Dielectric Strength in High Frequency Fields. 245 



application. This may be compared with equation (5) above, 

 -and the graphs of both are given below, taking 



125 



KV 



IOO 



75 



50 



25 



A = b 2 /4,c, 

 Curve T. 

 „ II. 



*=-33. 



1 l-6- T 



P 1=5 A+BT-*i 



I 



.i 

 i 











Y 



V 











V 



































10 



15 



20 25 



MINUTES 



The close resemblance o£ the curves would appear to 

 justify the view that the observed influence of time of 

 application on breakdown strength is largely, if not entirely, 

 caused by the rate of growth of intern ttraction, and that 

 Peek's formula might be replaced by a simpler exponential 

 type. 



4. The nature of dielectric hysteresis has long been under 

 discussion. That it is a time and not a static phenomenon 

 was recognized from the first, but it would appear that the 

 use of the term " viscosity " instead of hysteresis, or as indi- 

 cating the cause of it, is not tenable. The retarding force 





