448 H. A. Rowland — Electrical Measurement. 



satisfied. Also in method 22, when we know the ratio of the 

 self and mutual inductances in the coil, the resistances can be 

 adjusted to satisfy one equation while the experiment will 

 give the other and hence the capacity in terms of the induct- 

 ances. 



Again, pass a current whose phase can be varied through 

 one coil of the electrodynamometer, and the circuit to be tested 

 through the other. Vary the adjustments of resistances until 

 the deflection is zero, however the phase of current through 

 the first coil may be varied. 



The best methods to apply the first modification to are 15 A, 

 16 A and B, 18, 20, 21, 22 and 24. In these, either a Wheat- 

 stone bridge can be adjusted or the ratio of the self and mutual 

 inductances in a given coil can be assumed as known and the 

 resistances adjusted thereby. 



The value of this addition is in the increased accuracy and 

 sensitiveness of the method, an increase of more than one 

 hundred fold being assured. 



As a standard I recommend two or three coils laid together 

 with their inductances determined and not a condenser, even 

 an air condenser. 



