( 878°) 
line have been derived from our preceding communication ; those 
concerning the vapour-pressure-lines are spread in the literature ; we 
have referred to the original in every case. The cases of splitting 
up are marked by an S, those of retreat by an /, lower critical end- 
points by an £. The sign X indicates that the concentration of the 
vapour phase falls outside that of the liquid phases. A note of inter- 
rogation marks doubtful cases. We have also inserted the only case 
known of a minimum vapour pressure being attended by unmixing; 
as is known it is almost certain that for these systems there exist 
compounds between the components. 
§3. The last point we want to discuss is the occurrence of points 
of inflection in the p,z-line specially in the neighbourhood of a 
critical endpoint. As has been set forth at length by KUENEN*), in 
the critical end-point these lines possess a point of inflection with 
horizontal tangent. So above the critical end-point (we suppose it to 
be an upper mixing-point) there will continue to exist a point of 
inflection in the neighbourhood of the critical concentration, but the 
tangent is no longer horizontal in this point of inflection. This shape 
of the p,a-line is in close connection with a similar shape of the 
boiling-point or the melting-point lines in the neighbourhood of a 
critical end-point. With regard to the shape of the melting-point 
lines we possess important systematic investigations by FrASCHNER 
and RANKIN *). 
Concerning the boiling-point and the vapour tension lines of this 
TABLE MIL 
Temp. of the crit. end-point. 
System fie Ts Observer 
oe oF ©, ,D. Konowatow. Drudes Ann. 10 
Amylene + aniline eo 18 1 || p. 360 (1902). 
Isopentane+dichloroacetic acid <0 0 EE oe J. de Ch. pis 
Hexane + aniline [68.9 | 73.4 
| This communication. 
Cyclohexane + „ (SLB) SAE 
| | ~ 
Hexane + methylalcohol | 43 | 43.8 that Z. ph. Ch. 71. p 
i | ae -{ 9 |) F. A. H. SCHREINEMAKERS. Z. ph. Ch. 
Water + phenol | 68 ND 1 “35. p. 456 (1900). 
» + acetylacetone | Of 91.2 | 
| | SCHUKAREW. 
» + nicotine E60 | 59 6 | 
1) Verdampfung und Verflüssigmg von Gemischen. Leipzig Barth 1906 p. 170. 
2) O. Fiascuner and J. G. RANkin Monatshefte f. Gh. 31 p. 23 (1910). 
er tr en 
