1025 
16a| of the seven relations. The partition of the curves, which follows 
from 17a, 18a and 19a, is in accordance with the P,7-diagram. 
Stab. PET’ | eas Oi SOP chee” 
| | | | | | | | | | | | | | (20) 
Metast. S’ Q R’ PT v' U 
It is apparent from the P,7-diagram or from its symbolical repre- 
sentation (20) that the curves form five bundles, viz. the two two- 
curvical bundles (7” 7”) and (S’Q’) and the three onecurvical bundles 
Wee; and fi". 
When we include also the regions in the diagram, then we find 
the symbolical representation (21) 
Stab. P’ fh ae U’ S’ ()’ 18, P' 
mi ter } (ST) +-(ST) HST) ++ 
-(RV)--(BV} (RS\=- (RS) | (ROE 
++ (QT) (QV) (QD) | (QT) (QT) + 
£ PO PD LN (RO) RO) RO) 
S (PVII) | SV) ASV) |: CPS) -E (PS) = (PS) 
Oma (27) (OR Soy (QU)--(QU) (Rly ae 
Pt) 
(PT) TV) | CHIO GUY. CAS) ) COR 1 (PR) 
l- | | | | | | 
Metast. Sa Fi el v' (Ok 
We find 21 regions, some of them extend themselves over one or 
more curves; this is indicated in the diagram by horizontal lines of 
conjunction. The region (S7’) seems in (21) to consist of two parts, 
separated from one another; this is however not the case, both the 
parts meet one another viz. over curve P’. 
The region (ST) goes therefore starting from curve S’ over Q’, 
R’ and P’ up to 7”; it is apparent that it cannot go starting from 
S’ over U’ and JV’ towards 7”; viz. in this case it would cover 
the metastable part of curves S’ and 7”, which is not allowed. 
The same applies to the regions (RV), (QT) and (RT), which 
consist in (21) also seemingly of two parts separated from one another. 
We also see again the confirmation of the rule that each region, 
which extends itself over a curve /”,, contains the phase #. 
It appears from the previous considerations: when we know the 
compositions of the phases, occurring in an invariant point, then 
we can deduce the corresponding type of the P,7-diagram. 
Leiden, Anorg. Chem. Laboratory. (Lo be continued). 
66* 
21) 
