Surface energy and surface tension in solids and liquids

Abstract

Rayleigh's theory of surface tension, based on the quadrant theorem, is extended to solids and presented in a simple general form. The quadrant theorem is generalized to embrace the traction of a half-space upon a wedge in contact with it, and Young's equation for the angle of contact is derived as a condition of equilibrium between the surface tension of the liquid and the tangential traction of the solid half-space upon the liquid wedge. The historical theories of capillarity are correlated with the general theory.