Measuring the Electrical Capacity of a Condenser. 103 



We shall use N 16 &c. to denote the frequency of the fork 

 of approximate frequency 16. 

 The following are the results of the observations : — 



(1) Fork 16 used. 



Fork compared with pendulum. Fork loses 1 vibration in 

 7*46 seconds. 



N 16 = 15-866 sec. 



Resistance observation : — 



(1895) 

 a = 10; d = 1000; c= I 1892 V 



1 1893 ) 



1893 mean. 



C 16 ='3300 tj— ; i — — — microfarad. 



Sensitiveness 1 scale-division for alteration of 1 B. A. unit in c. 

 From these we find 



ohm 

 B.A. unit 



(2) Fork 32 used. 



16 beats occur in 42 seconds between octave of 16 and 32. 

 Fork 32 gaining. 



N 32 =32-ll. 



Resistance observations : — 

 a=10: d = 1000 ; c=- 



C 32 = , 3304-F T -^ — — tt microfarad. 



Hence r m 



^ «««, onm 



B.A. unit 

 (3) Fork 64 used. 



10 beats occur between 64 and octave of 32 in 50 seconds. 

 Fork 64 gaining. 



N 64 = 64-42. 



Resistance observations : — 



(a) a=10; d = 1000; c = 466; 



C fi4 = -3299 tt^ ^7 microfarad. 



64 B.A. unit 



(/3) a = 10; c = 1000; d= {^l^} 461 ' 3 



mean. 



N 64 =-3299 ^pt-t v microfarad. 



64 B.A. unit 



(4) Fork 128 used. 



16 beats occur between the 128 fork and octave of 64 fork 



in 26*25 seconds. Fork 128 gaining. 



N 12 « = 129-05. 



