Critical Points of Nickel and Iron. 



397 



greater the load, and for a given load is much greater in 

 nickel than in iron. 



With iron wire the curves may, and do, sometimes cut the 

 load line twice, so that for a given value of magnetizing force 

 there may be two loads which have no effect on the temporary 

 magnetization. In fig. 1 none of the curves actually cut the 

 load-line a second time, because the loading was not carried 

 quite far enough ; but with subsequent experiments made 

 with the same wire and with the same loads at a temperature 

 of 200° C. the two points of cutting were easily obtained, 

 within certain limits of magnetizing force, whilst the next 

 figure shows that with greater loads the second point can be 

 reached at the ordinary temperature of the room. 



Fig". 3. — Iron*. 



Fig. 3 illustrates the effect of loading on an iron wire 

 of *077 millini. diameter, which in the first instance was 



* Tn this experiment a load of-2 kilos was left permanently on the wire, 

 *o that the initial load is 2 instead of 0. 





