CHANGE OF ELASTICITY BY MAGNETIZATION. |g 



Comparing the above results with those g-iveii by the method of 

 ■elongation, we n(.)tiœ tluat in the present case, the field of no chano"e 

 l)ecomes less, whereas in the former, it becomes greater, as the load 

 is increased, and that the amount of the change is much less in the 

 present case than in the former. Our nickel rod was turned into a 

 square rod from a plate, and the meclianical ])rocess, which the 

 specimen underwent, hardened its magnetic quality. The nickel vvire 

 used in the preceding experiment was almost chemically pure, and 

 magnetically softer. Hence the discrepancy with regard 1o the 

 amount of the change may be explained by the diiterence of the 

 specimens ; but the discrepancy with regard \o the field of no change 

 can scarcely be explained by the same fact. 



Tangl's results are much smaller than ours, and moreover he did 

 not observe the decrease of elasticity in weak fields, because his initial 

 field was too strong to give such a decrease. 



Since nickel steel of suitable dimensions for determinintr the 

 modulus of elasticity by flexure was not at our disposal, we could 

 not test the result of the method of elongation. But from the above 

 results, we may conclude that the chîinge of elasticity by flexure does 

 not generally coincide with that of elasticity by elongation. As we 

 have observed, the elasticity is no longer independent of the stress 

 applied to the bar ; hence it is possible, and perhaps rather natural, to 

 conclude that in magnetic fields, the elasticity as given by flexure is 

 different from that given l)y elongation. 



In conclusion, we have to express our best thanks to Prof. H. 

 Nagaoka and also to Prof. A. Tanakadate for manv valuable 

 suggestions. 



