da 
ward ef oe es 
db bm, 
dit 4 ho 
Now we must investigate if there exist mixtures for which this 
temperature is the critical one on the right of B’. And so: 
Utr MRT — 8 a oe a, ie ened ned Vi : 
be, Bib 27 b, (a? + Zea.) 
1 
So for the determination of « we find the equation: 
: 8 38 8 ; 
ode as nate a + 27 an Pe a (27,—a,) — 0. 
If for the sake of brevity we call the coefficient of 2? A, the 
roots are: 
or POs ch nee i 
c= — 27 A = A DE za + 57 A z‚e, (2%,—2,) 
If A is positive, the roots are real, as according to the supposition 
uv, IS De, and the expression under the radical sign being larger 
19 : : 
than — «,4,, We get a positive and a negative root. So this means 
7 
that one mixture on the right of 5’ has its critical temperature at 
‚dp eee 
the said temperature. Hence the line ign Q has a direction // v-axis 
Ke) 
d ; , 
at this 2, and  —0 does not exist any longer on the right of this 
av 
mixture. 
If A is negative, both roots remain real, for then we get under 
the radical sign: 
LOPE ae ga GAL 
97° A2 1E 27 at bed a (2e, —e,) En 972 oS oak a 27: a 
As 2, >a, the second term is positive, and the third is smaller 
than the first. So the expression under the radical sign is positive, 
19 
but smaller than By 2 The first term of the expression for the 
roots now being positive, we have now two positive values of 
wv, 1 e. on the left of B’ we have first a region of mixtures 
which are below their critical temperature, then a region of 
mixtures which are already above if, and on this follows again a 
region of mixtures below their critical temperature. So the line 
