( 70 ) 



the situation of the 5-line which we have chosen, is such, that the 

 branch e remains on the right of the points of' three-phase-pressure. 

 From this ensues that if we have construed the p-line in fig. 16 

 correctly, the application of Maxwell's rule to the combination (c, e) 

 must vield a larger pressure for the points 6 than for the points 1 ; 

 but it also follows from this that the pressure for the points 2 

 (combination of a, e) lies between p x and p e — and so p 2 ^> p,- 

 But not all these 12 points are realisable. Every time an unstable 

 branch occurs in the combination the nodes determined by this 

 combination are not to be realised. So the points 3 (combination 



a, d), the points 4 (combination b, d), and the points 5 (combination 



b, e) are not to be realised under any circumstances. Thus already 

 6 of the 12 points are excluded as belonging to unstable coexisting 

 equilibria. Of the remaining 6 points 2 more are excluded, if meta- 

 stable states are set aside. So summarising we determine the following 

 points by means of the combination put by the side of it : 



points combination 



To construe all the points of the binodal curve we should have 

 to treat all the g-lines in a similar way. For the first component 

 (5 = — oo) the ^j-line is the ordinary isotherm, in the same way for 

 the second component (q = + go) the isotherm for this component. 

 So with increase of the value of q such a gradual change of the 

 5-line must take place that it passes from the first shape to the second. 

 With very large volume these extreme shapes may be considered to 

 coincide. This is also the case with all intermediate forms. The modi- 

 fication remains chiefly restricted to the smaller volumes, and in the 

 case of b, = b t such a conclusion would be admissible also for the 

 exceedingly small volumes. So long as the «/-line (see fig. 4 and fig. 8) 

 is still of so low a degree that it does not even pass through the 



lowest point of = 0, the p-line has still the usual shape of an 



dx* 



isotherm. Not before the o-line touches = 0, does a special point 



make its appearance in the unstable branch. For this point of contact 



