Lehfeldt's Results

The experiments of Lehfeldt2 show that the vapour pressures of mixtures of toluene and carbon tetrachloride are slightly lower than those calculated from the formula while those of Lehfeldt, of Zawidski and of

Young and Fortey show that the vapour pressures of mixtures of benzene and carbon tetrachloride are somewhat higher.

For toluene and carbon tetrachloride c appears to be a constant, but with benzene and carbon tetrachloride there is a small but distinct variation.

1 Linebarger, " The Vapour Tensions of Mixtures of Volatile Liquids," Journ. Amer. Chem. Soc, 1895, 17, 615.

2 Lehfeldt, " On the Properties of Liquid Mixtures," Part II., Phil. Mag., 1898, [V.], 46, 42.

Table 26

A=Toluene; B = Carbon tetrachloride; c = 2.76; t = 50.0°;

PB/PA at 50° = 3.33

In this case the difference between the values of c and PB/PA is much greater than in the previous ones, but the agreement between the observed and calculate'd percentages is good.

Table 27

A= Benzene; B = Carbon tetrachloride; c = 0.984+ 0.003m ; t = 500°; PB/PA at 50° = 1145