SOURCES OF ENERGY l75 



One must, therefore, take these radiations into consideration 

 if one wislies to picture to oneself the course of the chemical 

 transformation which took place in the primaeval lithosphere. 



Only a small proportion of the primary hydrocarbons and 

 their derivatives (mainly compounds of high molecular 

 ^veight) were retained in the lithosphere and later extracted 

 from it by the waters of the hydrosphere. All the volatile 

 carbon compounds were gradually given off from the crust 

 of the Earth into the atmosphere, just as we may now observe 

 the giving off of natural gases. The most important and most 

 frequently encountered of these gaseous hydrocarbons is meth- 

 ane.'^" At present, of course, it is partly formed secondarily, by 

 the breakdown of biogenic organic substances or by the reduc- 

 tion of carbon dioxide. According to V. Vernadskii, however, 

 methane occupies an important place among the carbon 

 compounds originating in the depths of the Earth. Hardly 

 anyone will deny the possibility that even now it is formed, 

 at least in part, as the result of inorganic processes, in volcanic 

 gases and emanations. 



As well as methane, the primitive atmosphere of the Earth 

 must have contained carbon monoxide which was formed 

 from methane. Ethylene and acetylene were more likely to 

 have undergone reactions of some kind while still in the 

 lithosphere on account of their chemical reactivity, which is 

 far gi'eater than that of methane. The average specific gravity 

 of the gases composing the primitive atmosphere must, there- 

 fore, have been relatively lo^v, which is what we now obser\ e 

 in natural gases. 



In the atmosphere the primary hydrocarbons and their 

 derivatives encountered new sources of energy which were 

 not present in the lithosphere. Electrical discharges" and 

 ultraviolet radiation®- enabled them readily to surmount the 

 barrier of the energy of activation and even to enter into 

 reactions which would be thermodynamically impossible in 

 the absence of external supplies of energy. For this reason 

 new reactions occurred in the atmosphere in addition to those 

 taking place in the absence of the factors just mentioned 

 (electrical discharges and ultraviolet radiations) and the 

 transformation of hydrocarbons was much wider in its scope. 

 In the atmosphere even such a chemically inert gas as 



