( 134 ) 
If also one of the other sides of the triangle presents a maximum 
pressure, e.g. the Y-axis, then we have to deal with still another 
locus: wy, =O. The circumstance whether the two curves gr, = 0 
and w',, =O intersect or not decides whether for a ternary system 
a maximum pressure exists or not. The given rules concerning the 
peculiar points of the envelopes enable us in this and other cases 
to conclude to the course. But I will no longer dwell upon this 
subject. I consider the preceding discussion as sufficient to draw 
attention to the significance of these curves for the knowledge of a 
ternary system. 
d. The addition of a third component to a gwen binary system. 
If we have a binary system consisting of 1—r, molecules of the 
first kind and «, molecules of the second kind, and we add to it a 
third component so that the final composition is given by 1—vr—y, 
v and y, then we have: 
a“ v 
ley ne EN 
From this relation we derive: 
d 
—=1—-y; 
Lv 
0 
from which we conclude, that the points representing the ternary 
system lie on a straight line, which counects the summit of the 
rightangled triangle with that point on the opposite side that represents 
the composition of the binary system. 
: 075 075 th ME 
Taking into account the values of Epa? a and of aa given on 
1 as & OY, Ji 
p. 5 and substituting the value —., dy, for dz,, we find from 
formula IL of p. 
Vs. dp ‚ (1—y) 1 " <Any | 
2 —e + Flag ela HH 
MRT dy, — ) Ee IE —y,) 1—wz,—y, mn a 
1—wz 
re (y =) TEN oe i en DU my, % 
c la stank! Wy (1—#,—y,) 
This equation may be simplified to: 
v dp " " ! ! 
MRT dy = («,—a,){ mn — Voll x Gm b= Y‚) U (1 en, "nh —& lh zal . 
4 Gy 1 
In order to get the corresponding equation for the vapour phases, 
we must interchange the indices 1 and 2; it has the following form: 
Vn dp 
MRT dy, = (Bj) Wl rijn old ro} + (WV: Nett pa | 
