1393 
When we seek the trivariant field 13, then we find it in the regions 
123, 134 and 135; consequently it occupies all the spaces of fig. 2 (II). 
In order to find the tetravariant field 1, we seek the fields 1 mm, 
in which m and n represent arbitrary phases; it appears that this 
field 1 occupies all spaces in fig. 2 (II). We find the same in this 
figure for each of the fields 2,3, 4, and 5. 
Now we take in a binary system | fig. 2(I)] a point X which 
coincides with the point #’, of the line AB. As it is apparent from 
its position on the line AB, this complex \ can represent six differ- 
ent equilibria, viz. either one of the monovariant ones (/,)= F, + F,-++ 
+ F,,(F, = F,+ #, + #, and(P,) = fF, + Ff, + For one of the 
bivariant ones PF, and FF, or a trivariant equilibrium, viz. the 
phase /’, itself. 
Now we see that the bivariant fields 13 and 14 and the trivariant 
field 2 occupy all spaces in the ?,7 diagram and that none of those 
fields covers one of the curves (2), (5) or (4). 
Consequently in a cyele of the phase /, occur the conversions 
OE 
or in reverse order of succession. Hence it is apparent that the 
phase F, may divide itself directly into the equilibria (8; = 1 + 
2+4 and (4)=1+2-+3. but not into (2)=1-+3- 4 or into 
14 or 13, those three last equilibria may be formed only then, when 
first some other ones have occurred. 
Similar considerations are true for the phase /,. 
Totally different however, it is, when we let the point \V coincide 
with one of the points /’, or #,. When X coincides with /’,, then Y 
cannot represent a mono- or divariant equilibrium, but nothing else 
but the phase #,. The trivariant equilibrium 1 must, therefore 
occupy all spaces in the P,7-diagram. In a eycle of the phase /’,, 
this remains, therefore, unchanged. The same applies to /’,. 
Now we take in the concentration diagram of a ternary system 
a point Y on one of the diagonals, e.g. in fig. 1 (IL) on the diagonal 12, 
we choose the point in such a way that it is situated within the 
triangle 134. It appears from the situation of this point that it can 
represent six different equilibria, viz. either one of the monovariant 
ones (2) = 1345, (8) = 1245 and (5) = 1234 or one of the bivariant 
ones 134 and 145 or the trivariant equilibrium 12. It appears from the 
P, T-diagram that the regions 134, 145 and 12 occupy all spaces and that 
they do not extend themselves over one of the curves (2), (3) or 
(5). In a eyele of this complex X occur, therefore, the conversions: 
12 = (5) — 134 — (2) — 145 (3) — 12 
in this or in the reverse order of succession. 
