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substances, which do not exercise any chemical action upon one 
another, for which therefore the molecules in the mixture may be 
considered to be simply mixed, without suffering any internal modi- 
fication. For such binary mixtures minimum critical temperatures have 
fy 
a minimum value of 7, corresponds to a negative value of We — 
Bit never with certainty maximum critical temperatures. If u’ and 
Wm Could be positive, and u em By (U! L'zmyn)y then we should also 
get ellipses for the curves of equal pressure, but then we should 
have p>pm, and the ternary system would present a minimum pressure, 
which would also lead to minimum pressures for the pairs of which 
the system consists. If maximum critical temperature for a binary 
system should really occur in nature, and if we then formed a ternary 
system, of which one pair of components Posen a actu and 
another pair a minimum value of Ds then Won and p" ym might have 
opposite signs, and the point for which Wem and u’ ym Vanish would be a 
Ter 
actually been found, — and the chief term of u being — /( — 1) 
a PR stationary point as to the pressure, and 
\ ba the curves of equal pressure would 
intersect in that point. 
In figure 12 the course of the curves 
of equal pressure has been represented 
schematically for the case of maxi- 
mum pressure for the three pairs of 
components and for maximum pressure 
for a point of the system. The suc- 
cession of the values of the pressure 
b EE * is then: 
Fig. 12. 
ag OY <P GPS Pas < Pm 
only the order of succession of Py, and 
ps and of p,, and p,, may be reversed. 
The figure does not require any further 
explanation. 
As intermediate case for the course 
of the curves of equal pressure, we 
assume a system, in which for two of 
the pairs the pressure increases or decrea- 
ses regularly, but the third pair has a 
Rist os Pi Pp, maximum pressure. So in fig. 13 the 
vindek Pek pressures follow each other in this 
Fig. 13, Way: PD, <P; << pi, LPs One of the 
