3 ickel, and Nickel-Steel at Various Temperatures. 83 



change of resistance at four fields, 50, 150, 400, 800, is 

 plotted against temperature. The decrease of resistance 



Fig. 4. 



310* 



5lj 



330' 344° 350' 360° 370' 380° 



Change of Resistance of Nickel at Temperatures 300° to 380° C. 



reaches a maximum at 340° C, at which temperature the 

 curve lies almost wholly beneath the axis, above this tempera- 

 ture the change of resistance diminishes and finally vanishes 

 at 380° C. 



Fig. 5. 



• 00 ?00 303 400 500 600 700 flt)0 900 



Change of Resistance of Iron at Temperatures 6° to 665° C. 



Iron. — The results obtained for iron are shown by the 

 curves in fig. 5. The results are very similar to those 

 obtained for nickel, but there is a very marked increase at 

 low fields for the temperature 580° C, 



Nickel - Steel. — Eight specimens of nickel - steel were 



G2 



