1890.] Magnetic Properties of Alloys of Nickel and Iron. 



CURVE 7. 



E. The analysis of this sample* was 



Fe. 

 74-31 



Ni. 

 24-5 



C. 



0-27 



Mn. 

 0-85 



S. 



o-oi 



p. 



0-04 



si. 

 0-02 



per cent.. 



As the material was given to me it was non-magnetisable at ordi- 

 nary temperature ; that is to say, the permeability was small, about 

 1*4, and the induction was precisely proportional to the magnetising 

 foi-ce. The ring on being heated remained non-magnetisable up to 

 700 C. or 800 C. A block of the material did not recalesce on being 

 heated to a high temperature and being allowed to cool. 



On being placed in a freezing mixture, the material became mag- 

 netic at a temperature a little below freezing point. 



The material was next cooled to a temperature of about 51 C. 

 by means of solid carbonic acid. After the temperature had returned 

 to 13 C. the curve of magnetisation was ascertained as shown in 

 Curve 8 ; from this it will be seen that the ring of the material which 

 was previously non-magnetisable at 13 C. is now decidedly mag- 

 netisable at the same temperature. On heating the material, it re- 

 mained magnetisable until it reached a temperature of 580 C. At 

 this temperature it became non-magnetisable, and, on cooling, re- 

 mained non-magnetisable at the ordinary temperature of the room. 

 Curve 9 shows the induction at various temperatures for a magnetis- 



* The results with this sample have already been presented to the Royal Society 

 (' Proceedings,' vol. 47, pp. 23 and 188), but are repeated now for completeness. 



