, 
| 1 Saal 1— 2.2) v—32 (1—2) d +Ya(v—b)? |» (L_a) HOB a) 
| + a(v—b) ea | == hae alte cor (8) 
where 6 — B /a may be substituted by ar — 23 Va. 
This is consequently the sought equation of the 7, v-projection of 
the locus of all the plaitpoints, which can appear on the y-surfaces 
at different values of 7. Combined with (6), we find the points of 
the surface, represented by (6), which satisfy the plaitpoint-condition, 
that is to say the equation of the plaitpoint-eurve as space-curve. 
Equation (6) may be written: 
a 
nt = [ras Hate | seth TG) 
5 
where thus 6 =a + a(r — b), and 7 =+), Va, — b, Va. 
For + = (8) passes into 
(L — 2x) b — 3a (1 — ee) B=0, 
er 1 > 
yielding «, = |e +1) —Vr+trt i], as we have deduced 
5: 
already above (in § 5) for that limiting-case. 
To conelude, we remark, that the sections for constant volume of 
the surface, given by (6), on/y extend down to 7 = 0 («=O and 1) 
for v=b. For all volumes >> 5, 7 will assume for «= 0 and 1, as 
: : : oes _ 2a(v — Bb)? 
is obvious from (6), a finite value, viz. — EDS The 7'‚r-boundary- 
curve suddenly ends then at the Z-axis at the designed value of 7 
(also compare the space-representation). 
The proper discussion of the equations (6) and (8) must be 
reserved for a separate communication. It will appear then, that the 
different forms of the spinodal- and plaitpoint-curves, which occur 
specially in the case of anomalous substances, are already possible 
in the case of normai substances, provided the proportion of the 
two critical temperatures 7/7 be sufficiently large. The spinodal 
curves, given by (6), will appear easily calculable, and as to the 
course of the plaitpoint-curve (there are two, independent of each 
other), some conclusions will be deduced in a simple way, 
It will also appear, which indeed results already from (6), that 
at least with respect to the 
the longitudinal- and the transversal plaits 
spinodal curves (compare also vaN per Waars, Cont. HU, p. 175) — 
are no separate plaits, but one single plait, of which the plaitpoint 
is lying, according to the different circumstances, either on the side 
of the small volumes, or somewhere else, 
