10 



The solar co-ordinates X, Y, and Z, were then taken from the tables in the 

 Nautical Almanac, and the apparent Right Ascension, A^, and Declination, 

 Dq, of Neptune, (increased by the geocentric motion in the aberration time,) were 

 obtained from the ordinary formulae, already referred to, applied to the geocen- 

 tric co-ordinates. The apparent values. 



D = Do — ( -JY' ' "^ ' 



were obtained by interpolation from the primitive results. 



The Ephemerides for the years 1846, 1847, 1848, and 1849, are here ap- 

 pended. 



Yours, truly and very respectfully, 



SEARS C. WALKER. 



