r. Cyrus Adler, 



Librarian U. S. Nat. Museum. j 



YOL. XII. JULY, 1901. 



Established by BENJAMIN SILLIMAN in 1818. 

 THE 



AMERICAN 



JOURNAL OF SCIENCE. 



Editor: EDWARD S. DAXA. 



ASSOCIATE EDITORS 



Professors GEO. L. GOODALE, JOHN TROWBRIDGE, 

 W. G. FARLOW axd WI. M. DAVIS, of Cambridge, 



Professors A. E. YERRILL, HENRY S. WILLIAMS and 

 L. V. PIRSSOX, of New Haven. 



Professor GEORGE F. BARKER, of Philadelphia, 



Professor JOSEPH S. AMES, of Baltimore, 



Mr. J. S. DILLER, of Washington. 



FOURT H SERIES. 



YOL. XII— [WHOLE NITMBEK, CLXIL] 



No. 67.— JULY, 1901. 



NEW HAVEN, CONNECTICUT. 

 1901. 



THE TUTTLE, MOREHOUSE & TAYLOR CO., PRINTERS, 125 TEMPLE STREET. 



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

 Union. Remittances should be made either by money orders, registered 

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