is hereby converted into a somewhat different liquid ZL". Now, so as 
to convert L" into ZL’ either solid / must dissolve in ZL” or erystallise 
from the same. If now this solution or crystallisation of Fis accom- 
panied by a great decrease in volume, this may exceed the increase 
of volume occurring in the generation of the vapour; the system 
F4 L is then converted with decrease in volume into F+ L'-+ G'. 
Such a conversion may be particularly expected in points of the 
saturation line under its own vapour pressure which are adjacent 
to the point /. The liquid then differs but little in composition from 
the solid substance / so that in order to slightly alter the compo- 
sition of the liquid large quantities of solid substance must either 
dissolve or else erystallise out. Moreover, if in this case the solid 
substance /’ melts with increase in volume, the latter will increase on 
addition of / and decrease on the separation of the same. If F 
melts with decrease in volume, the volume will decrease on addi- 
tion of # and increase when this substance is deposited. 
Hence, in the case of points of the saturation line of / under its 
own vapour pressure situated in the vicinity of /, the system /’+ L 
can be converted with decrease in volume into /’-+ L'+ G': 
|. if in that conversion solid matter separates and if this melts 
with increase of volume (V > 2). 
2. if in that conversion solid matter dissolves and if this melts 
with decrease of volume ( V < v). 
We may now apply the above considerations in different ways. 
If, for instance, we take the change in volume along the saturation 
line under its own vapour pressure as known, we may determine 
the change in pressure; if the value of the latter is known we may 
determine the change in volume. We now merely wish to demon- 
strate that these views support our previous considerations. We 
first take the case when all the points of the saturation line under 
its own vapour pressure are removed comparatively far from the 
point J, so that the two-phase complex /’-+ L is converted with 
increase in volume into the three-phase equilibrium + LH G’. 
We represent the equilibrium “+ LG by the three-phase 
triangle Faa, of fig. 3 (A) or 4 (1); the two-phase complex F+ L 
is then represented by a point of the line Fa. 
As, according to our assumption the system /’-+ ZL which exists 
at the pressure P, is converted with increase in volume into the 
three-phase equilibrium F+ L’-+ G’ existing at the pressure /, the 
new pressure /” must be smaller than P. 
From a consideration of fig. 3 (1) or 4(1) it follows at once that 
the new liquid ZL’ must be situated in such a way that the new 
