[en] Transport measurements of lower valent uranium halides require precise determinations of both total U and U⁺⁴. Dissolution of product from a nickel tube while maintaining the oxidation state of the uranium is required prior to determination of both total U and U⁺⁴ by a modified Davies-Gray analysis. Uranium⁺⁴ in the presence of U⁺⁶ can be easily titrated with standard dichromate and an overall precision of +-0.02 mg, at least between 4 and 80 mg in 100 ml of H₃PO₄. A sharp, rapid end-point is obtained by the addition of ferric ion, in addition to the vanadyl sulfate normally used as a catalyst. Nickel ion does not interfere, at least to levels of 4 mg/ml. (Al, Nb, V, Si, and Mn do not normally interfere with the Davies-Gray determination of total U, but have not been investigated)