PETROLEUM. 



083 





the shores of Lake Erie, exhibit such an ex- 

 traordinary accumulation of fucoids as to suggest 

 to l)r. J. S. Xewberry the idea that a 

 gasso sea'' existed at that point in the prime- 

 val ocean. The oil-sands overlie more thau 

 1,000 feet of the Devonian shales, and are them- 

 selves overlaid by beds of shale containing so 

 much silica as to form an impervious shell that 

 holds down the oil and gas under such a press- 

 ure that much of the material that is gaseous 

 when it reaches the surface, is doubtless liquid 

 while within theoil-saud. These "shells," being 

 impervious over wide areas, prevent the escape 

 of the oil except from minute fissures, where oil 

 or gas springs are produced. This fucoidal 

 shale has been subjected to destructive distil- 

 lation at a low temperature, and has yielded 

 fifty gallons to the ton of an oil resembling 

 petroleum. In like manner, other shales, coal, 

 peat, wood, or animal matter, either recent or 

 fossil, will yield petroleum-like eils, and the 

 lower the temperature and slower the distilla- 

 tion the more nearly will the product resem- 

 ble the natural oil. In the light of these facts, 

 with the added weight of laboratory experi- 

 ments that have confirmed them, the French 

 chemical geologists have maintained that all 

 forms of bitumen are the product of rneta- 

 morphism, or of those physical agencies that, 

 through the combined action of heat, steam, 

 and pressure exerted through indefinite periods 

 of time, have produced such changes as those 

 that have converted the sedimentary rocks of 

 the Eastern States. Xew York, and Pennsylva- 

 nia into crystalline schists, and the coal into 

 anthracite. These agencies, acting with less 

 violence upon the strata forming the gentle 

 western slope of the Alleghanies, have left in 

 undisturbed repose the strata that underlay 

 and inclosed the oil-sands, while the super- 

 ficial have heen subject to erosion through 

 immense cycles of geological time. Under 

 these conditions, no arbitrary line conld mark 

 the point at which such agencies ceased to 

 act, and the natural process of distillation go- 

 ing forward through indefinite periods of time 

 and of necessity at the lowest possible tem- 

 perature, must result in the accumulation of 

 distillates in any overlying strata porous enough 

 to act as a reservoir. Xo additional evidence 

 seems to be required to render this an adequate 

 origin for petroleum as it occurs in Pennsylva- 

 nia and Galicia. Petroleum occurs at many 

 points along the entire western slope of the 

 Appalachian System, from Point Gaspie on the 

 St. Lawrence river to northern Alabama, and 

 is most abundant where there is the greate-t 

 accumulation of organic remains. These sedi- 

 ments were deposited in a current whose course 

 was from northeast to southwest. The facts 

 that concern petroleum are found in the undis- 

 turbed and nearly level position in which the 

 rocks containing it lie like sand-bars in a flow- 

 ing stream, and the further evidence they af- 

 ford that the metamorphic action that has al- 

 tered nearly all the formations of the eastern 



border of the Appalachian System became ex- 

 tinct along a plane that descended deeper and 

 deeper, in many instances far below the surface 

 formations and the coal that they inclose. In 

 Galicia and Transylvania, the metamorphic core 

 of the Carpathians is flanked by beds of fucoidal 

 shale rich in the remains of marine animals, 

 intercalated with the sandstone strata holding 

 the oil. If petroleum is a product of meta- 

 morphism, the production is long since com- 

 pleted, and the vast natural reservoirs, when 

 once emptied of their contents, are as completely 

 removed from future consideration as a worked 

 out bed of coal. 



Throughout the world petroleum is obtained 

 by means of artesian wells. Dug wells were 

 used in Japan for many centuries, and other 

 primitive methods were employed in other re- 

 gions ; but the so-called American method is 

 now employed universally where petroleum is 

 handled in commercial quantities. The wells 

 are drilled like other artesian wells. Some- 

 times the oil pours forth in an artesian torrent 

 that flows without control until partial exhaus- 

 tion renders it possible to stop the flow. Such 

 wells have been of frequent occurrence in the 

 United States and at Baku. TVhen brought 

 within control, the oil is conducted into a tank. 

 Here it accumulates until the tack is nearly 

 filled when an agent of the pipe-line appears 

 and gauges the tank. The oil is then run from 

 the tank into the pipes of a pipe-line, and the 

 tank is gauged again. The difference between 

 the first and second gauging is the measure of 

 the oil run. ^ hen a w ell ceases to flow, a 

 pump is introduced. Often several wells are 

 so connected as to be pumped by one power. 

 At present it is usual to stimulate the flow of 

 wells of moderate productiveness by torpedoes. 

 The torpedo consists of several long cylinders 

 of tin, into which nitro-glycerin is poured, 

 and the whole is carefully lowered to that point 

 in the well at which it is desired to quicken the 

 flow of oil. To the last section a cap is attached, 

 upon which a mass of iron, called a " go-devil,'' 

 is allowed to descend. The charge is from 

 twenty-five to one hundred quarts of nitro- 

 glycerin. and the rtsult of its explosion is usu- 

 ally the projection of a column of oil, resem- 

 bling a geyser, above the top of the derrick, 

 often one hundred feet in height. After 

 a few minutes, the fountain gradually sub- 

 sides, and the flow continues uninterruptedly 

 in increased volume until the well is exhausted. 

 The effect upon the oil-sand is, first, an enor- 

 mous pressure in all directions, driving the oil 

 and gas back into the rock until a point of 

 maximum tension is reached, when the reac- 

 tion sends everything before it out of the rock 

 and into the air. The oil-rock is thus effectu- 

 ally cleared, and the flow of the oil unim- 

 peded. 



As soon as the flow of oil is established and 

 connection has been made with the pipe-line, 

 the action of the well goes on uninterruptedly, 

 often for months. The pipe-lines converge 



