474 



On the Question oj Dielectric Hysteresis. [Mar. 21, 



Since, until further experiments be made, this conclusion can only 

 be taken as applying to the condenser when under the conditions of 

 this experiment, it is necessary to form an idea as to the highest 

 value of the electromotive intensity which was produced in the 

 dielectric. Only a very rough estimate of its value can be made 

 without dismounting the condenser. If we assume that the thickness 

 of the paraffined paper is about "01 cm., then with 11 volts potential 

 difference between the plates, the electromotive intensity equals 1,100 

 volts per cm., or about 3*7 electrostatic units. If we take the dielectric 

 constant of paraffined paper as 2, the corresponding electrostatic induc- 

 tion is 7*4 electrostatic units. It may be mentioned that in the 

 experiments of Signer Arno the induction ranged from "03 to 14'58 

 electrostatic units. 



In order to give an idea of the viscous effects which come into play 

 in the same condenser, we have ascertained the variation of the charge 

 which it takes up on the application of an unvaried E.M.F. to its 

 terminals for different intervals of time. The results are plotted in 

 Fig. 4. The time constant of the rise of charge, calculated from the 

 capacity of the condenser and the resistance of the circuit through 



FIG. 4. Relation between Charge of Condenser and the Duration of Application 

 of Charging Electromotive Force. 



3 4 s Seconds. 



Duration, of charging contact. 



which it was charged, was less than ^ o o of a second : hence in. 

 7 times f a second the charge would have risen to within ^ per- 



