Show MEANING OF HORSE HORSEPOWER POWER Simple Manner by Which the Now Familiar Fa Familiar Fa- Fa Term Was First Brought Into Use The The use of the power horse horse power as a measure of an engines engine's work came came naturally from the fact that the first engines were built to do work which had formerly been performed by horses John Smeaton who built atmospheric atmospheric at at- engines before Bolton and Watt placed their more complete machine machine ma ma- chine on the market had valued the work done by a strong horse as equal to lifting a weight of pounds one foot high a minute When Bolton and Watt began to bid for public fa ta favor tavor vor they agreed to to place their engines engines en en- gines for the value of one third one third part of the coals which are saved in its use use They also increased the value of the horse horsepower power to foot foot- pounds so that their engines were half haf again as p powerful for their rated power as those of their competitors In this way they established th the alue lalue of the horse power The following are the various values of a horse power horse power Thirty three Thirty three thousand pounds foot foot pounds a minute foot pounds foot pounds a second 2 thermal units units' an hour 42 75 thermal thermal ther ther- mal mil units a minute The horse horsepower power er of a boiler depends on on its capacity for for fore e evaporation a oration The Thin evaporation of 30 pounds of water from JOO degrees Fahrenheit into steam at seven pounds pounds' gauge pressure equals 34 2 pounds and at degrees Fahrenheit Is equivalent equiv equiv- alent to toa a horsepower |