Periodic Precipitations and Diffuson

Abstract

IN a recent communication (Proc. Roy. Irish Acad., 38 B, p. 445) we classed Prof. Wolfgang Ostwald's theory of periodic precipitations amongst those in which precipitation should occur at or near the “head of the diffusion column”. In reality, as Prof. Ostwald has kindly pointed out to us in a private communication, according to his theory the “critical mixture ratio”, which determines the formation of a precipitate, should always lag behind the head of the diffusion column. This objection to Ostwald's theory is therefore not valid.