714 
ever, that the region 12 from fig. 2 (I) is missing in fig. 1 and is 
replaced by the singular curve (MV) = F, + F,,. 
We have seen in the previous communication that each region 
which extends over the stable or metastable part of a singular curve, 
contains the two indifferent phases. In fig. 1 the region 34 extends 
over the singular curves; and therefore it contains the two indifferent 
phases #, and F’,. 
P 
“ 
A OE 
9 x 
if fe 4, 
Fig. 1. Fig. 2. 
When in the concentrationdiagram of fig. 2 (1) PF, and F, are 
the indifferent phases, then /, and F, are the singular phases: 
Ff, and #, have then the same composition, so that the points /, and 
F, coincide | fig. 2). Then we have the singular equilibria : 
(M)=F,+ F, [Curve (Mj in fig. 2] 
E)=b EE, [Curve (1) in fig. 2 
(f= AE HF, [Curve (4) in fig. 2 
and further the equilibria: 
(fj=f,+f,+ f/, [Curve (2) in fig. 2] 
(1) =F, HEHE, [Curve (3) in fig. 2] 
When we wish to deduce the type of P,7-diagram from fig. 2 (I) 
then, as (1) and (4) are the singular curves, we have to let them 
coincide. Then we obtain fig. 2. The three singular curves (J/), 
(1) and (4) coincide now in the same direction; the (J/)-curve is, 
therefore, monodirectionable. Consequently the P,7-diagram consists 
of three onecurvical bundles. 
In order to find the bivariant regions, we have to bear in mind 
that between the curves (1) and (3) the region (13) = 24 is situated; 
~~ eT 
