B. Mechanical injuries, also remarkable for the wide area in which suffered.
C. Effects resulting from penetrating gamma radiation. The effects from radiation were due to instantaneous discharge of radiation at the moment of explosion and not to persistent radioactivity (of either fission products or other substances whose radioactivity might have been induced by proximity to the explosions).
The effects of the atomic bombs on structures and installations were of two types:
A. Destruction caused by the great pressure from the blast; and
B. Destruction caused by the fires, either started directly by the great heat radiation, or indirectly through the collapse of buildings, wiring, etc.
4. The actual tonnage of T.N.T. which would have caused the same blast damage was approximately of the order of 20,000 tons.
5. In respect to their height of burst, the bombs performed exactly according to design.
6. The bombs were placed in such positions that they could not have done more damage from any alternative bursting point in either city.
7. The heights of burst were correctly chosen having regard to the type of destruction it was desired to cause.
8. The information collected would enable a reasonably accurate prediction to be made of the blast damage likely to be caused in any city where an atomic explosion could be effected.