Elasticity of Ferromagnetic Substances by Magnetization. 53 



TIk 



lues of 



8E 



as calc 



ulated fr< 



the tension effect 



on the change of length differ from the above values rather 

 considerably for slight tension : but they approach each 

 other for high tension, as may be seen in Table XV. and 

 the dotted curves in fig. 10. Here the change of elongation 

 due to tension being verv small, the calculated values of 

 oE 



E 



are not verv certain. 



Table XV. 

 AT= +688 gr./mm.- 





T= 1427 gr. mm. 2 



T = 2798 gr. 'mm. 2 



T — 4170 gr./mm. 2 



H. 



5E ., „ , 

 X10-. 



0-17 







20 



0-ofi 



:»o 





0-08 



017 



] 00 



017 



073 



047 



200 



o-io 



0-82 



015 



300 



0-22 



090 



0-08 



400 



0-24 



0-D7 



006 



(ii.) 50* < 2 per cent. Nickel -Steel, 

 13, & 11. 



PI. IT. figs. 11, 12. 



The change of length due to magnetization differs widely 

 for different tensions. For slighter tensions, the wire 

 generally elongates by magnetization, except at very weak 

 fields, where it slightlv contracts, a fact not observed in 

 previous experiments*. The amount of the elongation 

 increases, rapidly at first, and tends soon to an asymptotic 

 value, as the field is increased. The increased tension 

 depresses the elongation in a remarkable degree, so that 

 be von d a certain tension, the change of length bv magneti- 

 zation changes its sign and becomes a contraction. The 

 effect of tension, however, decreases uniformly with the 

 increase of the tensions. The results are given in Table XVI.. 

 and graphically in figs. 11 and 12. 



* H. Nagaoka and I\. Honda, Jour. Sc. Coll. xix. Art. 11 (1903> 

 K. Honda and 8. Shimizu. ibid. xx. Art. (1905). 



