PEIRCE. — ANOMALOUS MAGNETIZATION OF IRON AND STEEL. 643 



111 all the observations mentioned in this paper the solenoid was 

 placed with its axis perpendicular to the meridian, and in all but a 

 very few instances to be mentioned specially, the rod was tested while 

 inside the solenoid. 



In almost every instance, also, the exciting current was applied 



Figure 4. OGF and OAB show the flux of magnetic induction through 

 a rod of very soft steel 2.86 cm. in diameter and 12 cm. long, after the mag- 

 netizing field had been gradually and quickly removed, respectively. OEC 

 shows on a reduced scale the flux in the rod while it was exposed to the mag- 

 netizing field. 



slowly to the magnetizing coil. That is, the circuit was closed with 

 a very much greater resistance in it than was finally needed, and this 

 was gradually reduced to the proper amount. If the circuit was sud- 

 denly closed with this final resistance in it, the residual moment of the 

 rod was much smaller in absolute value, whether the current had been 

 gradually or suddenly reduced to zero, than if the rise of the current 

 had been slower. 

 Figure 4 shows the results of tests similar to those described above, 



