Surface pressure-area and surface potential-area data are presented for the following systems: myristic acid, oleic acid, ethyl myristate, and ethyl pentadecanoate on aqueous solutions of n-butanol, t-butanol, 1,4-butanediol, glycerol, and d-glucose. The upper and lower limits on compression rate required in each case to assure monolayer uniformity and negligible dissolution are determined. The surface equations of state proposed by Lim and Berg [J. Colloid Interface Sci. 51, 162 (1975)] produce excellent fits of the II-α data and may be used to extrapolate such data outside the accessible range of solute concentrations. © 1979.