DE “Oi 
JN 
( 65 ) 
ees ERO — Dr), 
or 
eG ENKA 
since k R must be small with regard to 9, 
Now, in order that a distinct doublet may be seen, the distance 
of the components must be large as compared with the breadth of 
the absorption bands. 
Replacing (19) by 
9 
24> 2 922 q2 9. 2 
(SAP IP + 9? I? 
’ 
we see at once that for a value of @, such that 
S— PRE UHH 
the value of x will be 
4max 
Fe a 
We may therefore consider the borders of the absorption band to be 
determined by the last equation, if in it we take for s a moderate 
number, say 5. Hence, the necessary condition for a distinct 
doublet is seen to be LR > ed. If it is fulfilled, our above sup- 
position as to the value of & Ri, will likewise hold good. Indeed, 
we shall have 
ERN > UH I, , 
whereas q° 90? is much smaller than # Jo. 
§ 9. We now come to the propagation of light in a direction 
perpendicular to the lines of force. Let the vectors P be also per- 
pendicular to these lines, i. e. in the language of the electromagnetic 
theory of light, let the electric vibrations take place ata right angle 
to the direction of the field. Then, according to Vorar, the velocity 
of propagation @, and the absorption z% will be determined by his 
formulae (50) and (51), or if we neglect #° by 
gle Big Eg PS, 4g? dS, 9 
GT age SSL ee 
PO] + d d Sz + 4 DV 
and 
