TEST A: EXPLOSION IN AIR 



closely in the light of all information now available and 

 releasable. What the eye took in was relatively incon- 

 seqnential, but the complete sto-ry revealed by the pha- 

 lanx of instruments is a tremendous one. To analyze it 

 fully will require hundreds or even thousands of man- 

 years of effort by army and navy engineers. 



For simplicity, we shall use Zeropomt hereafter to 

 indicate the actual position of the bomb at the instant 

 of detonation (Mike Hour) ; projected Zeropoint re- 

 fers to the point on the Lagoon surface directly be- 

 neath the Zeropoint. 



SHOCK- WAVE VELOCITY 



From the detonating bomb the spherical shock wave 

 in air spread rapidly. High speed cameras clocked its 

 expansion. Very close to the bomb the shock wave ve- 

 locity was extremely great, undoubtedly more than 

 three miles per second, or 10,000 miles per hour. No 

 bullet or rocket has ever approached this speed. 



Even by the end of the first tenth of a second the 

 shock wave had slowed considerably. Before one sec- 

 ond had passed, it struck the water and forced the 

 surface down several feet throughout a wide area. The 

 shock wave reflected from the surface of the water now 

 joined the direct wave ; the merged wave then expanded 

 at very high speed, whipping the surface of the water 

 into shimmering fury. Many of the air-borne cameras 



109 



