1310 
From this follows: if we intersect a cluster of complex distillation 
curves by a conjugation line solid-liquid, the tangents in these points 
of intersection form a cluster of straight lines which all pass through 
the vapour point appertaining to that conjugation line. Further, it is 
evident that the vapour distillation curve representing the vapour 
distilling over at each moment is the vapour saturation line of / 
under its Own vapour pressure. 
We can now demonstrate that a complex distillation curve turns 
in each point its convex side towards the correlated vapour point 
and that a definite point will be a point of inflexion if the tangent 
which passes through this point meets the vapour saturation line 
of F under its own vapour pressure and if this latter point of 
contact is not itself a point of inflexion. 
If we intersect a cluster of complex distillation curves by a 
conjugation line solid-liquid, then as we have seen previously, the 
tangents in these points of intersection all pass through the vapour 
point correlated to this conjugation line. If now, in the proximity 
of this vapour point the vapour saturation curve under its own 
vapour pressure is situated outside the three-phase triangle none 
of the above mentioned points of intersection will be a point of 
inflexion. 
We can imagine a curve transmitted through the points of inflexion 
of the complex distillation curve, which we will call the point of 
inflexion curve; this curve may be found in the following manner, 
We draw to the point X of the vapour saturation line under its 
own vapour pressure a tangent; the point of intersection of this 
tangent with the conjugation line solid-liquid appertaining to the 
point X we will cail S. If now the point X traverses the saturation 
curve under its own vapour pressure the point S will traverse the 
looked for point of inflexion enrve. 
This point of inflexion curve always passes through the points 
M, and m, of the vapour saturation curve |Fig. 7 (D, 11 (D, 12 ()] 
and if we can draw through /’ a tangent to this vapour saturation 
curve also through the point £. For our purpose, only the part of 
the point of inflexion curve which is situated within the heterogeneous 
region has any significance, that is in so far as it intersects the 
conjugation line solid-liquid between the points indicating the solid 
substance and the liquid. 
In the points of intersection of the saturation curve under its own 
pressure with the point of inflexion curve, the conjugation line liquid- 
vapour meets the vapour saturation curve. 
In the proximity of a maximum or a minimum point of the three- 
