Surface Distortion and Electrostatic Balance of Metals

It is shown that the large internal electrostatic pressure found by Wannier for free-electron metals is a consequence of his having transformed some surface terms into internal terms while discarding other surface terms of the same magnitude. It is also shown that with small distortions of the surface electronic charge density and small displacements of the ions near the surface not only the pressure but also the force on every ion can be made to vanish.