Mendeleeff endeavoured to obtain a connexion between surface energy and constitution; more successful were the investigations of Schiff, who found that the " molecular surface tension," which he defined as the surface tension divided by the weight.
Ramsay and Shields suggested that there exists an equation for the surface energy of liquids, analogous to the volume-energy equation of gases, PV = RT.
Similarly with two liquids like oil and water, which do not mix, we have surface energy proportional to the area of contact.
The ordinary surface energy of a two-phase system tends to diminish the area of contact, and thus to help the growth of the larger aggregates required for coagulation.
The function of the electrolyte may be to annul such a natural charge and thus allow the non-electric surface energy to produce coagulation.
