In my paper on “Chemical Affinity and Solution,” read before the Royal Society of Edinburgh on 16th February last, I gave some general proofs of the correctness of my theory of solution, taken from Thomson's researches on thermo-chemistry, as given in Muir and Wilson's book on that subject. In the present paper I propose to extend these proofs, and to show the laws of solution, so far at least as chlorides, bromides, and iodides are concerned. I have verified these laws in the case of many sulphates, and have no doubt they govern all cases of solution. My theory is simply this, “Solution is due to the chemical affinities of the constituent atoms or elements of the body dissolved for the constituent atoms of the solvent.” For instance, the solubility of BaCl2 in water is due mainly to the affinity of the Ba of the salt for the O of the water, and of the Cl of the salt for the H of the water, and the degree of solubility depends on the relation between these affinities.