Joffe and McLean''s method for evaluating the degree of colloidality of soils by measuring their suction forces is criticized on the grounds that it fails to take into account differences in water-conductivity of soils having similar colloid contents but different degrees of cohesiveness. The water-supplying powers of 3 different types of soil (one of them a red lateritic soil), of approximately the same degree of colloidality, were measured by Mason''s writing-pencil soil-point method, which is based on Livingston''s conception of the dynamics of water movement in soils. The results obtained, together with other data derived from an examination of the soils by the methods of Green and Ampt, are inexplicable on the theory underlying the instrument devised by Joffe and McLean.