Private Research and Public Duty: George Biddell Airy and the Search for Neptune

Private communication (1986) from Miss Janet Dudley, formerly Librarian and Archivist, Royal Greenwich Observatory, Herstmonceux. When the Airy papers were re-catalogued as part of the Philip Laurie project in the early 1980s, the Neptune file, being missing, was never given an RGO 6 reference number. Its old catalogue number had been RGO 694. It is hereafter cited as “RGO Neptune file”.

Airy Biddell George , “Astronomer Royal's journal, Jan. 1836 — Dec. 1847”, RGO 6; hereafter cited as “Journal”. Also, “Astronomer Royal's correspondence with the First Assistant, 1835–1848”, RGO 6, 28.

Airy G. B. , “An account of some circumstances historically connected with the discovery of the planet exterior to Uranus …”, Memoirs of the Royal Astronomical Society, xvi (1847), 385–414 (dated 13 November 1846); hereafter cited as Airy , “Account”. This article was also printed under the same title in the Monthly notices of the Royal Astronomical Society (hereafter cited as MNRAS), vii (1846), 121–44. The Monthly notices and Memoirs of the RAS were intended to represent a complete record of the Society's proceedings. From 1847 onwards, both journals were to be issued in different formats, of octavo and quarto, and published each year as a bound volume. The new policy, along with prices, is included in the “Explanatory notice” following the title-page in the 1847 volume of MNRAS. The significance of Airy's “Account” is indicated by its inclusion in both MNRAS and Memoirs.

Glaisher James W. L. , “Biographical notice”, in The scientific papers of John Couch Adams, ed. by Adams Grylls W. , i (Cambridge, 1896), pp. xv–xlviii. Hereafter cited as Adams , Scientific papers.

Challis James , Special report of proceedings at the Observatory relative to the new planet, being part of the Cambridge University Observatory Syndicate reports, 12 December 1846 (hereafter Challis , Special report), and Second report of proceedings in the Observatory relating to the new planet (Neptune), 22 March 1847, Cambridge Observatory Library, R. 2932 and 2933. Challis also presented his case before the meeting of the RAS on 13 November 1846, and published “Account of observations at the Cambridge Observatory for detecting the planet exterior to Uranus”, MNRAS, vii (1846), 145–9.

Grosser Morton , The discovery of Neptune (Cambridge, Mass., 1962). Smart's W. M. “John Couch Adams and the discovery of Neptune”, Occasional notes of the Royal Astronomical Society , no. 11 (August 1947), 33–88, is a much better work in many ways, drawing as it does on original documents. The article still perpetuates the ‘heroes and villains’ approach to the Neptune question, though its main value lies in the citation and publication at length of several letters (probably in the RGO archives) which were still available in 1947, but which went missing as part of RGO 694, the “RGO Neptune file”. Smart's greatest weakness is his failure to cite the locations or references for his sources, which makes them difficult to trace. A more sympathetic appraisal of Airy's situation is found in Jones Spencer H. , John Couch Adams and the discovery of Neptune (Cambridge, 1947). In this little 43-page publication, Spencer Jones drew attention to Airy's extra-astronomical commitments, a point to which “P. J. M.” added informed amplification in his review of the pamphlet in The observatory, lxvii (1947), 233–4. Spencer Jones further championed Airy in “G. B. Airy and the discovery of Neptune”, Popular astronomy, lv (1947), 312–16, where he criticised Smart's article in Nature, clviii (1946), 648–52. Though citing several of Airy's letters, Spencer Jones also fails to give their archival location. Some of them, however, are in the Neptune file, Cambridge University Observatory Library, hereafter “Cambridge Neptune file”.

The need to work for his living, and absence of private funding, is clear in the Autobiography of Sir George Biddell Airy , ed. by Airy Wilfred (Cambridge, 1896), chap. 3. Airy had been discussing salary matters in the event of his taking up a Greenwich appointment, since 1832: Lord Auckland to Airy, 8 October 1832, RGO 6, 1/151-2. Two years later, money figured prominently when he was negotiating the Office of Astronomer Royal: Airy to Lord Auckland, 10 October 1834, RGO 6, 1/153.

This could have played a part in Airy's refusal of a knighthood in 1835, Autobiography, 111–13.

This sum was made up from a salary of £800 per annum, Airy to Lord Auckland, 10 October 1835, ibid. , and a £300 p.a. Civil List Pension, offered by Peel and eventually settled on Mrs Airy. See Autobiography, 105, and correspondence with Peel, 18–19 February 1835, ibid., 107, 108. John Pond's income from Office as Astronomer Royal had only been £600 p.a., Airy to Duke of Sussex, 19 May 1834, RGO 6, 1/145.

