1179 
and when we take firstly consecutively the positive groups and then 
the negative ones |consequently in series 18 the order of succession: 
ABCDRSTU, this is in accordance with fig. 8 (V) |. 
We can also take the order of succession of the groups, without 
taking the sign into consideration [consequently in series 18 the order 
of succession: ARBS...| Then we consider in the P,7-diagram not 
only the stable —, but also the metastable parts of the bundles 
[Consequently in fig. 3 (V) the order of succession of the bundles 
is ARBS....; Now we may say: in the P,7-diagram the bundles 
succeed one another in the same order as the groups in the series; 
the positive groups indicate the stable parts, the negative ones the 
metastable parts of the bundles. 
In each of the bundles the curves succeed one another as in the 
corresponding group of the series. 
2. We know the type of the P,7-diagram and we seek the 
corresponding type of the concentration-diagram, therefore, two reaction- 
equations between the phases. 
For this we firstly define the series of signs, which corresponds 
with the P,7-diagram; this is easiiy found after the above con- 
siderations. As by this only the signs of the coefficients of (1) are 
given, we may satisfy this reaction, therefore, in infinitely many 
ways. Equation (2) is also still to be chosen quite arbitrarily, on 
condition that (3) only is satisfied. Consequently we find an infinite 
number of solutions, which satisfy all, however, the same conditions 
and which form together the type of the concentration-diagram. 
Consequently the type depends on the series of signs, so that we 
may consider the series of signs as a representation of the type of 
the concentration-diagram and of the /,7-diagram. 
We shall refer with an example to this deduction of the type of 
the concentration diagram. 
We shall apply those general considerations to some definite cases. 
We have taken in communication IV as an example (reactions 13 
and 14) of 2 reactions in a septuplepoint: 
OSR ASIL ok dy ei ee 20) 
and PR TSA a ZE 
and we have found for the corresponding type of the P, 7-diagram the 
symbolical diagram 20 (IV) or fig. 1d(V). We shall deduce this 
diagram following the method indicated above. As in both the equa- 
tions (20) and (21) one phase is missing, we are not allowed to 
apply to it without more our previous considerations ; for this reason we 
