188 Dr. Harrison on Variation with Temperature of 
ordinate corresponding to the field, and then to read off 
values of w at the points in which this ordinate is cut by the 
curves. 
Hach value of » obtained in this way corresponds to a 
definite temperature, and a curve showing the variation of 
permeability with temperature can be constructed (figs. 5 & 6). 
Permeability. 
g 
= 
oe a 
r ‘Ss 
(SB PE 
Temperature Centigrade. 
Fig. 6. 
Permeability. 
100 200 300 400 
Temperature Centigrade. 
In view of the work of Morris and others on iron, it was 
thought unnecessary to examine that metal in such detail ag 
nickel. Hence the experiments on iron were chiefly confined 
to a determination of the critical temperature for the specimen 
