The Making of the Atomic Bomb

The third meeting of the new year, on Saturday, January 24, Compton conducted from his sickbed in one of the sparsely furnished spare bedrooms on the third floor of his large University Avenue house: he had the flu. Risking infection, Szilard attended, Ernest Lawrence, Luis Alvarez — Lawrence and Alvarez sitting together on the next bed — and several other men. “Each was arguing the merits of his own location,” Compton writes, “and every case was good. I presented the case for Chicago.” He had already won the support of his university's administration. “We will turn the university inside out if necessary to help win this war,” its vice president had sworn. That was Compton's first argument: he knew the management and had its support. Second, more scientists were available to staff the operation in the Midwest than on the coasts, where faculties and graduate schools had been “completely drained” for other war work. Third, Chicago was conveniently and centrally located for travel to other sites.

Which convinced no one. Szilard had forty tons of graphite on hand at Columbia and a going concern. The arguments continued. Compton, who was notoriously indecisive, suffered their brunt as long as he could bear it. “Finally, wearied to the point of exhaustion but needing to make a firm decision, I told them that Chicago would be [the project's] location.”

Lawrence scoffed. “You'll never get a chain reaction going here,” he baited his fellow laureate. “The whole tempo of the University of Chicago is too slow.”

“We'll have the chain reaction going here by the end of the year,” Compton predicted.

“I'll bet you a thousand dollars you won't.”

“I'll take you on that,” Compton says he answered, “and these men here are the witnesses.”

“I'll cut the stakes to a five-cent cigar,” Lawrence hedged.

“Agreed,” said Compton, who never smoked a cigar in his life.

After the crowd left, Compton shuffled wearily to his study and called Fermi. “He agreed at once to make the move to Chicago,” Compton writes. Fermi may have agreed, but he found the decision burdensome. He was preparing further experiment. His group was exactly the right size. He owned a pleasant house in a pleasant suburb. He and Laura had buried a cache of Nobel Prize money in a lead pipe under the concrete floor of their basement coal bin against the possibility that as enemy aliens their assets would be frozen. Laura Fermi “had come to consider Leonia as our permanent home,” she writes, “and loathed the idea of moving again.” She says her husband “was unhappy to move. They (I did not know who they were) had decided to concentrate all that work (I did not know what it was) in Chicago and to enlarge it greatly, Enrico grumbled. It was the work he had started at Columbia with a small group of physicists. There is much to be said for a small group. It can work quite efficiently.” But the country was at war. Fermi traveled back and forth by train until the end of April, then camped in Chicago. Laura dug up their buried treasure and followed at the end of June.

To Szilard, the day after the sickbed meeting — he had returned promptly to New York — Compton sent a respectful telegram: THANK YOU FOR COMING TO PRESENT ABLY COLUMBIA'S SITUATION. NOW WE NEED YOUR HELP IN ORGANIZING THE METALLURGICAL LABORATORY OF O.S.R.D. IN CHICAGO. CAN YOU ARRIVE HERE WEDNESDAY MORNING WITH FERMI AND WIGNER… TO DISCUSS DETAILS OF MOVING AND ORGANIZATION. Unlike the Radiation Laboratory at MIT, the new Metallurgical Laboratory hardly disguised its purpose in its name. Who would imagine its goal was the transmutation of the elements to make baseball-sized explosive spheres of unearthly metal?

Before Fermi and his team moved to Illinois they built one more exponential pile, this one loaded with cylindrical lumps of pressed uranium oxide three inches long and three inches in diameter that weighed four pounds each, some two thousand in all, set in blind holes drilled directly into graphite. A new recruit, a handsome, dark- haired young experimentalist named John Marshall, located a suitable press for the work in a junkyard in Jersey City and set it up on the seventh floor of Pupin; Walter Zinn designed stainless steel dies; the powdered oxide bound together under pressure as medicinal tablets pressed from powder — aspirin, for example — do.

