869 
and d'h'hsb, whereas the vapour region forms a coherent whole. 
In fig. 2 we find the following equilibria : 
Curve a'g' represents vapours in equilibrium with liquids of the 
curve apg ; 
Curve 6'h' represents vapours in equilibrium with liquids of the 
curve bsh; 
Curve a'b' and g'h' represents vapours in equilibrium with the 
solid substance /; 
Curve apg represents liquids in equilibrium with the vapours of 
the curve aug; 
Curve bsh represents liquids in equilibrium with vapours of the 
curve 614; 
Curve apg (and brh) represents liquids saturated with the solid 
substance /. 
If, at the temperature and the pressure applying to fig. 2, we 
join the components, then, according to the situation of the figura- 
ting point, there is formed within : 
the gasregion. . . . an unsaturated vapour : 
the liquidum region an unsaturated solution ; 
apgg,d, - vapour of a,g, + a liquid of apg ; 
bshh,o,........ & vapour of b‚h, +a liquid of bsh; 
a) 
a,b a vapour of a,b, + solid /; 
ghF a vapour of g,h, + solid F; 
agg .. a liquid of agg + solid F’; 
‘as a liquid of beh + solid FP; 
aa,F -......-. .. vapour a, + liquid a 4 solid #'; 
bb,F Re ee hd eae PE) b, ai EE) b + EE) JR 
ggk ORN MA EE) Ji =F ” g + ey B 
DEE TE eee Be Es fe ce eta es EN 7 
On further reduction of pressure, the liquidum line apg and hsb 
which surrounds the liquidum region contracts still more so that 
‘on the one side the points « and g coincide at a pressure P, this 
will be likewise the case with their conjugated points a, and gq, ; 
the two triangles Pa,a and Fy,g then coincide along a straight line 
and the pressure / for the system #+2-+G is a minimnm 
pressure. The same applies when the two triangles /6' and Fhh; 
coincide. 
After the four three-phase triangles have disappeared from fig. 2 
owing to reduction of pressure, the vapour saturation line of / 
composed in Fig. 2 of the two branches a,b, and g,h, forms a 
closed curve which surrounds the heterogeneous region LG as well 
57 
Proceedings Royal Acad. Amsterdam. Vol. XY. 