This self-adopted title was used by Airy in his Report to the Board of Visitors, (1842), 7.

It is true that, in many ways, Airy defined the details of his Office, though its functional character was implicit in the Royal Warrant under which he was appointed, William iv, 11 August 1835, and re-confirmed by Victoria in 1837, RGO 6, 1/193-4 and 195.

In the last months of his Office, before retirement in 1881, Airy wrote: “The Royal Observatory, as appears from the original inscriptions and the official warrants, was founded expressly for a definite utilitarian purpose…. And this utilitarian purpose has been steadily kept in view for two centuries, and is now followed with greater rigour and expansion than ever before”, Airy to The English mechanic, part 831 (25 February 1881), 586–7 (letter dated 10 February 1881). In this same letter, which was published in connection with the discussion of the state endowment of scientific research, Airy also emphasised his belief that original research should be paid for out of private endowments, for only when pursued thus could it retain its freedom from state interference. This item is not included in the list of publications in Airy's Autobiography, printed on pp. 373–403.

Airy , Report to the Board of Visitors , (1875), 26. These Reports, which Airy delivered to the Visitors each summer, not only give an excellent record of the Observatory's achievements over the previous year, but are rich in policy statements by the Astronomer Royal on the nature of his Office.

Airy , “Journal”, 22–23 December 1845. Airy did not search for Astraea, but true to his conception of his Office, circulated material about it and made “daily observations” after its discovery (in Germany on 13 December) had confirmed it as a fact of nature.

The “Journal” records two “general holidays” for the Assistants, 25 February 1846 and 26 June 1846. The precise durations of the Christmas and Easter holidays for the staff are not easy to ascertain, as Airy was absent for 4 and 6 days respectively. In addition to his late summer trip to Europe, which lasted around one month, some 24 further days were ascribed either to business trips outside the London area, or holidays, between 23 September 1845 and 10 August 1846.

Challis to Airy , 22 September 1845, reprinted in Airy , “Account”, item no. 9, 394. I have been unable to trace the original letter in the RGO archives, and presume it to be part of the missing “RGO Neptune file”.

Challis , Special report (ref. 5), 2–3.

Airy to Challis , 29 September 1845, in Airy , “Account”, item no. 10, 395.

Airy , “Journal”, 20 November 1845 (Croydon); 17 December 1845 (Didcot).

Airy usually dined at 3.30 pm, according to Wilfred Airy in “Personal sketch”, in Autobiography, chap. 1, p. 8. For Adams's account of the visit see Scientific papers, p. xxviii.

Original untraceable at RGO, presumed in missing “RGO Neptune file”. A facsimile was published in Spencer Jones's John Couch Adams (ref. 6), 15–17.

The 21 October date is cited without a manuscript source by Glaisher in Adams's Scientific papers , p. xvii. Airy's reference to the visit being at the end of October is in his “Account”, 395. As neither Airy nor Adams left any documents specifying the exact date of the visit of which I am aware, one must accept Adams's subsequently remembered date of 21 October as probably correct, and the most precise available source.

On 18 January 1846, Airy's “Journal” records that he was conducting vibration experiments at Kensal Green tunnel, and on the 23rd mentions that these experiments related to the proposed Greenwich line. His Assistant Edwin Dunkin was also dispatched to study train vibrations, 28 February and 9 March 1846, etc. As early as 25 January 1836, Airy had been conducting experiments on train vibrations as a possible threat to the Observatory, see Autobiography, 126.

Airy's affection for his wife is given testimony by Wilfred Airy in the Autobiography, 57. Though not much of Airy's private correspondence with his wife is known to have survived there are some items amongst the RGO 6 papers at Herstmonceux.

