UTAH ACADEMY OF SCIENCES 115 
The units constituting the atomic system are so ar- 
ranged that the system possesses great stability. It may 
happen, however, that this system reaches a state of in- 
stability, in which case it may lose electrons, the atomic 
weight remaining unaltered, or it may lose atoms of its 
constituent elements in which case a sensible change in 
atomic weight occurs. 
Only helium atoms have so far been observed to be 
.given off. during such changes. 
