416 SALTER Table 3—-STRONTIUM-930 CONCENTRATIONS AT 34°S IN 1962 AND 1963 Altitude, 1000 ft Sr concentration, dis/min per 16° scf ~ Total 1961 U.S.S.R. Maximum from 55-Mt test Starfish February—July 1962 50 60 70 80 90 105 10— 30 60—110 60— 80 40—90 30—40 10— 20 ~] ~] * * * ? * * * * * * September 1962 63 78 90 100 110 55 20 20 <10 * * ? * * * * * December 1962 63 78 130 80 20 <10 ~2 <2 * * 105 100 30 ~2 20 ~1 <3 <2 * 20 30 <2 10 * <1 10 30 30 ~] ~1 <1 20 20 2 20 89 25 * <3 * April 1963 77 91 104 75 120 130 ~2 10 40 May 1963 66 104 115 130 30 80 June 1963 67 17 86 130 620 600 30 450 500 October 1963 68 80 380 370 250 250 *Negligible. sible to assign a considerable fraction of the ?°Sr attributedhere to the 1961 series to these later tests; and, if it was 32, all of it. It is of interest to estimate what the major source of the debris that was assigned to the 1961 tests might have been. The detonations which reached into the lower stratosphere listed in the first line of Table 1 may account for the 1961 debris below 70,000 ft at 34°S, but they are unlikely to be the source of material observed at the higher