In 1916, in a paper on the size of the particles in deep-sea deposits, Odén showed that the distribution by mass of a suspension into classes of particles of different size could be inferred from a study of the course of sedimentation of such a suspension from a state of uniform dispersion in water. The experimental data required constitute the “sedimentation curve ” of the suspension, showing the total weight deposited, at a fixed depth, at the end of any assigned length of time.