We study equilibrium droplets in two-phase systems at parameter values
corresponding to phase coexistence. Specifically, we give a self-contained
microscopic derivation of the Gibbs-Thomson formula for the deviation of the
pressure and the density away from their equilibrium values which, according to
the interpretation of the classical thermodynamics, appears due to the presence
of a curved interface. The general--albeit heuristic--reasoning is corroborated
by a rigorous proof in the case of the two-dimensional Ising lattice gas.Comment: LaTeX+times; version to appear in J. Statist. Phy