ABSTRACT
Sir J. J. Thomson has developed a new method of representing physical processes in terms of moving entities and electric lines of force. Thomson's aim is to give a picture of processes of nature which are difficult to visualise, and inasmuch as the ideas are essentially atomic they form a fitting conclusion to the subject of atomic theories and allied subjects discussed throughout this chapter. In the case of a moving electron its mass is proportional to the square of its charge, and this mass is entirely electric. The amount of this mass per unit volume an any point P is regarded as being proportional to the square of the electric force at P. Radiation, therefore, consists of mass-producing material travelling with the velocity of light and carrying with it closed lines of electric force. It follows, as a consequence, that the emission of radiant energy must be accompanied by a diminution in the mass of the radiating body.
