356 



H. XAGA0KA AND K. HONDA ; 



The present paper will therefore be divided into the following 

 section« : — 



1. Change of volume produced by magnetization. 



2. Change of length produced by magnetization. 



3. Effect of hydrostatic and transverse pressures on the magne- 

 tization of iron and nickel. 



4. Effect of longitudinal pull on the magnetization of iron and 

 nickel . 



5. Calculation of the coefficients h' and k", and a comparison 

 between theory and experiment. 



§ 1. Change of volume produced by magnetization. 



We shall hereafter consider the strain produced by magnetization 

 as functions of the magnetizing force and the intensity of mag- 

 netization ; it will thus be necessary in the first place to determine 

 the magnetizations of the different specimens of the ferromagnetics 

 used in the present experiment. 



The ferromagnetics examined in the present investigation had 

 the following dimensions. 



1. Ovoid of Swedish iron. 



Length of the major axis = 20 cm. ; minor axis = 0.986 cm. ; 

 volume= 10.18 c. c. ; mass = 82 grin.; demagnetizing 

 factor N=0.0848. 1) 



2. Cylinder of Lowmoor iron. 



Length=25 cm. ; diameter = 0.947 cm. ; volume= 17.55 c.c. ; 

 mass=136 arm. ; demagnetizing; factor N= 0.0533. 



3. Nickel rod of square cross-section. 



Length = 26 cm. ; side = 0.514 cm. ; section = 0.264 sq. cm. ; 



1). Du Bois, Magnetisclie Kreise, Berlin und München (1894). 



