Diffraction of cathode rays—III

This paper is a continuation of work described in these 'Proceedings,' and the apparatus used was closely similar. The general method is to send a beam of cathode rays, of the order of 30,000 volts energy, through a thin film of crystalline material and examine the diffraction pattern formed by the action of the crystals on the de Broglie waves of the cathode rays. The patterns obtained are closely similar to those formed in tbs Hull-Debye-Scherrer method of X-ray analysis, thus in the case of a metal film containing a large number of small crystals orientated at random, they consist of a number of concentric rings, one corresponding to each spacing of crystal planes. The patterns are recorded by allowing the electrons which form them to strike a photographic plate and developing the plate in the ordinary way.