1908/07/30 by E. T. Whittaker · 2 citations
Engineering · #Phase Equilibria and Thermodynamics
paper · doi:10.1098/rspa.1908.0060
openalex publication_date 1908/07/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/05/21
Abstract 1. The fundamental quantities in the theory of capillary phenomena are the surface-tension γ (which we shall suppose expressed in dynes per centimetre), and the surface-energy λ (which we shall suppose expressed in ergs per square centimetre). The relation between these two quantities is at once given by the thermodynamic equation connecting available energy with total energy: it is therefore γ = λ + Tdγ/dT, where T denotes absolute temperature. This equation implies that when the area of a surface of separation is increased by 1 cm.2 at temperature T, the external agencies do work amounting to γ ergs against the surface-tension: and this energy, together with a further contribution of —Tdγ/dT ergs which is appropriated from the heat-energy of neighbouring bodies, becomes resident in the film, giving rise to an increase of λ ergs in its internal energy.