BIOGRAPHICAL NOTICE. xxi 



for eight weeks before the planet was found at Berlin. Adams's first complete in- 

 vestigation may be regarded as having been finished on October 21, 1845, when he left 

 his paper at the Royal Observatory. This was three weeks before Le Verrier presented to 

 the French Academy his first memoir, in which it was shown that the irregularities in the 

 motion of Uranus could not be attributed to the known planets, and seven months before 

 the date of presentation of his second memoir in which he first investigated the orbit of 

 the supposed disturbing planet. As we know, Adams had resolved to undertake the work 

 in 1841, and his first rough solution was effected, as soon as he had leisure, in 1843. 

 We may presume that Le Verrier did not attempt to determine the position or orbit 

 of the disturbing planet until after the completion of his memoir of November 10, 1845. 



The discovery of the actual planet by Dr Galle, in consequence of Le Verrier's pre- 

 diction, was received with the greatest enthusiasm by astronomers of all countries, and the 

 planet was at once called " Le Verrier's Planet." Adams's work was only known to the 

 Astronomer Royal, Challis, and a few other persons, chiefly private friends. The first public 

 mention of Adams's name occurred in a letter to the Athenceum from Sir J. Herschel, 

 which appeared under the heading " Le Verrier's Planet" in the number for October 8, 

 1846. In this letter, which is dated October 1, Herschel refers to the address he had 

 delivered on September 10, on the occasion of resigning the Presidential Chair of the 

 British Association at Southampton, in which, after referring to the astronomical events 

 of the year, which included the discovery of a new minor planet, he added: "It has 

 done more. It has given us the probable prospect of the discovery of another. We see 

 it as Columbus saw America from the shores of Spain. Its movements have been felt, 

 trembling along the far-reaching line of our analysis, with a certainty hardly inferior to 

 that of ocular demonstration." 



To justify the confidence which these words express, Herschel first describes a 

 conversation with Bessel in 1842, in which the latter had said that it was highly 

 probable that the deviations of Uranus might be due to an unknown planet (being 

 systematic, and such as an exterior planet would produce), and then proceeds: 



"The remarkable calculations of M. Le Verrier, which have pointed out, as now 

 appears, nearly the true situation of the new planet by resolving the inverse problem 

 of the perturbations if uncorroborated by repetition of the numerical calculations by 

 another hand, or by independent investigation from another quarter would hardly justify 

 so strong an assurance as that conveyed by my expressions above alluded to. But it 

 was known to me at that time (I will take the liberty to cite the Astronomer Royal as 

 my authority) that a similar investigation had been independently entered into, and a 

 conclusion as to the situation of the new planet very nearly coincident with M. Le 

 Verrier's arrived at (in entire ignorance of his conclusions) by a young Cambridge mathe- 

 matician, Mr Adams, who will, I hope, pardon this mention of his name (the matter 

 being one of great historical moment), and who will doubtless in his own good time and 

 manner, place his calculations before the public." 



This passage seems to have passed almost unnoticed by astronomers, in the 

 excitement produced by Le Verrier's discovery, and it was not till October 17, when a 

 letter from Challis appeared in the Athenceum, giving an account of the proceed- 

 ings at Cambridge in connexion with the new planet, that general attention was 

 directed to Adams's calculations. It was then known for the first time that his 



