Heating on the Magnetic Properties of Iron. 



153 



\2,000 



& 9 10 



Time of he&ting in days. 



12 /Z 14 15 



2,000 



J 4 5 6 7 Q 3 IO II 12 A3 '4 15 



Time of heating in days. 



this temperature. No. 5 shows greater rise than No. 1 at 120 C. in 

 the annealed state, although this identical sample appeared to be prac- 

 tically unaffected by heating for a fortnight in the state in which it 

 was supplied, but was then of somewhat higher initial hysteresis. It 

 is interesting to notice that this iron if annealed before use in a trans- 

 former would ultimately, through low temperature heating, show much 



