XXVIII.—On the Computation of the Specific Heat of Liquid Water at various Temperatures, from the Experiments of M. Regnault

Extract

Correction of M. Regnault's Experiments for the Effect of Agitation.

The discovery by Mr Joule of the fact, that mechanical power expended in the agitation of liquids is converted into heat as the visible agitation subsides, renders a certain correction necessary in calculating the results of experiments on specific heat in which such agitation has occurred.

Of this kind are the experiments of M. Regnault on the apparent specific heat of liquid water at different temperatures. Water at a high temperature, T₃, was emitted from a boiler into a calorimeter containing water at a low temperature, T_l, and the resulting intermediate temperature of the whole mass, T₂, was used as the means of calculating the ratio of the mean specific heat of water between T₃ and T₂, to its mean specific heat between T₂ and T₁. Now, the upper part of the boiler contained steam at a high pressure, so that the hot water was expelled with great force.