separated with fuming nitric acid. The sample was then stored to allow the Sr9° to equilibrate with its yttrium daughter, At this stage the yttrium was separated and precipitated as the oxalate for beta counting. sr70 was determined from the counting rate of y7°, and sr89 by counting total strontium and subtracting the Sr°” Reporting. me/mic/mo » 90 result. gr70 and total Bp activity are reported in units of These values were calculated from the original counting data (d/n/aliqiot) using the formule; D mo/mi Jno = d/m/aliquot Frojected ares Total sample volume Aliquot volume x of funnel (ft~) 1 7926 X For the purpose of these calculations "Total sample volume" refers to the volume of the month's rainfall computed from official U. S. Weather Bureau data, (>) The Sr&? values were obtained in the same way but for convenience of comparison, were extrapolated to the first day of each sampling month before calculating the sr°9/50 ratios. FINDINGS The data are completely summarized in Table 1. Total 6 activity, Sr?79 and sr&9/9 ratios and rainfall volumes are listed by station for each samplinz mont date . as . . . . es 7 “SRNR TA 8 at — = - . =u: Los, wt 2 bvecsuse the assiem FF . an Loe . - SR ae ~WTE ™ ~ = SR so ee = Sat Sisg Se aS RRS gr APESegeRE ge enesemeIEEEEPTTEF s . La car he ' ee . . yoo. & . et ~~ * 2 yy A FS a . rs Se a- es, Fee a . o™= May s ene s ~ . > ~~ “Nag, AQ ——-- s