190 PROCEEDINGS OF THE AMERICAN ACADEMY 



The three companions about which no doubt is entei'tained are, — 



It is quite possible that there may be one or two more. It is easy 

 to understand why these have not been seen before, as the early ex- 

 aminations were principally for the purpose of detecting the existence 

 of Struve's companion, and as the very finest atmospheric conditions 

 are required for their certain detection. It is believed, however, that 

 even in ordinarily good seeing two can be seen. 



