fuel, the tariff question may undergo some important modification in
politics. For, if the reduction in the cost of fuel should ever become
an offset to the lower rate of wages in Europe, the manufacturers of
Pennsylvania, who have long been the chief support of the protective
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