NEW YORK ACADEMY OF SCIENCES 



635 



If the general composition of the crust of the earth is cal- 

 culated as closely as possible on the basis of known chemical 

 analyses, the following table results, which has been compiled 

 by Dr. F. W. Clarke, of Washington, chief chemist of the U. S. 

 Geological Survey. 1 



Oxygen 47 



Silicon 27 



Aluminum 8 



Iron 4 



Calcium , 



Magnesium 2 



Potassium 2 



Sodium 2 



Titanium 



Hydrogen 



Carbon 



Phosphorus 



Manganese 



Sulphur 



Barium 



Chromium 



Nickel 



Strontium 



Lithium 



Chlorine 



Fluorine 



Total 100 . 00 



Elements less than .01 per cent, are not considered abundant 

 enough to affect the total, and equally exact data regarding 

 them are not accessible. Among those given only the following 

 appear which are metals of importance as such in everyday 

 life: aluminum 8.13, iron 4.71, manganese .07, chromium .01, 

 and nickel .01. They rank respectively, in the table, third, 

 fourth, thirteenth, sixteenth and seventeenth. Of the five, 

 iron is the only one of marked prominence. No one of the 

 remaining four is comparable in usefulness with at least five 

 other metals which are not mentioned, viz., copper, lead, zinc, 

 silver, and gold. 



An endeavor has been made by at least one_ investigator, 

 Professor J. H. L. Vogt, of Christiania, to establish some quan- 

 titative expression for these other metals. His estimates 

 are as follows : 2 



1 Bulletin 148, p. 13. 



2 Zeitschrift fur prak. Geologie, 1898, 324. 



