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A diffusion effect at the gas liquid interface during the determination of pressure viscosity values in a capillary instrument is shown to be a problem. A method to minimize the effects of gas diffusion is proposed. Pressure coefficients for fluids such as mineral oils, 'dumbbell' blends of mineral oil fractions, and paraffinic resin-solvent blends are shown to be independent of pressure at pressures up to at least 3000 lb per square in gravity at a variety of temperatures. Several empirical correlations involving viscosity level, ASTM slope, and density are presented for viscosity-pressure data. The Shell four-ball wear tester and the atomic absorption spectrophotometer have been used for the production and analysis of the wear debris. Temperature conditions at the contact area are varied by using static, slow-sliding, and high speed sliding at the lubricated surfaces. The junction temperature rise has been determined using a chemical conversion correlation between static and dynamic runs. It is shown to be higher than generally used flash temperatures. Chemical reactions are shown to play an important role in boundary lubrication. (Kursetz)