The Identity of the Colloidal Particles in Soap Sols and Jellies

TEN years ago we found that two portions of the same solution of soap could be brought into the states of either sol or typically transparent jelly respectively at the same temperature, and that such significant properties as conductivity, lowering of vapour pressure, concentration of sodium ion as measured with the sodium amalgam electrode, etc., were identical in both these states. Sol and jelly differed only in mechanical properties such as rigidity and elasticity. We therefore drew the obvious conclusion that the rigid structure of the jelly must be built up by progressive linkings together of the particles which pre-existed in the sol (Trans. Ghem. Soc, London, 117, 1506; 1920).