( 517 ) 



A 



If* we lower tlie temperature below 

 1i°, then (lie isolliernis in the vicinity 

 of the three-phase-triangle show a tbrin 

 as in tig. 5. Lines of saturation are 

 also known which lurn in their whole 

 course their concave side to the plait- 

 point of the binodal line; (hey have a 

 form as rr' in fig. 6. 



In the system^): water (C) — ether 

 {A) — malonic acid [P) such a line of 



6 é' 



Fig. 6. 



saturation and binodal line are determined at 15°. 



In the system -) : water (6') — ethylene cyanide (.4) — benzoic 

 acid {P) we find above 51° likewise isotherms as in tig. 6. When 

 lowering the temperature the two curves of fig. H approach each 

 other; at 51° the line of saturation vr' of (he benzoic acid (ouches 

 the binodal line in i(s plaitpoint O. At still lower (emperatures a 

 three-phase-triangle apjiears and the isotherms in the vicinity of that 

 triangle show a form as in fig. 5. 



Also in the systems 0': water-phenol-alkali lines of saturation appear 

 of the type as in fig. 4. 



II B- The line OP has the direction of the a,vis of the parabola. 



We assume OP as j'-axis, then /; = 0, c^ -■= and c^ = 0. So 

 the equation of the curve of contact becomes: 



{d,q-c,U^ + 2d,<iwy + M,qi/ + .... = . . . (19) 



So the curve of contact has in point a node ; therefore it consists, 

 as is drawn in fig. 8, of two intersecting branches rad and r'ab. 



By a variation of parameter (on the ^-surface temperature and 

 pressure come into consideration for this) out of fig. 8 are formed 

 fig. 7 and fig. 9. So fig. 8 is the transition form between fig. 7 

 and fig. 9. 



-J- 



Fig. 8. 



1) E. A. Klobbie. Z. t. Phys. Chcm. 24. 625. 



2) F. A. H. ScHREiNEMAKERs. Z f. Phys. Ghem. 26. 249 (1898). 



Proceedings Royal Acad. Amsterdam. Vol. XIV. 



do 



