on the Magnetic Properties of Iron. 33 



and shows that the rate of transition from stage to stage of 

 the magnetizing process as the temperature increases is much 

 greater for high than for low temperatures. 



Cr-Mn-C Alloy. 



The results of experiments made previously at the ordinary 

 temperature of the atmosphere on an alloy containing fairly 

 large percentages of chromium, manganese, and carbon 

 showed that unannealed the specimen was practically non- 

 magnetic, while after heating to a temperature of about 

 1000 c C, and allowing to cool very slowly, it was found to 

 be strongly magnetic. 



An alloy of very similar composition to the specimen 

 referred to was obtained in the form of a ring, and the 

 magnetic properties examined at different temperatures. 

 The specimen contains about 9 per cent. (Jr, 3 per cent. Mn, 

 and 1 per cent. C. The dimensions of the ring were as 

 shown: — 



The following results of observations of induction in terms 

 of magnetic force were obtained at the ordinary temperature: — 



Mag. Force... 0-88 3'51 702 11-4 15'4 19-3 21-9 237 26-3 307 35-1 4215 



Ind. per | __ 4Q lfi7 3g2 7gl 1M2 2g33 45Q6 5356 6261 W0Q 8QQi 

 sq. cm. J 



In this case the second stage of the magnetizing process is 

 not entered upon until the magnetic force is increased beyond 

 about 16 c.g.s. 



The ring was examined in successive experiments while 

 the temperature was kept as nearly constant as was practic- 

 able, and after each experiment the specimen was demag- 

 netized by reversals. 



Table V. gives the values of the permeability in terms of 

 magnetic force for different temperatures. 



PJtil. Mag. S. 5. Yol. 50. No. 302. July 1900. D 



