PHILOSOPHICAL SOCIETY 
WASHINGTON. 
VOL. X. 
1887. 
Containing the Minute.s of the Society and of the Mathematical 
Section for the year 1887; together with the pro¬ 
ceedings of the Baird Memorial Meeting 
AND 
AN INDEX TO THE FIRST TEN VOLUMES. 
PUBLISHED BY THE CO-OPERATION OF THE SMITHSONIAN INSTITUTION. 
WASHINGTON: 
1888. 
