658 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



brace the core alone and thus make it possible to study separately 

 the behavior of each part of the system. The results of experiments 

 of this kind proved instructive, as will appear from an account of a 

 typical case. 



FiGiTRE 15. A combination of shell and core, made of soft Bessemer steel, 

 was demagnetized as completely as possible and then tested in a long sole- 

 noid. The magnetizing current was built up gradually and then suddenly 

 broken. The ordinates of ABC show the residual flux through the metal 

 when the current gave a negative moment before it was interrupted, the 

 ordinates of PQZ show the remanent flux for oppositely directed currents. 

 There was a bias in the specimen which showed that the process of demag- 

 netizing it had not been wholly successful, and the anomalous magnetization 

 is of different magnitude on the opposite sides. 



A cylindrical shell 12 centimeters long, the diameters of which were 

 3.00 and 2.27 centimeters, was used with a core 1.90 centimeters in 

 diameter to form a combination (Z) which, after being thoroughly de- 

 magnetized, was placed in a long solenoid and exposed to a series of 

 magnetizing fields, each a little stronger than the preceding. At every 

 step, the metal was put a number of times through the hysteresis 

 cycle corresponding to the exciting current employed, and then the 

 fluxes through the central cross sections of core and shell were meas- 

 ured while the current was running. In Table V. H represents the 



