390 Mr. Gr. H. Livens on the Flvx of 



Maedonald's transformation is obtained in a different 

 manner. We start from the relation 



dT 



dt + 



I s ^ / =sI( H f)^ + &jm»^ 



established in the previous paragraph ; and then, using the 

 relation 



B = H + 4ttI, 



where I is the intensity of the magnetization at the typical 

 field point, we write 



The integral 



\ dt)~ 2 dt \ dt/ 



f 



B 2 dv 



can then be transformed by the substitution 



B = Curl A, 

 so that it becomes 



f(B Curl A) ^ = -( [BA] n df + f(ACurlB)^ 



Wtichis = £[AB]^ + ^J(AC')^ 



by Ampere's relation if 



C = 0+cCurlI 



is the total current density, including the effective repre- 

 sentation of the magnetic distribution. 

 Thus finally we deduce that 



dT 



+ ^ {CAB] * W/; 

 (AC')dv-(dv C(IdB), 



and therefore, if we take 



1 



we might assume that 



which is equivalent to Maedonald's vector. 



