866 
datt) 
Fa 2 (6) wo Fab, 
ds 
and from the polarization tensor we form a vector Pa: 
dat) 
Rab) wy Pa, 
8 
and the required generalization will be 
Pa — — (e—]) Fe, 
Secondly, to generalize the relation B — uH, or rather 
ul 
u 
we proceed in a similar manner. From the conjugate field tensor 
we form a vector Ga: 
M = 
B, 
da(4) 
ds 
and from the conjugate magnetization tensor a vector Q,: 
da(4) 
ds 
Ga = = (6) we) Faas, 
Qn ===" (6) 
The generalized relation is 
wb May. 
On ge Ga. 
u 
The current of the free electrons is partly a convection current, 
partly a conduction current. The latter will be the component of the 
four-dimensional vector-density Yg/* in a direction perpendicular to 
the four-dimensional velocity vector. The conduction vector thus is: 
ENE: 
ee (en iT. 
8 
Je [a — we 
This can be put otherwise, if we first form a skew-symmetrical 
tensor 
da) 
Me ass flaw) — [> wt 
ds 
and afterwards from this tensor form a vector again: 
dar 
Ja (b) wy Tet, 
ds 
The equation for the conduction current must be 
Jeu — ) Fe, 
We notice that in the common equation J=oE, 5 — Ay. 
16.1. Now take the contravariant tensor Pe? and form its con- 
jugate : 
Prat = > (ed) $ V9 dasca Pd. 
