Abstract
The non equilibrium thermodynamics of vapor‐membrane osmometers based on a simple theoretical model are discussed. The equations for mass and heat transport are given for three types of vapor‐membrane osmometers, of which two are known as “the method of bithermal equilibration after STOKES[4]” and as “the thermoelectric method after HILL[6] and BALDES[7]”. From the nonequilibrium thermodynamic theory the suggestion for the construction of a new type of vapor‐membrane osmometer is also given.