( 868 ) 
volatile component (hexane resp. cyclohexane) at the corresponding 
temperature. These values have been obtained by graphical interpola- 
tion from SypNey Youne’s results‘). The fifth column at last gives 
the difference between the vapour pressures of the pure substances 
and of the three-phase system. This column clearly sets forth the 
perfect parallelism of the two vapour pressure curves, which gives 
a further support to the accuracy of the given measurements. 
Here too the data for temperatures above the critical end-point 
refer to the two-phase pressures of mixtures of the critical con- 
centration. 
TABLE AL 
Cyclohexane + aniline. 
Temperature of the critical endpoint 319.09. 
dp 
AT for the plaitpoint line 166 atm. per degree. 
i | di : 
p in mm. CP in mm| ? cyclo | 
Pt 
of mercury of mercury hexane 
| | 
23, 90.65 89.4 | +1 25 
4.30 | 
25.50 100.45 Pasay | 4.95 
4 37 
27.80 110.50 109.3 1.20 
5.00 
29.98 121.40 | 120.3 | 1540 
9.19 
31.03 426.85 425.9 0.95 
4.74 | 
31.20 127.65 126.8 | 0.85 
Repeated the next day: 
31.495 | 127.75 126.8 +0 .95 
| 4.74 | 
31-400 1) 127230 196.3 1.00 
4,44 
30.48 | 124.55 123,0 Wel” 4.95 
| 5.07 | 
28.99 117.00 1454 1.50 
| 
27.29 108.00 | 106.6 | 2.30 
| 4.61 
25.61 | 101.15 99.2 1.95 
It appears most clearly from these measurements, first that the 
dp a ne. 
value of = for the three-phase pressure in the critical end-point is 
C 
of a perfectly different order of magnitude from that along the plait- 
1) S. Youre and J. Fortry. Chem. Soc. London 77 p. 1126 (1900). 
