PHILOSOPHICAL SOCIETY OF WASHINGTON 
BULLETIN. Vol. XV, no. 1-26 
SAMU E L 
P1ERPONT LANGLEY 
• 
•*“ 
t 
BY 
CYRUS ADLER 
Read before th 
Hi Philosophical Society of Washington 
November *24, 1906 
WASHINGTON 
PUBLISHED BY THE SOCIETY 
January, 1907 
