The aim of this work is to complete our studies on physical properties of binary mixtures of alkane+1-alkanols. This work reports densities, refractive indices, speeds of sound and isentropic compressibilities of the mixture octane + 1-butanol at different temperatures, from 288.15 to 308.15 K. From the experimental values, the corresponding excess and deviation values were computed (excess molar volumes, changes of refractive index on mixing, changes of speed of sound on mixing and changes of isentropic compressibilities on mixing). The results were fitted to variable-degree polynomials. Excess molar volumes were compared with the predictions of Nitta-Chao Group Contribution Model.