In the case of a solid or a liquid, the **latent heat** of isothermal expansion may often be neglected, and if the specific heat, s, be also taken as constant, we have simply 0-00 =s log e0/00.

In order to see whether the heat came out of the chips he compared the capacity for heat of the chips abraded by the boring bar with that of an equal quantity of the metal cut from the block by a fine saw, and obtained the same result in the two cases, from which he concluded that "the heat produced could not possibly have been furnished at the expense of the **latent heat** of the metallic chips."

If h is the water heat at the lower temperature, h l the water heat at the higher temperature, and L the **latent heat** at the higher temperature, the heat supply per pound of steam is equal to h1 - h2+L1, which, from the steam tables, with the values of the temperatures given, is equal to 1013 B.Th.U.

We can calculate the heat of formation from its ions for any substance dissolved in a given liquid, from a knowledge of the temperature coefficient of ionization, by means of an application of the well-known thermodynamical process, which also gives the **latent heat** of evaporation of a liquid when the temperature coefficient of its vapour pressure is known.

The **latent heat** of vaporization of mercury was found by Marignac to be 103 to 106.