106 NATURE AND ORIGIN" OF PETROLEUM. [Feb. 5, 



tion to such shells as occurring in various places, but especially in 

 the Val de Travers and its neighborhood, and seems to think they 

 offer convincing proof that the bitumen originated where it is now 

 found. Such an argument would never occur to one familiar with 

 the sea-shore. The shells are first filled with sand and then satu- 

 rated with bitumen, which enters them either as a liquid or hot 

 vapor. I have seen multitudes of shells filled with bitumen and 

 mixed with sand, fragments of shells, dirt, and crystallized carbon- 

 ate of lime, none of which are a part of the animal that occupied 

 the shell. 



The second work to which I refer is the late monumental publi- 

 cation by Boverton Redwood, on Petroleum. After the most com- 

 plete and wholly fair as well as the latest i-esunie of all the theories 

 that have been advanced by the writers of both Europe and Amer- 

 ica, he sums up as follows : 



" From the account given in this section, it will be seen that 

 there has been an abundance of speculation as to the origin of bitu- 

 men and that, in regard to some of the theories, a considerable 

 amount of experimental proof has been forthcoming. Probably, 

 on the whole, the Hofer-Engler views at present have the largest 

 number of adherents, and in respect, at any rate, to certain descrip- 

 tions of petroleum, are the most worthy of acceptance. At the 

 same time, a careful study of the subject leads to the conclusion 

 that some petroleum is of vegetable origin, and it therefore follows 

 that no theory is applicable in all cases." 



Engler, like Warren, distilled fish oil and obtained petroleum- 

 like products. He then distilled dried fish and other animal 

 remains, and obtained altogether different products. 



" Dr. Engler therefore considers that some change in the animal 

 remains must have taken place in the earth, whereby all nitrogenous 

 and other matters, save fats, were removed, the petroleum being 

 formed from this fat alone, by the combined action of pressure and 

 heat or by pressure only. 



"In summing up the evidence as to origin, Hofer expresses the 

 belief that petroleum is of animal origin, and has been formed 

 without the action of excessive heat, and observes that it is found 

 in all strata in which animal remains had been discovered." 



Combining these two statements, we arrive at this conclusion as 

 the Hofer-Engler theory, that bitumens are of animal origin, formed 



