The hand-book of household scienceA popular account of heat, light, air, aliment, and cleansing, in their scientific principles and domestic . e fire may be at oncereduced. Attention to this fact would save fuel in many culinaryoperations. 66. Doable Vessels to Regulate Heat.—If we have a substance which,placed directly over the fire, would receive an indefinite quantity ofheat, but which we desire to raise only to acertain temperature, we place it in a vesselsurrounded by another vessel; the outer onebeing filled with a liquid which boils at thedesired temperature. Heokees farin
The hand-book of household scienceA popular account of heat, light, air, aliment, and cleansing, in their scientific principles and domestic . e fire may be at oncereduced. Attention to this fact would save fuel in many culinaryoperations. 66. Doable Vessels to Regulate Heat.—If we have a substance which,placed directly over the fire, would receive an indefinite quantity ofheat, but which we desire to raise only to acertain temperature, we place it in a vesselsurrounded by another vessel; the outer onebeing filled with a liquid which boils at thedesired temperature. Heokees farina ket-tle. Fig. 11, is a .culinary contrivance ofthis kind. The outer vessel is filled withwater, while the inner one contains thematerial to be cooked, which, of course, can-not be heated higher than the boiling point,and is therefore protected from burning. Byusing any of the salt solutions mentioned(63), higher heats may be communicated tothe internal vessel. 67. Why Paddings, Pies, &c., cool have seen that water is a bad conductor of heat; that is, heat doesnot readily pass across its intervening spaces, from particle to Section of a culinary bath:opening to introduce water. 46 VARIOUS EFFECTS OP HEAT. and so become diftused through it. We do not, therefore, heat it byconduction, but by currents produced within it (46), which distributeand commingle the heat throngliout its mass. It cools in the sameway. As the particles at the surface or sides lose their heat, they fallto the bottom, and others succeed them. If the particles of watercould remain stationary, it would be slow and difficult to heat, andequally slow to cool. For this reason soups, puddings, pies, &c., whichcontain large amounts of hot water, so enclosed and detained in theirplaces that they are not free to circulate, and therefore, are not in acondition to lose their heat, keep hot longer, and cool slower thanequal bulks of simple fluids. 68. Concealed Heat of Vapor.—As the liquid stat
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