-jLuiaixau L . o. i>ai, ivj.uscui.ii 



VOL. XXIX 



JANUARY, 1910. 



Established by BENJAMIN SIILIMAN in 1818. 



THE 



AMERICAN 



JOURNAL OF SCIENCE 



Editor: EDWAED S. DANA. 



ASSOCIATE EDITORS 



Professors GEORGE L. GOODALE, JOHN TROWBRIDGE, 

 W. G. FARLOW and WM. M. DAVIS, op Cambridge, 



Professors ADDISON E. VERRILL, HORACE L. WELLS, 

 L. V. PIRSSON and H. E. GREGORY, of New Haven, 



Professor GEORGE F. BARKER, of Philadelphia, 

 Professor HENRY S. WILLIAMS, of Ithaca, 

 Professor JOSEPH S. AMES, of Baltimore, 

 Mr. J. S. DILLER, of Washington. 



FOURTH SERIES 

 VOL. XXIX-[WHOLE NUMBER, CLXXIX.] 



No. 169— JANUARY, 1910. 



NEW HAVEN, CONNECTICUT. 



1910. 



THE TUTTLE, MOREHOUSE & TAYLOR CO., PRINTERS. 123 TEMPLE STREET. 



.to countries in the' -. 



Published monthly. Six dollars per year, in advance. J._. 

 Postal Union ; SG.25 to Canada. Remittances should be made e/ftfer by money orders" 

 registered letters, or bank checks (preferably on New York banls). i * M S 1909* 



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