Vol. V No. 10 



May 19, 1915 



JOURNAL 



OP THE 



WASHINGTON ACADEMY 



OF SCIENCES 



BOARD OF EDITORS 

 Frkd E. Wbiqht Wiluam R. Maxon Edson S. Bastin 



OaOFHTSICAL LABORATOBT KATIOHAL MUBBUM QBOLOOICAi •UBVB'T 



PUBLISHED SEMI-MONTHL"i 

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



BT TRB 



WASHINGTON ACADEMY OF SCIENCES 



OKFICB OP PUBLICATION 



THE WAVERLT PRESS 



BALTIMORE, MD. 



