TE W CENT ELECTRIC CUREES r . 345 



iron ana nickel, as will be described afterwards. 



Considering the results of the preceding experiments, one 

 naturally asks, why does the transient current flow in the direction 

 above specified and why does it reach a maximum? Supposing that 

 aeolotropy is the only cause of the transient current, the increase 

 of the current would mean a greater magnetic induction in the 

 direction of stretching than in the direction of compression. The 

 susceptibility of the stretched iron is greater and that of the com- 

 pressed iron is less than that of iron in an unstrained state, up to a 

 certain critical value of the field. Thus the helices representing the 

 lines of induction would be inclined toward the direction of stretch- 

 ing, and the current must be constantly on the increase until at a 

 certain field the difference of magnetic induction in these two direc- 

 tions begins to diminish. Reasoning in this way, we may explain 

 the general feature of the curve in the following manner. 



The amount of compression as well as that of stretching 

 remaining constant throughout the course of experiment, incren 

 the magnetizing field produces a greater increase of the circular 

 component of the lines of induction in the direction of stretching, 

 than in the direction of compression. The difference in the circular 

 components of magnetization at last reaches a maximum fora certain 

 strength of the magnetizing force. This critical strength of the 

 magnetizing force depends upon the amount of compression and of 

 stretching. In the wire tried above, the position of the maximum is 

 gradually shifted into higher field as the compression as well as 

 î retching is increased, but at the same time, the current does not 

 increase proportionally. There is a certain maximum twisting for 

 which the difference of circular lines of induction in the direction 

 of compression and of stretching reaches the maximum. This 

 seems to occur for the twisting of about ±60° in the wire discussed, 



