From introduction: "The fact that tetravalent uranium either in the form of solutions of its salts or, in some cases, in the dry state is readily oxidized by gaseous oxygen, has been observed by various investigators. A quantitative study of this reaction appeared to be desirable as a means of learning more about the nature of the ionic species present in uranous solutions. It was also of potential value in determining the importance of autoxidation as an undesirable side reaction involved in the handling of uranous solutions, and, if necessary, in developing procedures for minimizing the reaction."