88 



Messrs. K. Honda and T. Terada on the 



(b) Magnetization under Constant Tensions : (I, HY r . 



Among other ferromagnetic metals and alloys, nickel-steels 

 are characterized by the extraordinary steepness of the curve 

 of magnetization; in a field of 5 C.G.S. units, the magnet- 

 ization attains a value which is only a little short o£ its 

 saturation value. The steepness increases with tension, first 

 rapidly and then gradually to an asymptotic value. The 

 enormous values of susceptibility k are given in the following- 

 table and plotted in fig. 28. It will be noticed that the 

 maximum value increases with the percentage of nickel. 

 In 70*32 per cent. Ni, the susceptibility even attains a 

 maximum value of 1015 for T = 4930 gr./mm. 2 , which is 

 several times as great as the maximum susceptibility of 

 a well annealed Swedish iron. In very weak fields, the 

 magnetization is considerably increased by tension, but in 

 higher fields comparatively little. 



II. 



28 '74 per cent. Ni. 



50'72 per cent. Ni. 



70-32 per cent. Ni. 



K. 



K. 



K. 



T = 134gr. 



T=6952gr. 



T=160gr. 



T=8344gr. 



T = 156gr. 



10 



T=4930gi\ 



0-20 



75 



90 



55 



10 



33 



0-30 



110 



390 



110 



25 



17 



95 



0-40 



125 



530 



153 



75 



28 



200 



060 



145 



445 



243 



380 



64 



470 



0-80 



150 



367 



337 



710 



120 



1015 



1-00 



140 



297 



410 



800 



230 



860 



1-30 



124 



230 



467 



685 



296 



677 



1-60 



113 



190 



442 



593 



288 



570 



200 



99 



157 



397 



503 



270 



470 



3-00 



73 



107 



299 



370 



220 



322 



5-00 



50 



64 



202 



232 



160 



196 



7-00 



36 



46 



350 



170 



123 



140 



Curves (81, H) T (figs. 25, 26, and 27, dotted lines) deduced 

 from (I, H) T take a course quite similar to those deduced 

 from (SF, T) H . In 28*74 per cent. Ni the maximum 81 is 

 generally greater, and the asymptotic value decidedly greater 

 than in (81;, T) H for the same tension and field. On the 

 contrary, 81 of 50*72 per cent. Ni is always less than the 

 corresponding value in the last experiment. In 70*32 per 

 cent. Ni there is a fair coincidence between the two values 

 of 81. 



