on the Magnetic Properties of Iron. 



15 



can only be examined under extremely weak fields. This 

 introduces a large percentage of possible error in estimating 

 the permeability, the kicks in the galvanometer being very 

 small. 



It was thought that the effect of temperature in hastening 

 the transition from stage to stage could be more satisfactorily 

 examined in the case of alloys of iron giving a magnetization- 

 curve the successive stages of which extend over a greater 

 range of magnetic force. 



Various investigations on the influence of elements on the 

 magnetic properties of iron have shown that the presence of 

 tungsten or chrornium considerably lessens the permeability, 

 the second stage of the magnetizing process not being entered 

 upon until the magnetic force is fairly high. 



Experiments of the same nature as those described above 

 were made on an alloy containing 4*5 per cent, tungsten. 

 The dimensions of the ring: were as shown : — 



1-94 



L*_ 



The values obtained for the induction with the corresr 

 ponding magnetic forces at the ordinary temperature of the 

 room were: — 



Mag. Force... 040 1'63 489 7-31 897 1060, 1376 1672 1876 214 



Intl. per | ^ lgg ^ n69 2Q7g g 97 g g742 1Q79g n57() U53i 



sq. cm. J 



These results are shown plotted in fig. 8, together with 

 the curve for tb,e specimen of wrought iron described above. 



It will be seen from the figure that for the tungsten alloy 

 the permeability does not increase appreciably until the field 

 is increased beyond about 7 C.G.S., and the point in the 

 second stage of the magnetizing process giving the maximum 

 permeability is only brought on when the field has reached a 

 value of about 15 C.G.S. 



