.284 Prof. Orme Masson on the 



are similarly indicated with the appropriate decrease in the 



number of electrons in the shell. 



We can now express in general terms (which, of course, 



may be made specific by substitution of the proper numbers 



for N and n) any action that occurs within the nucleus. 



Thus an a-ray change depends on the intranuclear action 



. / . 



2(b 2 e) = (b 2 e) 2 and is expressed by the sub-chemical equation 



/ 



where (b 2 e) 2 is the expelled He nucleus and the other 

 product is the ion of the new element, carrying a double 

 negative charge till, by discharge, it becomes the atom 

 \_{i> 2 e)^-2(be) n ~\e^-2' This clearly expresses the character- 

 istics of a-ray action — that the atomic number is lowered 

 by 2 and the mass by 4, to which may be added the state- 

 ment tfiat there is no change in the number of neutral 

 couplets (n). A /3-ray change, on the other hand, depends 



/ 

 on another intranuclear action, 2 (be) — (b 2 e) + e , thus sub- 



tractino- 2 from n and adding 1 to N, while the mass is 



unchanged and the main product is the single charged 



positive ion of an isobare. In full, the equation is 



/ 

 [ (b 2 e) N (be) n ] e N = [( VJn +i(^)„_ 2 ] e-$ + e, 



The results obtained by Sir E. Rutherford by the bom- 

 bardment of light atoms with swift a-par tides can be 

 expressed similarly. Thus the expulsion of a particle with 

 the mass 3 and a charge of + 2 (the nucleus of a lower 

 isotope of helium) can obviously be attributed to the change 



2(b 2 e) = (b z e) +■(&?), while the expulsion of a hydrogen nu- 

 cleus (a single baron) results from the action (b 2 e) = b + (be). 

 Sir E. Rutherford has shown that the nitrogen atom gives 

 both these particles, apparently by actions which occur 

 independently. The equations for them are 



[(MJ«r=[(MiM]^+(W^ 



and [(b 2 e) 7 ]e 7 = [b. 2 e) & (be)~\e 7 +b. 



In the first case the main product is the double charged 

 negative ion of Aston's higher isotope of boron. In the 

 second case it is the single charged negative ion of a pre- 

 viously unknown isotope of carbon. 



