.

Archives  
Birr Castle, Offaly, archives, letters to earls of Rosse
CUL, Royal Greenwich Observatory papers, corresp. and papers as astronomer royal, RGO6
Inst. EE, archives, corresp. with Sir Francis Ronalds
LUL, corresp. relating to London University
MHS Oxf., letters to Baden Powell
NHM, biography with his MS notes
NMM, letters to Professor Sedgwick and his daughter
Pembroke College, Oxford, letters to Bartholomew Price
PRO, letters to Sir Edward Sabine
RS, corresp. with Sir John Herschel
RS, letters to Sir John Lubbock
Trinity Cam., corresp. with William Whewell
U. Cam., department of manuscripts and university archives, journals, diaries, and memoranda
U. Cam., Institute of Astronomy Library, corresp. and papers
U. Edin. L., corresp. with Sir Charles Lyell
U. Lpool L., letters
U. St Andr. L., corresp. with James Forbes
University of Exeter Library, Lockyer Observatory archives, letters to Sir Norman Lockyer
Wellcome L., corresp. |  American Philosophical Society, Philadelphia, letters to Admiral W. H. Smyth
BL, letters to Charles Babbage, Add. MSS 37183-37186, 37194, 37196
BL, letters to S. Grimaldi, Add. MS 34189
BL, corresp. with Sir Robert Peel, Add. MSS 40414-40593, passim
Bodl. Oxf., letters to Lord Arthur Charles Hervey
Bucks. RLSS, corresp. with John Lee
CUL, letters to Sir George Stokes
Mitchell L., Glas., Glasgow City Archives, letters to Archibald Smith
NL Wales, letters to Sir George Cornewall Lewis
priv. coll., Enid Airy MSS
priv. coll., Milne-Read MSS
PRO, corresp. with Lord Ellenborough, PRO 30/12
Ransom HRC, corresp. with Sir John Herschel
RAS, letters to James Bosanquet
RAS, letters to James Glaisher
RAS, letters to Royal Astronomical Society
RAS, letters to Richard Sheepshanks
RGS, letters to Sir David Gill
Royal Institution of Great Britain, London, letters to John Tyndall, etc.

Likenesses  
J. Deville, plaster bust, 1823, Observatories Syndicate, Cambridge
J. Pardon, oils, 1833-4, Observatories Syndicate, Cambridge
portrait, c.1835, RS
T. H. Maguire, lithograph, 1852, BM, NPG
E. Edwards, photograph, 1860-69, NPG
G. B. Black, lithograph, 1864 (after unknown portrait), NPG
Maull & Polyblank, photograph, c.1864, NPG [see illus.]
Lock & Whitfield, woodburytype photograph, c.1877, NPG
W. T. Morgan & Co., group portrait, photograph, 1891, NPG
Morgan & Kidd, group portrait, photograph, 1891-1892, NPG
Miss A. Airy, watercolour drawing (after J. Collier, 1884), RAS
F. Artus, lithograph, BM, NPG
Maull & Polyblank, carte-de-visite, NPG
W. T. Morgan & Co., group portrait, photograph, NPG
I. W. Slater, lithograph (after T. C. Wageman), BM
J. Watkins, carte-de-visite, NPG
photographs, CUL
pictures and photographs, priv. coll.

Wealth at death  
£27,713 9s. 9d.: probate, 5 March 1892, CGPLA Eng. & Wales

[http://www.oxforddnb.com/view/article/251]

GO TO THE OUP ARTICLE (Sign-in required)