No abstract

The assumption of an immobile hydrous multilayer at a wall of fixed potential was used in deriving equations relating zeta potentials, concentrations of univalent salt solution, wall potential, and thickness of the immobile layer. Calculations were made using data taken from published papers of various experimenters. Values of 8A to 63A were obtained for the thickness of the immobile layer. The values of wall potential and film thickness were considered sufficiently consistent for each set of data to justify the original assumption.

The thickness of the water film between a quartz lens and disk was determined by measuring the radii of successive Newton's rings. The squares of these radii are a linear function of the order of the rings from the center, the intercept of the extrapolated graph of which is a function only of the radius of curvature of the lens and the vertical separation of the lens and plate. By comparing intercepts obtained from data taken before and after evaporation of a water layer, a value of the order of 100A was obtained for the thickness of the water film of each interface.