Vapour pressures of di-n-propylether + 1-hexanol or + 1-octanol were measured at several temperatures between 288.15 K and 323.15 K by a static method. Reduction of the vapour pressures to obtain activity coefficients and excess molar Gibbs free energies was carried out by Barkerts method. G(E), H-E, and V-E, at 298.15 K, are compared with predictions of the ERAS-model observing that the model reproduces acceptably the experimental behaviour.