The study of the oxidation of Cu and Fe by continuous recording of weight gain is described. Equations are given for the rates of oxidation at several temperatures of the metals, both uncoated and enamel‐coated. Uncoated Cu was less strongly oxidized than uncoated Fe, but coated Cu was more strongly oxidized than coated Fe. The presence of CoO in the coating caused no significant difference in the action of the enamels on the metal