The great similarity in the chemical properties of the rare earths has limited the application of the familiar reactions of analytical chemistry in the analysis of this group of elements. A number of physical and physico-chemical methods have been developed and of these the spectrophotometric method has possessed the greatest general utility. In connection with the studies on the separation of the rare earths by means of the ion-exchange column technique (1, 2) the spectrophotometric method was found inadequate for some of the necessary analytical work, namely; (a) the determination of small amounts of the respective elements below the concentrations detectable by the spectrophotometric method, and (b) the determination of large amounts of those members of the group which possess no absorption bands in the region 2200--10,000 Angstroms. An investigation of other physical methods which might yield the above information led to the development of satisfactory emission spectrographic methods which are described herein
