Density data are reported on 15 saturated hydrocarbon liquids in the rangeof 35? to 250?F. and 1000 to 8220 lb. per sq. in. The apparent liquid densitiesof methane and ethane are shown to vary with the density of the system in whichthey are present. A method is proposed whereby the densities of liquidhydrocarbon mixtures containing both methane and ethane in solution may becomputed at elevated temperature and pressures within the accuracy of usualengineering computations. A method of computing the shrinkage of crude oilsbased upon the gas-oil ratio, gas analysis, and crude gravity is outlined. Introduction The densities of naturally occurring liquid hydrocarbon mixtures areimportant in many petroleum engineering computations. Calculation of theshrinkage of a subsurface sample of crude oil as the natural gas is evolved isone example of the use of liquid-density data. Sage, Hicks, and Lacey have presented a method of computing the density ofhydrocarbon liquid mixtures based on partial molal volumes. Katz has indicateda method based on the principle of additive volumes of the components and usingapparent densities for methane and ethane. T.P. 1397