368 



GAS, NATURAL. 



ground. Looking clown from the roadside 

 upon the first well we saw in the valley, there 

 appeared to be an immense circus-ring, the verd- 

 ure having been burned and the earth baked 

 by the flame. The ring was quite round, as the 

 wind had driven the flame in one direction 

 after another, and the effect of the great gold- 

 en flame lying prone upon the earth, swaying 

 and swirling with the wind, was most startling. 

 The great beast Apollyon, minus the smoke, 

 seemed to have come forth from his lair again." 



The territory underlaid by the gas is not as 

 yet clearly defined. In general terms, a belt 

 half a mile wide running through Murraysville, 

 Pittsburg, and Washington, marks the richest 

 territory, the most abundant yield being in the 

 Murraysville district. Wells have been driven 

 at different points along this belt, and gas has 

 usually been found ; but salt-water often flows 

 into the wells and renders the gas useless. 

 Another gas-field exists twenty miles north- 

 west of Pittsburg, and still another in Taren- 

 tum, about the same distance above the city, 

 on the Alleghany river. The principal gas- 

 field, therefore, appears to be included in a 

 circle of twenty-five miles radius, with Pitts- 

 burg as a center. But discoveries have been 

 made of practicable sources of supply far out- 

 side of these limits in Ohio, West Virginia, 

 and New York, and no one at present vent- 

 ures confidently to predict where it does or 

 does not exist. The gas is believed to result 

 from the decomposition of animal and vegeta- 

 ble substances in locations whence it rises into 

 natural caverns, or reservoirs, roofed by im- 

 pervious rock or clay strata. To a limited 

 extent, gas has recently been discovered in Il- 

 linois and Kansas. 



The usual method of driving a well is to 

 erect a derrick and sink a six-inch iron pipe 

 until bed-rock is encountered ordinarily 75 to 

 100 feet. Eight-inch drills, weighing 3,000 to 

 4,000 pounds, are then brought into use and 

 worked with an up-and-down stroke of four 

 or five feet. An eight-inch well is thus bored 



to a depth of 500 feet, when a 5f-inch wrought- 

 iron pipe is put down and the drilling con- 

 tinued with six-inch drills until gas is struck, 

 when a four-inch pipe is put down. The aver- 

 age time consumed in sinking a well is forty to 

 sixty days, and the cost is about $5,000. The 

 cost of piping, including right of way, is esti- 

 mated at $8,000 a mile. Twelve lines of pipe 

 at present convey gas from the various wells 

 to the manufacturing establishments in and 

 around Pittsburg. The pipes are from six 

 to twelve inches in diameter. 



The initial pressure of the gas at the surface 

 of the earth is from 200 pounds to a square 

 inch upward to 1,000 pounds, and even more. 

 This decreases rapidly from leakage and other 

 causes until it is not more than 75 pounds to a 

 square inch ten miles from the well. Contracts 

 are now made in Pittsburg to supply private 

 houses with gas for all purposes at the same 

 price that was formerly paid for coal. Its 

 introduction in manufactories has thrown a 

 large number of stokers and firemen out of 

 work. One manufacturer says that a single 

 man is now employed to watch the water- 

 gauges, where thirty formerly engaged in feed- 

 ing the fires. The absence of smoke ren- 

 ders the city a far more agreeable place to 

 live in than formerly, and it is regarded as 

 within the range of probability that, instead of 

 being the grimiest city in the United States, it 

 may shortly become one of the cleanest and 

 most attractive. 



Elaborate tests have been made of the rela- 

 tive heating properties of natural as compared 

 with artificial gas, and, without following out 

 the details of calculation, the result may be 

 given: 54'4 pounds of bituminous or 58*4 of 

 anthracite coal is equal in heating-power to 

 1,000 cubic feet of natural gas. On this basis 

 calculations as to cost may easily be made. 



The following chemical analyses are from a 

 paper read by Dr. H. M. Chance before the 

 American Institute of Mining Engineers, as re- 

 ported in their proceedings (May, 1886) : 



1, 2, 3, 4. From well supplying Edgar Thomson Steel- 

 Works, by S. A. Ford. 



5. Burns well, Butler County, Pa., by Sadtler. 

 C. Luckburg well. Armstrong County, Pa., by Sadtler. 

 7. Harvey well, Butler County, Pa., by Sadtler. 



The attention of engineers is largely directed 

 at present to the possibility of long-distance 

 transportation of the gas, and some of the best 

 authorities believe that this will be accom- 

 plished by drawing it through large conduits, 



8. Cherry-Tree well, Indiana County, Pa , by Sadtler. 

 flow through fresh water. 



9, 10. Two wells near East Liberty, Allegheny Count 

 Pa., by S. A. Ford. 



say five feet in diameter, by means of suctk 

 fans. Whether the supply is destined short 

 to give out, in consequence of the increasii 

 and wasteful demands at present made up< 

 it, is purely problematical ; but the unvaryii 



