94 PETROLEUM AND NATUEAL GAS. [Feb. 5, 



Cinder these circumstances, it would be hard for the scientific 

 student to refrain from theorizing as to the origin and conditions of 

 formation and storage in nature of this great class of products. And 

 if these theories already possessed interest in the earlier half of this 

 century, might we not suppose that the great economic value which 

 petroleum and natural gas have attained in the last few decades 

 would add greatly to this? The question has indeed become a 

 very large one, and the mass of literature pertaining thereto has 

 already become so great that it would be impossible in the brief 

 limit of time assigned me to cover it even in outline. Leaving 

 therefore the broad subject of natural bitumens, it has been thought 

 well to take for such discussion, as time allows, the narrower ques- 

 tion of ^* the origin and chemical character of petroleum." And 

 as the Society is honored this evening by the presence of several 

 gentlemen who are known by contributions already made to this 

 question, and have consented to favor us with papers specially pre- 

 pared for this occasion, I shall merely state in brief outline the 

 several well-known theories that have been advanced from time to 

 time, and add an account of some experimental results that I have 

 myself obtained which I think will have a bearing upon some of the 

 views now held. 



The theories as to the origin of petroleum may be divided broadly 

 into those which attribute it to Inorganic Sources and those which 

 consider it to be derived from Organic Sources. Under the first of 

 these heads, we may again distinguish between the theories which 

 consider it merely as a natural emanation and those which attribute 

 it to the result of definite chemical reactions. 



The first suggestion of the emanation theory for the origin of 

 petroleum seems to have come from Alexander von Humboldt, who 

 in 1804, in describing the petroleum springs in the Bay of Cumaux 

 on the Venezuelan coast, throws out the suggestion that '^ the petro- 

 leum is the product of a distillation from great depths and issues 

 from the primitive rocks, beneath which the forces of all volcanic 

 action lie." Rozet (1835), Prott (1846), Parran (1854), and 

 There (1872), in writing upon the asphalt and petroleum occur- 

 rences in France, all seemed inclined to connect these formations 

 with volcanic, or at least igneous and eruptive, agencies. 



Somewhat similar was the theory advanced by the French geolo- 

 gist Coquand, who, because of the association of mud volcanoes with 

 the occurrence of petroleum in Sicily, the Apennines, the peninsula 



