THE FUEL OF THE FUTURE. 215 



The property of indicating the presence of very minute quantities 

 of gas in a room is claimed for an instrument recently described by 

 C. von Jahn, in the " Revue Industrielle." This is a porous cup, in- 

 verted and closed by a perforated rubber stopper. Through the perfo- 

 ration in the stopper the interior of the cup is connected with a press- 

 ure-gauge containing colored water. It is claimed that the diffusion 

 of gas through the earthenware raises the level of the water in the 

 gauge so delicately that the presence of one half of one per cent of 

 gas may be detected by it. Other instruments of a slightly different 

 character are credited by their inventors with most sensitive power 

 of indicating gas-leakages, but their practical efficiency remains to be 

 demonstrated. An automatic cut-off for use outside of houses in which 

 natural gas is consumed has been invented, but this writer knows 

 nothing of either its mode of action or its effectiveness. 



The great economic question, however, connected with the use of 

 natural gas is, How will it affect the industrial interests of the coun- 

 try ? There are grounds for the belief that a sufficient supply of natu- 

 ral gas may be found in the vicinity of Pittsburg to reduce the cost 

 of fuel to such a degree as to make competition in the manufacture of 

 iron, steel, and glass, in any part of the country where coal must be 

 used, out of the question. Such a condition of affairs would probably 

 result in driving the great manufacturing concerns of the country into 

 the region where natural gas is to be obtained. That may be any- 

 where from the western slope of the Alleghanies to Lake Erie or to 

 Lake Michigan. And, if the cost of producing iron, steel, and glass 

 can be so cheapened by the new 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 as- 

 sumed 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 can not 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 prom- 

 ising 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 



