(8 ) 



• •ulo^ 



A BO 



i-yt 



1 

 A 



Fig. 1. 



Let the electric field be horizontal. 



If now the magnetic field is superposed, then 



A remains. 



Two components, however, originate out of ^; 



r 

 they have displacements equal to — , and in oppi- 



site directions. The result is the triplet A'AB'. 



The electric doublet ^45 may still have different 

 positions relatively to the original line 0. In the 

 supposition of § 3 the line B coincides with the 

 line 0. In the supposition of § 1 the original line 

 is at a distance h s at the right of B. 



7. We shall now suppose that the electric 

 field is an oscillating one. Let B coincide with the original line. If 

 the electric force oscillates according to the formula « cos nt, then s 



may be represented by t^- cos- nt = — f 1 + cos 'Int). 



The lines A and B' retaiji their places. The middle line of the 

 dissymmetrical triplet must always be less narrow than the outer 

 components and darkest in the centre. All this applies with a 

 slight modification to the case when B does not coincide with the 

 original position of the line. 



8. In the second problem, which we will now consider, a vibra- 

 ting electron is subjected to a horizontal magnetic and a vertical 

 electric field. Let the magnetic force be parallel to OZ, the electric 

 to OX. 



The equations of motion now become : 



■| = — a-g + ri] ^] = — h"i] —rl . . . . (11) 



'iz=z — h% (12) 



Suppose again h > a and h ^ a-= s. s now as before determines 

 the electric, r the magnetic effect. 



The frequency of vibrations parallel to OZ is always b. 

 As in § 5 we put 



By (11) we have 



— 71^ = — a^ -\- inrq — ?i^q — — b'q — irn . . (13) 



or 



— n^q = — b'q — irn 



