< previous  next > 

40

ive policy of the country, may lose their present interest in that question, and leave the tariff to shift for itself elsewhere. It should be remembered that natural gas is not, as yet, much cheaper than coal in Pittsburg. But it may safely be assumed that it will cheapen, as petroleum has done, by a development of the territory in which it is known to exist in enormous quantities. It is quite possible that, instead of buying gas, many factories will bore for it with success, or remove convenient to its natural sources, so that a gas well may ultimately become an essential part of the "plant" of a mill or factory. Even now coal cannot compete with gas in the manufacture of window glass, for, the gas being free from sulphur and other impurities contained in coal, produces a superior quality of glass; so that in this branch of industry the question of superiority seems already settled.

Having said thus much of an industry now in its infancy but promising great growth, I submit tables of analyses of common and of the natural or marsh gas, the latter from a paper recently prepared by a committee of the Engineers' Society of Western Pennsylvania, and for the use of which I am indebted to that association:

COMMON GAS.

Hydrogen 46.0 Light carbureted hydrogen (marsh gas) 39.5 Condensible hydrocarbon 3.8 Carbonic oxide 7.5 " acid 0.6 Aqueous vapor 2.0 Oxygen 0.1 Nitrogen 0.5 ----- 100.0

Natural gas is now conveyed to Pittsburg through four lines of 5-5/8 inch pipe and one line of eight inch pipe. A line of ten inch pipe is also being laid. The pressure of the gas at the wells is from 150 to 230 pounds to the square inch. As the wells are on one side eighteen and on the other about twenty-five miles distant, and as the consumption is variable, the pressure at the city cannot be given. Greater pressure might be obtained at the wells, but this would increase the liability to leakage and bursting of pipes. For the prevention of such casualties safety valves are provided at the wells, permitting the

 < previous  next >