178 



PROCEEDINGS OP THE AMERICAN ACADEMY 



Adopting the following values of r, and using the star places given in 

 the catalogue of 529 stars issued by the Astronomischen Gesellschaft, 

 we have the data, — 



For Harvard College Observatory, t = — 16^260 ; 

 For "Waltham, Mass., t = — 42 .855 ; 



1«77, October, 17''.4. 



and the following values o{ y : — 



