374 
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 used for aniline and other dyes. He would 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 chai'acteristic of 
coal. 
As the Torbane Hill mineral is not coal ; as it is prohahly 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 phenonjena 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 phj^sical geography, and of 
the operations of naiture in her secret and deep-seated laboratory. 
