In this paper the author concludes that the measurement of the breaking-strain of liquids is the only universally applicable method of measuring their cohesion; and as dropping is the phenomenon in which the breaking-strain can be most easily measured, he examines the work already done in this direction. Dr Guthrie's theory that the increase in the size of drop, with the increase in the rate of dropping, is due to the attraction of the solid tearing more of the root of the drop in low than in high rates is put to a crucial test by an experiment in which mercury drops from a wide glass tube so arranged that the tube only acts as a support for a column of liquid from the end of which the drops fall.