Natural Gas
2 of the 7 encyclopedias on this shelf carry an entry for Natural Gas. Both are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
carburetted hydrogen, issuing from the earth in springs or wells. The fire damp of coal mines is practically the same gas, which was produced during the formation of the coal from vegetable matter and is set free by the miner's pick. Natural gas is generally found in connection with pools of petroleum. Though natural gas has long been known and is found in abundance at Baku, on the Caspian Sea, its practical development belongs to the industrial history of the United States. Natural gas is found in nearly all sections of the United States. The most important producing States are West Virginia, Oklahoma, Pennsylvania, Ohio, California, Louisiana, Kansas, Texas, and New York. The first extensive use of this gas was at Fairview, Pa. In 1775 it was first ap, plied to iron smelting; and in 1886 it was brought to Pittsburgh, Pa., from a reservoir 19 miles distant and introduced as a substitute for all other kinds of fuel, for domestic and economical purposes. The total number of gas wells in the United States at the close of 1917 was 39,277, a gain of 2,000 wells over the previous year. The approximate value of natural gas produced in the United States in 1917 was as follows: California, $6,816,524; Kansas, $5,201,436; New York, $2,499,- 303; Ohio, $18,434,814; Pennsylvania, $28,716,492; Texas, $3,192,625; West Virginia, $59,389,161; Louisiana, $3,262,- 37; Oklahoma, $13,984,656. Total, $142,- 89,334. This amount does not include value of gas produced in Canada and consumed in the United States. The production in 1919 was about 638,600,000 cubic feet.
The Encyclopedia of Founding (1892)
Gas-springs or gas-wells through which issue combustible gases from the earth are to be found in various parts of the world. It was by this means that the holy fires of Baku, on the Caspian, and the sacred fires of the Greeks were supplied with fuel. It is supposed to be the same as the fire-damp of coal-mines, which is liberated by the pick of the miner. In all cases these combustible gases consist to a large extent of marsh-gas, also called light carburetted hydrogen. (See MARSH-GAS.) In many cities throughout the States, notably Pittsburg, the gas is used altogether as a steam-producer; for heating metals,--iron, steel, brass, etc.,--in the diverse branches of their utilization, except for smelting ore, in which coke continues still to be employed. Natural gas has an intense heating-power, is free from substances deleterious to metals, is cheap and easily handled, and leaves no ashes. One thousand cubic feet of gas is equivalent in heating-power to 56 pounds of coal, which represents a saving of 20 per cent at first cost, besides the labor of handling and transportation. See FUEL.