840 Miss M. B. Moir on Magnetic Properties of a 



than at 15° C. The distinctive features of these curves are 

 characteristic in a more or less marked degree of all the 

 specimens of the series, the most notable being probably 

 the extraordinary widening of the hysteresis loop, and the 



consequent increase in the coercive force brought about by 

 quenching. The slight improvement in both the residual 

 magnetism and the coercive force, when the temperature is 

 lowered to — 190° C, is also a characteristic common to all 

 the specimens. 



A comparison of these curves with the hysteresis loops for 

 the specimen containing 1 per cent, chromium (see fig. 8) 

 shows that while in the case of the 1 per cent, chromium 

 specimen the residnal magnetism is greater in the quenched 

 than in the annealed condition, in the 16 per cent, chromium 

 specimen the reverse is the case. These results are not, 

 however, so irregular as they appear, for as an examination 

 of Table VII. shows, the residual magnetism in the annealed 

 condition increases with increasing percentage of chromium 

 to a maximum value for the specimen containing 8 per cent, 

 and thereafter steadily diminishes, while, in the quenched 



