Vol. V No. 21 



December 19, 1915 



JOURNAL 



OF THE 



WASHINGTON ACADEMY 



OF SCIENCES 



BOARD OF EDITORS 

 FREa>. E. Wright William R. Maxon Edson S. Bastw 



OBOPHTSICAL LABOBATOBT NATIONAL UUBSUM QSOLOaiCAL BURTXT 



PUBLISHED SEMI-MONTHLY 

 EXCEPT IN JULY, AUGUST, AND SEPTEMBER. WHEN MONTHLY. 



BT THB 



WASHINGTON ACADEMY OF SCIENCES 



OFFICE OF PUBLICATION 



THE WAVERLV PRESS 



BALTIMORE, MD. 



Entered as seooad-class matter July 14, 1911, at the post ofiSoe at Baltimore, Maryland, under me Aot of 



July 16, 1894 



