.Librarian u. o. ^><". «-.—- 



YOL. XIX. MAY, 1905. 



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 WI. M. DAVIS, of Cambridge, 



Professors ADDISON E. YEEEILL, HOEACE L. WELLS, 

 L. Y. PIESSON and H. E. GEEGOEY, of New Haven, 



Professor GEOEGE F. BAEKEE, of Philadelphia, 

 Professor HENEY S. WILLIAMS, of Ithaca, 

 Professor JOSEPH S. AMES, of Baltimore, 

 Mr. J. S. DILLEE, of Washington. 



FOURTH SERIES. 

 YOL. XIX— [WHOLE NUMBER, CLXIX.] 



No. 113.— MAY, 1905. 



NEW HAVEN, CONNECTICUT. 

 1905 



!TI4 



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



Published monthly. Six dollars per year, in advance. $6.40 to countries in the 

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