18 



THE ORIGIN OF ALKALI 



Compilations made by Clarke (6) show the earth's 

 crust to be made up largely of the important minerals 

 shown in Table IV (page 16). 



On the basis of the composition and relative amount of 

 the different rocks he computes the average composition 

 of the earth's crust as shown in Table V (page 17). 



Clarke (6) gives the composition of the ocean waters 

 as follows: 



TABLE VI. COMPOSITION OF OCEAN WATER 



He reports a maximum salinity of 37.37 grams of salts 

 to a kilogram of water, or 3.737 per cent with an average 

 of about 3.5 per cent. 



These figures give a general idea of the materials from 

 which soils are made and the substances which have been 

 leached from them. 



In order to determine soluble matter that might be 

 washed from rocks and minerals of various kinds, Whitney 

 and Means (23) compiled the material contained in Table 

 VII from the writings of G. P. Merrill. 



This table gives an idea of the material that is usually 

 washed from rocks and minerals of different kinds in the 



