The locations of the canisters relative to data. The historical records 26 of the mission by the Army Air Corps, the operational group formed both incomplete and inconsistent. For example, the burst have been elusive the 509th Composite Group of to deliver the weapons, are the crew members” logs, in particular included. mission in those of the bombardiers, and the debriefing notes are not A crucial fact, the aircraft altitude, is given for the Hiroshima the strike report26 as 30 200 ft, in the historical narrative 26 as 31 600 ft, and in Parsons- loglo as 32 700 ft. Upon discovery of the navigator-s log on the inside covers of Marx-s book,16 many of the inconsistencies were resolved: the true altitude is given there as 31 060 ft, possibly a transposition. Correction of the indicated pressure altitude gives a value of 32 200 ft, in reasonable agreement with Parsons” log or the 31 600 ft. An interview by J. A. Auxier and L. J. Deal with General Sweeney (then Major), who piloted the instrumentation aircraft from which the canisters were dropped, resolved the problem of the aircraft spacing in the formation.* Uncertainties which still remain include the time from “bomb away” or release tone to parachute deployment, the true altitude, and the gage calibrations. A summary of the missions is given in Tables I and II.