0018933 cedure after preliminary separation of the rare earth group by precipitation reactions and anion exchange (Reference 62). 4. Ca45 was separated by a procedure using precipitation reactions, Ba and Sr were removed by precipitation as the nitrates using fuming HNO; under contrelled conditions. The Ca was recovered from the nitric acid solution by precipitation as the sulfate, The sulfate was then dissolved, scavenged twice with Zr, Te, Fe and La hydroxides, once with basic Mo and Cd sulfides and once with acidic Mo and Cd sulfides. Ca was precipitated as the oxalate for mounting and counting, 5 sr°9 and sr?° were originally separated by precipitation pro- . cedures (References 68 and 64). For the determination of sr?°, the x? was allowed to grow into equilibrium, the SrCO, precipitate dissolved in HNO, centaining Y carrier, Y (OH), precipitated with ammonia gas and the Sr removed as the nitrate in fuming nitric acid. The Y was precipi- tated as the oxalate from an acetic acid solution in the pH range 3-5 and ignited to the oxide for mounting and ceunting. 6. The Cs procedure used for the determination of 65136 and cs!37 was a modification by the original author of a precipitation amd ion exchange procedure (Reference 65), The modification consisted mainly ef a Cs tetraphenyl boron precipitation in the presence of EDTA, theuse of Dowex-50 in place of Duelite C-3 in the cation exchange step and the addition of an anion exchange step. My RENO EEG a @G