467 



Elasticity of Ferromagnetic Substances by Magnetization. 



^ The above table shows that the increase of elasticity under a 

 given field becomes generally less as the load is increased. In 

 weak fields, however, a maximum is observed as in the case 

 of steel. ^ It also increases first rapidly and then slowly a* 

 the field is increased. 



7. Nickel. — Xickel rod shows an abnormal behaviour as 

 regards the change of elasticity by magnetization. The 



Fiar. 7. 



T 



io"V/ 













































-T=l 



-3 



+9 





u 











10 









— T-;<7fs 



4C 



)0 .- 



5/10 T=!>? 



% 



rf£= 



-J^-~ 

















H 





¥* 

































results of observation ;;re graphically shown in fig. 7, and 



SE 



the values of -pv are given in the following table : — 



H, T+fW. 



105 gr. 



287 gr. 



561 gr. 



832 gr. 

 -1-08X10" 2 



30 



-1 -80x10--' 



-1-60X10- 2 



-1-3OX10- 2 



70 



-4-08 



-140 



-0-70 



—0-38 



100 



-3-84 



-0-92 



-021 



+-0-30 



200 



-250 



+0-46 



4-1-20 



+ 1-80 



300 



-0-88 



+ 1-47 



+2-07 



+2-52 



400 



+0-42 



+217 



+2-56 



4-2-83 



500 



+1-34 



+2-67 



4-2-84 



+303 



Thus the modulus of elasticity considerably decreases in 

 weak fields and increases in the strong. The field of no change 

 decreases as the load is increased. In a given field the 

 amount of decrease becomes less as the load is increased ; in 

 strong fields, however, the increase becomes gradually greater 

 as the load is increased . 



Fisr. 8. 



5*^ cm 



8. Cobalt. — Our cobalt bar was too thick and the maximum 

 deflexion in the field of the telescope was only 1*5 divisions, 



