( 30 ) 
responding terms in which the other components occur, In order to 
show this we expand the squares of equation (9) and consider sepa- 
rately the terms: 
S a Og Oh 49 oh of 49 of Oy ) j aa 
| =-f PEPPEN: IE ee 
Og Oh Og Oh Oy Oh 
dz Oy dz dy | Oz dy 
partially according to z, the second according to y. The surface inte- . 
For 2 we write and integrate the first term 
erals vanish again and we get: 
3 ml 07h : O74 ‘ 077 027 j Og 077 : 
S= + |t Hop: Has + tans Tamy Hal 
Sr a LN 
| =|} J Ove (= 1e Oz v9 Oy de Ku =) ole Ow Si dy | dr. (24) 
OF 
sa— {| f55 dt. ° . ° 5 en 9 s 5 ; . ; k k (25) 
By integrating once more partially, where onee more the surface 
integrals vanish, we get: 
EDE 
so equation (21) is proved. Equation (22) is proved in the same way. 
Three constants occur in the exponent 4 namely w, @ and 4. wis 
a constant which must be chosen such, that integration of P over 
all systems of the ensemble yields 1. The two constants @ and 4 
determine therefore the state of the systems. This is connected with 
the fact, that the nature of the radiation inside a closed surface, as 
Lorentz*) has shown, depends besides on the temperature, also on 
the charge of the electrons by which the radiation is emitted. The fact 
that inside all bodies radiation of the same nature is formed, proves 
that in all bodies the electrons have the same charge. The constant 
quantity #4 must depend on that charge; it will therefore have the 
same value for spaces enclosed within all bodies as they are found in 
nature at least if the temperature is the same and its value would 
for a certain temperature only be different, if we imagined walls 
with electrons whose charge was different from those actually occurring. 
1) Lorentz. Proceedings. Vol. II, p. 436, 
