^;^j PROCEEDINGS 



OF THE 



American Philosophical Society 



HELD AT PHILADELPHIA 



FOR PROMOTING USEFUL KNOWLEDGE 

 Vol. LVIII. 1919. No. 7. 



CONTENTS 



PAGB 



Polarized Light in the Study of Ores and Metals. By Fred E. Wright 401 



On the Luciopimelodinae, a New Subfamily of the South American 



Siluridje. By Chas. S. Driver ....... 448 



MiNUTBS . . . . . . . . . . . . i 



Index , . . . . ' . . . . . . , . xv 



PHILADELPHIA 



THE AMERICAN PHILOSOPHICAL SOCIETY 

 / 104 South Fifth Street 



1919 



