The Making of the Atomic Bomb: 25th Anniversary Edition

by Richard Rhodes

Ernest Lawrence’s monumental effort had succeeded; every gram of U235 in the one Little Boy that should be ready by mid-1945 would pass at least once through his calutrons. Conant also contrasted his assumptions of June 1944 with his assumptions at the beginning of the new year to draw up a problematic balance sheet: while he had previously “believed a few bombs might do the trick” of ending the war, at the beginning of 1945 he was “convinced many bombs will now be required (German experience).” The German experience was probably the determined German resistance that was prolonging the war in Europe, particularly the counteroffensive through the Ardennes known as the Battle of the Bulge that had begun in mid-December and still threatened Allied lines at the time of Conant’s notes. It was partly Allied frustration with such continuing resistance that would lead in another month to the atrocity of the Dresden bombing.