Motion of electrons in gases

1.In order to find an explanation of many of the ordinary electrical phenomena in gases it is necessary to consider the effects that occur in collisions between electrons and molecules or atoms of the gas. Collisions may be divided into two classes, those in which the electrons move with a small velocity and lose or gain a small amount of energy in collisions with molecules, and those in which the velocity is large and the electrons may lose a large proportion of their energy. In collisions of the latter type the kinetic energy of the electron is of the order of the energy which corresponds to the ionising potentials. Many of the original investigation of phenomena where these effects predominate have been made at the Electrical Laboratory, Oxford, and this work is accepted by several authors as being of importance in the theory of the electrical properties of gases.