( 63 ) 
§ 8. In the application of the equations to the phenomena in 
question, I shall follow Vorer’s treatment of the case of a single 
vector P. 
In the first place Vorar examines the propagation of light along 
the lines of force, which are supposed parallel to the axis of 2. 
He denotes 
by & the strength of the field, 
by # the time of vibration, divided by 2 a, 
by @ the velocity of propagation, and by z the coefficient of 
absorption, in this sense, that over a distance equal to the wave- 
length the amplitude is diminished in ratio of 1 to ¢—®7¥. 
Further he puts: 
en a Oy g/d seen (18) 
The values of @ and z for circularly polarized light are given 
by Voret’s formulae (24) and (25), in which the upper signs are 
to be taken if the polarization is right handed, and the lower signs 
if it is left-handed. To simplify these formulae, I shall put 
PtkRI—I2=S; 
we have then 
o(l—#2) os 
ze y* — —______ 
(1 + #2)? ( S? + yg? may 
2022 = veg? WI 
(14-22? S2 +. #2 92 A 
Now, we may suppose that even the maximum value of z is a 
very small fraction. The left hand members of the equations may 
therefore be written 
w? and 2 wz; 
hence, by division, 
g2 H! 9 
Bie st a EE 
2— PPS HIP 
NEL, 
1) 2 r 39 is the period of the free vibrations of which the ions are capable. As 
to the time 3’, it depends on the magnitude of the resistance, 
