Till: OK BIT OF URANUS. Hi 



tin- ill. M nations. Tin- mean corrections in geocentric longitude for groups of 

 obsenatioiis are gi\cn iii column* (>'), ciAumn (1) showing tin- correction given 

 by the work of tlie lust chapter. 



Opposition isr,i-2 I-* -2 .; i-: 



(1) (-') (1) (2) (1) (2) 



+2".8 +2".4 : +2".6 +2-.6, 8'.6 -9'^ 



2.9 -J.4, 2 .8 2.3, -8.5 8.1, 



3.0 3.1, 2.1 2.0, -7.3 -7.5, 



2.4 2.4, 3.3 2.9 4 -7.3 7.7. 



>.(> 2.7, 7 .8 7 .6, 



M an +'2 .79 +2.6-2 +'>.(>:> ,2.50 7.65 7.82 



A systematic difference of OM6 would seem to be indicated, and on account of it 

 a correction of OMO was applied to the comparisons of the lust few years in 

 forming the equations of condition. 



In view of the possibility of systematic errors from this source it may be con- 

 sidered that too great relative weight lias been assigned to the results of the later 

 observations. If the residuals arise from errors of comparison and of theory, their 

 probable magnitude is nearly as great at one epoch as at another. It may there- 

 fore be interesting to inquire what result we should get if, instead of assigning 

 Midi different weights to the comparisons at different epochs, we sought only for 

 the best general agreement with observations during the period the planet has 

 been observed. The preceding system of mean residuals will enable us to discuss 

 this question quite easily. In the first solution we shall reject the results from 

 Flamstead's observations, owing to their assured uncertainty, and those from 

 I.e Monnier's of 1769, owing to the possible maladjustment of his quadrant. The 

 equations from the remaining residuals will be the following: 



