ELL 
that the liquid phase becomes unstable and unmixing appears already 
at very slight concentrations. So we shall have to expect that 
VAN ’T Horrs law does hold for substances with unlimited imbibition 
power. And our formulae prove in harmony with this. As we namely 
saw it is required e.g. in the case 6, =10006, and / not far from 
a. 5 5 Orv 
1 that — does not lie far below 35. Then, however, we find for 
d, 
dlpe 
L 
hand for substances with limited imbibition power van ’r Horr’s law 
may hold, but this is by no means necessary, or even probable, and 
we shall undoubtedly have to take this circumstance into account 
in attempts to derive the molecular weight of these substances from 
the properties of their solutions. 
PE \ 
about — 380, and so lim — of the order 10-15. On the other 
v 
1 
§ 7. Other systems with great difference in vapour pressure of the 
components. I already pointed out the possibility of such departures 
from vaN ’r Horr’s rule in an earlier communication published in 
These Proceedings, mentioned in the beginning of this paper. What 
was said there, will have been made sufficiently clear by the foregoing 
discussion. So I shall only add a few calculations here for systems 
as the one discussed there (aniline or nitrobenzene with isopentane 
or hexane). These systems agree in so far with the systems discussed 
in the foregoing that there exists'a very large difference in vapour 
pressure between the two components, though not nearly so great 
as in the cases examined .by Mr. Karz, where the second component 
nowhere shows a measurable vapour pressure. But for the rest the 
difference is great; whereas in the systems discussed up to now the 
sl 
ratio — reaches very great values, the ratio here is not far from 1, 
1 
the partial vapour pressure of a component in 
the maximum can of course considerably rise 
above the value for the component itself (see 
fig. 4), but then this is always in the metastable 
or unstable region. For the partial vapour pressures 
must be the same in the two coexisting liquid 
phases. So the point A must lie on the same 
level as B, and as both between A and C, and 
between B and D the partial vapour pressure line 
can only be ascending, the partial vapour pressure 
must be smaller than DE throughout the region 
Fig. 4. of the absolute stable mixtures. 
