The results here may represent the general characteristics to be found in drying oils. Irradiation of relatively fresh films usually initiated greater oxidation, cross-linking, and tensile strength, which effect may continue after irradiation has ceased. In more extensively aged films, irradiation caused a decrease in tensile strength at the breaking point. Irradiation generally results in decreased elongation at break and toughness in both the relatively fresh and the aged films. Gamma and X radiations in amounts of 0.5 to 15 million roentgens from a Cobalt 60 source did not in general have as great effects as those resulting from exposure in a Weatherometer. -- AATA