I viewed the test, with the Coordinating Committee expedition, from a point about twenty miles away. At the instant of the explosion I was looking directly at it, with no eye protection of any kind. I saw first a yellow glow, which grew almost instantly into an overwhelming white flash, so intense that I was completely blinded. There was a definite sensation of heat. The brilliant illumination seemed to last for about three to five seconds, changing to yellow and then to red; at this stage it appeared to have a radius of about twenty degrees. The first thing I succeeded in seeing after being blinded by the flash looked like a dark violet column several thousand feet high. This column must actually have been quite bright, or I would not have been able to distinguish it. By twenty or thirty seconds after the explosion I was regaining normal vision. At a height of perhaps twenty thousand feet, two or three thin horizontal
