( 807 ) 
d 
smaller volumes than + —0. The course of the other isobars only 
av 
undergoes modification as regards the isobars which intersect the line 
d : 
= 0 on the right of the double point. Near the double point posi- 
‚U 
tive isobars are found at this temperature. They come from a point 
on the line ==, at larger volume than the largest that the loop-isobar 
has in common with this line. They are // v-axis on the vapour 
d 
branch of + — 0, then they run back to smaller z, they are again 
Vv 
dp 
dp 
// v-axis on the liquid branch of = 0, and // a-axis on a= 0, 
v 
after which they proceed towards infinity between the last-mentioned 
line and the loop-isobar. So we have again got isobars here as in 
the rigthand part of Van per Waars’ diagram of isobars (Fig. 13). 
X 
Fig. 13. 
ae dp 
When we ascend above the critical temperature, so that ee 0 
Lv 
breaks up into a righthand part and into a lefthand part, this involves 
only that part of the isobars no longer possess the retrograde portion, 
d J 
Because the two points of intersection with = = 0 have coincided, 
i?) 
and then have become imaginary. The last isobar which has the 
shape described here, is that for p =O, the line at infinity included. 
: : dp 
It then runs from the line «=, to the vapour branch of Eel 
5 
