A catechism on the combustion of coal and the prevention of smoke; a practical treatise . ected to theinfluence of heat, its temperature will rise progressivelyfor each increment of heat received, until the temperatureof the ice reaches 320 F., when the melting of the ice willbegin. It will also be observed that, continuing the ap-plication of the heat to the ice, as before, there is no cor-responding rise in temperature either in the ice or in thewater in contact with the ice so long as any of the latterremains unmelted; and that during the process of meltingthe temperature of the water is co
A catechism on the combustion of coal and the prevention of smoke; a practical treatise . ected to theinfluence of heat, its temperature will rise progressivelyfor each increment of heat received, until the temperatureof the ice reaches 320 F., when the melting of the ice willbegin. It will also be observed that, continuing the ap-plication of the heat to the ice, as before, there is no cor-responding rise in temperature either in the ice or in thewater in contact with the ice so long as any of the latterremains unmelted; and that during the process of meltingthe temperature of the water is constant, and at 320 F. This change of state from solid to liquid, in the meltingof one pound of ice, requires 143 units of heat, the tem-perature being constant at 320 F. The heat does notraise the temperature of the ice, but disappears in causingits condition to change from the solid to the liquid is called the latent heat of fusion. Q. What is Joules equivalent? The exact mechanical equivalent of heat was first demon-strated experimentally by Dr. Joule, of Manchester, Eng-. FlG. 13. land, the apparatus employed by him being represented inFig. 13. A known weight was connected by means of 158 COMBUSTION OF COAL. cords to a shaft /, mounted on friction wheels not shownin the illustration. On this shaft a pulley was secured,which through the medium of another cord imparted motionto the shaft r, and caused it to revolve. At the lower endof this shaft r were fitted eight sets of paddles, which, whenconnected by means of a pin P, revolved with it. To theinterior of the copper vessel B were attached four station-ary vanes, cut out in such manner as to permit the freerevolution of the revolving paddles. Precautions weretaken to prevent a transfer of heat from the vessel B,which need not be described here. This vessel was filledwith a known weight of water, at the temperature of itsgreatest density, 390 F., and a thermometer / was insertedin the vessel B, to mark the rise in
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Keywords: ., bo, bookcentury1900, bookdecade1900, booksubjectcoal, bookyear1900
