A DYNAMICAL THEOBY OF THE ELECTROMAGNETIC FIELD. 



547 



M M 3 



The total quantity of electricity is c -~ , and the value of tydt is c 2 



The effects on the galvanometer and dynamometer are equal to those of a 

 M 



unilonn current 



f +' 



tor a time 2 - . 



The heating effect is therefore greater than that of the current on making- 

 contact. 



(42) If an electromotive force of the form g=Ecospt acts on the circuit 

 R, then if the circuit S is removed, the value of x will be 



E 



: = -. sm(pt-a), 



where 

 and 



tan a = 



i t =R*+Ly > 

 j. 



R ' 



The effect of the presence of the circuit S in the neighbourhood is to 

 alter the value of A and a, to that which they would be if R became 



and L became 



R+p* 



L-p> 



MS 



MN 

 tf+pW 



Hence the effect of the presence of the circuit S is to increase the apparent 

 resistance and diminish the apparent self-induction of the circuit R. 



On the Determination of Coefficients of Induction by the Electric Balance. 



(43) The electric balance consists of six con- 

 ductors joining four points, A, C, D, E, two 

 and two. One pair, AC, of these points is con- 

 nected through the battery B. The opposite pair, A , 

 DE, is connected through the galvanometer G, 

 Then if the resistances of the four remaining 

 conductors are represented by P, Q, R, S, and 

 the currents in them by x, x z, y, and y + z, 



692 



