MAGNET STEELS AND PERMANENT MAGNETS 401 



at the time of testing. The'relation of all of these variables to the rema- 

 nence of a permanent magnet, fortunately, is focussed, as it were, 

 in the values of Br and Ho for the material, and the relation of these 

 variables to Brem is as shown by Fig. 6. 



References 



1. "Permanent Magnets in Theory and P'ractise," Evershed, S., Journ. Inst. Elect. 



Eng. 58, 780 (1920); 63, 725 (1925). 



2. "Ein neues Material fur permanente Magnate," Guinlich, E., Elektrot. Zeils. 44, 



147 (1923). 



3. "Magnetic Habits of Alloy Steels," Mathews, J. A., Proc. Anier. Soc. Testing. Mat. 



14, 50 (1914). 



4. In discussion, loc. citA^\ Journ. Inst. Elect. Eng. 58, 829 (1920), also ibid. 61, 641 



(1923). 



5. "Calcul des appareils niagnetiques, Diagramme generale," Picou, R. V., Rev. gen. 



del' elect., 22, 259 (1928). 



6. " Une solution sans fiction du probleme de I'attraction magnetique," Lehmann, T., 



Rev. gen. de I' elect. 20, 433 (1926). 



7. "An Improved Permeameter for Testing Magnet Steel," Babbitt, B. J., Jour. Opt. 



Soc. Amer. 17, 47 (1928). 



