( 812 ) 
the first-mentioned point of intersection, which continues to distin- 
guish the figure from the figures given by us. At still lower ese 
rature the two points of intersection with the liquid branch of ? 0 
Vv 
may coincide. It is true that this clashes with the thesis concerning 
d; 
the contact of P — Oana? =0, mentioned in the beginning of 
& av 
the previous communication, which gave rise to this investigation, 
but then this thesis holds only if 6 is a linear function of « 
and in this case the said point of intersection on the right does 
not make its appearance. If the two points of intersection have 
coincided, the loop-line and the closed rings at small volume have 
disappeared and only those at large volumes remain. (fig. 17). It is, 
however, also possible that the points of intersection continue to 
exist down to the absolute zero point, viz. when a minimum anda 
maximum occurs in the critical pressure. That this is possible for a 
quadratic function for b is shown by fig. 18, if we bear in mind 
Fig. 18. 
that a and so the critical pressure never become zero now. In this 
case the points of intersection in the liquid branch continue to exist 
down to the lowest temperatures, their limiting situation is the value 
for # at which the critical pressure is stationary. 
With this exception and with those exceptions which arise by the 
dp Soe 
modified course of fae this diagram and ours harmonize. 
2 
In a following communication I hope to show that so long as 
no maximum critical temperature occurs, no other diagrams of isobars 
but those discussed are possible in the realizable region (also the 
unstable one) for whatever values of a, 6 and a,, we combine. 
