EXPLOSIONS IN COAL MINES. 209 



of nature, and which exists in large qxiantities in various parts of the 

 world. It is, comparatively speaking, a very recent discovery. The 

 first well was sunk in Pennsylvania in 1858. The first " flowing well," 

 or bore hole from which the rock oil flows naturally, dates in 1861. 

 From that date the annual production has increased with marvelous 

 rapidity. In 1878 it was computed that several hundred million gal- 

 lons were annually raised, although only about one-half per cent, of 

 the 2,000 square miles of area in which the mineral oil is to be found 

 was then worked. The oil is also known to exist in Virginia, in Ohio, 

 in Kentucky, in California, in Canada, in South America, in China, in 

 Japan, in Java, on the north coast of Africa, in Italy, France, Austria, 

 Wallachia, Turkey, and Russia. There is every reason to suppose 

 that an unfailing supply might be obtained by boring in the valley of 

 the Jordan, in which rapid stream masses of bitumen are often found 

 borne down to the salt waters of the Dead Sea. On the shores of the 

 Caspian it is found in such abundance that it is used as fuel for steam- 

 ers. At Cheeriley, about twenty-five miles to the west of Kertch, it 

 is stated by Mr. Ross * that there are five wells owned by an English- 

 man, two of which produce about one hundred and thirty-five barrels 

 of petroleum daily. Bitumen and bituminous shales producing oil are 

 to be found in every country of Europe, and there is good reason to 

 suppose that the existing stores of the liquid mineral are no less ample 

 than those of the solid beds of coal. 



As to cost, the crude petroleum oil is sold at the mouth of the wells, 

 in Pennsylvania, at from 10s. to 15s. per ton, or from \d. to f d. per 

 gallon. The refined petroleum at New York is worth about Qd. per 

 gallon, but half of this is the price of the casks or other vessels that 

 contain it. If a large and steady demand were to set up, it would be 

 easy to construct ships of which the hold should be composed of a 

 series of air-tight compartments, in wrought iron, into which the oil 

 might be turned directly by means of mains, like gas or water mains 

 in our cities, and from which it might be pumped on its arrival in the 

 Thames or in the Mersey. The cost of the delivery of this liquid fuel 

 may thus be expected to be, hereafter, less per ton than that of coal. 

 It only needs the first expense, that of sinking the shaft. It will then 

 mine itself, raise itself, carry itself, and may be made to load itself on 

 shipboard. As to the cost of the process of refinement, we are with- 

 out adequate information. But, in the event of a brisk demand for the 

 refined oil, there can be little doubt that the usual course of manufac- 

 turing industry would be followed, and that an economical method 

 would be applied. 



It is thus of interest to compare the respective properties of coal, 

 coal-gas, and petroleum, both as regards their lighting and their heat- 

 ing capacities, as far as the present state of definite scientific informa- 

 tion attainable will allow us to do so. 



* "Minutes of Proceedings of the Institution of Civil Engineers," vol. xl., p. 150. 

 vol. xv. 14 



