produced in Iron Wires by Magnetization. 357 



Although the observed change for the hardened wire was a 

 contraction, the contraction due to the B 2 /87r force was suffi- 

 cient to bring the values above the zero axis. So, again, the 



Fig. 4. 



A. — Wire natural. 

 A'. — Do. corrected. 



B.- 

 B'.- 



■Wire hardened. 

 -Do. corrected. 



direct action of the magnetization is to elongate the wire. 

 The corrected curve is very similar to the curve for the iron 

 in its original state. The absolute values are, however, much 

 diminished and the maximum occurs, for the specimen, with 

 a less intensity. The correction for the change of elasticity 

 can be neglected as in the first case. 



Effect of Strain. 



To find the effect of strain the wire was loaded with a 

 weight of 750 kilog. per square centimetre, and the relation 



