GASEOUS FUELS. 



105 



NATURAL GAS. 



Natural gas has been known for thousands of years in 

 Asia, on the Caspian Sea, where it has long been a feature in 

 religious services, but it is only recently that it has become 

 of any use to man and played any part in the fuel world. 



The natural gas output in the United States has attracted 

 considerable attention since 187$, and especially since 1880. 

 This gas always accompanies petroleum, although petroleum 

 does not always accompany the gas. The wells are situated 

 in various portions of New York, Pennsylvania, Ohio, 

 Indiana, West Virginia, Kentucky, Tennessee, Colorado, Cal- 

 ifornia, and on the Canadian side also in numerous locations. 



Natural gas is not of a constant or uniform composition, 

 varying very much according to the locality from which it is 

 taken. The individual constituent gases vary between wide 

 limits, hydrogen at some places being almost wanting, while 

 at others it is as high as 35 or 40 per cent. Marsh gas is in 

 every case the principal constituent, but this runs down as 

 low as 40 per cent in some analyses. Nitrogen is some- 

 times absent, and when present in large amounts, it is suppos- 

 able that the gas analyzed was contaminated with atmospheric 

 air. 



The Ohio and Indiana fields yield gas of nearer a uniform 

 composition than any of the others. The following table is 

 typical: 



