Conditions of Silver Chromate in Gelatine Hydrolysed and Electrodialysed to Different Extents

Abstract

IN a series of papers, Dhar, Chatterji, and collaborators have shown that if a reaction between two salts giving rise to an insoluble product is allowed to take place in gels, the insoluble substance exists in colloidal condition in the gel and the formation of Liesegang rings is due to the coagulation of the colloid. It has been shown, however, by Williams and Mackenzie¹ and Bolam,² that the insoluble substance produced by the reaction between two salts exists in supersaturated condition in the gel, and their results support the theory of the formation of Liesegang rings proposed by Wi. Ostwald.³ Experiments have been carried out by us to study the condition of silver chromate in gelatine hydrolysed (by heating) and electrodialysed to different extents, by determining the contact potential of pure silver in a mixture of N/100 silver nitrate, N/100 potassium chromate, and 3 per cent gelatine.