THE ORIGIN OF PETROLEUM OIL.

Daily Telegraph (Napier), Issue 3054, 9 April 1881, Page 4

THE ORIGIN OF PETROLEUM OIL.

The manner of the formation of the deposits of mineral oil found in America, Germany, and other countries is still involved in some doubt. The only statement that may safely be made concerning it, ia that it is a product of the decomposition of animal or vegetable matter of former geological epochs. Some regard it as the product of the decomposition of land or marine plants ; others, that it has' been produced by the decomposition of animal matter ; others again, that it is a species of coral oil, not formed by the bodies of the coral polyps, but secreted by corals, principally of the Devonion age ; others, that it is distilled from bituminous shales by subterranean heat, the shales being made up of the mud of lakes and estuaries that weje once largely filled with vegetable and animal debris. Other authorities again think that the true solution of the problem is not to look to one source only for the origin of petroleum. Dr. Lawrence Smith, for example, in discussing this subject, asserts that there can be not doubt that the primal sources of petroleum were both vegetable and animal; that the Pennsylvania and Virginia petroleums were derived almost exclusively from vegetable decomposition ; and that those of Canada, and _cf Kentucky and Illinois, were derived principally from animal matter.

In an article on the subject in a recent number of the Builder and Manufacturer the writer says :—"How the transformation of animal or vegetable matter into petroleum was effected, we do not know, further -than that temperature and pressure were important factors in the operation. Prof. Peckham supposes that petroleum is the normal or primary product of the decomposition of animal or vegetable organism—chiefly the former—and that nearly all other varieties of bitumen are products of a subsequent decomposition of petroleum. Prof. Lesquereus attributes its origin to the partial decomposition of low forms of marine vegetation. The first named savant again affirms his conviction that the remains of animal life have contributed much more largely to the formation of petroleum than lias generally been supposed; and further, that the different varieties of petroleum are largely due to the varied forms of animal life existing during the different geological epochs to which the rocks belong from which oil primarily issues. Dr. Sterry Hunt, a high authority, entertains similar opinions. He holds that the presence of the petroleum oils of Pennsylvania and Canada in the lower palaeozoic rocks, which contain no tracts of land plants, shows that they have not in all cases been derived from terrestrial vegetation, but many have been formed from marine plants or animals. The latter view, he adds, is not surprising when wo consider that a considerable portion of the tissues of the lower marine animals is destitute of nitrogen, and very similar in chemical constitution to the woody fibre of plants." These abstracts of the opinions of eminent authorities will suffice to show that there is still considerable uncertainty as to tho exact method by which petroleum has been formed. While some differences exist, however, in respect to the modus operandi of its formation, it will nevertheless be observed that all these authorities are agreed that petroleum is a product of the decomposition of organisms that have lived in early geological epochs. Beyond this fact, nothing has been determined with certainty. It may be added, in conclusion, that M. Berthelot a distinguished French chemist, has presented an ingenious hypothesis in which he attempts to show that petroleum may have had a purely mineral origin ; but his argument, though plausible, has found no supporters.