1. 1. The preparation of a series of sulfonated polystyrene-divinyl-benzene cation-exchange resins is described. 2. 2. Exchange capacities are found to be identical to all inorganic and organic univalent cations studied, with the possible exception of the tetra-(n)-butylammonium ion. The divalent cation capacities are slightly larger in every case. 3. 3. Studies of rates of uptake are presented, and diffusion coefficients calculated. The rate of uptake is correlated with both the ionic volume and the degree of cross-linking of the resin structure.
