VOL. XLIV. 



NOVEMBER, 1892. 



Established by BENJAMIN SILLIMAN in 1818. 



THE 



AMERICAN 



JOURNAL OF SCIENCE. 



EDITOES 



JAMES D. and EDWARD S. DANA. 



ASSOCIATE EDITOES ■ 



Peofessoes JOSIAH P. COOKE, GEORGE L. GOOD ALE 

 and JOHN TROWBRIDGE, of Cambridge. 



Peofessoes H. A. NEWTON and A. E. VERRILL, of 



New Haven, 



Professoe GEORGE F. BARKER, of Philadelphia. 



THIRD SERIES. 

 YOL. XLIV.— [WHOLE NUMBER, CXLIV.] 



N(x 263— NOVEMBER* 1892. 



NEW HA YEN, CONN.: J. D. & E. S. DANA. 



1892. 



TUTTLE, MOREHOUSE & TAYLOR, PRINTERS. 371 STATE STREET. 



Published monthly. Six dollars per year (postage prepaid). $6.40 to foreign sub- 

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