. ‘teeamaniesnenpneteresintommeye m= PRIVACY ACT MATERIAL REMOVED @ 3. ‘The constancy ef the mea _s@vex a period of one hour in Table 1 is consistent with of the cloud. ‘Meseurements by weground sere axe not eo eonsigcent and ealculated heights apneax te deczesse ~mith time, prebably due te enincrease in true base werd Movement ef the eloud, data place the top ef the sloud augeriously between 127,000 and 99,000 feet. , 4, She rate of rise of the cloud can be ebtained from Figce I. <It ds to be aoted thet a marked vartical deceleration eccurred at tuo my dminutes, at which tine the eonspicueus lateral spreading eccurred. This | { is in agreement with the observations of C, BE. Palmer exeppt that ectusl a) s@eagurement indicates the "aplashing” eecurred aguinst s barries between * 00,000 and 110,000 fest, which may be ef significance in conection with the usual increase in temperature at sround _bagiven te by 7000 feet, Some ebuervetions i in the &8/%6 jumpling eentro] aircraft are plotted also in Figure 1. *s ebservetion at 40 seconds =! «~ | as the <.); -gloud went by his altitude is in fair agreement with | "@eurv e. ss ae “y nf five At . tes mim 20 ‘wimleo is his observation some tine after “s ebservation is eonsiderebly lower than “a but the ate ? ot mae Oe Ate * a ny of Neadquarters USAF, APOAT1 perder einilar eenditions, but st 30 te 40 neutical alles from ground ez0 at the tine of Ivy King test are shown on Pigure I for scaperison. _ ame Be iegeme ebservations by tt eo, Rp ‘meep is well within the stratosphere, . ’ ae spin,” -, be "The hypothesis put feeward by Professcr C. H. Paluer in his a4 mecond letter ef 2 February 1953 for the secondary fermation ef the mln '* ‘sdarge cloud appears to the author to be plausible but it aleo appears equally “npertain that the bulk of this main eloud ended up in the botunen “»@O0 and 120 thousand feet. Ihe maintenance of Sts shape and fora sre believed |; we pn rd * -"ale et ‘+o be due to its internal turbulence and unequal heat distribution. : -mupatinate of the degree of mixing of the eesondarily farmed large main with @ peimary column ef auclear debris, if indeed this did act intimately es 2 F4 weccur during rise, is purely harardeus quesework. As far as is know, ne gts tebeexvetions were made for guidance on this aspect of the proble. tt seems es ‘apparent that eempling was gonducted some thousands ef feet below the betten -ef the min cleud, oe statements by some of the pilots ef the F-64 sampling -yaizezeft, appears te confirs. Te ~ “are 4a sttadint hereto an an integral partOf Ode preblena eemosendum from itr, Po MW. Allen to Dre %. De. Urry dated 11 December 1952,° =<‘ Glecuasing a well-defined ee cctone OREFate of wine of the cloud vend the energy ef a muclear explosion. . Office of the Techniondirectors “APOAT~; 3 Incls Table 1 {9440 “ . dade " Zz ~_ em ee - we =~ owe .

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