Vol. III. No. 10. 



May 19, 1913. 



JOURNAL 



OF THE 



WASHINGTON ACADEMY 



OF SCIENCES 



BOARD OF EDITORS 

 Frederick Leslie Ransoms Carl S. Scofield Fred. Eugene Weight 



GEOLOGICAL SURVEY BUREAU OP PLANT INDUSTRY GEOPHYSICAL LABORATORY 



PUBLISHED SEMI-MONTHLY 

 EXCEPT IN JULY, AUGUST AND SEPTEMBER, WHEN MONTHLY. 



BY THE 



WASHINGTON ACADEMY OF SCIENCES 



OFFICE OF PUBLICATION 



THE WAVERLY PRESS 



BALTIMORE, MD. 



