Page:Aether and Matter, 1900.djvu/65

CHAP.II] Faraday, and Neumann. But to the case of bodies in motion such a scheme can give no clue, except the first approximation based on the assumption of an equilibrium state of the surrounding field at each instant of the motion. And it can give no account of mechanical or ponderomotive forces, nor therefore of electrostatic phenomena in general, except by the empirical formation in simple cases of a fragment of a mechanical-energy function by taking advantage of the indications of independent observation and experiment.