522 The American Naturalist. [June, 
From the mean of 880 analyses he finds that the solid crust 
constitutes 93 p.c.; the ocean 7 p. c.; and the air much less 
than I p. c. by weight (so that the latter is added as a slight cor- 
rection applied to the ocean). 
Taking these figures, he has calculated from the above 880 
analyses, made in all parts of our own country and Europe and 
throughly combined and sifted, the following curious table of the 
frequency of the various elements. He adds that the fifty odd 
elements not included here can hardly aggregate 1 p. c. alto- 
gether.* 
PE 
Oxygen. : ‘ : ; 49.98 
Silicon . : : : ; 28.30 
Aluminum . : ; ; 7.26 
Iron : : i ; ; oo eae 
Calcium sy. i ; : : 3.51 
Magnesium. 7 i : r, 
Sodium : : : ; ; 2.28 
Potassium : : ` : Mine Fe 
Hydrogen . : ; ; ; 0.94 
Titanium i : : ; 7. 30 
Carbon : : ; : $ 0.21 
Chlorine and Bromine . : 1 0T 
Phosphorus . : ; : : 0.09 
Manganese 0.07 
Sulphur 0.04 
Barium . ; i ; i : 1003 
Nitrogen . : : i 0.02 
Chromium ; : : 00t 
Total . : : ‘ ; 100.00 
The effect of acid rains upon this slag-like material can easily 
be predicted, and the prediction agrees with the facts as observed. 
Thus the deduction from La Place’s hypothesis would lead to a soil 
and air composed as we observe them, and the growth of all 
* See Chem. and Geol. Essays, pp. 35-47. 
