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Dang unions could have caused us to lose the war.

There was a great deal of theorizing, calculating, discussing, and changing of plans. There was a great deal, too, of piling and repiling of graphite bricks, hence the name pile for the uranium reactor. On the final day of trial Fermi, Compton, Zinn, and Herbert Lawrence Anderson (1914-1988) stood in front of the control panel located on a balcony ten feet above the floor of the court. Here stood George L. Weil (1908-1995), who was to handle the final control rod which held the reaction in check until it was withdrawn the proper distance. Another safety rod, automatically controlled, was placed in the center of the pile and operated by two electric motors which responded to an ionizing chamber. When a dangerously high number of neutrons were escaping, the gas in the ionizing chamber would become highly electrified. This would automatically set the motor operating to shoot a neutron-absorbing, cadmium-plated steel rod into the pile. As an added precaution an emergency safety rod call Zip was withdrawn from the pile and tied by a rope to the balcony. Horace Van Norman Hilberry (?-1986) stood ready to cut this rope if the automatic rods failed for any reason. Finally, a liquid control squad stood on a platform above the pile trained and ready to flood the whole pile with water containing a cadmium salt in solution.

Fermi started the test at 9:54 am by ordering the control rods withdrawn. Six minutes later Zinn withdrew Zip by hand and tied it to the rail of the balcony. At 10:37 Fermi, still tensely watching the control board, ordered Weil to pull out the vernier control rod thirteen feet. Half an hour passed and the automatic safety rod was withdrawn and set. The clicking in the Geiger counter grew faster and the air more tense. "I'm hungry. Let's go to lunch," said Fermi, and his staff eased off to return to the pile at 2 o'clock in the afternoon. More adjustments, more orders, and at 3:21 Fermi computed the rate of rise of neutron count. Then suddenly, quietly, and visibly pleased, Fermi remarked, "the reaction is self-sustaining. The curve is exponential." Then for 28 more minutes the pile was allowed to operate. At 3:54 P.M. Fermi called "OK" to Zinn, and the rod was pushed into the pile. The counters slowed down. It was over. The job that came close to being a miracle was completed. December 2, 1942 marked the first time in history that men had initiated a successful, self-sustaining nuclear chain reaction. Only a handful of men surrounding Enrico Fermi knew that on this wintry Wednesday afternoon mankind had turned another crucial corner.

The Story of the Atomic Bomb

Control of atomic fission and development of the atomic bomb marked the coming of age of US physics as dominant not just over Europe, but also over chemistry and other sciences. In just a few decades, physics had moved from the discovery of subatomic particles to unlocking vast power from that discovery and from a cascade of scientific discoveries that ensued. As much as the 20th Century was the American Century, it was also the Physics Century, and America’s scientific and technological strength continuing to depend on our strength and discoveries in physics.

David Hill, a young physicist from Corinth, Mississippi, and working on his undergraduate degree from UC Berkley, was a member of Fermi's staff and was there when Fermi demonstrated nuclear fission for the first time. One of his classmates from Corinth was a B-29 pilot flying from Tinian was killed over Tokyo in May of 1944. The Class of 1937 was brilliant, even in rural America.