PEIRCE. — ANOMALOUS MAGNETIZATION OF IRON AND STEEL. 657 



Figure 15 shows some observations made upon a shell and core which 

 were not very successfully demagnetized. A slight bias exists : ABC 

 and PQZ show the residual fluxes through shell and core, the first for 

 currents which give a negative moment while they are running, the 

 second for positive currents. 



CURRENT. 



Figure 14. Two similar shells of soft steel, one intact, the other sUt length- 

 wise by a thin saw cut, were used successively over the same core. LMNZ 

 and OAB show the fluxes through the combinations in the two cases. 



Figure 16 shows how greatly the manner of building up the current, 

 which is then to be quickly broken, affects the amount of the negative 

 or reversed magnetizations. Both of these curves show anomalous 

 magnetization for moderate currents, but the residual flux is very 

 much greater if the current is built up gradually than if it is built up 

 suddenly. 



The gap between core and shell in the combinations X and Y of 

 Figure 13 and some others we have used, was purposely made wide 

 enough to permit of the introduction of a very thin ring coil to em- 



VOL. XLVII. — 42 



