TII i: MI: I:IT OF URANUS. H3 



It will be seen that the effect of th< - changes of weights is, that the older 

 oli-ervations ;in- a little better, and the later a little \\orse represented. I conct i\e 

 that our choice must lie between the first and third solutions the tiist being the 

 more probable it \ve conceive tlie outstanding re>iduals to he due to errors of 

 oliM nation only, and the third if we suppose them c<iuully due to errors of com- 

 putation. On the whole, I consider the mean of the two to be about the most 

 probable, and this will give the muss of Neptune very near the round number 



1 

 I97(M) 



which will be adopted as the definitive value. The definitive corrections to 

 Elements III (p. 9'J) will then be 



fc' (1830) 3".56 



fe (1850) -12.45 



10Sn 4.44 



oe - 4.12 



eon - 0.25 



op - 0.137 



Corrections to the Inclination and Nide. 



These corrections have been derived entirely from the modern observations, the 

 ancient ones being too uncertain to add anything to the weight of the result. The 

 mode in which the correction to the latitude of the provisional ephemcris has been 

 concluded from the observations has been sufficiently explained : it is only necessary 

 to add that the immediate results from the data of the preceding chapter require 

 two corrections, namely: 



(1) A correction to the theoretical latitude for the change in the adopted mass 

 of Neptune. The value of this correction, as derived from the data of Chapter V, 

 is with sufficient approximation 



(2) A correction to the observed latitude on account of the difference between 

 the obliquity of the ecliptic adopted in the various ephemerides compared, and that 

 of llansen's Tables du Soleil, which having been adopted in the theory should be 

 used throughout. 



Applying the correction (2) (1) to all the observed latitudes, we have the 

 following corrections to the latitude of the provisional ephemeris derived from all 

 the observations of each opposition since 1781. The third column gives the 

 number of observations in declination. These numbers may, however, in some 

 cases be inaccurate. The fourth and fifth columns give the sine and cosine of the 

 argument of latitude, to be used in forming the equations of condition. 



