Abstract
The thermodynamic formula for the change of surface tension with pressure is interpreted for a one‐component system and for a two‐component system consisting of an inert gas over a liquid. In the latter case the effect of pressure on surface tension can be attributed in part to absorption of gas at the surface of the liquid and in part to an intrinsic decrease in density of the liquid in the neighborhood of the surface. The equations are interpreted in terms of the Gibbs adsorption isotherm. The adsorption of gas at the liquid surface has been estimated in several cases from data in the literature.