Elasticity of Ferromagnetic Substances by Magnetization. 65 



The values of rigidity at no field were calculated from the 

 period of oscillation for the bar only, whose moment of 

 inertia was known from its dimensions. 



In the oscillation method the right order of applying the 

 twist and the field was followed. Since the oscillation was 

 very slow, the value of the rigidity thus determined may 

 properlv be considered to be the statical value. The results 

 of experiments are as follows : — 



Nickel PL III. fig. 29. 

 Table XXY. 

 K,=0-96xl0 12 . t = U c -7 0, 



T=1158 gr./min.2 



T = 3410gr.'mrn.? 



T — 6215 gr./nim.2 



T = 9075 gr./nim.= 



H. 



^xio= 



H. 



T -,- xio 2 . 



H. 



!?xio*. 



H. 





39 



-021 



39 



-o-io , 



4-1 



-o-oo 







105 



-1-61 



10-2 



-0-25 



120 



-o-io 



11-8 



-o-oi 



237 



-4-21 



241 



-1-51 



24-1 



-0-34 



24-1 



-0-08 



46-9 



-680 



48-2 



-5-82 



47-9 



-1-87 



47-7 



-0-67 



78-2 



-6-80 



77-8 



-8-65 



78-0 



-5-11 



77-6 



-204 



1170 



-5-92 



116-2 



-S-5o 



116-5 



-9-14 



123-7 



-5-06 



190 



-3-33 



189 



-6-58 



190 



-9-22 



196 



-8-57 



276 



-0-43 



297 



-2-86 



276 



-693 



287 



-8-59 



406 



+2-12 



390 



-062 



401 



-3-21 



382 



-6-35 



Among ferromagnetic metals tested, nickel undergoes the 

 greatest change of rigidity and shows the most remarkable 

 feature as regards the effect of tension. For small tensions, 

 the rigidity at first decreases rapidly and after passing- 

 through a minimum increases slowly with the field. In a 

 certain field the change is zero, beyond which there is an 

 increase. As the tension is increased, the change becomes 

 less for low fields, but greater for higher fields; the maximum 

 change occurs in a higher field, and its amount increases up 

 to a certain tension, and then slowly decreases. The point 

 of no change shifts toward higher fields, as the tension 

 increases. 



Phil. Mag. S. G. Vol. 13. No. 73. Jan. 1907. F 



