332 PROCEEDINGS OF THE AMERICAN ACADEMT 



" The ephemeris from these elements II., after applying the values 

 of the perturbations 8 v and S r, from your paper of Dec. 17th, 1847, 

 before referred to, requires, in order to conform to observation, the 

 following corrections in R. A. and Dec. 



The agreement is so close, that I shall not attempt any farther appro.xi- 

 mation towards the true elements till after the next opposition has 

 been observed. For the Lalande observations, I have used Mauvais's 

 places from the Comtes Rendus. They furnish internal evidence of 

 their excellence, by their perfect representation of the two days' mo- 

 tion of the planet. 



" Yours, truly and respectfully, 



" Seaks C. Walker." 



Professor Peirce communicated a memoir from Mr. G. P. 

 Bond, on the direct computation of the orbit of a comet, from 

 three observations of its right ascension and declination, and 

 remarked upon the clear and simple views which Mr. Bond 

 had taken of the subject. 



Professor Peirce announced that he had completed his in- 

 vestigation into the action of Neptune upon Uranus, and had 

 ascertained that this planet will completely account for the 

 observed irregularities in the motions of Uranus, provided that 

 mass of Neptune is adopted which is derived from Mr. Bond's 

 observations of Lassell's satellite. 



" The following table exhibits the residual differences between the 

 observed and computed longitudes of Uranus, from which it appears 

 that, with the mass of Neptune deduced from Mr. Bond's observations 

 of Lassell's satellite, the theory of Uranus is now perfect, and the 

 motions of this planet do not indicate that there is any other unknown 

 source of perturbation. It appears, moreover, that the mass which is 



