British Accounts of Neptune’s Discovery, 1852 - 2000
1852 History of Physical Astronomy, Ch.12 by Robert Grant p124-164,
Appendix 603-617. (35 pages).
1896 Biographical Notice, foreword to The Scientific Papers of
J.C.Adams Vol.1, ppi – xxxi (30 pages) by James Lee Glaisher,
FRS, son of James Glaisher.
Over the century after the discovery, all five of the main authors
who told the story between 1852 and 1947 were at some stage RAS
presidents: Glaisher, Turner, Sampson, Smart and Spencer-Jones .
Adams had twice been president. Naturally, they were all cantabs,
all but one being from Trinity or John's College (see:"
A Cantab. clique?").
1904 Astronomical Discovery Herbert Turner.
Glaisher studied at Trinity college, Cambridge, was on the Greenwich
staff from the 1830s to the 1870s, attained eminence in astronomy
and mathematics, knew both Airy and Adams, and was offered but declined
the post of Astronomer Royal after Airy. He had originally been
an assistant to Airy in Cambridge. RAS President 1886-8 and 1901-3.
Turner was at Trinity College, Cambridge. He became
Chief Assistant at the RGO 1884-1894, after which he became Savilian
Professor of Astronomy at Oxford. RAS President 1903-4
1904 A Description of Adams’s Manuscripts on the Perturbations
R.A.Sampson FRS Memoirs of RAS, LIV, pp.143-161.
Sampson was at John’s College Cambridge, and was RAS President
in 1915, then became Astronomer Royal for Scotland.
1947 John Couch Adams and the Discovery of Neptune , in ‘Occasional
Notes of the RAS’, vol.2 33-88, by William Smart.
1947 John Couch Adams and the Discovery of Neptune Harold Spencer
Smart was at Trinity college, Cambridge, then became the first ‘John
Couch Adams Astronomer’ of the University of Cambridge, and
wrote a textbook on positional astronomy. He was RAS President 1949-51.
1953 The Discovery of Neptune, A.Pannekoek, Centaurus 3 126-37 (11
pp). 1962 The Discovery of Neptune, Morton Grosser, from PhD at Harvard,
in 1961, 167 pp. HUP.
1988 Private Research and Public Duty: George Biddell Airy and
the Search for Neptune, Allan Chapman, Journal for the History of
Astronomy 1988 19 121-39. (18 pp)'
1989 The Cambridge Network in Action: The discovery of Neptune
Robert Smith, Isis
1989, 80, p.395-422. 1997 In Search of Planet Vulcan Chs 7,8 Richard
Baum & William Sheehan
Spencer Jones was at Jesus’ college, Cambridge, then Chief
Assistant at the RGO 1913-23, then the Astronomer Royal , RAS President
1937-9, then became President of the IAU 1945-48.
2000 The Neptune File, Tom Standage, Penguin Press.
‘The Neptune File’
This is a two-inch thick wad of relevant documents collated by Airy,
and, as Turner commented in 1904:
‘The letters reproduced in this [i.e., Turner;’s] "account"
are still in the Observatory at Greenwich, pinned together just
as Airy left them’ (p.48).
The file has returned from a clandestine journey
to Australia and Chile, c.1965-1999, and now resides quietly in
the Cambridge University Library (see "Eggen
Takes the Papers"). Only three of the above accounts allude
to this file. Turner's account quoted from various letters, eleven
of them, all cited in Airy's Account. He abbreviated them just as
Airy had done, and as Airy omitted phrases, so did he. In the July
9th letter of Airy to Challis, Airy had omitted the key phrase 'a
possible shadow of':
'You know that I attach importance to the examination of that part
of the heavens in which there is ... reason for suspecting the existence
of a planet exterior to Uranus.'
No historian would, given the choice, reiterate so crucial an act
of censorship. These things suggest that in 1904 Turner had no access
to the RGO's Neptune file. Clearly, however, he had seen it! This
suggests that it enjoyed a highly secretive status, as not subject
to prying eyes. Allan Chapman’s 1988 article was the first
after Turner to refer to it, as missing.
William Smart’s account in 1946 cites a letter to Airy from
Sedgwick, then surmises: ‘Airy evidently replied on 1846 December
8, to this letter, as may be gathered from,’(p.74) indicating
that he did not have access to the complete file. Morton Grosser’s
book written in 1962 did not allude to the file either in its text,
where he was unaware of the intense correspondence of seven letters
between Airy and Sedgwick over December 2-9th 1846, nor in its extensive
bibliography. Tom Standage, who wrote ‘The Neptune File’
soon its recovery, appears to have been the first person who both
saw the file and used it to give a historical account - which is
curious. Whether he fully apprehended its implications, before rather
quickly re-telling the traditional story, is another matter.
The Essential Illusion
Glaisher’s account (1896) fifty years after the discovery
reiterated Airy’s bogus claim, made brazenly before the Royal
Astronomical Society on November 13th 1846, that
‘The position thus assigned by Le Verrier to the disturbing
planet differed by only 1 degree from that given by Adams in the
paper which he had left at the Royal Observatory more than seven
months before.’ (p.xviii)
They differed by over four degrees. One here needs to compare true
helio longitudes, at the same epoch (see "Within
one Degree"). The ‘within one degree’ concept
was a vital part of the myth built up of Adams’ prediction,
and had the advantage that persons re-telling the story did not
have to bother about the confusing astronomical details.
To some extent, the confusion resulted from Adams’ ‘predictions’
being given as mean rather than true helio longitude. Owing to the
large eccentricities involved, the Equation of Centre which converts
mean helio long. to true required four terms in its expansion, which
would no doubt have been hard work. The relevant calculations were
however given in John Herschel’s Outline of Astronomy 1852,
which Glaisher would have consulted.
Journeys of the Neptune-Papers
Sir Donald MacAlister collected and preserved the diaries, letters
and papers of Adams, whom he knew well. In 1907 MacAlister became
employed at Glasgow University and so the papers went North, then
they journeyed South again when he retired back to Cambridge. He
there copied out many of the other Neptune-discovery manuscripts,
which is fortunate as his handwriting is now more legible than the
faded originals. On his death in 1929 the papers passed to William
Smart, who obtained a position at Glasgow university so the papers
went North again. When in 1959 they returned South, they were presented
to St John’s College archive. They remained, surprisingly
inaccessible to scholars, in 19 unsorted boxes. In 1990 MacAlister’s
niece presented some more papers to St John’s, which she had
found in her attic. The 150th anniversary in 1996 focussed sufficient
interest on the subject, for a comprehensive computer-indexing to
take place at John’s , as was completed early in 1999.
This website shows a fragment of Adams’ diary for 1846, which
I obtained in 1999 merely by asking for it at St John’s library
archives (see:"Adams’ forgotten
Diary"). No previous scholar (it would appear) had seen
it! Equally, MacAlister’s copy of the rather censored letter
by Airy of December 8th Sedgwick, was available on request, although
top Neptune-discovery scholars Allan Chapman and Dennis Rawlins
had earlier been unable to obtain it. The recovery of Britain’s
Neptune-file synchronously with the becoming-accessible of the Adams
Archives at John’s, both in the year 1999, means that, at
last, one can begin to tell the story!