126 Prof. R, Clausius on the 



act is already magnetized by other far stronger forces, which 

 is of great influence on the numerator of the desired expression. 

 In accordance with the expression given in § 14 for the mag- 

 netic moment P, we have for the moment in question the 

 expression 



1 + /K ' 



in which D is a constant corresponding to the constant C 

 which occurs in (14). As both the moments previously de- 

 termined have a common direction of their axes, we may 

 combine them by addition, and thus obtain a moment of the 

 magnitude of 



WJP+B"(l+ I ^). 



The direction of the axis of this magnetic moment, which is 

 due to induction, is at right angles to the direction of the force 

 which the induction produces, so that in determining it we must 

 use the angle $ + 7r/2 instead of the angle <£, which defines the 

 direction of the force. Hence if we wish to decompose this 

 moment into components which are in the same directions as 

 the components P x and P 2 of the moment P, we must multiply 

 the moment by cos (c/> + tt/2) and sin (<£ + tt/2), or, what is the 

 same thing, by — sin <£ and cos (f>. We thus obtain in the 

 direction of P x the components 



-WM 2 + N 2 (l+ i^m) sine/), 



and in the direction of P 2 the components 



V vs/W + W(l + j-^) cos<£. 



If we replace in these sin </> and cos by their values given in 

 (15), the expressions of the two components are 



-"- N ( 1+ rps)> *" M ( 1+ i|^)- 



We must add these two magnitudes to the magnitudes P x ' 

 and P/, which are derived from P x and P 2 , by taking into 

 consideration the magnetic inertia of the iron, in order to 

 allow for the induction in the iron core. The values of the 

 components of the whole magnetic moment which is produced 

 in the iron core may be called P/ 7 and P 2 ", and we may then 

 put 



