868 
dax 
—— { Paw — Pb wa}. 
s 
In order to show that this is the same as our tensor Pe, take 
a special case, a=1, b—= 2 eg., and write in full 
dal) de)? 
—— | Pa wb— Pow — | 
ds ds 
wl?) (w, PE + w, PY + w, Pi) — 
— wb (w, PE + wy, P?*? + w, P?*)). 
We can rearrange: 
(do) 
Pace) ds 
P? (wD w, + ww, + w) w, -+ wt) w,) + 
+ w, (wh) P?? + wl) PES + wl) PA) + w, WD PP u?) PH wt) P?1)) . 
and now we remark that the latter two bracket forms vanish in 
virtue of (16.1), for 
de) 
ds 
1 de 
T V4 ds 
(wD PE? +. w@) PB Ll) PII) = 
(w(t) Jr wf?) Ln + w3) Peso) = 0. 
As 
da\*))? 
St a) om, = IE 
ds 
the required identity is shown to exist. 
In the same way it can be shown that the magnetization tensor 
or rather its conjugate in the form 
dal) 
ds 
| Qa wy — Qo wa} 
agrees with our Mss. 
18. Let us make the simplifying assumption of the absence of 
gravitation. Then the ya, and ge? have the values: 
Neier Om OO ihe Oe Ou 80 
ORO RKO Ee ONO 
dab (=) OM OMIM 80: EEE) tae Onell Oleg ce) 
OO O° One Ome OMmaly/c7 
If A and p denote the common vector and scalar potentials, then 
the components g, are A, A, A. and — cp. The components of 
the field are 
1) In order to avoid imaginaries, we shall everywhere in Vg take |g]. 
