A previous study on the physical properties of (1-alcohol + n-alkane) has established a correlation between dielectric permittivity at 1 GHz and excess molar Volumes V-E for all binary systems that were studied. In order to determine whether this behaviour is similar at lower frequencies, relative permittivity epsilon' was measured at 100 kHz. The refractive index n(D) was measured to explore the effects at higher frequencies. Mixtures under study are in particular the systems (n-hexane + 1-pentanol, or 1-hexanol, or 1-heptanol) at T = 298.15 K and atmospheric pressure, over the entire composition range. From the experimental values, the corresponding increments of relative permittivity and refractive index were computed using polynomials of variable degree to fit the data. The results obtained for relative permittivity and refractive indices were used respectively to test the influence of molar volume on the prediction of various theoretical models for permittivity and various equations for refractive index. Both properties are expressed as functions of volume fraction of the mixture components.