Page:Scientific Papers of Josiah Willard Gibbs.djvu/461

Rh In case of one molecular formula in liquid and none in gas, we may give the molecules repelling forces which will make the gas possible. (?) [See p. 417.]

Deduce Ostwald's law in more general form.

Deduce interpolation formula.

What use can we make of Latent Differences? $$\mu_{\text{A}}, \mu_{\text{AA}}, \mu_{\text{B}}, \mu_{\text{BB}}, \mu_{\text{AB}}$$ all conform to law, I think.

My dear Prof. Bancroft:

A working theory of galvanic cells requires (as you suggest) that we should be able to evaluate the (intrinsic or chemical) potentials involved, and your formula is all right as you interpret it. I should perhaps prefer to write  for small values of $$\gamma_{\text{D}}$$, where $$\gamma_{\text{D}}$$ is the density of a component (say the mass of the solutum divided by the volume of the solution), $$M_{\text{D}}$$ its molecular weight (viz., for the kind of molecule which actually exists in the solution), $$A$$ the constant of Avogadro's Law $$\left( \frac{pv}{mt} = \frac{A}{M} \right),$$ and $$B$$ a quantity which depends upon the solvent and the solutum, as well as the temperature, but which may be regarded as independent of $$\gamma_{\text{D}}$$ so long as this is small, and which is practically independent of the pressure in ordinary cases.