300 P'fi'of' Zeeman on Magneto-Optics. [March 30, 



The laws discovered, however, seem to point to the conclusion 

 that all the Hues of a series are emitted by one oscillating system, that 

 there are, therefore, as many series in the spectrum of a substance as 

 oscillating systems in its atom ; moreover, that the oscillating 

 mechanism is the same in different elements. We are reminded here 

 of the view advocated by Sir Norman Lockyer that the different ele- 

 ments have something in common. 



The relation between these spectral series and resolution in the 

 magnetic field is so close that we may expect that the solution of the 

 problem of the series will give at the same time the solution of 

 the magnetic separation problem. 



That Lorentz's theory is on the right track even in the case of 

 the more complicated magnetic effects appears from the polarisa- 

 tion of the nonet shown in the slide. (Fig. 25.) 



Three groups of vibrating lines here correspond to the three lines 

 of the triplet. 



The circular polarisation corresponds also to that of the doublet 

 indicating that it is always the negative electron which executes the 

 vibrations. 



There is yet room enough for experimental work in extending 

 these investigations in different directions and to other elements. 



Much light on our present subject will be thrown undoubtedly by 

 the activity in adjacent chapters of physics. I can only mention in 

 this relation the extremely interesting experiments by Leuard and 

 Stark on the centres of emission of different spectral series, end the 

 important theoretical work by Drude* on the optical properties and 

 electronic theory. 



Maxwell has said " an intelligent student armed with the calculus 

 and the spectroscope can hardly fail to discover some important fact 

 about the interior structure of a molecule," I think this statement 

 remains as true now as it was thirty-two years ago. 



There can be no doubt, I think, that spectrum analysis and es- 

 pecially the magnetisation of the spectral lines will give us a clue to 

 the inner structure of the atom. 



I hope that I have succeeded in imparting to you this, my con- 

 viction. 

 [P. Z-] 



• Drude. Annalen del- Physik, pp. 677, 936. Bd. 14, 1904. 



