Adams, John Couch

(1819-1892), astronomer

by Roger Hutchins

© Oxford University Press 2004 All rights reserved

Adams, John Couch (1819-1892), astronomer, was born on 5 June 1819 at Lidcot, a farm near Launceston, Cornwall, the eldest of the seven children of Thomas Adams (1788-1859), a poor tenant farmer, and his wife, Tabitha Knill Grylls (1796-1866), a farmer's daughter who had received some education from her uncle John Couch. She inherited Couch's library, including a few astronomy books, which engaged John in boyhood. Of his brothers, Thomas became a missionary, George a farmer, and the third, William Grylls Adams FRS (1836-1915), professor of natural philosophy and astronomy at King's College, London. Adams was brought up in a close Wesleyan family and had his mother's good ear and love of music. From the nearby village school at Laneast, where he learned Greek and algebra, at the age of twelve he moved to the private school at Devonport (later at Saltash and Landulph) run by his cousin the Revd John Couch Grylls. There he learned classics and largely taught himself mathematics. Astronomy was his passion; in the Devonport Mechanics' Institute he studied astronomy articles in Rees's Cyclopaedia, and Vince's Fluxions introduced him to higher mathematics. In 1835 at Landulph he observed Halley's comet, and in 1836 he calculated and observed an annular eclipse and planetary conjunctions. The following year he became a private tutor. A small inheritance left to his mother in 1836 enabled the family to make the further sacrifices involved in sending Adams to university; he won a scholarship and entered St John's College, Cambridge, as a sizar in October 1839. He won the first prize in Greek testament every year, and in 1843 graduated as senior wrangler and first Smith's prizeman, and was elected a fellow of his college.

Adams achieved lasting fame as the co-discoverer of the giant planet Neptune by mathematical calculation. He is remembered for two other major achievements: his memoir on the secular acceleration of the moon's mean motion and his determination of the orbit of the Leonid meteorids. These resulted from 'a great deal of intricate and elaborate mathematical investigation' carried out with great skill and accuracy on 'specific, well-expressed problems', rather than by someone exploring 'completely new fields and making startling discoveries' (private information). Adams modestly and rightly regarded himself as a celestial mechanician in the strong line of J. L. Lagrange, P.-S. Laplace, C. Delaunay, C. F. Gauss, and P. A. Hansen.

Adams's long career may be seen as having three principal elements: his work between 1841 and 1846 which, when he was only twenty-seven, led to his co-discovery of Neptune; his subsequent career as a mathematical astronomer, which included thirty-three years as a professor at Cambridge (from 1859 until his death); and his concurrent direction of the Cambridge observatory (from 1861 to 1892).

Neptune
By the 1820s it was known that the planet Uranus was not following the orbit predicted since its discovery in 1781. Adams rejected various hypotheses because they were incapable of being tested by exact calculation; he realized that the amount of observed deviation could not be caused by the perturbations due to the masses of Jupiter and Saturn alone. Either Newton's laws of gravitation were wrong or there must be an unknown planet beyond Uranus. Because he had complete faith that Newton was not in error, and because the physical quantities of Uranus's mass and the extent of deviation were known, Adams's great inspiration was to believe that he could break all precedent and work from known perturbations to deduce the orbit, position, and mass of the body that must be exerting a gravitational attraction upon Uranus. On 3 July 1841 he recorded his determination to investigate the problem. It was later hailed as one of the grandest intellectual problems ever tackled. After finals, in the summer of 1843 he calculated the first of six solutions of ever-increasing accuracy. He tutored undergraduates in order to send money to contribute to his brothers' education, and even made time to teach his bedmaker, Mrs Ireland, to read. In September 1845 he gave the elements and position of the new planet to James Challis (1803-1882), director of the Cambridge observatory, who gave him a letter of introduction to the astronomer royal at Greenwich, G. B. Airy (1801-1892). In October, without prior appointment, Adams twice called at Greenwich and left his derived elements. Airy responded with what he considered a fundamental question; Adams thought it trivial and neglected to reply.

