CONTEMPORARY ADVANCES IN PHYSICS 



241 



confidence values for the true saturation of iron, nickel, cobalt, gado- 

 linium, and many ferromagnetic alloys. 



(The reader may properly wonder why, instead of solving equation 

 (12) obtained by putting H — in equation (10), it is not the practice 

 to put for // the field strengths actually applied to iron when aligning 



0.2 



0.3 



0.5 



J_ 



e 



0.6 



0.7 



0.8 



0.9 



1.0 



Fig. 3 — Intrinsic magnetization plotted against T/d, for the domains of three 

 ferromagnetic elementary metals (the constant 6 has different values for the three). 

 The ordinate is /„ referred to its saturation-value (deduced by extrapolation) as unity. 

 The curves are theoretical, the dashed one by classical theory (» = « ), the full one by 

 quantum-theory (w = 2). 



the domains or in any other circumstances, and to solve the equation 

 (10) under these conditions? This of course is the correct procedure, 

 but in ferromagnetic bodies ^/ is usually so enormous by comparison 

 with //, that the latter may be disregarded without appreciable 

 error.) 



