ness was pure SCHWERTE nickel. M and RH are given in C.G.S. 
units. J was 0.7 to 09 amp. 
The results given in Table XX are shown graphically in Figs. 
1 and 2. 
The Harreffect for nickel decreases as the temperature falls from 
ordinary room temperature; this has already been found by A. W. 
SuitH') to be the case down to liquid air temperatures. According 
to A. Kunpr*) the Harreffect for ferro-magnetic substances is 
proportional to the magnetisation and not to the field. Hence, when 
the magnetisation attains its maximum value, the Harreffeet must 
also exhibit a state of saturation, that is to say, the curves giving 
the Hatueffect as a function of the field must show a bend. SMiru’s 
C89 C. 0. 
50 
40 
20 
10 
eet Se ees 
4 
A Hata! ed ‘ a Leetje 
0 2000 4000 6000 8000 10000 Gauss, O 2009 #90 650 800 10000 Gouw, 
> A + I 
Fig. 1. Fig. 2. 
curves, covering a region of temperature from — 198° C. to 
+ 546° C., show such a bend, which, as the temperature increases 
right up to the critical temperature for nickel, is displaced towards 
the weaker fields, thus corresponding to a diminution of the saturation 
magnetisation as the temperature rises. At 290° K. our present 
measurements show this bend clearly at about 5000 to 6000 gauss. 
At the lower temperatures there is no decided bend visible within 
the region of fields covered by our observations (/7 << 10400); thus 
if there are any bends at these temperatures, they must occur at 
still stronger fields. 
W. Smiru. Phys. Rev. 30, 1, 1910. 
1) A. 
2) A Kunpr. Wied. Ann. 49, 257, 1893 
64* 