In the summer of 1845, unaware of Adams's work, U. J. J. Le Verrier in Paris investigated the problem. Adams's diffidence deterred him from publishing results until they were checked very carefully. Le Verrier published papers on his own method and progress, then in June 1846 a first predicted position which Airy saw was very close to that given by Adams in October 1845. Convinced, Airy pressed Challis to use the Cambridge 11.25 inch telescope, 'in the hope of rescuing the matter from a state which is ... almost desperate' (Smart, 1947, 59). There were three ways of finding a predicted planet: noticing that a 'stellar' object was a disc, not a point source; noticing that in a specific region there was a 'star' not recorded on accurate star maps which included faint stars; and noticing that a particular 'star' had moved. Having no star charts, on 29 July Challis commenced an unavoidably laborious search, relying on the third method. Since Paris had no suitable telescope, Le Verrier sent his own prediction to J. G. Galle at the Berlin observatory. There H. C. D'Arrest found that one corner of a newly available star chart covered the predicted position. This was very important, because Neptune was too small to be recognized as a disc when using the magnification appropriate for a planet search. The planet was duly found on the first night's search, 23 September, only 2° 27' from the position Adams had given--a marvellous prediction. It was found because Le Verrier had published his prediction and then energetically pressed a search. French triumph was spoiled when Sir John Herschel and then Richard Sheepshanks, foreign secretary of the Royal Astronomical Society (RAS), insisted on having Adams's prior solution recognized.

Adams had not given Airy or Challis the details of his work or method which might have persuaded them. Then he took 'for granted' that Airy would have 'communicated my results among his correspondents' (Glaisher, 'Biographical notice', xxviii). J. W. L. Glaisher, who knew all three men, excused Adams on the grounds of youth and extreme modesty. He concluded that Challis: 'As professor in the University ... should not have allowed a young Senior Wrangler, through modesty or diffidence or inexperience, to do such injustice to himself' (ibid., xxvi). Challis admitted his failures. Airy's explanation that such a search was not the business of the national observatory has been upheld by his biographers. But contemporaries found it inexplicable that Airy, even when his doubts were removed, did nothing to urge Adams to publish or adequately to affirm his work when lavishing praise on Le Verrier. Hence the Royal Society was led to blunder by awarding the Copley medal to Le Verrier in 1846 without mentioning Adams. This was remedied only when they awarded the Copley to him in 1848 and elected him FRS in 1849. Adams's work on comets had secured his election to the RAS in 1845; the society awarded no medal for Neptune. In 1847 Adams declined a knighthood because he could not afford the social consequences. However, in 1848 his college established an Adams prize in his honour and the government awarded him a pension. Adams was lionized in his university, perceived as having the most imaginative English mathematical mind and power of calculation since Newton. He never uttered a word against Challis or Airy, and that reticence and his genial nature endeared him to many.

Celestial mechanician
Adams continued as a tutor at St John's until his fellowship expired in 1852. A congenial career post eluded him for more than a decade. He was extraordinarily uncompetitive, reluctant to publish imperfect work to stimulate debate or claim priority, averse to correspondence about it, and forgetful in practical matters. The pension, then additional stipends, enabled him to work in his own way.

When he was elected president of the RAS for 1851-3, Adams urged the need to reinvestigate the lunar and planetary theories and prepare new tables. This led him to his second major achievement. By 1851 he had started work on several problems contributing to the three body problem of the interactions between earth, sun, and moon, known as the lunar theory. Edmond Halley had discovered a fundamental problem, the acceleration of the moon. In 1787 Laplace had discovered the cause, the action of the sun upon the moon and the decrease of the eccentricity of the earth's orbit. In a paper to the Royal Society on the secular acceleration of the moon's mean motion (1853) Adams showed that Laplace's supposed definitive work had omitted some terms from the equations and accounted for only half the observed change in longitude of nearly 12 arc seconds per century. Calculating for additional tangential force, Adams's residual discrepancy of 5.7 arc seconds, very close to modern values, is now known to be due to the moon's tidal drag leading to a slowing down of the rate of rotation of the earth, and thus an increase in the length of the day. His paper caused great controversy among French astronomers, but he simply disproved each objection as it arose.

