404 BELL SYSTEM TECHNICAL JOURNAL 



it is true, independent evidence exists in the case of carbon. Boron 

 supplies a group of alpha-particles which may be due to the reaction, 



iH2 + sBio = SzHe^ (6) 



and which comprises the most energetic subatomic particles yet 

 known, those of the cosmic rays excepted (12.3 MEY, range 15 cm.). 

 Blocks of various heavier elements emit both alpha-particles and 

 protons, of which the amounts both relative and absolute vary tre- 

 mendously with heat-treatment, degassing, and other circumstances, 

 so that evidently they cannot altogether proceed from the element 

 constituting most of the block, and their origins furnish a severe 

 problem for research. 



