ABSTRACT
The Kelvin equation is the first thermodynamic work on phase equilibrium for small systems. It was the basis of all subsequent work. Very often the derivation of the formula for the saturated vapour pressure over the curved drop surface is carried out as follows [34,103]: first, the conditions of mechanical equilibrium on the curved surface of the vapour-liquid interface are sought, and then the chemical potentials in the vapour and liquid are equated.
