( 769 ) 
runs vertically upwards, after which it bends sharply to the red 
side, and meets the mixed-crystal curve of the pseudo-binary system 
near the axis of the red modification. 
As therefore, this inner equilibrium curve appeal's to traverse the 
T-^-figure over a large concentration range, this pointed already to 
a region of partial-miscibility in the pseudo-binary figure, which was 
closed at the top, and so also to a continuous mixed crystal curve acb. 
In order to test this supposition more closely, the following ex¬ 
periments were made with HgJ 2 , either in thin-walled narrow capil¬ 
laries or in so-called alcaloid tubes ^ it was, namely, quite immaterial 
which of these were taken, for in either case the experiment yielded 
the same result. 
In these tubes the HgJ a was heated in a melting-apparatus up to 
a certain temperature above the transition-point, and then all at once 
transferred to an oil-bath of lower temperature, but always above 
the transition point. 
The considerations which led us to these experiments, were the 
following. 
If it is possible to make the cooling take place so rapidly that 
the inner equilibrium cannot keep pace with the temperature, the 
pseudo-binary character must appear, and entering the region of 
partial-miscibility the substance must split up into two phases. 
Suppose that we start from the inner equilibrium p and that we 
cool this suddenly, in which not the curve of equilibrium, but the 
curve pS z is followed; then the red phase S 4 will appeal’ by the 
side of the yellow phase S 3 and will have to be clearly visible. 
This three-phase system will be strongly metastable, so that it is 
not to be expected that it will be very permanent; on the contrary, 
we may confidently predict that this state will very soon change 
into the only stable equilibrium which must lie on the curve SS 
If we now start from the inner equilibrium q, which lies on the 
right of the critical mixing-point K, the mixing-curve can be reached 
in S s , and by the side of phase S ,, the phase S, must be found, 
which has a lighter colour. 
As appears from the subjoined table (p. 770) not only these phenomena 
could be observed with great clearness, but moreover it was ascer¬ 
tained by these preliminary experiments that the mixing-point K 
mnst lie above 147° *). 
Though it follows from these experiments that above the transition 
temperature the 2 7 ,<r-figure of the system HgJ, would be as indicated 
i) This investigation is continued in different directions. 
