Tlie Origin and Relations of the Carbon Minerals. 283 



In a paper pnblishea in the Awiales de Chimie et de Physique, 

 Vol. IX. p. 481, M. Bertlielot attempts to show that the forma- 

 tion of petrolenm and earburetted hydrogen from inorganic 

 substances is possible, if it is true, as suggested by Daub: ee, that 

 there are vast masses of the alkaline metals — jtotassium, sodium, 

 etc.— deeply burii d in the earth, and at a high temperature, to 

 which Ciirbonic acid should gain access ; and he demonstrates 

 that these j)remises being granted, the formation of hydro- 

 carbons would necessarily follow. 



But it should be said that no satisfactory evidence has ever 

 been offered of the existence of zones or masses of the unoxidized 

 alkaline metals in the earth, and it is not claimed by Berthelot 

 that there are any facts in the occurrence of petroleum and ear- 

 buretted hydrogen in nature which seem to exemplify the chemi- 

 cal action which he simply claims is theoretically possible. Ber- 

 thelot also says that, in most cases, there can be no doubt of 

 the organic origin of the hydro carbons. 



Mendeleeff, in the Revue Scientifique, 1877, p. 409, discusses 

 at considerable length the genesis of petroleum, and attempts to 

 sustain the view that it is of inorganic origin. His arguments 

 and illustrations are chiefly drawn from the oil-wells of Penn- 

 sylvania and Canada, and for the petroleum of these two dis- 

 tricts he claims an inorganic origin, because, as he says, tliere 

 are no accumulations of organic matter below the horizons at 

 which the oils and gases occur. He then goes into a lengthy 

 discussion of the possible* and probable source of peti'oleum, 

 where, as in the instances cited, an organic origin "is not possi- 

 ble." It is a sufficient answer to M. Mendeleeff to say, that 

 beneath the oil-bearing strata of western Pennsylvania are sheets 

 of bituminous shale, from one hundred to five hundred feet in 

 thickness, which afford an adequate, and it may be proven the 

 true, source of the petroleum, and that no petroleum has been 

 found below these shales ; also, that the oil-fields of Canada are 

 all underlain by the Collingwood shales, the equivalent of the 

 Utica carbonaceous shales of New York, and that from the out- 

 crops of these shales petroleum and hydro-carbon gases are con- 

 stantly escaping. With a better knowledge of the geology of 

 the districts he refers to, he would have seen that the facts in 

 the cases he cites afford the strongest evidence of the organic 

 origin of petroleum. 



