170 



PROCEEDINGS OF THE AMERICAN ACADEMY 



result is exhibited, save for the first pair. The probable errors (1) are 

 derived from the estimated values as derived from the separate stars, 

 and the probable error of one observation ±0"428 as given by Dr. 

 Kampf. 



PAIRS TWICE OBSERVED. 



PAIRS THREE TO SIX TIMES OBSERVED. 



AVERAGE NUMBER, FOUR.* 



* The number of observations now makes but a trifling difference in the prob- 

 able errors. 



