Heat, Specific

The capacity of a body for heat; a coefficient representing the relative quantity of heat required to raise the temperature of an identical weight of a given body a defined and identical amount. The standard of comparison is water; its specific heat is taken as unity. The specific heats by weight of other substances are le than unity. The specific heat varies with the temperature. Thus the specific heat of water is more strictly 1+.00015 tº C. Specific heat is greater when a substance is in the liquid than when it is in the solid state. Thus the specific heat of ice is 0.489; le than half that of water. It differs with the allotropic modifications of bodies; the specific heat of graphite is.202; of diamond,.147. The product of the specific heat by the atomic weight of elements gives a figure approximately the same. A similar law applies in the case of molecules. (See Heat, Atomic-Heat, Molecular.) The true specific heat of a substance should be separated from the heat expended in expanding a body against molecular and atomic forces, and against the atmospheric pre ure. So far this separation has not been po ible to introduce in any calculations. 288   STANDARD ELECTRICAL DICTIONARY.