482 BELL SYSTEM TECHNICAL JOURNAL 



closely related to the subject of this discourse, the difficult and beauti- 

 fully executed experiments by which Stern and Esterman in 1929 

 showed that atomic hydrogen also is diffracted in accordance with the 

 de Broglie-Schroedinger theory. 



Important and timely as was the discovery of electron diffraction in 

 inspiring confidence in the physical reality of material waves, our 

 confidence in this regard would hardly be less today, one imagines, 

 were diffraction yet to be discovered, so great has been the success of 

 the mechanics built upon the conception of such waves in clarifying 

 the phenomena of atomic and subatomic physics. 



