1. The effect of pH and of wetting agents on the adsorption of crystal violet at the surface of glass has been investigated.
2. At low pH values, a wetting agent at first increases the adsorption of the dye. But with an increase in the concentration of the wetting agent the adsorption falls off rapidly and drops almost to zero. At higher pH values the wetting agent diminishes increased adsorption of the dye. An explanation has been offered to account for these observations.