ABSTRACT

This chapter describes the experimental work on evaporation and condensation coefficients. It utilizes equilibrium according to the kinetic theory, as a balance between the rate of evaporation and the rate of condensation, these two processes going on simultaneously at equal rates. T. Alty endeavored to determine whether, and what percentage of, water vapor molecules are reflected at the surface of evaporating liquid. Alty stated that, if the water vapor pressure at the temperature of the experiment were sufficiently small, the mass flux would be affected only very slightly by the presence of the vapor in the surrounding space. The evaporation coefficient is used to account for the deviations from kinetic theory that may be due to the anomalous molecular interactions at the interface which are exposed in the dynamic state and which are not properly accounted for in thermodynamic properties.