They Told The Story
A Neptune Chronology
Adams Dated Computations
The Forgotten Diary
Within One Degree
The Crown Jewels Document
Announcing The Discovery
Challis' Unseen Testimony
A Retrospective History
A Cantab. Clique
Adam's July Ephemeris
Mapless In Cambridge
Airy Tells the Truth
The Radius Vector: A Trivial Question?
Airy Blows His Top
Eggen Takes the Papers
Selected Correspondence
Primary Sources
Related Links.



OCT1845.jpg (2628171 bytes)The ‘physical basis for Britain’s claim of priority,’ as Dennis Rawlins has described it (Dio Oct 1992 p125), has now resurfaced, after an eventful antipodean journey (see "Eggen Takes the Papers"). It is the note allegedly presented by Adams in the autumn of 1845 to Airy, containing his prediction of the new planet's place. It concludes with the stirring words '... assumed mean motion of the new planet,' whereas the version of this letter which Airy presented before the RAS on November 13th 1846, and which has been since then widely reprinted, eg in Grosser's The Discovery of Neptune, ended merely with '... of the planet,' a curious adjustment (p.89). The version printed by Airy was also undated.

There is no record of Airy showing this document to anyone or intimating that he owned it in the thirteen months during which he was supposedly in possession of the most remarkable astronomical prediction ever made. Even in the weeks after the planet had been found, no-one stepped forward to claim that Britain's Astronomer Royal was to be seen with a document demonstrating an agreement within several degrees of the Adams and Leverrier predictions. When the 'original' was produced, it had a month and year inscribed at the top by way of dating , in a different handwriting from the rest, presumably Airy's. Given Airy's meticulous propensity to date every document around him, how likely is it that he would write only the month and not the day, unless indeed he was doing so long after the supposed date?

Adams wrote a letter to his parents (23rd October 1845), saying he had left a note with the Astronomer Royal ‘containing a short statement of the results at which I had arrived.’ On Adam Perkins' telling of the story, upon returning a second time, Adams was ‘told by the butler’ that Airy and his wife were not to be disturbed. ‘Adams then and there wrote Airy a letter containing the elements of the new planet with its present position, which he gave to the butler.’ (G.B.Airy, J.C.Adams & the discovery of Neptune’ 1996 unpublished p.4)
But, the document produced by Airy, on the top of which he wrote ‘September 1845,’ contained several hundred digits, with long columns of residual angular values to hundredths of an arcsecond. Does that sound like the ‘short statement’ put through a letter-box? These residual values (of the Uranus perturbation) were identical to the hundredth-arcsecond with those presented by Adams thirteen months later to the RAS: would he really have found no further cause to recalculate them?

Airy replied to Adams’ note on November 5th, thanking him for ‘the paper shewing the perturbations on the place of Uranus’ The perturbation of Uranus’ orbit, as had been of much concern to the astronomers of Europe for a couple of decades, was around one arcminute. Speculation was ongoing as to whether it resulted from the action of an unknown planet, and Airy was Britain’s top expert on the subject. However, the Adams note as later produced by Airy did not contain these, but only columns of ‘residuals’ of around one arcsecond. No-one could make any sense of them, unless Adams’ calculation procedures were first explained, which the note certainly didn't do.

The Great Day: When Was It?

Airy put Adams's visit to the RGO at the ‘end of October’ (Account p.395). Adams diary is missing over this period, but he first recalled that it was ‘about’ the 20th of October (letter to Airy on 15th October). Then, in an undated memoir, he recalled that
"The paper containing the statement of my results was left at the Royal Observatory in October 1845, when I was returning to Cambridge from my vacation. I am not certain on the day, but I think it was about the 10th of October ... Mr Airy says it was left at the Obsy. on one of the last days of Octr. but I think that must be a mistake."
(John's College Archives, 20.23.2). So neither of them could recall the date. This didn't prevent Grosser from assigning the date of 21st October to the visit, placing it on the front cover of his book (1962), with no reference. Adams wrote the letter to his parents on the 23rd so it must have been before then.

Accounts of Adams' visit to Greenwich always involve the Airy family having a late lunch and a recalcitrant butler omitting to deliver Adams' vital message. Humorous comments are made, about blaming the butler. Such accounts always omit the one written testimony on the matter, that by Mrs Richarda Airy to Sedgwick (Dec. 5th, 1846). It is here quoted - for the first time! Her recollection is not well compatible with the time-honoured story. Airy was accused of "snubbing" Adams by not receiving him, from which he suffered much, and Mrs Airy responded to this allegation:

"I quite well recollect Adams's calling, after George's return from abroad, and seeing his card brought into the room: but George had gone out perhaps to London, or more likely for the daily walk which is absolutely necessary for his health, and so Mr Adams did not see him. But George wrote to him directly ... And as for "snubbing," I cannot think what this means, unless they say that George's being out of the house when Adams called was "snubbing" him."

She returned to this theme a few days later (December 9th) in another letter to Sedgwick, as regards whether Adams might have called once more, while the Airys were having dinner. She was evidently under pressure from the telling of such a story - which continues to this day, see e.g. Tom Standage's recent 'The Neptune File,' p.79. "I have no recollection of Mr Adams's second call, while we were at dinner, ever being mentioned. And I think it most likely that it was not mentioned," she wrote.

Airy remembers

Soon after Airy had received his copy of the Comptes Rendus with Leverrier's June 1st 1prediction - which apparently took three weeks to reach him - he wrote on June 25th to William Whewell about how the two predictions converged (See "Correspondence" for excerpt) The first page of this important letter is reproduced below. (It was discovered by Neptune scholar Robert Smith, as reported in his 1989 Isis article.) The letter doesn't indicate that Airy still has a document which Adams gave him, but merely that he recalls having seen it. As regards when he received Adams' note, all it tells us is that it was 'prior to' that of LeVerrier's June paper that he had received a few days earlier - which, as Denis Rawlins observed, doesn't sound much like an allusion to the previous year..

Extract of letter from Airy to Whewell, June 1846, Trinity college archives.

Whewell letter (0-15-48-4), by permission of the Master & Fellows of Trinity College, Cambridge