1689 
When #5, is the last phase of group 7, then the last sign of 
series /£ (table 2) changes. The last eurve of group 7’ no more 
goes then towards lower, but towards higher temperatures, it does go 
however still towards lower pressures. The corresponding curve of 
the sub-group 7, consequently the curve, which is situated the closest 
to (A,), turns therefore, in fig. 3 within the second quadrant. The more 
the phase /’, goes towards the left, the more curves of the sub-gronp 7’ 
turn within the second quadrant, when /, coincides with the first 
phase of group 7, then in fig. 3 this whole sub-group 7’ takes its 
place within the second quadrant. 
As soon as the phase #), comes within the group C, a part of 
bundle C turns within the fourth quadrant ; when F, coincides with 
the first phase of group C, then the whole bundle C is situated 
within the fourth quadrant. 
At further movement of the phase #, first some and at last all 
curves of bundle S come within the second quadrant, afterwards 
some and at last all curves of bundle B within the fourth quadrant; 
afterwards some and at last all curves of R within the second 
quadrant. When F', coincides with A,, then curve (A) goes towards 
the fourth quadrant, and when F, coincides at last with A,, then 
also curve (A) goes within this quadrant. 
The displacement of #, from right to left involves, therefore, that 
the P,7-diagram changes; the curves turn viz. from the third qua- 
drant towards the second and from the first quadrant towards the 
fourth quadrant. Only the curve (A,) remains in the first quadrant. 
In all there arise, therefore, n + 2 different P,7-diagrams, which 
belong all, however, to the same type. 
Consequently it is apparent from the previous considerations: the 
series of signs of reaction (21) defines the P,7-diagramtype; viz. 
the number of bundles of curves and their order of succession; the 
number of curves and their order of succession in each bundle. It 
defines also which curves go in the same direction of pressure starting 
from the invariant point. This series of signs does not define, however, 
the partition of the bundles over the different quadrants and therefore 
also not which of the n+ 2 different P,7-diagrams, belonging to 
the type, will occur. In order to define this, we have to know 
also the series of signs of reaction (22). 
In our previous considerations we might have taken instead ot 
the series of signs of the isentropical reaction also that of the iso- 
volumetrical reaction. This is as we have shown in communication 
