PETROLEUM, ASPHALT, AND BITUMEN. 381 



uses and applications of petroleum have been immensely and won- 

 derfully extended. The discovery of the American beds of petro- 

 leum and the application of industrial processes of distillation to 

 them have been the beginning of a new industry, and of largely 

 extended researches in all countries. Leopold von Buch (1801), who 

 seems to have been the first to discuss the origin of the natural 

 hydrocarbons scientifically, supposed that they were of animal 

 origin. Violet d'Aoust, in 1814, believed them to be of the same 

 origin as the rocks with which they were associated, native erup- 

 tive products, the resultants of causes still unknown ; and repeated 

 this opinion ten years later. Puvis thought, in 183G, that bitu- 

 men penetrated the rocks, according to their porosity, after their 

 formation. Rozet, in 1836, thought that the bitumen of Pyri- 

 mont was sublimed from the depths of the globe through a crack 

 that marked the direction of the formation, and was condensed in 

 the porous rocks. Millet, in 1840, thought the same bitumen was 

 derived from the decomposition of accumulations of vegetable 

 matter, and ran down through the rocks. Itier, in 1839, supposed 

 that the bitumens of the Jura were derived from the adjacent 

 bituminous schists, which were full of vegetable fossils. Dau- 

 brde, in 1850, believed that the mode of their formation was simi- 

 lar to that of coal, but admitted the possibility of their having 

 been derived from mineral synthesis. These views and the the- 

 ory of volcanic origin have been reiterated in various modified 

 shapes by other authors. M. Lartet published, in 18GG, a valu- 

 able study of the geological relations of the bituminous deposits 

 of the region of the Dead Sea. 



When the mineral oils of the United States had become a 

 prominent subject of attention, Mr. Leo Lesquereux made an 

 elaborate discussion of them in the form of a letter to Liebig, in 

 1865, in which he gave his reasons for supposing that they were 

 the products of the decomposition of marine plants. Dr. Sterry 

 Hunt about the same time concluded, from an examination of the 

 petroleum beds of Kentucky, that the oil, or the organic sub- 

 stances from which it was produced, were deposited in the strata 

 where the oil is found contemporaneously with the formation of 

 the rock. Mr. Orton, after a thorough study of the petroleum of 

 the Trenton limestone of Ohio, published his conclusion in 1884, 

 that it was of organic origin derived from the decomposition of 

 vegetable and animal matter. The supply could not be renewed, 

 and was therefore not inexhaustible. It was probably produced 

 at the ordinary temperature and not by distillation. 



Some authors, assuming that these hydrocarbons are derived 

 from the decomposition of organic matter, have tried to imagine 

 the manner of the process, and to distinguish between it and ordi- 

 nary or putrefactive decomposition. 



