[wILson] THE NUMBER OF ELECTRONS IN ATOMS 51 
If we take A, — 19 we get— 
m A 
1 19 Pl 
2 42 Cas 
3 79 Br) == 80 
4 133 JE 7 
Similar results can be obtained for the other series of similar ele- 
ments. The comparison of the theoretical results with the observed 
atomic weights appears, therefore, to support the view that Sir J. J. 
Thomson’s theory of atoms contains a considerable element of truth. 