Richardson William had been a Warrant Assistant at Greenwich since either 1822 or 1824 (sources differ), until his formal dismissal on 30 October 1845. His dismissal allowed promotion amongst the lower Assistants, Richardson being immediately succeeded by Thomas Ellis, and he by the newly Warranted Dunkin; see Dunkin Edwin , “Autobiographical notes by Edwin Dunkin FRS, FRAS” (1894) in the Royal Astronomical Society, Additional MSS 55, pp. 129, 163–4. Airy had tried, unsuccessfully, to have Richardson discharged for dishonest practices in 1835, see Meadows A. J. , Greenwich Observatory, ii: Recent history, 1835–1975 (London, 1975), 2. Irrespective of whatever criminal traits may have lurked in Richardson, he possessed talent. Rising up from obscure Yorkshire origins, he had received the Gold Medal of the RAS in 1830, see MNRAS, i (1830), 165. Airy also spoke well of Richardson's abilities in a letter to Captain Beaufort, the Navy Hydrographer, on 5 July 1841: “Mr Richardson; a valuable assistant but who requires a good master to keep him in order.” Richardson's good work earned him a salary of £190 in 1841, RGO 6, 72/34v–35. Orders for the payment of the outstanding salary for the incarcerated Richardson exist for February 1846, though so great was the family shame about the incest murder, that relatives refused to accept it, RGO 6, 73/88. Richardson's name does not appear on any of Airy's published staff lists presented in his annual Reports to the Visitors. Though Airy generally thanked and praised his staff in these Reports, he did not commence the practice of specifying each man by name, along with his duties, until the June 1846 Report, by which time Richardson had been discharged.

Adams , Scientific papers , p. xxii. Airy had also written with a similar question to Le Verrier, following the publication of his Comptes rendus article, Airy to Le Verrier, 26 June 1846. Le Verrier responded with a detailed reply, see Smart , “John Couch Adams” (ref. 6), 58–59.

Airy , “Account”, 397.

Adams to Airy , 2 September 1846, see Airy , “Account”, item no. 20, 405. Adams and Main corresponded on 5 and 7 September, see Airy , “Account”, 408.

Airy to Challis , 21 December 1846, “Cambridge Neptune file”, 7, reproduced in Adams , Scientific papers, p. xxxi (emphasis in original).

Ibid. Even after Neptune's discovery, Airy felt quite vindicated in his actions because the new planet's orbital elements were found (by the summer of 1847) only to have corresponded with the discovered position by a fortunate coincidence. Bode's Law, indeed, failed for Neptune, as Airy pointed out in MNRAS, vii (1847), 270. Airy's scientific reservations had been wholly correct, and only his luck had been at fault.

Airy was quite adamant that conditions in Cambridge were the most suitable for a search, the most important being the Northumberland Telescope, followed by “declination, latitude of place, feebleness of light and regularity of superintendence”, Airy to Challis, 9 July 1846, “Cambridge Neptune file”, 2. Airy did also appreciate that Challis's establishment at Cambridge was much smaller in contrast with the total staff of around a dozen at Greenwich, and offered the loan of an assistant. It seems, though, that one of the Greenwich junior Assistants was already being considered for an appointment at the Cambridge Observatory before the possible search for Neptune prompted his offer of 9 July 1846. On 30 June 1846, Airy had written to Challis offering either Breen or Ellis for consideration, Airy to Challis, 30 June 1846, “Cambridge Neptune file”, 1. See also Dewhirst D. W. , “The Greenwich-Cambridge axis”, Vistas in astronomy, xx (1976), 109–12.

Airy , “Account”, 339.

Hansen had been visiting Airy between 10 June and 4 July 1846, according to the “Journal”. 34. Airy, Autobiography, 183.

Grosser , Discovery, 119.

Airy to Main, headed “Gotha”, 30 September 1846, RGO 6, 28/176.

Airy to Challis , “Gotha”, 30 September 1846, “Cambridge Neptune file”, 13.

In addition to details given in the “Journal”, see also Autobiography, 183.

Airy to Challis , 14 October 1846, “Cambridge Neptune file”, 18.

Hind to Challis , 30 September 1846, “Cambridge Neptune file”, 12.

Main to Challis , 1 October 1846, “Cambridge Neptune file”, 14.

Airy to Main , 30 September 1846, RGO 6, 28/176. The Neptune correspondence tells us much about the speed and efficiency of the postal services in 1846, from dates and replies to letters. Greenwich to Cambridge took a day or less, Paris 2 days, and Berlin about 5 days. English railways were also fast: Airy made a day return trip to Cambridge from Greenwich with Hansen, see “Journal”, 2 July 1846.

Challis to Cambridge chronicle, 1 and 16 October 1846. Cuttings of these letters are in “Cambridge Neptune file”, 15, 16.

Airy , “Account”, 408.

Airy to Main , 9 and 16 September 1846, RGO 6, 28/173-4.

Grosser , Discovery, 114.

