

T II £ 



AMERICAN 



JOURNAL OF SCIENCE. 



itor: EDWARD S. DANA. 



ASSOCIATE H 



tEO. L. GOODALK, JOHN TBOWJBRIE II 



H. P. BOWDITCH avd XV. a FABLC aiojbidg*, 



A. £. VLRKILL, HENRY 8. WILLIAMS 

 L. V. PIBSS 



Peofes- )KGB F. BAR?:. Philadeu>hia : 



Peofessoe H. A. ROWLAND, ov Baltim 

 Me. J. S. DILLER. of Wash; 



FOURTH SERIES 

 VOL. VII— 'WHOLE NUMBER, CLVIL] 





XEW HA'- 



