817 
and further the curves: 
(C)=A+B+D+4+4 
(D)=A+B+CH+ EK 
(A)=A+6B4+C+ D 
In the singular equilibrium (J/) the reaction: 
C+ k2D 
may occur. Hence it follows for the partition of the curves with 
respect to the (J/)-curve: 
ROME) |M OPIN MET eere oe ll) 
In each of the figs. 2, 4, 6, and 8 the curves (C) and (//) must 
be situated, therefore, at the one side and curve (D) at the other 
side of the (M)-curve. 
In communication | we have deduced the rule for the partition 
of the curves for the general case, that each curve of a system of 
n components represents an equilibrium of ” + 1 phases. As the 
(M)-curve represents, however, an equilibrium of only 2 phases, we 
have to deduce this rule also for this case. 
As the (M)-curve coincides with the two other singular curves 
(A) and (B), we may consider instead of the (J/)-curve also curve 
(A) or (B). In the equilibrium (A) —= B+ C+ D+ E, as B takes 
no part in the reaction as indifferent phase, the reaction: 
C4H+EZD 
occurs. Hence follows for the partition of the regions with respect 
to curve (4): 
SENS 
B+C+t EE cian tae 
$ BCD 
Each of those regions is limited, besides bv curve (A), also by 
an other curve; the region B+ C+ EF by eurve (D), the region 
B EHD by curve (C) and the region 6+ C+ D by curve 
(fH). As each region-angle is smaller than 180°, it appears that 
curve (D) must be situated at the one side, and the curves (C) and 
(#) at the other side of (A). Consequently we find: 
(CE) | (A) | Dj 
or, as the curves (A) and (M) coincide: 
(C) (EE) | (WM) | (Dd). 
Now already we know, therefore, that in each P,7-diagram-ty pe 
the curves (C* and (#) must be situated at the one, and curve (D) 
at the other side of the (M)-eurve. It is apparent, however, that 
this is not sufficient to determine the P,7-diagram-type completely. 
Now we shali deduce this type for each of the four cases. 
