130 



for each year were collected in groups, according to the value of 

 (), so that each group contained a range of 20°; the mean for each 

 group was taken to hold for the mean value for g in that group. 



In this way, T got for each year 18 equations of the form 

 c-^ /i sing -\-k cos g = r, in which c is the residual error in the mean 

 longitude for that year and h and k have the same meaning as in 

 Newcomb's investigation. The errors are taken in the sense calculation 

 minus observation. These equations were now solved for eacli year 

 by the method of least squares, taking the weights for each group 

 proportional to the number of observations. 



This gave the following results: 



