It is not inconceivable that practical engineering applications and war use may emerge in the end. But I am assured by American colleagues that there is no sign of them at present and that it would be a sheer waste of time for people busy with urgent matters in England to turn to uranium as a war investigation. If anything likely to be of war value emerges they will certainly give us a hint of it in good time. A large number of American physicists are working on or interested in the subject; they have excellent facilities and equipment: they are extremely well disposed towards us: and they feel that it is much better that they should be pressing on with this than that our people should be wasting their time on what is scientifically very interesting, but for present practical needs probably a wild goose chase.
The opinion from the Carnegie may have been hardheaded, but it was based on more than prejudice. Roberts, Hafstad and fellow DTM physicist Norman P. Heydenburg had improved their measurements of cross sections for fast-neutron fission, scattering and capture in natural uranium. Using their numbers, Edward Teller in one of the many calculations he made during this period arrived at a critical mass in excess of thirty tons, the same order of magnitude as Perrin and Peierls had calculated before him. With only slightly more pessimistic assumptions Roberts concluded that “the cross-section for capture [in natural uranium] is sufficiently large that it now seems impossible for a fast-neutron chain reaction to occur, even in an infinitely large block of pure uranium.” By the spring of 1940 experiments at Columbia and the DTM had thus ruled out both slow- and significant fast-neutron fission in U238 and ruled in slow-neutron fission in U235. The asymmetry might have been a clue. No one picked it up.
Since at least the time of Einstein's first letter to FDR, Edward Teller had debated within himself the morality of weapons work. His life had twice been cruelly uprooted by totalitarianism. He understood Germany's frightening technological advantages at the outset of the war. “I came to the United States in 1935,” he notes. “… The handwriting was on the wall. At that time, I believed that Hitler would conquer the world unless a miracle happened.” But pure science still pacified him. “To deflect my attention from physics, my full-time job which I liked, to work on weapons, was not an easy matter. And for quite a time I did not make up my mind.”
The accidental juxtaposition of two events led him to decision. “In the spring of 1940 it was announced that President Roosevelt would speak to a Pan American Scientific Congress in Washington, and as one of the professors of George Washington University I was invited. I did not intend to go.” The other event of that crucial day, May 10, 1940, reversed his intention: the phony war abruptly ended. With seventy-seven divisions and 3,500 aircraft Germany without declaration or warning invaded Belgium, the Netherlands and Luxembourg to make way for the invasion of France. Teller thought Roosevelt might speak to that outrage. In his voluntary prewar isolation he had never bothered, Teller says, to visit the Capitol or listen to one of FDR's radio talks or otherwise involve himself in the political life of his adopted country, but he wanted now to see the President of the United States in person.
Alone among the scientists at the congress Teller knew about the Einstein letter. It was a direct link, he was an emotional man and the encounter with Roosevelt was eerily personal: “We had never met, but I had an irrational feeling he was talking to me.” The President mentioned the German invasion, its challenge to “the continuance of the type of civilization” the people of the Americas valued, the distances of the modern world shortened by modern technology to timetables that removed the “mystic immunity” Americans once felt from European war. “Then he started to talk about the role of the scientist,” Teller recalls, “who has been accused of inventing deadly weapons. He concluded: ‘If the scientists in the free countries will not make weapons to defend the freedom of their countries, then freedom will be lost.’” Teller believed Roosevelt was not proposing what scientists
Teller's memory of Roosevelt's speech differs from its text. The President said that most people abhor “conquest and war and bloodshed.” He said that the search for truth was a great adventure but that “in other parts of the world, teachers and scholars are not permitted” that search — an observation of which Teller had personal knowledge. And then, cannily, Roosevelt offered absolution in advance for war work:
You who are scientists may have been told that you are in part responsible for the debacle of today… but I assure you that it is not the scientists of the world who are responsible… What has come about has been caused solely by those who would use, and are using, the progress that you have made along lines of peace in an entirely different cause.
“My mind was made up,” Teller reports, “and it has not changed since.”
Vannevar Bush made a similar choice that spring. The sharp-eyed Yankee engineer, who looked like a beardless Uncle Sam, had left his MIT vice presidency for the Carnegie Institution in the first place to position himself closer to the sources of government authority as war approached. Karl Compton had offered to move up to chairman of the MIT corporation and give him the presidency to keep him, but Bush had larger plans.
As a young man, with a doctorate in engineering behind him jointly from MIT and Harvard earned in one intense year, Bush in 1917 had gone patriotically to work for a research corporation developing a magnetic submarine detector. The device was effective, and one hundred sets got built; but because of bureaucratic confusion they were never put to use against German submarines. “That experience,” Bush writes in a memoir, “forced into my mind pretty solidly the complete lack of proper liaison between the military and the civilian in the development of weapons in time of war, and what that lack meant.”
In Washington after the invasion of Poland the Carnegie president gathered with a group of fellow science administrators — Frank Jewett, president of Bell Telephone Laboratories and the National Academy of Sciences; James Bryant Conant, the young president of Harvard, a distinguished chemist; Richard Tolman of Caltech, the theoretician who had wooed Einstein; Karl Compton — to worry about the approaching conflict:
It was during the period of the “phony” war. We were agreed that the war was bound to break out into an intense struggle, that America was sure to get into it in one way or another sooner or later, that it would be a highly technical struggle, that we were by no means prepared in this regard, and finally and most importantly, that the military system as it existed… would never fully produce the new instrumentalities which we would certainly need.
They devised a national organization to do the job. Bush had learned his way around Washington and took the lead. The organization Bush wanted needed independent authority. He thought it should report directly to the President rather than through military channels and should have its own source of funds. He drafted a proposal. Then he arranged an introduction to Harry Hopkins.
A small-town Iowa boy, idealistic and energetic, Harry Lloyd Hopkins had fallen into New York social work after four years at Grinnell and won appointment at the beginning of the Depression administering emergency state relief. When the governor of New York was elected President, Hopkins moved with Roosevelt to Washington to help out with the New Deal. He ran the vast Works Progress Administration, then took over as Secretary of Commerce. His performance moved him closer and closer to the President, who picked up talent wherever he could find it; as war approached, Roosevelt invited Hopkins to dinner at the White House one evening and moved the man in for the duration as his closest adviser and aide. Hopkins was tall, a chain smoker and emaciated to the point of cachexia, his ghastly health the result of cancer surgery that took most of his stomach and left him unable to absorb much protein and therefore slowly starving to death. He kept an office in the White House basement but usually worked out of a cluttered bedroom suite — the Lincoln Bedroom — down the hall from FDR's.
When Bush met Hopkins, though the presidential aide was a liberal Democrat and the Carnegie president an admirer of Herbert Hoover and a self-styled Tory, “something meshed,” writes Bush, “and we found we spoke the same language.” Hopkins had a scheme for an Inventors Council. Bush countered with his more comprehensive National Defense Research Council. “Each of us was trying to sell something to the other.” Bush won. Hopkins liked his plan.
In early June Bush made the rounds of Washington touching bases: the Army, the Navy, Congress, the National Academy of Sciences. On June 12 “Harry and I then went in to see the President. It was the first time I had met Franklin D. Roosevelt… I had the plan for N.D.R.C. in four short paragraphs in the middle of a sheet of paper. The whole audience lasted less than ten minutes (Harry had no doubt been there before me). I came out with my ‘OK-FDR’ and all the wheels began to turn.”