Adams continued with work on the fine detail of variables in the moon's orbit--lunar parallax and perigee. By rigorous comparison he traced errors, and in 1852 produced valuable new tables of the moon's parallax and in 1856 added corrections for the values given in the Nautical Almanac. He was anxious to obtain the superintendence of the Nautical Almanac office which became available in 1853, but he had displayed no organizational ability, and the Admiralty selected John Hind (1823-1895). In February 1853 Adams was elected a fellow of Pembroke College, which enabled him to continue tutoring. In autumn 1857 he was elected professor of mathematics at the University of St Andrews, but shortly afterwards the Lowndean chair of astronomy and geometry became vacant at Cambridge. His appointment in March 1859 was a formality; the university publicly recognized his achievements by bestowing a prestigious post and stipend which allowed him to remain among friends.

Director, Cambridge observatory
The commonly perceived inefficiency at the Cambridge observatory during the search for Neptune had been due not least to a lack of funds for employing and retaining sufficient assistants. In 1858 Challis was ill and had a huge backlog of observations to reduce and publish. Airy was fully aware of this. By December 1858 he had negotiated Anne Sheepshanks's donation of a fund for the observatory in memory of her brother. In November 1860 she was persuaded to add £2000 for a new instrument; in December Challis asked to be relieved. By February 1861 he and Adams's close friend G. G. Stokes, the Lucasian professor, had persuaded Adams to accept the superintendence for £250, conditional upon his not having to observe or process reductions or publications, and that if these interfered with his research he could resign. These extraordinary terms were acceptable only because the Sheepshanks fund would enable him to retain an experienced senior assistant.

Thus Adams chose, and at the age of forty-two was appointed to, one of the most prestigious and important astronomical posts in Britain. He moved to the observatory beyond the city in September 1861. In October 1862 he met Elizabeth (Eliza; 1827-1919) , the 34-year-old daughter of Halliday Bruce of Dublin. She was a guest and friend of Stokes's wife, herself a daughter of T. R. Robinson, the director of Armagh observatory. Probably on Robinson's recommendation Adams visited Ireland in December to engage Andrew Graham (1815-1908), director of Markree observatory, to become his chief assistant at Cambridge. While he was staying with Robinson at Armagh, Eliza, also a guest there, agreed to marry him. They were married on 2 May 1863; they had no children.

Adams loved his university, his science, and the academic life. He fulfilled his primary duty from 1860 to 1889 by diligently lecturing in one term of each year. His course was on the lunar theory, which illustrated geometrically the analytical process so important to advanced mathematicians. Every year he rewrote several lectures.

Adams's second responsibility was the observatory. Cost precluded replacing the Northumberland refractor. Graham's expertise and interest lay in continuing to catalogue and chart accurate star positions for zones along the ecliptic, the great circle of the earth's orbit intersecting the celestial sphere. This was useful for precise determination of planetary orbits, and therefore of real utility. Adams's policy was to limit use of the Northumberland refractor to special observations. A new 8 inch transit circle by Troughton and Simms was ordered in 1867 and installed in December 1870. The Astronomische Gesellschaft (the German astronomical society) asked Adams to deploy the powerful new instrument on their last available zone, which happened to extend Graham's Markree ecliptic zone. Observations commenced in 1871 and were mainly completed by 1886, and the zone was published in 1897. Beyond Adams's initial help evaluating instrument errors, everything was delegated to Graham. The single programme for twenty-six years, continuity of staff, and funds for computing prevented stress. Yet by 1872 Airy complained that, with nothing published since 1859, 'Cambridge is beginning to lose place' (letter from Airy to G. H. Richards, 13 Sept 1872, CUL, RGO 6 150/158). The observations for 1861-5 were not published until 1879. In 1882 Adams helped the ageing and widowed Graham by allowing the keenest of the computers, Anne Walker (b. c.1864), to move into the observatory and to be remunerated and work effectively as his third assistant. Even so the observations for 1866-9 were published only in 1890.

