1005 
curves are then situated with respect to one another as in fig. 1. 
We are able to deduce the position of the three curves also from 
fig. 3 (VIII). Curve (M) == dg, which touches iv in d, represents the 
turning-line of the region (ZZ) == Z, LG. When we let coincide 
d with 7, then ig, ta and ib must touch one another in 7. Hence 
we see also that the position of the three singular curves and that 
of the region (Z, Z,) = Z, LG is in accordance with fig. 1. 
As long as point L is situated in fig. 1 (VIII) at the right side 
of the line GZ,, in figs. 2(VIII) and 3 (VIII) curve ja is situated 
above 76. When, however, in fig. 1 (VIII) Z falls on GZ,, then in 
the figs. 2(VIID) and 3 (VIII) ta and 75 touch one another in 7, but 
za may be situated as well above as below 7b. This appears at once 
from fig. 1 (VIII). 
We may consider the position of Z on the line GZ, as a transition 
case viz. between the case that ZL is situated at the right [fig. 1 
(VIII)} and that Z is situated at the left of the line GZ,. In the 
first case ia is situated above 7b [fig. 2 (VIID), in the second case 
ib must be situated above ia. 
[When we wish to consider this transition more in detail, then 
we have to bear in mind the following. When JZ is situated as in 
fig. 1 (VIII), then in fig. 2 (VIII) curve (Z,) must be situated above 
(Z,). This is only true, however, in so far as we consider points 
of those curves in the vicinity of point 7. It is apparent from fig. 1 
(VIII) that this is certainly true for points on Ld and Lm. At a 
further distance from 7 the curves (Z,) and (Z,) in fig. 2 (VIII) may, 
however, intersect one another. It appears viz. from the direction of 
the little arrows e.g. on curve agb in fig. 1 (VIII) that the pressure 
in a and 6 might be the same. When this is the case, then in 
fig. 2 (VIII) the points a and 6 must coincide and consequently the 
curves (Z,) and (Z,) have a point of intersection. | 
II. Both the curves La and Lb are situated in fig. 1(VIII) at 
the right side of he line GZ, The equilibrium (J/) is, therefore, 
metastable, except in the point ZL. 
Now we imagine in fig. 2 (VIII) to be also drawn the metastable 
(M)-curve. It appears from fig. 1 (VIII) that the (J/)-curve must be 
situated above curve (Z,) and this curve above curve (Z,). Those 
three curves must then touch one another in 2. The position cf the 
three singular curves and of the region (Z,Z,) = Z,LG is then in 
accordance with fig. 2. 
Now we imagine in fig. 1 (VIII) the liquid Z on the line GZ,, so 
that Lande coincide. Then we have the variable singular equilibrium : 
(i) = ZEG 
