( 515 ) 



If we introduce instead of the radii of curvature R the curvatures 

 K we find 



2K,. = 37^6 - Ks 



im 



For the rest the curve of contact has nothing remarkable in the 

 vicinity of the plaitpoint except that its course there is in a high 

 degree independent of the situation of the vertex F of the cone, if 

 bul this vertex is not too close to the plaitpoint or not too close to 

 the tangent to the spinodal line in the plaitpoint. 



In fig. 2 sOs' represents the spinodal line, 

 bOb' the binodal line, and rOr' the curve of 

 contact of the cone P, or in other words the 

 line of saturation of the solid substance P. As 

 ensues out of the curvatures (IS"» and 18'') of 

 these three lines, these must have a position 

 with respect to each other as in fig. 2. 



If we draw in this figure a line m7ip parallel 

 to and in the vicinity of OP, then np must be 

 equal to 2mn. If namely we calculate av, Xs, a-nd iv^ out of (13), (14) 

 and (15) we find for a same value of y: 



2 {Xl, — Xr) = Xs — Xb. 



In so far as the binodal line has been drawn in fig. 2 the con- 

 jugated pairs of fluids represented by it are metastable; they all 

 break up into the solid substance P and a solution of the line of 

 saturation rOr' . 



In fig. 3 the point P lies on the other side 

 of the tangent in as in fig. 2. Line vOr' is 

 the line of saturation, bOb' the binodal line; 

 the spinodal line has not been drawn. 



In the vicinity of the plaitpoint the line of 

 saturation must be curved, as has been repre- 

 sented in fig. 3, in the same direction as the 

 binodal line. In its further course two or more 

 points of inflection can of course appear. If e. g. P is a ternary 

 solid substance, so that the line of saturation is a curve enclosing 

 point P, then at least two points of inflection must appear, as has 

 been assumed in fig. 3. 



If now we change the temperature or the pressure, then the ^- 

 surface changes according to position and form; point P rises and 

 falls. Now the binodal line and the line of saturation of course also 

 change their form. 



Fig. 3. 