The Leonids
Adams's third major achievement resulted from H. A. Newton of Yale's having analysed historical observations to predict correctly in 1864 a meteor shower that would occur in November 1866 from a radiant point in Leo. Newton asserted that the longitude of that node (intersection of the orbit with the celestial equator) was increasing. This presented a difficult but attractive problem of celestial mechanics. The leading astronomers of Europe made various contributions, but it was Adams who by March 1867 calculated the effect of planetary perturbations upon the advance of the node and derived 'a definitive orbit' for the Leonids which coincided with that of Tempel's comet, thus establishing 'the close relation between comets and meteors' (Dreyer and Turner, 162). Some experts considered this a more difficult work than lunar acceleration.

Because of his pre-eminent expertise on the lunar theory, Adams often received queries from the Nautical Almanac office when revising the ephemerides for their tables, which were so essential to navigators; he always responded promptly. In 1881 he contributed refined ephemeris tables of the positions of the Galilean satellites of Jupiter.

Adams neither did much research in nor searched for new mathematical principles, and he played no major role in the mathematical societies of his day. From eleven published papers on pure mathematics he is remembered for the somewhat eccentric calculation of Euler's constant, which is used in integration and calculation, to 236 decimal places. Although few observations emerged from Cambridge, Adams's work was admired for reaffirming Newton's laws, eliminating errors, and refining fundamental theory. Altogether he published sixty-two scientific papers in various journals (only three with the Royal Society), nearly fifty of them with the RAS. He wrote seventeen of them while a tutor at St John's, only four in his first decade as director of the observatory, and only two after 1884 as his health failed. For work on lunar perigee and acceleration he was awarded the RAS gold medal in 1866.

Adams's mass of unpublished work was edited by his brother William and R. A. Sampson (1896 and 1900). From 1849 Adams attempted to work towards a theory of terrestrial magnetism and determination of the Gaussian magnetic constants for any part of the globe. William published: 'The numerous tables ... calculated with the utmost care under Professor Adams' minute supervision and instruction ... by Mr Graham, who has done a great part of the work, and by Mr Todd [the second assistant] and other assistants' (Papers, 2.xxvii-xxviii). Global maps with contour lines of equal magnetic variation were attached. But a major constraint had been the lack of observational data for the southern hemisphere, where there were only three stations.

By accepting directorship of a leading scientific institution, Adams not only assumed a responsibility for the scientific output of the observatory but raised expectations for his potential influence in matters of patronage upon which the community of observers completely depended. His office made him a visitor to the Royal Greenwich Observatory and ensured a place on the RAS council, which he served from 1854 to 1892. His lack of engagement with the politics of the discipline may be inferred from his attendance at the dinners of the RAS Club, which preceded the eight RAS meetings each year. The club was the élite policy-forming coterie to which he was elected 'by acclamation' in 1851 (Turner, xxxiv) and which in 1876 elected him vice-president (he served until 1887), and later an honorary life member. While council member and society president from November 1851 to June 1853 he attended five of sixteen dinners. From 1866 to 1873, years notable for the endowment for solar research debate which split the RAS in 1872, he attended less than once a year; as president again from November 1874 to June 1876 he was absent six times.

