311 
central force directed towards the centre (Q) will always correspond 
to the resulting repulsion of the surrounding molecules. 
Also for gases can this take place, but as the distance of the 
molecules is then greater, hence the oscillations in the value of u 
much smaller, the limiting value of u, (point of degeneration) 
lies much lower than the corresponding value of w, (melting-point) 
for solid bodies. Besides — in accordance with the mutual distance 
Fig. 4b. (Gases). 
of the molecules — this transition may take place at different places, 
during the 1st period, the 2°¢, the 3rd period ete. (Cf. Fig. 46, where 
the return takes place at the third period). 
To given mutual distance of the molecules (gas density) corresponds, 
therefore, a definite value of wu, for which the transition already 
takes place at the 4st period, (deyeneration point proper), a value 
where the transition does not occur until the 2"¢ period, etc. ete. 
Here too the molecules will, therefore, revolve round the positions 
of equilibrium in closed, ever narrower orbits — as the tempera- 
ture descends. 
And thus the phenomenon of gas-generation has been explained 
in a natural way. 
When at a given gas-density u, becomes too great, then u does 
not become 0 before the molecule comes in contact with P (“collides”), 
as is drawn at A in Fig. 3 and 4. Hence no longer any closed 
orbits (solid bodies above the melting-point; gases above the 
degeneration point). 
It is very remarkable in this, that when u, (for gases) becomes 
gradually smaller and smaller (hence the temperature lower and 
lower), the place where w becomes zero suddenly skips from C'to D 
(see Fig. 45), from U to F, ete. — which corresponds to this that 
the corresponding wider orbit round the position of equilibrium 
abruptly, hence discontinuously, changes into a narrower orbit. The 
latter varies only between D and £, lying close to each other (the 
figure represents time-abscissae, but distance-abscissae of course 
correspond with them in a corresponding z—w diagram), after which 
it suddenly skips again to the still narrower orbit, corresponding to 
F. This is then the final orbit, which as u, gets still lower, again 
gradually shrinks. It does not diminish to 0, however, but to a 
