As the equilibrium (£2), = H, + H;-+ G may be converted in 
the point g into the invariant equilibrium q viz. into G + L,-+ H,+ Ho 
curve (Z), terminates in the point g. Consequently curve (Z), is 
represented in fig. 10 by curve q,q. 
The equilibrium (G), =H, + Hs 4 L may not be converted in 
the point q into the invariant equilibrium g= G+ L, + H, + Ho: 
curve ((7), does not terminate, therefore, in the point g, but it pro- 
ceeds further. It is represented in fig. 10 by curve ¢,¢go0=4, G0. 
When we represent the solutions of the equilibrium (G),= A,+H;+ L 
in fig. 9, then we get a curve as q, 0,. 
The singular equilibria 
(= H,+H;+G and (GO) =H, + Hs + L 
start from the point g. As the (M)-curve is bidirectionable in g, 
the singular curves (£) and (() go in opposite direction. Conse- 
quently curve (Z) goes starting from g towards lower pressures and 
it terminates in q,. Curve (G) goes starting from g towards higher 
pressures, it is represented in fig. 10 by qo=qo,. The solutions of . 
the equilibrium (@)=H, JH; L are represented in fig. 9 by 
curve go. 
Let us now consider the P,7-diagram in the vicinity of the point 
q. In this point ‘the ‘equilibrium: G + L, + H,-+ H; occurs, it 
appears from the position of those phases with respect to one ano- 
ther in fig. 9 that the P,7-diagram must belong to the type of fig. 1. 
We see that this is really the case. 
In the point g, the equilibrium G + L%, + H.-+ H; occurs. In 
accordance with the position of those phases with respect to one 
another in fig. 9, it is apparent that the /?,7-diagram belongs to 
the type of fig. 2 in the vicinity of the point q, in fig. 10. 
The curves go =(G) = H,+ H;+ Land g,0,=(G@), =H, +Hs +L 
are no separate curves in fig. 9, but parts of one single curve 
goro,g,; this curve has a point of maximum- or of minimum-tem- 
perature in its point of intersection 7 with the line « (viz. with 
the prolongation of this line). In fig. 9 we have assumed that 7’ 
is a maximum. In this point 7 the equilibrium: HM, + Ha + Ly; 
occurs, in which Zi: represents a liquid of the composition HM, = H,. 
In fig. 10 the point 7 has not been drawn, of course it is situated 
somewhere on that part of the (J/)-curve, which ascends starting 
from the point g, for we have assumed in fig. 9 Td. his 
point 7 is the stable terminating-point of the curves go and q,0, 
and, as we shall see further, the common point of intersection of 
three curves viz. of the (J/)-curve, of the melting-line of 77, and 
of the melting-line of /7,, 
