The density, refractive index, magnetic susceptibility and viscosity of Aniline, three other substituted anilines and benzene, and of nine sets of binary mixtures made up from pairs of the five pure liquids have been measured at a temperature of 25?c, benzene being a component of all mixtures, and property composition curves have been constructed in each case. The results show that none of the mixtures is ideal. Deviations from the curve constructed from values calculated from the simple mixture law are shewn graphically for every property for each mixture examined, with the exception of magnetic susceptibility where the deviation was too irregular. It is noticed that the property viscosity gives deviation values which are distinctly greater than those of denisty and refractive index. The property magnetic susceptibility in the cases of Benzene-Aniline and Benzene Diethylaniline seems to give deviations which resemble those?of the property viscosity for these mixtures. In the case of Benzene and Monoethylan-ine the trend of the deviations does not seem marked enough to enable one to draw any conculsions from it. In the case of Benzene and Methylaniline, on the other hand, there is practically no deviation from the calculated values. Of the anilines used, the diethylaniline with Benzene gave the greatest deviation values for density and refractivity, but this mixture gave the lowest viscosity deviation value. The position of maximum deviation is similar in density and refractivity composition curves. The specific heat and heat of mixing curves were only completed for one set of mixtures as it proved a great difficulty to eliminate experimental error and the results were rather uncertain. In the case of heat of mixing the maximum seems to he nearer the benzene end of the series than the aniline end. The results indicate that co-ordination occurs at least to some extent between benzene and the anilines considered, on mixing, but that no definite compounds appear to have been formed.<p
