The Bureau of Mines conducted experiments to measure the influence of environment on the friction and wear of a steel-quartz system at several speeds and loads. In each test a quartz block was pressed against a rotating ring of low-carbon steel. Environments used were moist air, dry air, dry nitrogen, water, aqueous oleylammonium acetate (c18h35nh3+-ococh3), and aqueous aluminum chloride (alcl3). The sliding speeds were 2.2, 13, and 33 cm/sec, and the loads were 6.8 and 13.6 Kg. The coefficient of friction, the wear, and the roughness of the surfaces were measured, and the wear debris was examined. The coefficient of friction was significantly lower in moist air at 2.2 Cm/sec than for any other combination of environment and speed employed, and was generally an inverse function of the oxidizing ability of the environment. The coefficient of friction increased somewhat with increasing load. The wear of the steel rings was greatest in dry air at all speeds and loads. The wear of the quartz blocks at 180 rpm was greatest in dry air, but at 12 rpm it was greatest in nitrogen. Friction and wear in aqueous oleylammonium acetate and in aqueous aluminum chloride were similar to effect in water alone.