( 550°) 
a 
b 1 a 1 dh 
dy dd bb dy 
. a . ‘ . 
If we assume that J decreases with @, = must increase with z and in 
) 
the case of a minimum it must have passed that minimum. So the 
point for which the coincidence pressure is maximum, and for which 
also there is equality of composition of liquid- and vapour phasis, 
lies more to the side of the components with the smallest molecules 
than the point indicating the mixture with minimum-critical-tempe- 
rature — and this will be the more so in proportion as 7 is higher. 
For the case that 7, as function of «and y might be represented 
by approximation as a plane (see Cont. IJ, p. 153) we find 
pe constant, and so the line of the double points under a constant 
dx 
pressure is a straight one. 
RELATION OF VOLUME, CONCENTRATION AND TEMPERATURE FOR 
COEXISTING PHASES OF A TERNARY SYSTEM. 
In fig. 2 of the preceding communication the curve ABPRBA 
represents the projection of the connodal curve on the w-surface of 
a binary system in the «v-diagram at a constant temperature. This 
line may also be taken as representing the relation between molecular 
volume and concentration of a binary mixture at given temperature. 
If the temperature was put lower, this curve would have consisted 
of two isolated branches, one representing the liquid volumes, and 
the other the gas-volumes. Let us now think as third axis, a y-axis, 
and let us think also in the oyr-plane a similar curve drawn for 
a binary mixture that consists of the first and the third substance. 
If we further draw for every point of the right-angled triangle of 
the ozy-plane the volume at which a mixture represented by that 
point loses or resumes its homogeneity at increasing pressure, we get 
a surface which consists of two isolated sheets at low temperatures, 
and which at higher temperatures e. g. when 7’ is above 7, of one 
of the components, is contracted to one sheet. 
If 7 is increased the form of the surface is modified in that sense 
that the new surface lies quite within that of lower temperature. 
At least for substances which do not enter into chemical combi- 
nations with each other, and which continue to consist in them- 
— ee, 
