Steam

stem, a vapor of water. Under ordinary atmospheric conditions water is changed into steam at a temperature of 100 deg. C or 212 deg. F. If water be heated so as to generate steam in a closed receptacle, as in a boiler, the steam struggles with the strength of a giant to escape. The more steam is generated, the greater the bursting force. Advantage has been taken of this fact to apply steam pressure to the movable pistons of engines in order to perform work. Making allowance for loss by cold and friction, it is estimated that the work done by from five to twenty-five pounds of steam passing through an engine in an hour is equal to that of a horse. Where water and cheap fuel are at hand, steam power is considered more trustworthy and not much more expensive than falling water. The statisticians of the United States census estimate that at the present time (1909) the steam used in manufactories is doing an amount of work that would require the employment of 8,742,416 horses. The work done by water power, which ranks next, amounts to an equivalent of only 1,727,258 horses. See Steam Engine