THE LIFELESS EARTH 



31 



compounds, or to transform their energy without the friendly 

 aid of sunshine. The only forms of hfe to-day which can exist 

 in such an inhospitable environment as that of the lifeless 

 earth are certain of the simplest bacteria, which, as we shall 

 see, feed directly upon the chemical elements. 



It is interesting to note that, in the period when the sun's 

 light was partly shut off by watery and gaseous vapors, the 

 early volcanic condition of the earth^s surface may have supplied 

 life with fundamentally important chemical elements, as well 

 as with the heat-energy of the waters or of the soils. Volcanic 

 emanations contain^ free hydrogen, both oxides of carbon, and 

 frequently hydrocarbons such as methane (CH4) and ammo- 

 nium chloride: the last compound is often very abundant. 

 Volcanic waters sometimes contain ammonium (NH4) salts, 

 from which life may have derived its first nitrogen supply. 

 For example, in the Devil's Inkpot, Yellowstone Park, ammo- 

 nium sulphate forms ^^^ per cent of the dissolved saline matter: 

 it is also the principal constituent of the mother liquor of the 

 boric fumaroles of Tuscany, after the boric acid has crystallized 

 out. A hot spring on the margin of Clear Lake, California, 

 contains 107.76 grains per gallon of ammonium bicarbonate. 



There were absent from the primordial earth the greater 

 part of the fine sediments and detrital material which now 

 cover three-fourths of its surface, and from which a large part 

 of the sodium content has been leached. The original surface 

 of the earth was thus composed of granitic and other igneous 

 rocks to the exclusion of all others,'- the essential constituents 

 of these rocks being the lime-soda feldspars from which the 

 sodium of the ocean has since been leached. Waters issuing 

 from such rocks are, as a rule, relatively richer in silica than 



1 Clarke, F. W., 1916, chap. VIII., also pp. 197, 199, 243, 244. 

 ^Becker, George F., 1910, p. 12. 



