(7 ) 



2 ^ 



The two solutions represent circular vibrations in the [)lane of 



1 

 XY, right-handed with the frequency a -\- - r, lett-handed with the 



Li 



frequency a — - r. The vibrations parallel to the axis OZ iiave the 



frequency a. In short we have to do with Lorentz's elementary 

 theory. 



All this is independent of the sign of r, i. e. of the direction of 

 the magnetic field. If r be negative, the right-lianded circular vibrations 

 belong to a frequency smaller than a. 



Case II. Magnetic field = 0, hence r = 0. 



Vibrations of arbitrary form with frequency b are now performed 

 in the plane of X,Y. Parallel to the axis Oi^ we still have vibrations 

 with frequency a. 



Case III. Simultaneous electric and magnetic fields. Let r be positive. 

 According to (9j and (10) and taking the upper signs we find 



r 1 



n z= b -\ m a --(- s -| r q :=^ -^ i 



representing right handed circular vibrations in the plane of A^ }', 



1 

 with the frequency a-{-s-]- - r. 



The lower signs give : 



1 1 



n ^z b ?'=:a-[-s r or= — I 



jj 2 



being left-handed circular vibrations in the plane of A^, Y with the 



1 

 frequency a -{- s r. 



If r be negative, the circular motions are described in the opposite 

 direction. 



Vibrations parallel to the axis OZ always have the frequency a. 



We therefore obtain when observing at right angles to the fields 

 a dissymmetrical triplet, the relative position of its components being 

 determined by the following rule. 



I shall suppose that the violet, consequently the higher frequencies, 

 is on the right. 



Let A and B be the lines with the frequencies a and b, if there 

 is solely an electric field. 



