84 



Transaotions of the Royal Canadian Institute 



was earthed and connected to the third terminal D of the SHde through 

 a Brown telephone of 5,000 ohms resistance. The bottom could be 

 connected to either of the other terminals A and B of the Slide. 



From Vreeland Oscillator, 



Fig. 1 



Let R, R', be the resistances included in arms AD, DB, respectively. 



Let C be the capacity to be measured. 



Let C be the capacity between the sheath and the lead to A. 



Let C" be the capacity between the sheath and the lead to B. 



If Ri, Ri' are the values of R, R' when balance is obtained with C 

 connected up as in the figure, we have, 



(C+C")/C = Rx/Ri'. (1) 



If R2 = R2' are the values of R, R' when balance is obtained with C 

 connected up as in the figure, we have, 



(C + C')/C" = RVR2. (2) 



After C, C" have been determined as indicated below, equations 

 (1) and (2) give us two values of C, the mean of which may be taken. 



By deducting the lead capacity obtained in the usual way, the net 

 capacity of the insulators can be determined. 



The value of the capacities C and C" can be obtained as follows. 