Fermi was concerned to free the pile as completely as possible of moisture to reduce neutron absorption. He had canned the oxide before; now he decided to can the entire nine-foot graphite cube. “There are no ready-made cans of the needed size,” Laura Fermi says dryly, “so Enrico ordered one.” That, writes Albert Wattenberg, who joined the group in January, “required soldering together many strips of sheet metal. We were very fortunate in getting a sheet metal worker who made excellent solder joints. It was, however, quite a challenge to deal with him, since he could neither read nor speak English. We communicated with pictures, and somehow he did the job.” Laura Fermi picks up the story: “To insure proper assembly, they marked each section with a little figure of a man: if the can were put together as it should be, all men would stand on their feet, otherwise on their heads.” The Columbia men preheated the oxide lumps to 480°F before loading. They heated the contents of the room-sized can to the boiling point of water and pumped down a partial vacuum. Their heroic efforts reduced the pile's moisture to 0.03 percent. With the same relatively impure uranium and graphite they had used before but with these improved conditions and arrangements they measured k at the end of April at an encouraging 0.918.

In Chicago in the meantime Samuel Allison had built a smaller seven-foot exponential pile and measured k for his arrangement at 0.94. The University of Chicago had long ago sacrificed football to scholarship; Compton took over the warren of disused rooms under the west stands of Stagg Field, which was conveniently located immediately north of the main campus, and made space available there to Allison. Below solid masonry faqades set with Gothic windows and crenellated towers the stands concealed ball courts as well as locker areas. The unheated room Allison had used for his experiment, sixty feet long, thirty feet wide, twenty-six feet high and sunk half below street level, was a doubles squash court.

December 6, 1941, the day of the bomb program expansion, marked another tidal event: Soviet forces under General Georgi Zhukov counterattacked across a two-hundred-mile front against the German Army congealed in snow and — 35 °F cold only thirty miles outside Moscow. “Like the supreme military genius who had trod this road a century before him,” Churchill writes, evoking Napoleon Bonaparte, “Hitler now discovered what Russian winter meant.” Zhukov's hundred divisions came as a bitter surprise — “well-fed, warmly clad and fresh Siberians,” a German general describes them, “fully equipped for winter fighting” as the Wehr-macht troops were not — and armies that had advanced half a thousand miles to push within sight of the Kremlin stumbled back toward Germany nearly in rout. For the first time since Hitler began his conquests Blitzkrieg had failed. “The winter had fallen,” Churchill writes. “The long war was certain.” Hitler relieved his Army commander in chief of duty and appropriated that office to himself. By the end of March his casualties in the East, counting not the sick but only the wounded, numbered nearly 1.2 million men.

It was clear in Berlin that the German economy had reached the limits of its expansion. Tradeoffs must follow. The Minister of Munitions installed a rule similar to the rule upon which Conant was insisting in the United States, and the director of Reich military research promulgated it to the physicists studying uranium: “The work… is making demands which can be justified in the current recruiting and raw materials crisis only if there is a certainty of getting some benefit from it in the near future.” After considering the question the War Office decided to reduce the priority of uranium research by assigning most of it to the Ministry of Education under Bernhard Rust, the scientifically illiterate SS Obergruppenfiihrer and former provincial schoolteacher who had refused to sanction Lise Meitner's emigration following the Anschluss. The academic physicists were happy to be out from under the Army but chagrined to be consigned to a backwater ministry run by a party hack. Rust delegated authority to the Reich Research Council. That organization was part of the Reich Bureau of Standards. The KWI physicists considered its physics section head, Abraham Esau, incompetent. In effect, the German uranium program had slipped in status to the level of the old U.S. Uranium Committee and now had its Briggs.

The Research Council decided to appeal directly to the highest levels of the Reich for support. It organized an elaborate presentation and invited such dignitaries as Hermann Goring, Martin Bormann, Heinrich Himmler, Navy commander in chief Admiral Erich Raeder, Field Marshal Wilhelm Keitel and Albert Speer, Hitler's admired patrician architect who was Minister of Armaments and War Production. Heisenberg, Hahn, Bothe, Geiger, Clusius and Harteck were scheduled to speak at the February 26 meeting, Rust presiding, and an “Experimental Luncheon” would be served offering entries prepared from frozen foods basted with synthetic shortening and bread made with soy flour.

Unfortunately for the council's ambitious plans, the secretary assigned to send out invitations enclosed the wrong lecture program. A secret scientific conference under the auspices of Army Ordnance had been scheduled at the Kaiser Wilhelm Society's Harnack House for the same day. Its program listed twenty-five highly technical