18 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



to investicrators of orbits and to double-star observers. In 

 the same volume Mr. Gledhill, of Mr. Edward Crossley's 

 observatory at Halifax, gives the results of his measures of 

 484 doubles, which were made in concert with those of the 

 Rugby Observatory, Mr. Gledhill observing those stars not 

 taken by Rugby, in a list common to both observatories. 

 Particular attention has been paid to the subject of binary 

 stars, and it is announced that a work is in preparation on 

 this topic. 



Already the joint labor of these two observatories has de- 

 cided the question of orbital motion in many cases. 



ON THE ORBIT OF THE DOUBLE STAR 2 634. 



Otto Struve states that in preparing his micrometric meas- 

 urements of double stars for publication, he came upon the 

 star 2 634, whose movements seemed to have especial interest. 

 When the elder Struve compiled his well-known catalogue 

 of new stars, the distance of the two from each other was 

 nearly 37". Their brightness was, on the average, as de- 

 duced from many estimations, respectively 4.5 and 7.9. To 

 the orreat distance of these stars from each other is to be at- 

 tributed the fact that they have been measured but seldom 

 by good observers. At present the stars are about 20" 

 apart ; their respective proper motions are nearly identi- 

 cal, but in direction are opposite to each other, and we are 

 obliged to conclude that the two bodies may, in all proba- 

 bility, have some physical connection with each other, and 

 are not merely optically double. Bulletin Acad. Imp. des 

 Sciences, St. Petersburg.^ V. 



THE COMPANION OF SIRIUS. 



It has been noted that the Washino-ton observations of 



Clark's companion oi Sirius do not agree with the computed 



positions from the theory of Auwers; the corrections to 



Auwers are 



1872.25 -5.6in;> +0.40" in s. 



1874.18 -6.3 ill p -0.46" in s. 



1875.24 -7.2 in p -0.72" in s. 



This is confirmed by the measures of Mr. W. Erck, of Ire- 

 land, who, under date of March 21, 1876, gives its position- 

 angle as 55. The Washington observations for 1876 give 



