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tinuous also as to its direction. In the second place we may, between 
the ends of the pieces which are experimentally determined, trace 
a curve which presents in those ends abrupt changes of direction 
and which has about the same course as the three-phase pressure, 
though it lies everywhere lower than that pressure. 
I then thought that the two pieces of the plaitpoint curve were 
to be connected in the first manner. The experiment had shown 
that the peculiarities which must then occur, namely the existence 
of a minimum and of a maximum temperature, were possible and 
really occurred in nature; at any rate the minimum temperature. 
The peculiarity, on the other hand, which occurs, if we make the 
connection in the second manner, namely the abrupt change of the 
direction, was never observed. . 
Now when we have made a choice and when we wish to examine 
its meaning, all conclusions must of course be in accordance with 
the choice we have made. Here | will mention the following 
conclusions from the first way of bringing about the connection : 
Ist. A mixture with minimum critical temperature exists. 2nd, A 
mixture with maximum critical temperature exists. 38'¢. Plaitpoints 
occur outside the borders of the three-phase temperature, which 
cannot be observed, as they lie above the empirical w-surface. 
In this case a plait must necessarily at a certain temperature be 
separated from the principal plait, which at higher temperature (the 
maximum critical temperature) has contracted to one point. In short 
then the phenomenon quite corresponds to the description I have 
given Cont. Il, p. 187. If therefore Kurnen accepts the way in which 
the connection of the two pieces of the plaitpoint curve he has 
determined experimentally, is brought about, then I cannot but consider 
it to be inconsistent, if he raises objections to the interpretation. 
But more important is the question whether the choice we have 
made is the right one; whether, therefore, the connection between 
the two pieces of the curve should not rather be brought about with 
two abrupt changes in the direction. This has at the same time the 
following meaning: Is the plaitpoint the course of which is indicated 
by the theoretic curve, perhaps quite another plaitpoint as that whose 
course is indicated by the experimental curve? Now I read in the 
paper of KvrNEN p. 321 that he has obtained the figure I have 
originally given, with the aid of other curves. But I think that this 
must be understood in such a way that he has succeeded in pointing 
out, that the two ends of the experimental branches may be connected. 
The way in which the connection must be established can here, after 
my opinion, not be decided. I have already doubted some time as to 
