1899.] on Magnetic Perturbations of the Spectral Lines. 



1G1 



Larnior. In the same way the lines B 1} B 2 , B 3 , etc., form another series 

 which also obeys the theoretical law, and possess a common value 

 for the quantity ejm, similarly for the lines C 15 C 2 , C 3 , etc. The value 

 of ejm for the A series differs from that possessed by the B series or 

 the C series, and this leads us to infer that the atom of zinc is built 

 up of ions which differ from each other in the value of the quantity 

 e/m, and that each of these different ions is effective in producing a cer- 

 tain series of lines in the spectrum of the metal. When we examine 

 the spectrum of cadmium, or of magnesium — that is, when we examine 

 the spectra of other metals of the same chemical group — wo find that 

 not only are the spectra homologous, not only do the lines group 

 themselves in similar groups, but we find in addition that the corre- 

 sponding lines of the different spectra are similarly affected by the 

 magnetic field. And further, not only is the character of the mag- 

 netic effect the same for the corresponding lines of the different 

 metals of the same chemical group, but the actual magnitude of 

 the resolution as measured by the quantity ejm is the same for the 

 corresponding series of lines in the different spectra. This is illus- 

 trated in the following table, and leads us to believe, or at least to 



[This table shows the effect for the three lines which form the first natural 

 triplet in the spectrum of cadmium compared with the corresponding lines in 

 the spectra of zinc and magnesium. It will be seen that the corresponding lines 

 in the different spectra suffer the same magnetic effect both in character and 

 magnitude. Thus the corresponding lines 4800, 4722, 5173 are each resolved 

 into sextets, and the rate at which the ionic orbit is caused to precess is the same 

 for each (denoted by e/m = 87 in the table). Similarly for the other corre- 

 sponding lines.] 



suspect, that the ion which produces the lines A 15 A 2 , A 3 , etc., in the 

 spectrum of zinc is the same as that which produces the corresponding 

 series A 1? A 2 , A 3 , etc., in cadmium, and the same for the corresponding 

 sets in the other metals of this chemical group. In other words, we 

 are led to suspect that not only is the atom a complex composed of an 

 association of different ions, but that the atoms of those substances 

 which lie in the same chemical group are perhaps built up from the 

 same kind of ions, or at least from ions which possess the same e/m, 

 Vol. XVI. (No. 93.) m 



