Proceedings of the section of sciences - DWC - KNAW

I( 587 )
;Fig. 3a gives an enlal'ged, schematiral repl'eselltation of tllat isolated
cOllnodal line, where some straight lines represent ihe "hidden",
.non-realizable equilibria. The points a and a', and in the same way
band b' are corresponding points. The "tail" ar b' is ahvays directed
,towards the side of the plaitpoint (which has al ready disappeared in
.our diagram) of the principal plaiL, the "point" at a lies on the
'opposite side.
We point out thai the shape of the spinodal line, as i& drawn
in figs. 3 and 3a; impJies, that if touches the plaitpoint line in the
peculiar _ way, indicated in fig', 2. In the immediate neighbourhood of
Rl the uppermost portion lies left of the common tangent, the lowermost
portion on its 1'ight.
At somewhat lowel' temperatures, in om example at T = 0,61
fig. 4), the isolated connodal line begins to touch (in Af) the connodal
'line proper, and from this moment one of the two new plaitpoints,
viz. p, will become the plaitpoint of a new branch plait, which has
'thus arisen from the pl'incipal plait in the way described above.
Cf. e. g. fig. 5, where T = 0,60. The point p' is always unrealizable,
and this continues so down to the absolute zero, where the plaitpoint
'line tel'minates in A. On the other hand all the plaitpoints P fi'om
M to Cl will form realizable plaitpoints of the new plait.
In fig. '* ph ase 3 begins to split up into two new phases, the gas
,phase proper 3, and a new liquid phase j, rich in the 11 st component
of the· mixture. The1'e is a th1'ee phase line, the beginning of a th1'ee
'phase triangle (see fig. 5), which continue::; to exist from this point
down to the lowest temperatures.
In' fig. 5 it is also seen how the connodal line which passed on
uninterruptedly before, but which is now brokE'll off in the angles
1 and 3 of the th ree -phase triangle" proceeds on the ll,-surface.
With this corresponds the well-Imown "ridge" on the connodal line
, at 2:'
At T = 0,59 the new plaitpoint P reaches the lower critical temperature
Cl' and from this moment the branch plait is always open
on the side :1: = 0, and this continues so down to the lowest
tem peratures.
The p,.'lJ-repl·esentations are omitLeci for want of space,
Fig. 6 gives the p,T-diagram of the plaiipoint lines. Noteworthy is,
thaL we meeL with a CllSp in the lino elA at Ru wh ere the spinodal
line touches the plaiLpoinL line (cf. fig. 2). We shaH prove this fm'ther
on. As we have already SI10W11 in our formel' paper, the pressUl'e p
appl'oaches - 27]h at A, ·where T = 0. (Thi& derivaiion holds
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