“‘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 suggests Adams’ visit to Greenwich. 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.
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° 30′.9 | |
| Mean longitude, 1st October 1845 | 323 34 | |
| Longitude of perihelion | 315 55 | |
| Eccentricity | 0.1610. | |
| Mass (that of the sun being unity) | 0.0001656. |