390 
take place, the slight variability of Ap with the gas-pressure, which 
has been observed in this region for different gases, becomes expli- 
cable also in this way (cf. e.g. Diss. p. 92). 
The increase of Ap with the current density is also easy to see. 
For in the case that the nature of the bearers is not modified with 
the current density which may be assumed with a single excep- 
tion (argon) for the region examined experimentally, the following 
formula may be substituted for formula 5: 
1 100% 
I= AEO rn 
a p 
in which at constant gas pressure and not greatly varying tension 
a is a constant whose value is many times the unit. Putting: 
760 
—.2,32.10-4=b) 
oP 
(9) becomes 
gb oo) ois = oe. nnn 
We can also say something further about the diffusion: Both 
formula (1), and formula (2) show that the diffusion varies directly 
with Ap. In connection with the electrical conditions it must also 
be a function of variables of electric nature. The only motive force 
for the diffusion is, however, Ap; therefore the reflux must always 
be proportional to it. Hence may be written: 
g = Bp op yy, na) - aes eel 
As soon as a few more cem. of the greatly rarefied gas have 
entered the anode space, the stationary state sets in. 
Combination of (11) with (10) gives: 
ba. = Bape las yf: =.) 
or 
A p= Agi Oy). sf a a 
through which the proportionality of Ap with A finds expression. 
7. The Centres of Luminescense. 
a. Making use of the obtained experimental measurements regarding 
the intensity of light-emission of gases and mixtures of gases at 
electrical discharges, we have devoted some attention in our Thesis 
for the Doctorate to the consideration of the mechanism of electro- 
luminescence. Also in connection with the pressure-effect studied more 
fully tere, we will consider some points somewhat more closely. 
Let us first remind of this that the objective measurements of 
intensity taught that the intensity of the emission of light of a gas 
is in direct ratio to the supplied energy, if not on change of the 
