As the field (#,F) consists 
of two leaves, each point of 
this field represents two equi- 
libria (F'F,)' and (F'F,)"; both 
equilibria consist under the same 
P and 7, but they differ from 
one another by the compositi- 
ons of the variable phases. 
Fig 5. We imagine in fig. 5 the 
curve (/,) to be drawn. As the equilibrium (#,) contains all phases 
of the equilibrium (#,F), curve (/,) cannot come outside the field 
(F,F,), therefore, also not outside the turning-line. When curve (F,) 
meets therefore the turning-line somewhere in a point d, then d is 
not a point of intersection, but a point of contact of those curves. In this 
point of contact curve (F,) passes from the one leaf into the other. 
When we imagine in fig. 5 a curve within the turning-line, then 
we see that this curve must have points of maximum- or minimum 
pressure and temperature. 
For the deduction of the P,7-diagramtypes and of the properties 
of their fields we have used the following properties [deduced in 
communication I}: 
each point of a field (#, F,) represents one single equilibrium 
(F, F,) only; 
the stable part of a field (#, F,) extends itself between the stable 
parts of its limit-curves (/,) and (4) without covering them; 
a field-angle is smaller than 180°. 
Now the question arises in how far those properties are still valid now. 
For this we imagine in the field (7, F,) a point 7 on the leaf (F,F,)’. 
The curves (/,) and (F,) are situated, starting from this point, first 
in the leaf (7, F,)’; in their point of contact with the turning-line 
they pass into the other leaf. 
When we deduce the properties mentioned above, just as in 
Comm. I, then it appears that they are valid, when we leave out 
of consideration the leaf (/,/,)". 
When the invariant point 7 is situated in the leaf (#,F), then 
we shall say that the equilibria of this leaf are situated within, and 
those of the leaf (F,F,)" outside the turning-line. We do not say 
that with respect to the P and 7 of those equilibria, but with 
respect to the compositions of their phases. In order to convert viz. 
an equilibrium (/,F,)' continually into an equilibrium (Ff, F,)", the 
first one must pass starting from a point of the leaf (#,F‚) through 
the turning-line into the leaf (F,/’,)". 
