THIS • ri f ll'l lllllaCOPY X 1-JMC 'f' ' _ ' OF CF 3 c' SWES PAGE ' _ -- TOP BECR T July 16 1945 _ _ CO iTROL S'f OL 5 -11 9 SWP Our group a ssemtled at e point 27 mile frum the bomb Ei 't4I a bout two in the morn1 nr ' 'it were on B plain e xtendinr e 11 the way tc the bomb a nd u lth0ur h l die nut notice cu refully the mountains seemed tc te some miles u vmy - 'le could eee in the distance lights iefininp the pc sitic r of the bomt 8 I d i t about four a m our radio picked up convcrEations between the B-29s and the ground organization fif soon learned thi t zero huur wa s 5 30 a m which was just lirea k of da wh llt turally our tonsene s grev1 as zer r hour a p pro l ched We were m rned of the probable brilliance of the explosion -- so bright it w0uld blind one lookinf directly a t it for FOmetime and there we s even dane er of s · mtuml _ - _ decided the best place to view the flame would be through the wirccow of the car 1 was dttinr in wr ich would take out ultra violet but a t the la st minute decided to get out of the car evidence indeed l wa s excitedl and just as I put my foot on the ground I wa s enveloped with a warm brilliant yellow white lie ht -- from darkness to brilliant sunshine in an instant and as I remember I momentarily wa s stunned by the surprise It took me a second thought to tell myself this is indeed itll and then through my dark sun glasses there was a gigantic ba 11 of' fire rising rapidly from the earth -- at first as brilliant a a the sun crowir g less brilliant as it grew boiling and sw-irling into the heavens Ten or fifteen thousand feet above the ground it wa s orange in color a nd I judge a mile in diameter At higher levels it became purple and this purple afterglow persisted for what seemed a long time possibly it was only for a minute or two at an elevation of 20-25 000 feet This purple glow was due to the enormous radioactivity of the gases The light is in large pa rt due to nitrogen of the a ir and in the laboratory we occasionally produce it in miniature vii th the cyclotron In the earlier stages of rise of the flame the clouds above were illuminated and as the flame rose it was a grand speota cle also to see the great clouds immediately above melt away before our eyes The final phases was the column of hot gases smoke and dust funneling from the earth into the heavens to 40 000 feet The column was to me surprisingly narrow until high elevations were reached when it foamed out considerably The great funnel was visible a long time We could still make it out as we drove a way a half hour later But to retrace a little over two minutes after the beginning of the flash the shock wave hit us It wa s a sharp loud era ck and then ·for a bout a minute thereafter there were resounding echos from the surrounding mountains The pressure of the shook wave was not great enough to be disturbing but the noise was very loud and sharp indeed The noise of h ock • ve e 1 1 B s a she cr'1 fs f6E d'R£J5ED UN CLASSI FIED _ Orlier SecertfJfTl e - - ------ ---' -_ -_ - - I a giant firecracker set off a report of 3-7 mm artillery at a • away - or perhaps like the of about one hundred yards A number of observers near me were looking right at the explosion through welders goggles or the same dark glass 9 lld they tol-d' 1ne the light through these glasses w11 11 so bright as to blind them for an instant• ' ' As l was not actively ooncerned with the problemsJ of Y I had on occasions aeked my colleagues the re what the e-vent would be like and their predicted picture of the event was borne out completely I e m amazed that the whole business went' off so exactly as their calculations had predicted The grand indeed almost cataclysmic proportion of the explosion produced a kind of solemnity in everyones behavior immediately afterwards There was restrained applause but more a hushed murmuring bordering on reverence in manner as the event was commented upon Dr Charles Thomae Monaanto spoke to me of this being the greatest single event in the history of mankind etc eto Ae far ae all of us are concerned although we knew the fundamentals were sound and that the explosion could be produoed we share a feeling that we have this day c ossed a great milestone in human progress• ERNEST LAWRENCE • This was written in an airplan$ and not corrected by the author I I' THIS PAGE REGRADED UNCLASSIFIED · Order Sec Arfj' jYl Gfff --------- -- - I I I - I