DR. C. J. DAVISSON 781 



agement and leadership. His compelling interest in scientific research led 

 Dr. Arnold to make a place in it for him, very rare in industrial laboratories 

 of the time. A pattern of work of his own choosing gradually evolved, and 

 he worked within it throughout his career. One or two young physicists 

 and a few laboratory technicians made up the team that worked on his 

 research problems. The young physicists and technicians did most of the 

 work in the laboratory, although Davisson would frequently be found in 

 the laboratory making observations in association with his co-workers. He 

 took a leading part in planning the experiments and in designing the appa- 

 ratus. His thoroughness and absorbing interest in detail were especially 

 rewarding in this area for his experiments were always well conceived and 

 their instrumentation w^as beautiful. 



The maximum of reliability, long life (measured in years) and the highest 

 electron-emitting efficiency from the cathode were early recognized as im- 

 portant to the full utilization of the thermionic high-vacuum tube in tele- 

 communications. For several years after the close of the war, Davisson's 

 researches were directed at a complete understanding of the emission phe- 

 nomena of oxide-coated cathodes. This emitter is an unusually complex 

 system. Chemical, metallurgical, and physical problems of great complexity 

 are interleaved. Over the years, our laboratories have made great progress 

 in reliability, long life, and high electron-emitting efficiency of thermionic 

 vacuum tubes for telecommunication uses. The benefits of this work to the 

 telephone user have been large, and annual savings to the Bell System of 

 many millions of dollars have resulted. Davisson's researches during the 

 five years following the close of the war. and his continuing advice to others 

 through a longer period were significant in the advances that our labora- 

 tories have made. 



As multigrid structures came into use and the tubes came to be used in 

 circuits of ever increasing complexity, unwanted secondary electron emis- 

 sion from the grid structures became a major problem. The presence of this 

 emission and its variation in amount from tube to tube brought about mal- 

 functioning and unreliability. If it were to be controlled, its complete under- 

 standing was essential. A basic study of secondary emission was Davisson's 

 next area of research. In these studies he came upon patterns of emission 

 from the surface of single crystals of nickel that aroused his curiosity. His 

 examination of these patterns led to his discovery of electron diffraction 

 and the w^ave properties of electrons. In recognition of this masterful re- 

 search with its important and highly significant results, he was awarded 

 the Nobel Prize in 1937. 



After the discovery of electron diffraction, Dr. L. H. Germer, who had 

 worked with Davisson on the secondary emission researches, took the prob- 



