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THE GEOLOGIST. 



coal naptha consists of hydro-carbons, of the benzol class and the 

 paraffin class : the greatest proportion being of the former, which has 

 been extensively nsed for aniline and other dyes. He wonld tell ns, 

 too, that for a long time the paraffin series was too difficult to extract 

 in any quantity, and was, therefore, suffered to remain in the pitch and 

 tar ; that subsequently, however, an Edinburgh chemist stated that 

 he had found a means of obtaining large quantities by the distillation 

 of coal at low temperatures, but that when his method was tried com- 

 mercially in Scotland it was found that the only mineral which could 

 be used profitably by his process was the Torbane Hill mineral ! 

 Hence there was an additional reason for the Russells attempting at 

 the great trial to prove that substance to be coal, because it was the 

 only substance commercially usable in the patented process, for which 

 ordinary coal was wholly unfit. If we inquire further as to the pro- 

 ducts resulting from distillation, we find that coal gives off at low 

 temperatures chiefly benzol oils, with a small proportion of paraffin, 

 whilst from the Torbane Hill mineral there are three series of hydro- 

 carbons, the benzol, the paraffin, and alcohol, of which the proportions 

 are large of paraffin and alcohol, but small of benzol. Indeed the 

 two latter are the chief constituents in the products of all the similar 

 minerals to the Torbane Hill such as the Rangoon tar, the Trinidad 

 Lake pitch, the Pensylvanian well-oils, and native petroleum and 

 bitumen, while, as we have said, benzol products are characteristic of 

 coal. 



As the Torbane Hill mineral is not COAL ; as it is probably not 

 bituminous shale even, it must have a history of its own, and 

 would it not be an interesting inquiry for geologists to make it out to 

 be a deposit of the hardened bitumen of a great pitch-lake like the 

 great pitch lake of Trinidad ? 



Geologists have never compared the phenomena of such districts 

 as that of Trinidad, the Rangoon tars, or the oil-well region of Pen- 

 sylvania, in their bearings on the origin of various bituminous shales, 

 flagstones, asphaltes and other bituminous substances certainly not 

 coals, and, whenever the inquiry is gone into, many extraordinary 

 revelations will be made in geological physical geography, and of 

 the operations of nature in her secret and deep-seated laboratory. 



