THE ORIGIN AND DURATION OF PETROLEUM. 271 



of the origin of this important natural product. They prove that 

 mineral oil may be produced in connection with coal seams and ap- 

 parently from the coal itself. A sound theory of the origin of petro- 

 leum is of practical as well as theoretical value, inasmuch as the very 

 practical question of the probable permanency of supply depends 

 entirely on the nature of the origin of that supply. Some very odd 

 theories have been put forth, especially in America. 



Seeing that petroleum is commonly found associated with sand- 

 stone and limestone, especially in cavities of the latter, it has been 

 supposed that these minerals somehow produce it. Turning back to 

 the Grocer for April 18th, 1872, I find some speculations of this kind 

 quoted from the Petroleum Monthly. The writer sets aside altogether, 

 as an antiquated and exploded fallacy, the idea that petroleum is pro- 

 duced from coal, and maintains " that petroleum is mainly produced 

 from, or generated through, limestone," and argues that the genera- 

 tion of petroleum by such rocks is a continuous process, from the 

 fact that exhausted wells have recovered after being abandoned, his 

 explanation being " that the formerly abandoned territory was given 

 up because the machinery for extracting petroleum from the earth 

 exceeded in its power of exhausting the fluid the generative powers 

 by which it is produced ;" these generative powers somehow resid- 

 ing in the limestone and sandstone, but how is not specified. 



Some writers have, however, gone a little further toward answering 

 the question of how limestone may generate petroleum. They have 

 pointed to the fossilized remains of animals, their shells, etc., exist- 

 ing in the limestone, and have supposed that the animal matter has 

 been distilled, and has thus formed the oil. 



If such a process could be imitated artificially by distilling some of 

 the later deposits of similar fossil character this theory would have a 

 better basis, or even if a collection of oysters, mussels, or any other 

 animal matters could by distillation be shown to produce an oil simi- 

 lar to petroleum. 



The contrary is the case. We may obtain oil from such material, 

 but it is utterly different from any kind of mineral oil, while, on the 

 other hand, by distilling natural bituminous shales, or cannel coal, or 

 peat, we obtain a crude oil almost identical with natural petroleum, 

 and the little difference between the two is perfectly accounted for 

 by the greater rapidity of our methods of distillation as compared 

 with the slow natural process. We may go on approximating more 

 and more nearly to the natural petroleum by distilling more and 

 more slowly. As it is, the refined products of the natural and artifi- 

 cial oil which is commercially distilled in Scotland, are scarcely dis- 

 tinguishable some of them are not at all distinguishable the solid 

 paraffme, for example. I now offer my own theory of the origin of oil 

 springs. 



To render this the more intelligible, let us first consider the origin 

 of ordinary water springs. St. Winifred's Well, at Holywell, in Flint- 

 shire, may be taken as an example, not merely on account of its mag- 

 nitude, but because it is quite typical, and is connected with lime- 

 stone and sandstone in about the same manner as are the petroleum 

 wells of Pennsylvania. 



Here we have a wondrous uprush of water just between the sand- 

 stone and mountain limestone rocks, which amounts to above twenty 

 tons per minute, and flows down to the Dee, a small river turning 



