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VOLUME 8 JUNE, 1922 NUMBER 6 
PROCEEDINGS 
OF THE 
National Academy 
OF Sciences 
OF THB 
UNITED STATES OP AMERICA 
EXECUTIVE COMMITTEE 
I Edwxn BiDweLL Wilson, Managing Editor 
Raymond Pearl Vernon Kellogg 
I PUBLISHED MONTHLY | 
I Publication Ofi&ce : Eschenbach Printing Company, Easton, Pa, \ 1 
I k Editorial Office: Massachusetts Institute of Technology, Cambridge 1 
1 ' Home Office of the Academy: Washington, D. C. 1 
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Bntered as second-class matter June 21, 1920, at the postoffice at Easton, Pennsylvania, under the act of August 24, 1912. 
Acceptance for mailine at special rate of postage provided for in section 1103, Act of October 3, 1917. Authorized Jan* 18, 1920, 
Price per annum, $^.00 
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