PEIRCE. — BEHAVIOR OF THE CORE OF AN ELECTROMAGNET. 133 



Figure 20. 



Direct and reverse current curves in the coil of the electromagnet Q for five 

 different values of r when E and the number of active turns were kept fixed. 



Figure 27. 



Currents in the coil of 2788 turns belonging to the magnet Q for three differ- 

 ent values of the applied voltage with the same value of r. At the starting of 

 each current the core was magnetically neutral. 