Adams's correspondence shows that he was prompt to help with information but avoided controversy, and he usually did not reply to appeals for intervention or patronage. The exceptions were his unselfish proposal of Hencke and Hind for the 1848 RAS medal, soliciting a government pension for Hind in 1851, and in 1879 moving with uncharacteristic speed to ensure that Hind was elected RAS president despite Airy's mooted intervention. Adams's generosity and love of truth are exemplified by his securing Cambridge's honorary LLD for Le Verrier in 1874 and, when president, the RAS gold medal for him in 1876. On Airy's retirement in 1881 Adams was offered the post of astronomer royal, but surprised nobody when he declined.

When Isaac Newton's mathematical papers were left to Cambridge University in 1872 Adams was perceived as 'so penetrated with Newton's style and thought that he was peculiarly fitted to be his interpreter' (Glaisher, 'Biographical notice', xlv), and he gave immense time and care to the catalogue which was published in 1888. From 1869 he was an early and active supporter of the provision of higher education for women in Cambridge: from 1873 until Newnham College was incorporated in 1880 he was the first president of the association which lobbied for such provision, and he was one of the first Cambridge professors to admit women to his lectures.

Adams necessarily worked alone. He was a consummate master of all the refined and delicate methods in the highest and most complicated and difficult field of astronomy, as well as of the detailed processes by which theory and observation are connected. From analysis of Adams's diary and dated work, Glaisher summarized that 'For forty-five years [1843-88] his [powerful] mind was constantly directed to mathematical research relating principally to astronomy' but that, owing to an 'innate craving for perfection', he published only a fraction of what he accomplished (Glaisher, 'Biographical notice', xlii-xliii), and thereby limited his contribution to the discipline. Adams and his contemporaries used classical methods of computing which involved an iteration of successive approximations for each perturbation. Such analytical methods have been replaced by methods of numerical integration. But although much of Adams's work was therefore superseded, fifty years later an astronomical professor declared it impossible to do justice to his 'multifarious researches' on celestial mechanics (Smart, 1947, 85).

Adams was happily married, profoundly devout, and enjoyed social visits, house guests, entertaining, music, dancing, parties, long daily walks, croquet, bowls, and whist. He shared contemporary interests in mesmerism and the occult. A bibliophile, when not socializing in the evenings he read. He attended the weekly meetings of The Family, a university dining club, at least from 1860 to 1889. He was much involved in college and university business. He did not shirk the public exposure of accepting honorary degrees from Oxford, Dublin, Edinburgh, and Bologna; he was a correspondent of the Académie Royale des Sciences and of the academy at St Petersburg.

Adams became seriously ill in October 1889 and had a stomach haemorrhage. Partial recovery was followed several times by relapses, the last of which in June 1891 left no hope. He died at the observatory on 21 January 1892. The queen wished him buried in Westminster Abbey, but following a funeral service at Pembroke College he was buried five days later in St Giles's cemetery, close to the observatory. Memorials were erected in both Truro and Westminster cathedrals. In 1919 Eliza Adams died in Cambridge of influenza, aged ninety-one. In her husband's memory she left a bequest to augment the stipend of a John Couch Adams astronomer, who was not to be a professor.

