Electrometer as a Wattmeter and Voltmeter. 359 



Table I. 



Observed 

 deflection. 6. 



A + B 

 volts. 



C volts. 



A 1 TO' 



(C-^^VA + B). 



d 



+ 106 



57-5 . 



20 -7 



436 



-140 



58 -6 



39-5 



427 



-331 



53 3 



53-4 



431 



-552 



52-7 



71-6 



432 



-773 



51 5 



91 -0 



434 



-551 



32-5 



89-7 



433 



-268 



14-2 



89 -7 



438 



-352 



14-1 



115*0 



432 



— t _j 



09.0 



Oil 



114 "0 





-726 



48-5 ' 



88-9 



432 



-427 



60-6 



60-7 



431 



-338 



88 "9 



60-7 



427 



-110 



113 



60-7 



432 



+ 626 



113-0 



32-2 



439 



+ 987 



113-0 



18-1 



439 









433 mean 



-2. 



where A, is a constant, it follows that if A and B are in phase with 

 one another and with the alternate current, and have the same wave 

 form as the alternate current ; and if C is in phase with the potential 

 difference between two points of the circuit where the power is to be 

 measured, and has the same wave form, A must be equal and oppo- 

 site in sign to B, since the instantaneous rate at which work is done 

 on or by the circuit must be proportional to AC or BC. 



