Fuel
any combustible substance In this extended sense of the term, alcohol, wax , tallow, coal-gas, oil, and other used, especially in the chemical laborainflammable bodies which are occasionally tory, as sources of heat as well as light, might be included under it. But the term fuel is more properly limited to coal, coke, charcoal, wood, and a few other substances, which are our common grates, stoves, fireplaces, and furnaces. sources of heat , and as such are burnt in In this country , as in England, coal, from commonly employed; but in other counits abundance and cheapness, is the fuel tries , as France, Germany, etc., wood is chiefly used, either in its original state or in the form of charcoal. But whatever substance be used, the essential ultimate elements of fuel are carbon and hydrogen; and the heat which is evolved by their combustion is derived from their combination at high temperatures with the oxygen of the air; the principal results or products of this combustion are carbonic acid and water, these escaping into ing into the atmosphere by the flue or chimney generally attached to furnaces and fireplaces. The different kinds of pit-coal give out variable quantities of heat during their combustion; upon an average, one pound of coal should raise 60 pounds of water from the freezing to its boiling point. The heating power of coke as compared with coal is nearly in the ratio of 75 to 69: a pound of good coke, heating from 64 to 66 pounds of water from 32° to 212°. A pound of turf will heat about 26 pounds of water from about 30 pounds; by compressing and 32° to 212°, and a pound of dense peat drying peat, its value as a fuel is greatly increased. The following table, by Dr. from 32° to 212° by one pound weight Ure, shows the quantity of water raised of the different combustibles enumerated in the first column; it also shows the number of pounds of boiling water which the same weight of fuel will evaporate and the quantity of atmospheric air absolutely consumed during combustion:
Pounds of Weight of which a boiling atmoswater Combustible. pound can common wood.
Charcoal Dry wood.....
Pit coal..
Coke Coal-gas Turf Oil, wax, tallow Alcohol water pheric air raise from evaporated at 32° re- 32° to by one quired to 212° pound burn one pound. 35.00 6.36 5.96 26.00 4.72 4.47 FUENTERRABIA,