NOTES. CXXX1X 



C 88 ) p. 391. Le Verner, Recherches sur les Mouvemens de la Planete 

 lerschel, 1846, fn the Connaissauce des Temps pour Tan 1849, p. 254. 



( 639 ) p. 391. The very important element of the mass of Neptune has 

 gradually increased from 2o | af according to Adams, Tsi^ir according to 

 Peirce, l5 ^ OQ according to Bond, and rsrwo according to John Herschel ; to 

 \S4a^ according to Lassell, and i4 ^ 4( i according to Otto and August Struve. 

 The last-named Pulkowa result has been adopted in the text. 



O 540 ) p. 392. Airy, in the Monthly Notices of the Royal Astr. Soc. Vol. 

 vii. No. 9 (Nov. 1846), p. 121 152 ; Bernhard von Lindenau, Beitrag. 

 zur Gesch. der Neptun's-Entdeckung, S. 1 32 and 235 238. Le Verrier, 

 at the instance of Arago, began in the summer of 1845, to work at the theory 

 of Uranus. He laid the results of his investigation before the Institute on 

 the 10th of Nov. 1845, the 1st of June, 31st of August, and 5th of Oct. 

 1846, and published them at once ; but his greatest and most important 

 work, which contained the solution of the whole problem, only appeared in 

 the Connaissance des Temps poor 1'an 1849. Adams, without printing any- 

 thing, laid the first results which he had obtained for the perturbing planet 

 before Professor Challis, in September 1845, and the same, with some modi- 

 fication, in the following month, Oct. 1845, before the Astronomer -Royal, 

 still without publishing anything. The Astronomer-Royal received from 

 Adams his final results, with some fresh corrections relating to a dimi- 

 nution of the distance, in the beginning of September 1846. The young 

 Cambridge geometrician has expressed himself with noble modesty and 

 self-denial on the subject of this chronological succession of labours, which 

 were all directed to the same great object : " I mention these earlier dates 

 merely to shew that my results were arrived at independently, and pre- 

 viously to the publication of M. Le Verrier, and not with the intention of 

 interfering with his just claims to the honours of the discovery ; for there is 

 no doubt that his researches were first published to the world, and led to the 

 actual discovery of the planet by Dr. Galle : so that the facts stated above 

 cannot detract in the slightest degree from the credit due to M. Le Verrier." 

 As in the history of the discovery of Neptune mention has often been made 

 of the early participation of the great astronomer of Kouigsberg in the expec- 

 tation already expressed in 1834 by Alexis Bouvard (the author of the 

 Tables of Uranus), that the perturbations of Uranus might be caused by 

 planet still unknown to us, I think it may perhaps be agreeable to some of 

 my readers that I should publish here a portion of a letter written to me by 

 BessclJ, under date 8th May, 1840, two years, therefore, before his conver- 



