The density rho of n-octane at temperatures of 298.03 K and 313.15 K and at pressures between 0.7 MPa and 32 MPa have been obtained with a pycnometer. The results, which we estimate have a best-case precision of +/- 7 . 10(-5).rho, are compared with values reported in the literature where the differences are less than +/- 4 . 10(-4).rho. At each temperature and pressure the cell volume V-c was obtained from the mass of mercury required to fill it at T = 293.12 K and p = 0.813 MPa and from the literature values of the mechanical properties of Inconel 625 from which the cell was formed. The volume was also obtained with a mercury-filled positive displacement pump at three temperatures between 298.15 K and 333.15 K and pressure below 30 MPa. The volumes so determined differed by less than 6 . 10(-5). V-c, from the calculated values.