to a rather irregular shape several times as large as the ball. At about two minutes, the blast came. It was remarkably sharp, being more of a "crack" than a "boom". I did not feel any earth shock.
The later stages of motion of the cloud consisted of a slow drifting in the wind, showing the existence of several different wind directions at different altitudes. A current at a few hundred feet carrying the lower part of the "stem" toward the North 10,000 station was particularly striking. The cloud was a different color than the ordinary clouds through which it passed, having a brownish tinge; this could be caused by nitrogen dioxide formed from air by the intense ionization.
The whole spectacle was so tremendous and one might almost say fantastic that the immediate reaction of the watchers was one of awe rather than excitement.
After some minutes of silence, a few people made remarks like, "Well, it worked," and then
