OF ARTS AND SCIENCES. 185 



X. 



THE COMPANIONS OF PROCYON. 



[Communicated by Rear-Admiral C. H. Davis, Superintendent of the Naval Ohser- 



vatori], Washinijton.] 



Bead, Feb. 9, 1876. 



The discovery in 1862, by IMr. Alvan G. Clark, of a companion of 

 Sirius very near the place indicated by the theory proposed by Bessel 

 to account for the variable proper motion of this star, naturally led 

 astronomers to an examination of Procyon, a star which also has a 

 variable proper motion. On March 19, 1873, a companion of Procyon 

 was discovered by JNIr. Otto Struve, Director of the Pulkowa Observa- 

 tory, near the place indicated by the theory of Professor Anwers. 



As soon as the 26-inch refractor of the Naval Observatory was 

 ready for use, Professors Newcomb and Holden began an examina- 

 tion of Procyon, which has been continued, on convenient occasions, to 

 the present time. 



Struve's companion has not been seen by either of these astrono- 

 mers ; nor, indeed, by any one who has examined the star through our 

 instrument. Another companion, however, was soon suspected ; and 

 the existence of this and other companions has now been so well 

 established that an account of the examination of this star will be 

 interesting. 



EXAMINATION OF PROCYON FOR THE DETECTION OF STRUVE'S 



COMPANION. 



[Extracts from Observing BooJc.s.) 



(1) 1873. Nor. 29. Procyon carefully examined, and all small stars within 2' 



mapped down. Struve's companion not seen. Seeing 

 very good, except possibly a slight haze. Observer: 

 Newcomb. 



(2) 1873. Dec. 30. Examined Procyon. Struve's companion not seen. New- 



comb. 



(3) 1874. Jan. 2. Procyon's distant companion measured. Struve's com- 



panion not seen. Newcojib. 



