During the electrolysis of a solution of potassium ethyl di-propyl-malonate it was discovered by Crichton that when a concentrated aqueous solution of the salt was shaken up with a concentrated aqueous solution of potassium carbonate two distinct layers were formed. The peculiarity of this case lies in the fact that both substances are salts of the same metal, though cases of the non-miscibility of aqueous solutions of two totally different substances are common, as, for example, that of potassium carbonate and alcohol.