ROGER HUTCHINS

Sources  
W. M. Smart, 'John Couch Adams and the discovery of Neptune', Occasional Notes of the Royal Astronomical Society, 2 (1947), 33-88
M. Grosser, 'Adams, John Couch', DSB
D. W. Hughes, 'J. C. Adams, Cambridge and Neptune', Notes and Records of the Royal Society, 50 (1996), 245-8
The scientific papers of John Couch Adams, ed. W. G. Adams and others, 2 vols. (1896-1900)
J. W. L. Glaisher, 'Biographical notice', in The scientific papers of John Couch Adams, ed. W. G. Adams and others, 1 (1896), xv-xlviii
History of the Royal Astronomical Society, [1]: 1820-1920, ed. J. L. E. Dreyer and H. H. Turner (1923); repr. (1987), 161-2
H. H. Turner, ed., Records of the RAS Club (1904)
F. J. M. Stratton, 'The history of the Cambridge observatories', Annals of the Solar Physics Observatory, Cambridge, 1 (1949), 1-26
private information (2004) [D. W. Hughes]
A. Chapman, 'Private research and public duty: G. B. Airy and the search for Neptune', Journal for the History of Astronomy, 19 (1988), 121-39
H. M. Harrison, Voyager in time and space: the life of John Couch Adams, Cambridge astronomer (1994)
L. E. Doggett, 'Celestial mechanics', History of astronomy, an encylopedia, ed. J. Lankford (1997), 131-40
G. B. Airy, letter to G. H. Richards, 13 Sept 1872, CUL, Royal Greenwich Observatory papers, RGO 6 150/158
A. J. Meadows, Greenwich observatory: the story of Britain's oldest scientific institution, 2: Recent history (1836-1975) (1975)
Catalogue of scientific papers, Royal Society, 19 vols. (1867-1925)
G. B. Airy, Autobiography of Sir George Biddell Airy, ed. W. Airy (1896)
J. W. L. G. [J. W. L. Glaisher], 'James Challis', Monthly Notices of the Royal Astronomical Society, 43 (1882-3), 160-79
R. Sheepshanks, letter to G. B. Airy, 15 Dec 1846, CUL, Royal Greenwich Observatory papers, RGO 6, 229, 63
[J. W. L. Glaisher], Monthly Notices of the Royal Astronomical Society, 53 (1892-3), 184-209
DNB
Journal of the British Astronomical Association, 2 (1891-2), 196-7
'The collected papers of Prof. Adams', Journal of the British Astronomical Association, 7 (1896-7), 486
I. B. Cohen, 'Newton, Isaac', DSB
J. W. L. Glaisher, The Observatory, 15 (1892), 173
W. M. Smart, 'John Couch Adams and the discovery of Neptune', Nature, 158 (1946), 648-52
H. S. Jones, 'G. B. Airy and the discovery of Neptune', Nature, 158 (1946), 829-30
St John Cam., Adams MSS
CUL, Royal Greenwich Observatory papers
RAS, letters
RAS, Sheepshanks MSS

Archives  
Cornwall RO, awards, corresp., and papers
St John Cam., corresp., diaries, and papers |  CUL, Royal Greenwich Observatory papers, corresp. with Sir George Airy, RGO/6 941-53 RGO/6
CUL, letters to Sir George Stokes, Add. 7342 and 7656
RAS, letters to the Royal Astronomical Society
RAS, letters to Richard Sheepshanks
RS, corresp. with Sir J. F. W. Herschel
RS, letters to Sir John Lubbock, A38-A64

Likenesses  
photograph, 1846-1856, repro. in Smart, 'John Couch Adams', facing pp. 62, 63
N. N. Burnard, marble bust, exh. RA 1849, RAS
S. Cousins, mezzotint, pubd 1851 (after T. Mogford), BM, NPG
T. Mogford, oils, 1851, St John Cam.
L. E. Barker, drawing, 1869, St John Cam.
cartoon, pen, 1872, St John Cam.
A. B. Joy, marble bust, exh. RA 1873?, St John Cam.
H. von Herkomer, oils, 1888, Pembroke Cam. [see illus.]
H. C. Fehr, marble bust, 1903, Launceston Library, Cornwall
A. G. Dew Smith, photograph (as an old man), St John Cam.
Fawks, drawing, St John Cam.
H. von Herkomer, oils, replica, NPG
A. B. Joy, medallion, Westminster Abbey, London
F. W. H. Myers, photograph, repro. in Glaisher, The Observatory, facing p. 173
Stodart, portrait (after steel engraving from photograph by Mayall), repro. in Adams, ed., Collected scientific papers, vol. 1, frontispiece
drawing, St John Cam.
plaster bust, St John Cam.
stained-glass window, St John Cam.

Wealth at death  
£32,433 12s. 8d.: probate, 2 March 1892, CGPLA Eng. & Wales


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