300 fl. E. J. G. du Bois on Magnetization in 



Table I. 



Cobalt. 



Nickel. 



e. 



SB'. 



e . 



3- 



9. 



$8'. 



e . 



3. 



100° 

 100 

 100 

 100 

 100 

 100 

 100 

 100 



14120 

 14180 

 14410 

 14650 

 16750 

 19550 

 21710 

 23330 



-20-97 



-22-45 

 -23-24 

 -23-38 

 -23-60 



1058 



1060* 



1070 



1081 



1134t 



1174t 



1181t 



1192t 





 100 



100 



100 



100 



100 



100 



100 



100 



5980 



6420 



6490 



6810 



9920 



12850 



16250 



19290 



-7-25 



-8-29 

 -8-36 

 -8-43 

 -8-40 



437 



453* 



456 



461 



518t 



522t 



527t 



525t 



0° 



23330 



-24'-39 



1232 x 



0° 



19290 



-9"27 



579 x 



both quantities gives Kerr's constant for red light, in minutes 

 per unit magnetization, as follows : — 



Cobalt. Nickel. Steel. Iron. 



e . . — 20'-97 -7'-25 -24'-81 -22'-99 



3 . . 1060 453 1531 1669 



K. . --0198 --0160 --0162 --0138 



Inversely the four remaining values of e were now divided 

 by K, thus giving 3 = funct. ($&') marked f in the Table. 

 From this again @ = funct. (.£)') could be calculated, which 

 thus forms a continuation of the curves obtained before 

 (in § 6). 



§ 12. In fig. 2 the results of both methods are combined 

 into continuous magnetic curves, now extending, at least 

 in the case of nickel, from .0' = 150 to .g' = 13,000 C.G.& 

 The scale of abscissae is ten times smaller than in fig. 1, and the 

 additional points © are those derived from the optical method. 

 As the strongest field .jj of the RuhmkorfF attained about 

 25,000 C.G.S. it is evident that the maximum intensity »£)', 

 obtainable inside the metal (.($'=,0— 4tt3), is less the more 

 strongly magnetic the metal used. Thus in fig. 2 the 

 abscissae extend to 8500 for cobalt, to 4500 for steel, to but 

 2500 for iron ; the latter's curve is therefore not continued 

 beyond .0 = 1200, the point reached in fig. 1 ; the more so as 

 the iron gave somewhat irregular results on account of the 

 mirror's polish not being perfect. The rotational dispersion 

 being much greater for iron and steel contributed to make the 



