28 



labors for the U. S. Coast Survey did not allow sufficient leisure lor completing 

 the task with the requisite despatch. I theretore deferred it to a future day, 

 and availed myself of the kind offer of Frof Peirce to furnish me in due season 

 with an Fphemeris of the perturbations of Neptune by all the other planets. 

 Prof Peirce's first Ephemeris of these perturbations \yas communicated to me 

 in November, 1847. The year of Neptune, assumed as the basis of Prof. 

 Peirce's computations, was double of that of Uranus, and the eccentricity of 

 Neptune's orbit was omitted. 



No. 37. Being now in a condition, through the friendly communication of 

 Prof Peirce, to resume the research with better prospect of success, I extended 

 the Ephemeris of Neptune, in R. A. and Dec, from the 30th of April, 1847, to 

 the 1st of February, 1848, and compared with it all the European and American 

 observations received to the 1st of December, 1847. In this manner were 

 obtained the following normal corrections of the Ephemeris from Elements IV, 

 in R. A. and Dec. 



THIRD GEOCENTRIC NORMAL PLACES OF NEPTUNE. 



Equatorial. 





Obs.— Eph. IV. 



A A 



No. 

 Obs. 



Obs.-Eph. IV. 

 A D 



No. 

 Obs. 





A 



-^-^ 



A 







// 



// 





1847, April 6 



— 1.65 



27 



— 0.67 



41 



May 9 



— 3.52 



20 



— 2.98 



30 



June 1 



— 0.30 



5 



— 4.16 



10 



June 23 



— 7.63 



12 



— 5.53 



20 



July 8 



— 6.73 



5 



— 5.96 



10 



July 31 



— 5.93 



17 



— 5.52 



15 



Aug. 12 



— 6.99 



12 



— 5.50 



11 



Aug. 22 



— 7.65 



19 



— 6.58 



19 



Sept. 7 



— 7.33 



4 



— 5.83 



4 



Sept. 18 



— 8.24 



3 



— 6.09 



8 



Sept. 27 



— 11.77 



3 



— 7.07 



3 



Oct. 4 



— 10.33 



2 



— 7.08 



2 



Mer. & Eq. 



By extending Ephemeris IV, corrected by the normal places, back to August 

 20, 1 derived an estimated opposition for 1846. That of August 22 served for 

 1847. By means of the two, there was found the correction of the angular 

 motion of Neptune by Ephemeris IV, from August 20, 1846, to August 22, 1847, 

 that is, for a synodic year. Also, a value was obtained for the synodic year 

 from September 26, 1846, to September 28, 1847. In both instances, the effect 

 of change of the relative perturbations from Prof Peirce's 1st Ephemeris was 

 taken into account. The results are, for the true average daily sidereal motion : 



// 

 Ephemeris from Elements IV . . . j/ = 21.64548 



(A) .... By the two oppositions, 1847, April 30, v = 21.62637 



(B) .... By the two normal places v— 21.60833 



Mean of (A) and (B) adopted . . . v =. 21.61735 



