Dielectrics in a Steady Field of Force. 



397 



Ellipsoid of density 3*3. — Free period 14*9 seconds. After 

 22 hours in ¥ = '271, period 12-33 ; after 48 hours longer in 

 F = -136, period 139. For the former F 2 /(n a -n 2 ) = 26*85, 

 and the latter 27'2. 



K—=6-98. 



Time 



1 m. 



15 in. 



lb. 



2h. 



4h. 



10 b. 



22 b. 



K 



7-0 



8-1 



10-5 



12-4 



16 



206 



220 



On reversing the field the ellipsoid did not reverse. The 

 rate of fall of K under a reversing field and the early part 

 of its rise after passing through zero are given below. 



Field reversed. 



Time 



12 m. 



9 J m. 



230 m. 



5 1, 



7 1). : 



Oli. 



lib. 



X 



-Go 



-4-0 







!, 



I 

 ,7| 



4, 



5-6 



This shows the forced depolarization of a dielectric by a 

 method distinct from discharge through a galvanometer. 

 These rates of change are drawn in fig. 1. Their chief 



Fiir. 1 



K 













T 

















A_ 



^r^ 























^r^ 

















1 









1 



I 





















KouiS exposal* '-- :\eiX 



A item start. B from reversal of fieU. 



interest lies in the fact that whether the polarization is in- 

 creasing from zero or being reversed, the rate of change is 

 for a long time the same. It is also noticeable that the time 

 occupied in the linear polarization is nearly the same in both 



