Surface temperatures generated by dry sliding friction were measured with the use of an infrared radiometric microscope system developed at Virginia Polytechnic Institute and State University. Silver was used as the test material because of its resistance to oxide formation. The effects of load, velocity, geometry, and environment on surface temperatures, friction, and wear were investigated for the system of silver sliding on sapphire. Results of this investigation indicate that load, velocity, and geometry had significant effects on surface temperature rise, with load having the strongest effect. Measured values of surface temperature rise agreed reasonably well with the theoretical predictions of Archard and Jaeger. Load and environment were found to have a significant effect on the coefficient of friction. The average value of the coefficient of friction for each test was lower in nitrogen than in air. Load, geometry, velocity, and environment were significant to the wear rate. A striking difference was noticed in the structure that formed adjacent to the contact region for the different environments. / M.S.