( 310 ) f 
in order to show this difference clearly, but then also in order to 
bring us into agreement. 
For the case of ethane and methylaleohol the theoretical plaitpoint 
belonging to the sideplait of the side of alcohol coincides at 7’, (see 
fig. 2, p. 326) with the practical plaitpoint of the side of ethane. At 
lower value of 7’ it is displaced in the «,7-plane towards the side of 
alcohol and when the temperature continues to decrease it approaches 
asymptotically to the plaitpoint with which it forms a #système 
double hétérogène” (after the terminology of Korrewee). If we draw 
this series of points in the plaitpoint diagram, it must of course satisfy 
the condition which follows from the fact, that they le below the 
three-phase triangle, namely on the side of the small pressures. At 
low temperatures it lies even in the region of the negative pressures. 
Fig. 2 of Kurnen p. 326 must therefore be completed with a 
theoretic curve which starts at point A, retrogrades immediately to 
lower temperatures and lies below the curve of the three-phase 
pressure. The theoretical branch approaches to the same asymptote 
as the highest branch that starts at C,. For the theoretic branch also 
(ee) must be positive, and therefore we have: 
dp Op j 
IT ~ (55). 
The rapid rising of this branch at low values of 7’ seems to be 
contradictory to this explanation. But if we take into account that also 
OT 
approach to the limiting volume, this apparent contradiction disappears. 
What is surprising, at least to me, is that these theoretic plait- 
Op 
( approaches to an infinitely great value for values of v which 
v 
points serve to make the course of the practical plaitpoints continuous. 
But on the other hand the circumstance, that also for the course of 
these theoretic plaitpoints a so important and at the same time a so 
simple meaning has been found, confirms my opinion that now the 
true description of the phenomenon has been given, at least for those 
cases, in which the longitudinal plait has its summit on the side of 
the small volumes. 
But though the accuracy of the description of the phenomenon has 
increased, we must acknowledge that the chance to find a satisfactory 
explanation for the phenomenon is not greater than before; on the 
contrary it has diminished. The circumstance in which a mixture of 
two substances has a maximum and a minimum critical temperature 
needs now no longer be inquired into. The question whether the 
