( 456 ) 
La possibility du type III (before called type II by me). On p. 4 
of this paper in Teyler in fig. 2 the coexistence region of this type 
is graphically represented, viz. the region PBQB. This figure has 
been reproduced in the paper in These Proc. of Sept. 1906 (see the 
Plate, fig. 1). In this paper on p. 225—231 1 gave a recapitulation 
of all my previous papers. Compare particularly p. 230: “It is now 
of the greatest importance,” etc. “This investigation forms the con¬ 
clusion of the last paper in the Arch. Teyler.” And on p. 231: “In 
any case the investigations described in the Arch. Teyler have proved 
that this very abnormal type III is possible for mixtures of normal 
substances” etc. (The italics are already found in the original paper). 
b. Further T. and K. object to my investigations (p. 235 of their 
paper) that they, “very onesidedly, lay the stress on the existence 
of open plaits, a circumstance, which by no means can be considered 
as a result, as it immediately follows from the arbitrary, if not 
erroneous supposition of the linear dependence of b and x” 
Now I have never asserted that — - = 0 would always agree 
dv* 
with what actually happens; again I have simply assumed this, in 
order to make the calculations possible. (See p. 649 of the paper of 
March 1905 under 2). 
c. The remark on p. 235: “For the case at last that one of the 
components is abnormal, van Laar arrives at saturation lines of a 
very complicated form”, etc. — this remarks seems very strange to me. 
I do not remember having ever theoretically treated the case that one 
of the components is abnormal. The papers, viz. published by me 
before the paper of March 1905 cannot be considered as belonging 
to the series which begins with this paper, in which for the first 
time the problem of the plaitpoint lines, and everything in connection 
with it, was strictly treated. And I never published anything concern¬ 
ing anomalous substances in this series of papers either. I hope to 
do this perhaps on a future occasion. 
d. In connection with p. 236 of T. and K’s paper I only mention 
that it was by no means generally doubted up to now that for 
perfectly normal substances non-miscibility can occur. VanderWaaW 
himself already stated the conditions of non-miscibility for nor ® 
substances in his Continuity II, p. 43. But it was only doubted 
whether some “abnormal” fqrms of non-miscibility (Type I and 
