860 
0 Tab 
due : 
and putting it in the right hand members of the equations of the 
field, we get for the fundamental equations for moving non-conduct- 
ing media, in three-dimensional vector notation: 
> (0) 
rot B — eae 4 Mr Ln [p.w] ate 
C CG C C 
and 
div E = — div p. 
These are Lorentz’ equations with the addition of rotk to the 
current. We see a polarization current p, a RONTGENCurrent rot [p.w]| 
and the current of magnetization rot cm. 
A proposed Experiment. 
11. Let us inquire further into the nature of the second order 
current 
rot k. 
Referring to the definition : 
ke (OS Vo ll, 
we see that it is an effect due to the non-uniformity of motion in matter 
where the atomical charges lie outside one another. If these charges 
bad fixed positions, i.e. if the electrons were rigidly fixed between 
the nuclei and if they therefore could be said to have exactly the 
motion of matter in bulk (i.e. of the nuclei, or rather motions inter- 
polated between the nuclei) then our calculus indicates, that there 
would be no current resulting from the charges: the streams of 
positive and negative particles cancelling each other. 
But in this case, the motion of matter being non-uniform, the 
electrons clearly would turn round the nuclei in an absolute sense, 
and the atoms would have a magnetic momentum. It is the part of 
k to counterbalance this slight magnetization, it then equals cm with 
opposite sign. 
On the other hand, in case the electrons, instead of being rigidly 
fixed in the frame of the nuclei, always kept the same distance and 
in the same direction from the nuclei, not turning round in the 
rotating motion of matter, then k comes into play, not being balanced 
by a slight magnetization; so an induction field will be produced. 
It should be possible to keep the electrons in the same direction 
from the nuclei by applying an electric field and maintaining a 
constant polarization. A rotatory motion then should produce an 
induction. We must be careful, however, to separate this from the 
