ls 
FFF F, and F, F,. We see that the fields 12, 13, and 14 
occupy all spaces in the P,7-diagram; the field 12 extends itself 
viz. over two spaces. Also we see that none of. those fields covers 
one of the curves (2), (8) or (4). If this complex is made to de- 
scribe a cycle, then consequently the conversions : 
(2) > 18 > (4) ~ 12 | (38) = 14 | (2). 
occur. 
When we had taken a complex, represented by a point between 
F, and #,, then we could convert it into four monovariant and 
four bivariant equilibria. 
Let us take a ternary system, of which the concentration-diagram 
is represented by fig. 1 (ID. When we take a point X within the 
quintangle, formed by the points of intersection of the diagonals, 
then this point can represent one of the monovariant equilibria 
(1), (2), (8), (4) and (5) or one of the bivariant equilibria 128, 145, 
234, 125 and 345. When we consider those curves and regions in 
the P,7-diagram, then we see again the confirmation of the rules. 
The following conversions occur at a cycle of ‘this complex : 
(1) — 845 — (2) — 145 — (3) > 125 — (4) — 125 — (5) — 234 — (1) 
It follows from the deduction of the properties discussed above, 
that those are also valid, when, besides mono- and divariant equi- 
libria, also occur tri-, tetravariant ones, ete. We have to read in 
those rules instead of bivariant equilibria (or fields): bi, tri-, tetra- 
variant ete. equilibria (or fields). It may occur however, as we shall 
see further, that one single equilibrium occurs only; the number 
of monovariant equilibria is then of course no more equal to the 
number of bi-, tri-, tetravariant ones, ete. Yet this one region 
occupies all spaces of the /,7-diagram. 
Before elucidating those rules also for these cases with some 
examples, we shall first seek the tri-, tetravariant ete. regions in 
a P,T-diagram. 
Although in our P,7-diagrams only tbe bivariant ‘regions are 
indicated, yet we are able to find at once the other ones. Let us take 
e..g a bivariant region /’, /’,/;, in which, therefore, exists the phases- 
complex /’, + #,-+ HF. Now it is clear that in this same region 
also the complexes 4, + F,, F+ F, and #,-+ F, can occur and 
also each of the phases Pand /’, separately. 
In order to find e.g. in fig. 2 (ID) the trivariant field 12, we have 
only to take therefore, the fields 12m, in which m represents an 
arbitrary phase, here these ave the fields 124, 125 and 123. Conse- 
quently the field 12 occupies in fig. 2 (II) the spaces (3) (4) and (4) (5). 
