points, also of the fusion of 
parts of the one critical line 
with those of the other. 
In the second place we 
will now consider the oecur- 
rence of critical terminating 
points on those three-phase 
lines where one of the phases 
Fig. 5. is solid. We may then limit 
ourselves to the case where B occurs as a solid phase as no critical 
phenomena can occur in presence of solid A. 
In many cases where the line GL,L, proceeds to lower tempe- 
ratures the solid phase will occur ina point Q. According to previous 
research by myself, 4 three-phase lines then meet in the quadruple 
point Q. If we take the ease of Fig. 1 we obtain in Fig. 6 QM 
for GL,L,, QB for GL,S, EQ for GL,S, whilst QN indicates the 
equilibrium of the solid phase S with the liquid layers L, /,. Similar 
lines have been formerly 
studied by me in cases 
where hydrates of SO, 
HBr, HCI occurred as 
solid phases. For the com- 
ponent B as solid phase 
their courses will be ana- 
logous, and like all ordi- 
nary melting lines the 
direction will diverge only 
Fig. 6. a little from the vertical 
either to the right or the left according to the volume differences 
of the phases. 
If the line runs to the 
right and the critical 
line MD to the left there 
might be a possibility of 
their meeting in a critical 
terminating point N as 
the two liquid layers 
A, might here become ident- 
ical in presence of solid B. 
The chances that this will 
Fig. 7. occur with an attainable 
pressure only exist when Q and J/ do not differ too much in temperature, 
N 
