570 PHENOMENA OF INDUCTION IN NON-LINEAR CONDUCTORS. 



The action on A of this infinitely small magnet placed at M', 

 at the distance /, is equivalent to that of an infinitely small magnet 

 of moment 57 placed at M, at the distance r, and such that 



*/. 



Fig. 125. 



If x and c are the distances MO and AO, we have 



c c x cot a 



r x 



r' x 2C + x cot a 



2C 



From which we get 



m c - x cot a 







4 * 



It is seen that the action of the induced currents on the point 

 A is equivalent to that of a complex solenoid (327) situate on the 

 plane starting from the point O, in a direction contrary to that 

 of the motion, and the magnetic strength of which at each point 

 will be 



CT m c - x cot a 

 dx 4 c 



We find accordingly, for the components X and Z of the force, 

 the same values as before. 



