that occur in the Telephone. 37 



(b) For the other closed circuit, which contains the excited 

 telephone T, let 



Wi signify the resistance of the circuit, 

 Ii the intensity of the current excited, 

 Q x the electrodynamic potential of this circuit upon itself. 

 Lastly, let R be the reciprocal electrodynamic potential of the 

 two circuits. 



The general law of induction furnishes, for the determina- 

 tion of the two current-intensities I and I l9 the two equations 



I,. Wl . - 0,§-B|i J 



Let the electromagnetic potential P have the form 



P=P +Asin(27m£). 



The equations 



I =C sin (2777i* + a), 

 I x = d sin (2777i£ + c^), 



satisfy the equations (1), if the amplitudes C and Ci have the 

 following values, 



C =H1/ -^ .., ^ Ki T^L ^r-^ (2) 



• 



A / 1 + 



L27 TO Q i "27rnQ 1 J "*" L QQ t (27rn) 2 QQ 1 J 



ft- 



on /r w i w i i 8 1 n R2 ww x -., 



Wl V L2t™Q + 27rnQj + L 1 QQ X (2tt») 2 QQ 1 J , (3) 

 and to the phases a and a x the following values be given, 



L ^\2imQj J 2 



w; ( r 2 w t 



- 27771 QJ 27771 ..s 



tan a = , tt7 — T9=i fT9 > • • W 



QQi \27mQ/V2TOQ 1 / 



If both telephones be in one and the same circuit, of which 

 the resistance is W , and the electrodynamic potential upon 



