-22MEV Y peak was considered to be from Co?!” The two cobalt separation methods and the subsequent vanadium separations were made on the pH 3.3 l-p fraction. The re- sults were similar to those for the pH 3.3 c-h samples. The above results indicate that Co’ (170,000 afm), Co™ (162,000 d/m), and Co®° (32,200 d/m) comprise this fraction. All subsequent studies on cobalt in samples from the Pacific Proving Ground by means of cationic and anionic exchange resin techniques, chemical and Y spectrometric methods, and byobser- vations of decay rates support this conclusion and will be dis- cussed later in this paper. The third peak in the second elution curve occurred at pH 3.4 (Fig. 1, inset). respect to the The ¥ P activity in the fraction was low with activity and had a maximum energy of approxi- mately 1.0 MEV (range 410 me/em* aluminum), a pronounced peak at .84 MEV (Fig. 5). The Y Both the spectrum had B and 7 char- acteristics of the fraction are identical with those of Mn?4 balt separations on the fraction done by both the naphthol and the Los Alamos methods did not have significantly above background, Co- @ -nitroso- PB B: or J activity Chemical separation for Mn? (Meinke, 1949) was not done on the fraction containing Min, How- ever, subsequent chemical separations on other samples containing the .84 MEV 7Y peak have given positive Mn>4 separations and will be discussed later, The ashed resin from the second elution experiment on clam kidney sample I also contained only Min 24 (Fig. 5).