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VOLUME 8 MARCH, 1922 NUMBER 3 
PROCEEDINGS 
OF THB 
National Academy 
OF Sciences 
OP THE 
UNITED STATES OF AMERICA 
EXECUTIVE COMMITTEE 
Edwin Bidwell Wilson, Managing Editor 
Raymond Pearl Vernon Kellooo 
I PUBUSHBD MONTHLY | 
1 Publication Office: Eschenbach Printing Company, Easton, Pa. | 
I Editorial Office: Massachusetts Institute of Technology, Cambridge 1 
i Home Office of the Academy: Washington, C. 1 
B ■ ' M 
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Entered as aecond-ciasa matter June 21, 1920, at the postoflSce at Baston, Pennsylvania, under the act of August 24, 1912. 
Acceptance for mailing at special rate of postage provided for in section 1103, Act of October 3, 1917, Authorized June 18, 1920. 
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