1207 
solutions of the same temperature and the same vapour pressure, and 
saturated with 4 
Of all straight lines which unite two such correlated points of 
the two branches one is sure to pass through the point £. If now, 
we allow the line ZZ, of fig. 1 to coincide with the above men- 
tioned connecting line, we then find two solutions situated at different 
sides of 7, which have the same temperature and the same vapour 
pressure. The branches FZ and FZ, of fig. 4 then must intersect 
each other at that temperature and pressure. 
Vv <v. The melting point line Al of fig. 4 now proceeds from 
the point /’ towards lower temperatures and higher pressures; the 
point / of curve ZFZ, now gets situated between the point with 
a maximum temperature and that with a maximum vapour pressure. 
To each of the solutions of the line ZZ, of fig. 1 saturated 
with solid /’, appertains of course a definite vapour; the points 
representing these vapours form a curve which we will call the 
vapour line conjugated with the line ZFZ,. It is evident that this 
vapour curve conjugated with Z/Z, must pass through the point 
Dof fig. 1. If the line Z#Z, is turned, the conjugated vapour curve 
will also alter its position and form, but still pass through the point 
D. In fig. 5, the vapour curve conjugated with ZHZ, is represented 
by the dotted curve ( fca De). É 
In fig. 5 it is assumed that the straight line ZFZ, and its con- 
jugated vapour curve intersect each other in a; that such a point 
of intersection can appear is easy to understand. On each of the. 
boiling point lines of fig. 1 occurs a point where the tempera- 
ture along this curve is a maximum and another point where 
er it is a minimum. If now we 
take the vapour phase apper- 
taining to a similar” solution, 
this with the liquid and the 
point £, will lie on a straight 
line. We now draw, through 
a similar liquid 5 with a maxi- 
mum or minimum temperature, 
the line ZFZ, (fig. 5); the 
vapour « which is in equili- 
brium with this liquid 4 is. then also situated on the line ZFZ. so 
that the vapour curve fe must intersect the line ZZ, in a. With 
each liquid of the line 67, is now in equilibrium a vapour of curve 
ae, such as liquid d with vapour e, liquid # with vapour D, liquid 
6 with vapour a. With each liquid of line baZ a vapour of curve 
Fig. 5. 
