835 



The three binodal lines for solid-fluid indicated in tiie two (igiires 

 correspond to the equilibria marked by the same letters in figs. 9a 

 and b. It will be clear from what has been discussed that the point 



Fig. 9a. 



Fig. 96. 



dP 



wiiere — , =: oo, may lie both at higher and at lower pressure than 

 dT 



P, '). This point corresponds to a nodal line (FG) passing through 



*S in figs 8(7 and Sb. On still further displacement the binodal curve 



for solid lies outside the longitudinal plait. Then the point of contact 



can appear at higher temperature; in figs, da and b such a point 



of contact is indicated by M. The situation of the three-phase line 



passing through Af has been found experimentally by Büchnkr in 



the system diphenylamine-carbonic acid "), by Ad.\ Prins in the system 



ethane-naphtalene '). 



7. The transition of the systems with quadruple point SL^ L^G 

 to the type diphenylamine-carbonic acid has been derived in the 

 preceding paragraph by the aid of the rules given in § 2. The shape 

 of the binodal curves is indicated by them, however, only in the 

 neighbourhood of the points of intersection. The course throughout 

 the region, which is remarkable especially in the covered i-egion, 

 could be dispensed with in the above discussion. A full insight can 

 only be obtained by considerations on the course of binodal lines 

 solid-tluid in general. For this the discussion of some loci on the 

 ifj-surface is required. 



{To be continued.) 



November 20^1' 1918. Delft. Technical Higkschool. 



1) At lower temperatures this point lies in the covered region ; it will appear on 

 a fuller treatment of the transformation that the displacement of this point follows 

 easily from the transition of the two three phase lines SLjLo and SLjG into each 

 other (unstable ridge), and the change in this on approach to the critical endpoint. 

 These changes may also be directly examined by the aid of the rules of § 2. 



2) BiicHNER. Thesis for the Doctorate. Amsterdam. 1905, p. 85. fig. 36. 

 ' ») Ada Prins. These Proc. XVII p. 1095. 



