Elasticity of Ferromagnetic Substances by Magnetization. 71 



further increased, the rigidity increases by magnetization. 

 If the tension is increased, the field corresponding to the 

 maximum decrease moves towards higher fields, and the 

 amount of decrease is remarkably increased. Tensions here 

 used were so adjusted as to be nearly equal to those in the 

 oscillation method. The effect o£ the amplitude of twist was 

 to diminish the change of rigidity in its absolute amount. 



Comparing the above results with those of the oscillation 

 method, we notice that with weak tensions, the curve of the 

 change of rigidity as given by Barus's method lies consider- 

 ably above the curve of the change by the oscillation method, 

 and that with greater tensions the contrary is the case. 



Swedish Iron and Tungsten Steel. PL III. figs. 36 & 37 

 Table XXIX. 

 SvcedisJi Iron. Tungsten-Steel. 



T=32Tl gr./inm.a t=20°0C. T=3405 er./ium. 2 t=2D°'l C. 



e= 



2 3 -5. 



= 



5°0. 





oK 





£K 



H. 



K Xl ° 2 - 



H. 



^-XlQ 2 . 



44 



032 



39 



0-19 



10-5 



1-00 



10-2 



101 



200 



1-36 



16-5 



1-27 



426 



1-88 



252 



1-51 



755 



2-20 



42 '2 



1-81 



1231 



2-35 



75-5 



206 



1740 



2-51 



1714 



2-34 



306 



2-56 



301 



2-42 



434 



267 



423 



2-51 



0= 



4°-0. 



e=i 



s°-o. 





SK M 





oK 



H. 



~-Xl0 2 . 



H. 

 12-6 



^ xltF - 



13-6 



o-oo 



o-oo 



21-8 



008 



18-3 



007 



27-1 



0-14 



29 3 



0-17 



46-0 



0-20 



447 



0-21 



81-3 



030 



76-4 



0-30 



134-1 



0-3S 



123-8 



0-38 



1729 



0-40 



172-2 



0-41 



304 



045 



300 



0-49 



429 



0-51 



425 



0-52 



Thus the rigidity of these metals always increases with the 

 field ; the change for Swedish iron is tolerably large ; but 

 for tungsten -steel it is very small. As to the effect of 

 amplitude of twist, it is slightly to diminish the change in 

 Swedish iron, but is almost insensible in tungsten -steel. 

 The change of rigidity obtained by Barus's method is several 

 times greater than that by the oscillation method. Thus, in 

 the case of ferromagnetic metals, relation (3) does not hold 

 even approximately. 



