ABSTRACT
At the beginning of this century, no serious theory of the the metallic state exists. The position of metals in the periodic table suggests that these are substances in which some electrons outside the atom to which they are only loosely bonded are liable to leave the latter from the moment when the solid forms from isolated atoms. The existence of free electrons in metals received direct confirmation in 1916 in an experiment by Tolman. A metal wire is wound on a coil which may turn around its axis. This plasma oscillation constitutes a collective excitation of the electron gas created by a local fluctuation. One important objective of energy-saving programmes, is to reduce the consumption expended on heating houses and buildings. It is easy to imagine the technical difficulties involved in the industrial manufacturing of large surface areas of such films, with a thickness which must be constant to within 2 nm.
