( 802 ) 
dp d : 
no point of intersection of “ =0-and 0 will occur for very 
v Vv 
low temperature in the region on the right of z,. For, as VAN DER 
Waats has demonstrated (These Proc. June 1908) for such a point 
of intersection the equations 
da dai" 
be 
ab ae Ye dz dz 
Wi ee ES 
v v db db 
DE ai ; 
zr a 
(1) 
db 
co 
dz 
9 = — 
da 
dx 
hold, so for very low temperature a point of intersection is only 
; da 
possible in the neighbourhood of an 2, where either — — 0 or the 
Lv 
critical pressure is stationary. Both these possibilities, however are 
not realised here, for as we shall show later on, a minimum critical 
temperature at the same time with a’,, >> a,a, is only possible for 
a relative position of the lines a and 5 as indicated in fig. 11, i. e. 
Fig. 11. 
da db 
the point a, on the left of 6, and eN on the right of en 
x x 
Now for 6, and h, the critical pressure is infinite, for a, and a, it 
