HYDROCARBONS FORMED A B lO GEN I C A LL Y 1 27 



off Greenland. Their chemical composition was similar to 

 that of iron meteorites but later studies have shown that they 

 were undoubtedly of terrestrial origin.*' 



Numerous analyses of the ' Ovifak iron ', in particular the 

 work of J. L. Smith, ®° R. T. Chamberlin" and others, have 

 revealed the presence in it of nickel-containing carbides of 

 iron (cohenite). Carbides of this sort have also been found 

 in native iron derived from many different sources ; for 

 example, they have been found in native iron ore from 

 Santa Caterina and Kersut, in the basalts of Oregon and 

 Hawaii, in the geological formations of the Transvaal, etc. 

 " It is very probable ", wrote Vernadskii,'^ " that a more 

 detailed study of these minerals will show that they are 

 present everywhere in the deep basalts (the basaltic layer)." 



It has already been mentioned that cohenite is the parent 

 substance both of the native forms of carbon (especially 

 graphite) and of the hydrocarbons present in meteorites. The 

 connection between terrestrial cohenites and hydrocarbons 

 can easily be understood from a purely chemical point of 

 view. As long ago as the nineteenth century M. Berthelot,®^ 

 H. Abich,'* and H. Moissan'^ indicated the possibility that 

 hydrocarbons might be formed directly from the carbon of 

 carbides, and substantiated this by direct chemical experi- 

 ment. A great deal of work in this direction had been done 

 by D. Mendeleev.'^ As early as 1877 he described the reaction 

 leading to the formation of hydrocarbons, according to the 



equation 3 ^^m ^n + 4mH20^mFe304 + CgnHgnj. 



Mendeleev wrote as follows : 



Cloez studied the hydrocarbons formed by dissolving pig 

 iron in hydrochloric acid and found representatives of the 

 series CnH,,, and other hydrocarbons. I treated crystalline man- 

 ganese-containing pig iron (containing 8 per cent of carbon) with 

 hydrochloric acid and obtained a liquid mixture of hydrocarbons 

 which, in its smell, appearance and reactions, was just like 

 natural petroleum. 



On the basis of these reactions Mendeleev constructed his 

 well-known theory of the mineral origin of petroleum. He 

 wrote : 



