Cahir BP SPR Kec v= NE 
M. I. Pupin—Studies in the Flectro-magnetic Theory. 337 
are applicable to such functions. Integrating by parts we 
obtain 
t 
VR OY.) 2h 
xX Y h — AES A. ane a pels = 
J werk Gor, adr faf | + dt IG +h ral kad sEQ 
j 0 
where the suffix 1 denotes that the value at the moment of 
cessation of the integral current is to be taken. 
Now it can be easily shown that the first integral equals EQ. 
Hence 
ut 
df dX ‘dg av dh _dZ t 
Su) (xi a) + (vt-9F) + (27-1) dr=0 
0 
Every functional relation between X... f/f... which will 
satisfy this equation will be a permissible form of the law of 
flux. 
For instance, 
K K K 
te aka dn 
is one set of relations which will satisfy this equation. 
Here is another set 
ae a5 GR a ie ,4) 
1 
g=7, (KX ae K,jY+ K,,Z) 
h=— (K,X+K,,Y+K,,Z) 
470 
where We eK KK 
By a suitable selection of codrdinate axes this set can be 
written 
21? 31) 
A third set of relations is obtainable by supposing /, g, A to 
vary harmonically, since in this case 
at 
ig —1)"p'"f, ete. 
where p = 27x frequency, we obtain 
