1238 
into that of fig. 3, we should have found above the critical point 
a curve with a maximum and an inflexion point. The curves 
however appeared to run very flat (fig. 6); it was therefore impos- 
sible to ascertain, where the maximum lies, while the inflexion 
point has already disappeared immediately above the critical point. *) 
It still remained to investigate, if a satisfactory result might be 
obtained by determinations of the vapour concentrations. We heated 
therefore a two layer system to boiling, distilled off a part of the 
vapour and determined the solution point of the distillate in order 
to find the concentration thereof. 
First of all, we wanted the determination of the whole solubility 
curve, which we carried out by the well-known synthetic method in 
sealed tubes. Our results (table 3 and fig. 7) differ from those 
obtained formerly by Rorumunp; our critical point lies 2.5° lower. 
Doubtless this difference is to be explained by difference in purity 
of the substances; in the first place we think’ of traces of water. *) 
620 
600 
580 
0 10 20 30 40 TRT OEL 90 100 
Fig. 5. 
1) Cf. the system phenol-water investigated by ScHREINEMAKERS, Z. f. phys. Ch 
35, 459, 1900. 
2) We found experimentally, that the solution point is increascd 0.7° by addition 
of 1 %/o9 water. 
