518 PARTICULAR CASES OF INDUCTION. 



integrals \dt and I'dt by equations (27). If I and I' are the 

 intensities of the two currents at the beginning of the time in 

 question, we shall have 





Suppose that we close the circuit, and that we consider the 

 phenomenon after a sufficiently long time, we shall have 



i =o, i;=o, 

 i-f, r-oi 



and therefore, 



(-D-K'-i)- 



<"> M EM V 



m : = 1= . 



R' RR' 



If, on the contrary, we open the circuit C, after the steady con- 

 dition has been attained, we shall have at the two limits, 



i =0, r = o. 



The quantities of electricity induced in the two circuits are then 

 equal, and of opposite signs to those of the preceding case which 

 was evident, for the variation of the flow of force was the same in 

 both cases. 



It is to be observed that the extra current of C is independent 

 of C', and, on the other hand, that the induction on the circuit C' 

 only depends on its resistance R', on the coefficient of mutual 

 induction of the two currents, and on the strength I of the permanent 

 current in the circuit C. The direct consideration of the flow 

 of force still enables us to foresee these results. 



If we wish to know the strength of the currents at each instant, 

 the solution of the problem must be completed by determining 

 the constants. 



