The following report follows a series of experiments on the freezing points of 25 UN-H2O-HNO3 solutions.

Because of the relative simplicity of the X-Ray spectra and recent improvements in instrumentation, analytical applications of X-Ray of spectrography are becoming very popular. The method us applicable to both qualitative and quantitative determinations of all elements heavier than sodium. Elements in multicomponent systems, such as alloys and minerals, and elements such as, W, Pt, Nb, Ta, Hf, Zr, and the rare earths, which are difficult to separate or determine by other methods, can usually be determined directly without special sample treatment. The method is rapid and precision is comparable to wet chemical analyses. It is applicable over the very wide concentration range from parts per 10,000 to 100 percent, and can be applied to the analysis of all kinds of samples- metals, drillings and thin films, powders, glasses, or liquids. The method is described and its advantages and limitations are discussed. Typical analyses are mentioned and sensitivity limits for determination of the various elements are illustrated as a guide to possible uses of X-ray spectrography.