410 NEW YORK STATE MUSEUM 



This fact alone constitutes a weighty argument against the 

 hypotheses already presented. If the real centers at which 

 petroleum originated are to be found in the primeval crust, ac- 

 cording to Berthelot and Mendel jeff, the carbonated water essen- 

 tial to the process would certainly have a shorter course in 

 reaching these masses of uncombined elements or metallic car- 

 bids by descending through the uncovered Archaean than by 

 going down through thousands of feet of the stratified and fossil- 

 iferous rocks that overlie this formation. 



Another fact that bears against the theory named above is 

 the steady and notable increase in bituminous products that has 

 seemed to go forward throughout geologic history. Their 

 maximum production was apparently reached in Tertiary time. 

 But the internal heat of the earth, which is an important factor 

 in the theories named has been gradually reduced during these 

 same ages. The results are thus directly contradictory to those 

 required by Berthelot's and Mendeljeff's assumptions. 



We come, therefore, to another line of explanations. 



b Origin from organic sources 



The reference of petroleum to an organic source stands in very 

 different relation to familiar facts from the theories already re- 

 viewed. Petroleum is a combustible substance and every other 

 substance that we know in nature that can be burned is of or- 

 ganic origin. Moreover we can produce artificially from vege- 

 table and animal substances gaseous and liquid compounds that 

 are closely allied to the bituminous series or even identical with 

 them. The manufacture of illuminating gas furnishes a case in 

 point. We obtain by this process not only the volatile combusti- 

 ble, but the liquid coal tar as well, that is closely analogous to 

 some of the petroleum compounds. Illuminating gas is ordi- 

 narily manufactured from bituminous coal, but we can use all 

 varieties of vegetable and animal substances for the same pur- 

 pose. Even street sweepings and the ordinary refuse of a city 

 have been by a patented process applied to the same manufac- 

 ture. The occurrence of gas at the bottoms of ponds, produced 

 from decaying leaves, or in boulder clay, from buried vegetation, 

 are phenomena of common note. 



