A simple method is described for measuring low oxidation rates at elevated temperatures. The oxidation rate of copper is measured in pure oxygen at five temperatures from 100° C to 256° C and is shown to approach a rate law of the form . The rate of oxidation of copper at 100° C, 139° C, and 169° C is lower in moist oxygen of low relative humidity than in dry oxygen. Annealed copper is shown to oxidize more rapidly than unannealed copper at 169° C, an effect which is believed to be due to an increase in specific surface due to recrystallization in annealing. The oxidation rate curves for a large number of copper alloys, nickel and stainless steel are presented at 194° C, 256° C and 302° C. With the exception of stainless steel, which conforms accurately to the logarithmic law, and nickel, which conforms approximately to this law, none of the metals conforms to the commonly accepted rate laws. The metals conform to an equation of the form where n varies from 2.5 to 4. On the theory that the rate determining process is the diffusion of metal ions in an imperfect cationic lattice, it is pointed out that the Wagner parabolic law cannot be expected to hold for thicknesses such as are generally measured in low temperature studies on copper, because of the space charge near the metal. This fact is probably the reason why the parabolic law is not followed by any of the metals studied.