Article révisé par les pairs
Résumé : Experiments on thermodiffusion of binary organic solutions by the thermogravitational method are described. The separation curves are discussed in connexion with the "forgotten effect". For nearly perfect solutions, the Soret coefficient D′/D is independent of the composition. The sign of D′/D is determined by the difference of the cohesion densities (energy of vaporisation/molar volume) of the pure constituents. The constituent with higher density of cohesion is enriched at the cold wall. A derivation of this rule based on the elementary theory of transport phenomena in liquid phase is given. © 1950.