COMPARISON OF CATALOGUES OF STARS. 



395 



Auwers minus Harvard College. — Continued. 



Auwers minus Safford. 



In the reduction of a given series of observations from the system of one funda- 

 mental catalogue to that of another system, it is obvious that the most independent 

 method of procedure would be to apply to the given series the sj-stematic corrections 

 derived from comparing the system upon -which it is based with that to which it is to 

 be reduced. The fact already stated that the Harvard College Catalogue for 1875 

 depends upon two systems which differ systematically, makes it imperative that the 

 comparison shall be made directly with the system of Auwers. There is also an addi- 

 tional consideration which makes it necessary that this course should be pursued. It 



