( 530 ) 
or that of fig. 6, when partial miscibility presents itself. The normal 
plait with the critical point in A will appear only in a great minority 
of cases, and can be regarded as highly exceptional. So the mixtures 
of water with phenol (ALExesmw), with succinitrile (SCHREINEMAKERS), 
with aniline (ALEXEIEW), with dsohutylic-acid (id), ete, ete. — which 
all present an upper critical point — will offer with great certainty 
examples of the very general case of fig. 6 or of that of fig. 4. 
e. Fig. 5 again represents a transitory case, where the value of 
K, is still a little greater than in fig. 4. The two plaits — the 
normal one and the isolated one — will coincide from this moment 
into one continual plait. 
f. This will be the case in fig. 6. lt is observed for mixtures 
of water and secondary butyl-alcohol (Aurxesew). But, as we already 
remarked above, many observations with an upper critical point 
may belong just as well — whether the compositions of the two 
coexisting phases approach each other at lower temperatures or 
not — to this case as to that of fig. 4. The example mentioned 
belongs with certainty to the class of fig. 6, because it is observed, 
that the values of 7 after beginning to approach each other diverge 
again at still lower temperatures. 
Fig. 7 shows, that the contraction at D, where the curve A = f(T) 
comes into the neighbourhood of the line O.J/, gradually vanishes, so 
that the plait at last again will assume the normal form — only 
with this difference, however, that the critical point C of our quasi- 
normal plait will appear at higher temperatures than the critical 
point A of the real normal plait. 
Remark. It will be superfluous to remark, that the numerical 
calculations by means of the formula (10) can be executed only 
then, when the conditions are satisfied, on which that expression is 
deduced. That will accordingly only be the case, when really p is to 
. . a . . 
be omitted against — (see $2), that is to say at temperatures, which 
5 
are not higher than circa half the eritical temperature (in the ordi- 
nary meaning) of the mixture. 
7. “The question rises now, what will be the conditions to be 
satisfied, that the transitory cases of the figs. 3 and 5 may present 
themselves. Here too we only communicate the results of the caleu- 
lations, that we have made on this subject. We found namely, that 
the isolated plait (fig. 4) is only possible, when the second (normal) 
substance has a critical pressure between circa 35 and TO atm, and 
