1155 
the equation of the straight line 6, 6,. When we put viz. c=2, 
and y= y, then follows from (15) 4,=1 and 4,=0so that S (Az) 
= 0; consequently the line goes through the point 6,. In the same 
way it is apparent that this line goes through the point 6,. When 
the point wy is not situated on the line 6, b,, then 2 (Ax) is not zero, 
but positive or negative, in accordance to the situation of this point 
on the one or on the other side of this line. Now we imagine in 
the figs 1—4 a horizontal line drawn through a; as 6 is situated in 
the immediate vicinity of a, this line goes also, by approximation, 
through 6; we call 7 the point of intersection of this line with the 
line 6, 6,. On this horizontal line in 7 consequently Z (Ax) = 0, at 
the right of » 2 (Az) is > O at the left of r 2 (4x) is < 0. Conse- 
quently when we trace the line 6, 6, in the direction from 6, towards 
6,, then 2 (Av) is at the right of this line positive and negative at 
the left of this line. 
As in figs 1 and 2 the vapour point 6 is situated at the right of 
the line 6,6, consequently (4x) is positive. Therefore, follows 
from (7): 
| EDA hen W(dP)n > AB LA (16) 
which is also indicated in those figures. Hence follows: when we 
trace the three phases-curves (viz. a6c, a,b,c, and a,6,c,) beginning 
at their binary terminating-points (viz. aa, and a,) then the tempe- 
rature decreases under constant pressure and the pressure increases 
at constant temperature. 
In figs 3 and 4 the vapour-point is situated at the left of the line 
6, 6, so that 2 (4x) is negative. Now it follows from (7): 
(ETT A05 eM AAP) Jrg DTZ) 
which is also indicated in the figs 3 and 4. Hence it follows, there- 
fore: when we trace the 3 three-phases-curves, beginning at their 
binary terminating-points, then the temperature increases under 
constant pressure and the pressure decreases at constant temperature. 
We may summarise those results in the following way: 
When we trace the three-phases-curves of the ternary equilibrium 
L, + L,+ G beginning at their binary terminating-points. 
then under constant P the temperature decreases and at constant 
T the pressure increases, when the three-phases-triangle turns its 
vapour-point away from the side (with the binary terminating-points) 
(figs. 1 and 2) 
and under constant P the temperature increases and at constant 
T the pressure decreases, when the three-phases-triangle turns its 
vapour-point towards the side (with the binary terminating-points) 
(figs. 3 and 4). 
