( 558 ) 
2 2 92 TN 2 22 
meae 
ow Pp ey _ 
2 
i dxdy Ord» dydv — 
RE . 
putting a= co as it must be in the ovy coordinate plane: 
dw 92 2 
ot (oe) = 
But just as the spinodal curve for a binary mixture (fig. 7 and 
9 
fig. 8) can have points in common with the curve ee = 0, so it 
Uv 
can also happen that the two surfaces corresponding to these curves 
have points in common for a ternary system. First of all they 
dw dw 
touch if —— a ae and Qo dy 
place they have points in common in the edges of the prism, so for 
the simple substances. And finally just as the spinodal curve and 
the connodal curve can have a point in common (the plaitpoint) for 
a binary system, in the same way the corresponding surfaces can 
have points in common for the ternary system, and touch each 
other in these points. For if for the second phasis we have: 
are both equal to zero — and in the second 
vg = vj + doy #3 = vy + dr, and yy = 1 + dn 
the equation (1) becomes: 
an +505 at +5 Tay? Een ze dv, dx, +- 
dw dw 
EEn B dv, dy, + 2 —— da, dy, = 0 
Oe Oy 
or 
