Examining the treatment in meteorological works of thermodynamical problems involving the ideas of surface tension and of adsorption, one is struck by the fact that such questions are almost always dealt with in a fragmentary manner. The reader is referred to various works which he is recommended to study in order to understand the statements presented. The multiplicity of sources on which it is desirable to draw leads him to feel the need for a general treatment, and to wish for a single account uniting in a coherent manner the variousproblems of a similar nature involving the thermodynamics of capillarity. Only an account of this kind enables one to get to the root of problems, to perceive what physical hypotheses are required in the process, and to judge the consistency or inconsistency of various theories.