Science: Progress

The crude, primitive atom bomb that wrecked Hiroshima had the force of only 20,000 tons of TNT. The Nagasaki and Bikini bombs, not much improved, are called "Model Ts" by atomic experts. Last week in Manhattan, before a conference of 250 U.S. mayors, Major General Harold R. Bull, attached to the Army General Staff, hinted at something bigger & better: a bomb equivalent to 40,000 tons of explosive. Apparently an improvement of at least 100% is already in the bag.

The general was probably not telling the whole story. Early, inefficient bombs released only about 1% of the "fission energy" of their...

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