475 



According to A as well as \o B (cf. § 52^/j : 



In calculating h and.r/ we have to distinguish between A and B: 

 Assumption A. In this case formulae are valid which correspond 

 to those which are valid for electrically polarized particles, viz. : 



ó^-lilfT/Z+^JiV [cf. (150)] 



whereas in calculating q we have to take for each particle [cf. (152)J 



— k (m. h/i) , 

 here h^ is the magnetic force wiiich at the place occupied by one 

 particle is brought about by the remaining particles situated inside 

 the sphere B, m the magnetic moment of that particle, considered 

 as a vector, (a, b) representing the scalar product of two vectors a 

 and b. If we take the sum for all particles inside B, we can write 



q = — ^,Mha. 

 Assumption B. Now [cf. (151)] 



2 / 1 



In calculating q we have to take for each particle 



i (m . hn ). [cf. § 52 rt,y]. 



This gives 



q=i k ^J^^H\ ■ 

 On the assumption B we still have to consider the term p. 

 For the own energy of a magnet we may write (§ 48^) 



but we must take into consideration, that the angular velocity // 

 according to equation (140) differs from </„. From (140) follows 



o„^|h| cos •9' 

 c 

 if the second power of the last term in (140) is omitted (if we 

 j-etained this we should take account of a term wliicli is even 

 smaller than the energy of the weak diamagnelism, which always 

 occurs as a consequence of the appearance of the field and which 

 is superposed on the paramagnetism, respectively ferromagnetism). 

 To distinguish it from the coefficient of the molecular field the 

 quantity k of (140) is indicated here by k. 



From the formulae of ^ 15 one finds for the moment of the particle 



1 



