.
Adams the means of carrying on in the most effective manner the
inquiry in which he is engaged.'

"The next letter shows that Mr. Adams has derived results from these
errors.

No. 9.--PROFESSOR CHALLIS _to_ G. B. AIRY.

"'CAMBRIDGE OBSERVATORY, _Sept. 22, 1845_.

"'My friend Mr. Adams (who will probably deliver this note to you)
has completed his calculations respecting the perturbation of the
orbit of _Uranus_ by a supposed ulterior planet, and has arrived at
results which he would be glad to communicate to you personally, if
you could spare him a few moments of your valuable time. His
calculations are founded on the observations you were so good as to
furnish him with some time ago; and from his character as a
mathematician, and his practice in calculation, I should consider the
deductions from his premises to be made in a trustworthy manner. If
he should not have the good fortune to see you at Greenwich, he hopes
to be allowed to write to you on this subject.'

"On the day on which this letter was dated, I was present at a
meeting of the French Institute. I acknowledged it by the following
letter:--

NO. 10.--G. B. AIRY _to_ PROFESSOR CHALLIS.

"'ROYAL OBSERVATORY, GREENWICH, _1845, Sept. 29_.

"'I was, I suppose, on my way from France, when Mr. Adams called
here; at all events, I had not reached home, and therefore, to my
regret, I have not seen him. Would you mention to Mr. Adams that I am
very much interested with the subject of his investigations, and that
I should be delighted to hear of them by letter from him?'

"On one of the last days of October 1845, Mr. Adams called at the
Royal Observatory, Greenwich, in my absence and left the following
important paper:--

No. 11.--J. C. ADAMS, Esq., _to_ G. B. AIRY.

[Sidenote: Adams' announcement of the new planet.]

"'According to my calculations, the observed irregularities in the
motion of _Uranus_ may be accounted for by supposing the existence of
an exterior planet, the mass and orbit of which are as follows:--

Mean distance (assumed nearly in accordance
with Bode's Law) 38.4
Mean sidereal motion in 365.25 days 1 deg.30'.9
Mean longitude, 1st October 1845 323 34
Longitude of