112 



BELL SYSTEM TECHNICAL JOURNAL 



Until the building of this apparatus proton streams had been so 

 scanty, that to bring about disintegrations in measurable number it 

 had been needful to project the protons against thick layers of dense 

 matter. In going through these layers they were slowed down and 



V/////////// 



r 



'ZZZZZZZZZZZZ2 



Fig. 2- 



-Apparatus of Oliphant and Rutherford for producing transmutation by 

 intense streams of protons. {Proceedings of the Royal Society) 



stopped, and there was no direct way of telling whether the observed 

 transmutations were achieved by protons of full speed, or by those 

 which had already lost some energy, or both. Moreover if the energy 

 of the bombarding particles was raised, the number of disintegrations 

 infallibly went up, but a part of this increase (and sometimes the 