Maunder E. W. , The Royal Observatory, Greenwich (London, 1900), 116. Airy's invulnerability came not so much from arrogance, as from assurance. Even making allowances for a son's affection for his father, Wilfred Airy sums him up nicely: “He had a remarkably well-balanced mind, and a simplicity of nature that appeared invulnerable. No amount of hero worship seemed to have the least effect upon him.” See “Personal sketch”, in Autobiography, 5. One might suggest that not only hero worship, but also criticism, left him unaffected.

Grosser , Discovery, 137.

Maunder , Royal Observatory (ref. 47), 116.

Glaisher , “Biographical notice”, in Adams , Scientific papers, p. xxiv.

Glaisher , ibid., p. xxxi.

Adams , Scientific papers , p. xxxiii, and Airy , Autobiography, 187.

Though several contemporaries refer to Adams's “youth” and even “extreme youth” (Glaisher), one must not forget that in 1846 he was 27 years old, the age at which Airy, in 1828, had resigned the Lucasian Professorship to take up the Plumian Chair along with the Directorship of the Cambridge University Observatory. One suspects that these references may have more to do with Adams's manner and the way he appeared to people, than with his age in years.

Grosser , Discovery , 105, mentions that “His [Airy's] otherwise excellent memory invariably failed him in matters involving Adams”. Grosser states that Airy “totally forgot” his first meeting with Adams in December 1845, and had only the vaguest recollections of having met him on St John's bridge eight months later. No source is given by Grosser for these interesting incidents, but as they are cited in Smart's “John Couch Adams” (ref. 6), I suspect that they were taken from him. As Smart gives none of his sources, one suspects that he may have got the information from the missing “RGO Neptune file”. According to Airy's “Journal”, he was in Cambridge 4–6 December 1845, in the midst of a very busy schedule, while the chance meeting on St John's bridge in July 1846 occurred on his ‘day return’ visit when he was entertaining Hansen on the 2nd. These meetings were only chance and fleeting, and in no way given to discussion. One must remember that in the year 1845–46, Airy met and interviewed so many people in the course of his official business that it would be unwise to give a perjorative meaning to the forgetting of two chance encounters to which, at the time, he had no need to attach any significance.

See ref. 43. Le Verrier's “Recherches sur les mouvements d'Uranus”, Comptes rendus, xxii (1846), 907–18, was published on 1 June 1846. The paper reached Airy at Greenwich “about the 23rd or 24th of June”, see Airy , “Account”, 398. It is likely that internationally dispatched copies of Comptes reached Cambridge around the same time, thereby dating quite accurately the genesis of Challis's serious interest in the new planet to some four months prior to October 1846.

Challis virtually admitted the same. Between September 1845 and the midsummer of 1846, “…I had little communication with Mr Adams respecting the New Planet. Attention was again called to the subject by the publication of M. Leverrier's [sic] first Researches in the Compte Rendu [sic] for June 1 1846”, Challis , Special report (ref. 5), 4.

Airy to Sedgwick , 4 December 1846. I have not been able to trace the original of this letter, cited in Smart's “John Couch Adams” (ref. 6), 71–72. This letter is not amongst the surviving Airy/Sedgwick correspondence in the Cambridge University Library (which is primarily concerned with geological matters for the years 1839–42 and some items from the 1850s), nor is it in the RGO archives. Airy made duplicate copies of all his official correspondence, and one is left to assume that Smart used Airy's duplicates, which in 1947 would still have been in the now-missing “RGO Neptune file”. Adams took his B.A. at the late age of 24, in 1843, and his M.A. in 1846 ( Venn J. A. , Alumni Cantabrigiensis, pt II: 1752–1900, i (Cambridge, 1940)). Adams never took Holy Orders, and like Airy, determined upon a secular scientific career.

Reference to these multifarious activities is to be found in Airy's annual Reports, as well as in the over 500 published works listed in his Autobiography, 373–403.

Though the eventual values obtained were neither as consistent nor as accurate as expected, Airy's experiments formed a model example of how to apply the latest technology from one field to render advances in another: Airy G. B. , Account of pendulum experiments undertaken at the Harton Colliery for the purpose of determining the mean density of the Earth (London, 1855).

Airy , Report, (1874), 8.

This was the Order of St Stanislas, about which Airy was approached by Count Ouvaroff in September 1847. For diplomatic reasons, however, he was not permitted by the British authorities to accept the honour, correspondence in Autobiography, 190–3.

Airy's international standing in science is evident in the seven volumes of documents and correspondence covering the Spanish eclipse, RGO 6, 123–9.