A Second Trinity

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iitnry Wo ifewsoa In ooafldor&tloa of tho now tott, I haro Interrlswod as largo a frastlon as posslblo of tho poopio Involrod In tho last trluitj, and havo triad to got a piotuipo hoth as to thoir opinions ss to hov saothor t^st should bo run and tho possl* bilitios of obtaining saqporioneod porsonnol. Tho opinion soons to bo asarlx uaaniisoas that oarly noxt siunor a loTitatod gadgot v U l bo availftblo and should bo tostod. This tost should bo suoh as to giYo as nmoh iafonsation as posslblo on tho lovitatod bstsb, aad should eonsofuoatlj bo ooaiplotolj laad-basod. In ordor not to spoil tho saaipling aothod usod b/ tho radio ohsnists sad tho suooossful aothod of aoasuroaoat of alpha duo tho aoasuroBMats of tho ball of flro aad to a lossor oztoat tho higbsr* litheut any partloular study of tho oaginooriim problaaui iavolvod,. it sosas liholy that • to«or botwooa 360 and 900 foot oo«ld bo e«Bstmotod within tho sTsilablo tiao sad would aaswor tho ooaditions of hsi|^ fairly satisfasttrily for AX ooneomod. Soao furthor oousidoratioa will bo nooosssry as to ths aoohaniaga of doposit of nkdlo ootiTlty at Trinity boforo it will bo sorts! a tlMit as iatwuo ssatplos aay bo obtalaod for tho radio ehomists as wsro obtsiaod thoro* If a loTitatod is tostod, it would also bo dosirmblo that tho ooro bo puro plutoaiua ia ordor aot to soaqklisato tho radio ehmsioal dotoraiaatioa by th» asoossity of dotoraialag tho 89 fhoro soosia^to bo ao strwag fsoliag withia tho laboratory that aay groat ohaaco ia tho sohodalo of aoasuroaonts shemld bo aado. Additioas aad itlotitas havo booa suggostod ia rolativoly fow oaoos sad aaoaat ia g sssrml to ohsagos la do tail. An aotual sshtdalo osaaot bo drawa vp boforo group loadors aro appoiatod who w i n bo rospoaalblo for tho warious sots of aoasurviMats* I would sail your attontioa again to ay msittorsndua of Sowoabor $, ia whioh X arguod that any suoh tost should bo sohodulod boforo July !• A tost boforo that data eotad oouat oa a suffioioat kaow^haw of tho toohaiqass usod at Trinity to prooood hawo aado dthor plaas foUowlag that oato aad will probably aot bo awailablo* Aa oxooptioa aay bo aado la tlM easo of ths radio Mthe eaee ef the radi

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chemistry group, none of whom is at present planning to stay much beyond the first of the yearo It is urgently desirable that, if these 2nen aaxmot be retained, the few suitable people not in this laboratory be approached immediatelyo Referring again to my November 5 memorandumt it would appear by exai/iining the Trinity schedule that it will be necessary to haire the teat definitely scheduled and the site selected not long after Janxiary 1, if this proposal is to be carried out* In addition to the land«based meaaia^ementa, whieh are primarily for the purpose of testing the leTltated besab, the test should hare two other parts# Airborne measur^aents of air blast, r«»raye, the growth of ^be ball of fire, and possibly of oi should be made a A sample for the radio chMiists ahotild also be collected frmei the cloud* This work should check and calibrate airborne Instruments so that later teste may be carried out if desirable without a land base ov a towera In addltl^m, the tower should be placed aa close as possible to the water^s edge and apparatua for measuring under--water shook should be testeda If a suitable site essi be found, it should be poaslble to snehor naral Teesela in the Ticinity for damage tests a Such a test might simulate a beaming attack on a fleet Hmtci Henry Va Mewson