PEIRCE. — ANOMALOUS MAGNETIZATION OF IRON AND STEEL. 6-15 



zero. The line OAB shows the residual flux after the current had 

 been suddenly interrupted. The solenoid used in this work has 1460 

 turns in a length of 47 centimeters. The horizontal unit in the dia- 

 grams corresponds to about 80 gausses for the field (47rw //lO) in the 

 solenoid due to the current in its coil. A discharge of 1 microcoulomb 



Figure 6. The ordinates of these curves represent the residual magnet- 

 ism in a certain short, stout piece of soft steel magnetized in a solenoid, 

 when the exciting current had been suddenly interrupted. A positive ordi- 

 nate indicates reversed or anomalous magnetization. The observations 

 recorded in each curve were taken after the specimen had been newly an- 

 nealed, and the differences between the curves show that it is difficult to 

 demagnetize a cylinder of such dimensions completely. 



sent through the low-resistance galvanometer would cause a throw of 

 186 miUimeters of the scale, and a throw of 1 millimeter corresponded 

 to a flux of about 0.74 maxwells through the steel. The vertical unit 

 in the diagram for the lines OGF, OAB, is 15 maxwells. It is evidence 

 of the extraordinary magnetic softness of this specimen that whereas 

 the flux through the rod corresponding to the point C was 70,000 max- 

 wells, this sank to 11 3 maxwells when the current was slowly removed. 

 Figure 5 represents the results of experiments upon a soft steel shell 

 about 12 centimeters long, 2.83 centimeters in outside diameter, and 



