

VOL. XXXYII. APRIL, 1914. 



Established by BENJAMIN SILLIMAN in 1818. 



THE 



AMERICAN 



JOURNAL OF SCIENCE. 



Editor: EDWAED S. DANA. 



ASSOCIATE EDITORS 



Professors GEOEGE L. GOODALE, JOHN TEOWBEIDGE, 

 W. G. FAELOW and WM. M. DAVIS, of Cambridge, 



Professors ADDISON E. VEEEILL, HOEACE L. WELLS, 



LOUIS V. PIES SON, HEEBEET E. GEEGOEY 



and HOEACE S. UHLEE, of New Haven, 



Professor HENEY S. WILLIAMS, of Ithaca, 



Professor JOSEPH S. AMES, of Baltimore, 



Mr. J. S. DILLEE, of Washington. 



FOURTH SERIES 



VOL. XXXYII— [WHOLE NUMBER, CLXXXYIIJ. 

 No. 220— APRIL, 1914. ___. 



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( APR 2 1914 



NEW HAVEN, CONNECTICUT. 



1914 . ^^JAo^^ 



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