on the Magnetic Properties oj Iron. 21 



The figure also shows that at a temperature as high as 

 649° C. the permeability remains practically constant until 

 the magnetic force is increased beyond about 0'4 c.G.s. 



At a temperature of 655° C, when the metal is just about 

 to enter the critical condition, the values of the permeability 

 for different magnetizing forces were: — 



Force ...0082 033 065 98 147 1-79 2-45 326 489 6-52 

 Permeability... 1026 1026 1134 1353 1985 2141 2044 1645 1188 922 



This shows that the second stage of the magnetizing pro- 

 cess is not brought on until the magnetic force is about 

 0*4 c.G.s. With weaker fields than this the effect of 

 temperature in hastening the transition from one stage to the 

 other is unable to bring on the second stage before the 

 critical condition is reached and the magnetic quality lost. 



The values of the permeability at different temperatures for 

 a magnetic force of about 0"4 C.G s. are given above, from 

 which it will be seen that the permeability increases more than 

 ninefold, although the second stage is not entered upon. 



3 



3 









Fig. 11. 









IK 

















16 



^ 















12 

















8 

















b 



4 

































100° 200° 300° 400° 500° 



Temperature in Degrees Centigrade. 



Fig. 11 is drawn to show the magnetizing force giving 

 the maximum permeability at different temperatures. It 

 will be seen that the points lie very nearly on a straight line, 

 showing that the rate of transition from stage to stage with 

 respect to temperature is fairly uniform. 



