Vol. V No. 12 



June 19, 1915 



JOUENAL 



OF THE 



WASHINGTON ACADEMY 



OF SCIENCES 



BOARD OF EDITORS 

 Fbed. E. Wright William R. Maxon Edson S. Bastin 



OXOFHYBICAL LABORATOBT ' NATIONAL MUSEUM OSOLOaiCAX BUBTBT 



PUBLISHED SEMI-MONTHLY 

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



BT THB 



WASHINGTON ACADEMY OF SCIENCES 



OFFICE OP PUBLICATION 



THE "WAVERLV PRESS 



BALTIMORE, MD. 



