BOOK REVIEWS improved models are proposed to explain various phenomena. The two papers on the Soret effect constitute an important contribution since that field has been neglected in the past. The review paper on the state of the proton in aqueous solution covers the topic quite adequately and contains references to many of the more recent papers in this field. The other topics covered include activity coefficients and viscosity effects in concentrated aqueous solutions and Raman spertral investigation of ionic equilibrium in such solutions; proton transfer in aqueous, methanol-water, and hydrogen peroxide systems; ionization constants for various systems obtained from emf, conductance, high field condnctrtnce, and spectrophatometric measurements; pH in non-aqueous solvents; electrolytic properties of the rare earths; electrophoresis and conductivity in ~olutions containing polyelectrolytes; diffusion in binary and ternary systems, ionic vibration potentials, anion exchange of metal complexes and complex ions in molten salts; thermodynamic properties of aquo-ions and ion pairs with an application of cryst,al field theory; melting mechanisms of ionic crystals It is regrettable that a few papPrs a n the program of the symposium, particularly those of J. E. Mayer, J. G. Iiirl
