﻿682 Dr. G-. H. Henderson on the Decrease of 



energy might be determined by appeal to experiment 

 before the mechanism is understood. 



Accordingly, it seemed of interest to apply the classical 

 theory of the exchange of energy as given by (1) to the case 

 of the a particle and electron, having regard to the limited 

 number of stationary states which the electron can occupy 

 within the atom, and to compare the resulting law of motion 

 of the a particle with experiment. 



This has been done in the following paper, taking as a basis 

 the following assumptions. 



Interchange of energy with an electron takes place 

 according to (1) provided that the energy transferable, 

 according to (1), is greater than the ionization potential of 

 that electron. 



Thus for any given V a definite upper limit is placed upon 

 p by (1), where Q is equal to the ionization potential. For 

 values of p less than this limiting value p , the excess of 

 energy over that required to remove the electron from 

 the atom may be in the form of kinetic energy of the 

 electron. 



The existence of resonance potentials is taken into account 

 by assuming that when the energy available according to (1) 

 lies between the ionization and resonance potentials, or 

 between two resonance potentials, the energy transferred is 

 constant and equal to the lower resonance potential. 



For encounters where p is greater than p , given by (1) 

 for the lowest resonance potential, it is assumed that practi- 

 cally no energy is transferred to the electron, the latter con- 

 tinuing to move in its stable orbit and behaving as if rigidly 

 bound to the atom. 



§ 3. Calculation of the Law of Motion of ol Particles. 



Consider a substance in each of the atoms of which there 

 aren 1? n 2 . . . n r electrons with the ionization potentials Q 1? Q 2 

 . . . Q r respectively. The total number of electrons 



n = ni + n 2 + . . . n r . 



Than, for the n v electrons having the ionization potential 

 Qd 



AT_2A^ il " 



Jp 2 + a< 



