‘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
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
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& the discovery of Neptune’ 1996 unpublished p.4)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
"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.
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