929 
ves (viz. those, which have the same sign) coincide with the one 
direction of the (M)-curve, the third curve coincides with the other 
direction of the (J/)-curve. 
With the aid of those rules we may deduce again, just as in 
Comm. X, the main-types of the P,7-diagrams; we leave this, 
however, to the reader and we shall consider more in detail one 
single example only. 
We take a ternary system with the components W(W = water), 
A and B. Let occur in the invariant point the equilibrium: 
A+6+le+L,+G 
in which L, represents the liquid q (fig 1) and G represents the 
vapour. When (G consists of water vapour only, then in the equili- 
brium (5) also the reaction /cee = G may occur; A, B and L, are 
then the indifferent phases, /ce and G the singular phases. Then 
we have the singular curves: 
(M) = Ice + G [Curve (M) in fig 3] 
(4) = B+ Lee H+ LAG |qb in fig. 1; go = (A) in fig. 3] 
(B)= AH lee + LH G [qa in fig. 1; qa =(B) in fig. 3] 
(L)= A+ B+ Lee + G [Curve (L) in fig. 3] 
and further the curves 
Vee) = A + BHA LG [ge in tig 1; U) in fig. 3] 
(G)= A+ B+ lee + L [Curve (G) in fig. 3] 
With the aid of the previous considerations we may deduce the 
type of P,7-diagram; first, however, we shall do this in another way. 
Let us consider viz. the case that the vapour G does not consist 
of water only, but that it contains also a little of the components 
A and B. Then we have the equilibrium: 
A+B+tee+ L, + Go. .. - . - (6) 
in which G,, represents the vapour g, (fg. 1). The point gq, is situ- 
ated in the vicinity of the point W. The five phases of equilibrium 
(6) now form a type of concentration-diagram as in fig. 5 (II), conse- 
_ quently the type of P,7-diagram must be as in fig. 6 (II). [We 
have to bear in mind that the figs. 4 (II) and 6 (II) have to be 
changed inter se]. As q, is situated in fig. 1 in the vicinity of W, 
the line qq, intersects either WB and AB or WA and BA. It is 
apparent from fig. 6 (II) that the curves (/), (A) and (B) must form 
now a three-curvical bundle, as in fig. 2. When we assume that 
the line gq, intersects the lines WB and AB, then curve (B) must 
be situated between the curves (A) and (/). We now easily see 
(amongst others yet also from the diagonal succession of the curves) 
