Oliphant, whom Lawrence had met and liked on a visit to the Cavendish after the 1933 Solvay Conference.
Lawrence had encouraged the search for plutonium partly because he saw little hope for isotope separation by any of the methods so far discussed — by centrifuge, thermal diffusion or barrier diffusion. But around the beginning of the year he began thinking about separating isotopes electromagnetically, by the process that had already worked on a microscopic scale for Alfred Nier. It occurred to Lawrence that he could modify his superseded 37-inch cyclotron into a big mass spectrometer. The fact that Nier thought electromagnetic separation on an industrial scale impossible only spurred the Berkeley laureate on. Lawrence lived from machine to machine, as it were; conceiving a machine to do the job of liberating U235 from its confinement within U238 (while Fermi's uranium-graphite reactor manufactured Berkeley-born plutonium) gave him something solid to fight for, a tangible program to push.
It assembled itself by stages. He was not yet ready emotionally to set aside his peacetime plans. Warren Weaver, the director of the division of natural sciences at the Rockefeller Foundation, visited Berkeley in February to see how construction was progressing on the 4,900-ton, 184-inch cyclotron for which the foundation had awarded a $1,150,000 grant less than twelve months earlier. Lawrence took time to complain about the Uranium Committee's sloth — Weaver worked with another division of the NDRC — but then drove up behind the university to the cyclotron site on the hillside and first irritated and then enthralled the Rockefeller administrator with visions of a superior and much larger machine.
Lawrence rehearsed his complaint again in March when Conant, back from London, traveled out to deliver an address. “Light a fire under the Briggs committee,” the energetic Californian badgered the president of Harvard. “What if German scientists succeed in making a nuclear bomb before we even investigate possibilities?” That prepared Lawrence for a full assault. He launched it on March 17 when he met with Karl Compton and Alfred Loomis at MIT.
Loomis had turned to physics after a lucrative career in the law and investment banking. Compton was a physicist of distinction who had taught for fifteen years at Princeton, where he took his Ph.D., before becoming president of MIT in 1930. Both men understood the politics of organizations. Yet they were sufficiently seized with Lawrence's fervor that Compton telephoned Vannevar Bush almost as soon as Lawrence left the room and dictated a follow-up letter the same day. Briggs was “by nature slow, conservative, methodical and accustomed to operate at peacetime government bureau tempo,” Compton wrote, conveying Lawrence's blunt complaints, and had been “following a policy consistent with these qualities and still further inhibited by the requirement of secrecy.” The British were ahead even though America had “the most in number and the best in quality of the nuclear physicists of the world.” The Germans were “very active.” Briggs had invited only a very few U.S. nuclear physicists into the work. There were other possibilities in fission research besides the pursuit of a slow-neutron chain reaction for power, possibilities “capable, if successful, of far more important military usage.”
Though they felt free thus to lecture Bush, both Loomis and Compton stood in awe of Lawrence — Loomis had recently contributed $30,000 to a private fund simply to make it easier for Lawrence to travel around the country — and thought Bush could do no better than to turn him loose: “I hasten to say that the idea of Ernest himself taking an active part in any reorganization was in no sense suggested by him or even in his mind, but I do believe that it would be an ideal solution.”
Bush's ego was commensurate with his responsibilities, as Loomis and Compton ought to have known. It might have been politic to welcome Lawrence's campaign, especially since Loomis was a first cousin and close friend of Henry L. Stimson, the respected and influential Secretary of War; but Bush decided instead to take it as a challenge to his authority, the first the physics community had mounted since he invented the NDRC, welcoming a fight he knew he could win. He met Lawrence in New York two days after the MIT meeting and let fly:
I told him flatly that I was running the show, that we had established a procedure for handling it, that he could either conform to that as a member of the NDRC and put in his kicks through the internal mechanism, or he could be utterly on the outside and act as an individual in any way that he saw fit. He got into line and I arranged for him to have with Briggs a series of excellent conferences. However, I made it very clear to Lawrence that I proposed to make available to Briggs the best advice and consultation possible, but that in the last analysis I proposed to back up Briggs and his committee in their decision unless there was some decidedly strong case for entering into it personally. I think this matter was thoroughly straightened out, therefore, but it left its trail behind.
By threatening to push Ernest Lawrence out into the cold with the emigres Bush managed temporarily to confine the uranium problem. Confinement lasted less than a month.
In 1940 Lawrence had recruited a Harvard experimentalist named Kenneth Bainbridge, by trade a nuclear physicist — Bainbridge built the Harvard cyclotron — to work on radar at MIT. When Conant went to London to open the new NDRC office there, Bainbridge and others had followed, to work with the British each in his own field of competence. But since Bainbridge knew nuclear physics as well as radar and had even looked into isotope separation, the British allowed him also to attend a full-dress meeting of the MAUD Committee. To Bainbridge's surprise, the committee had “a very good idea of the critical mass and [bomb] assembly [mechanism], and urged the exchange of personnel… Their estimate was that a minimum of three years would be required to solve all the problems involved in producing an atomic weapon.” Bainbridge immediately contacted Briggs and suggested he send someone over to represent the United States in uranium matters.
Beneath Bush's organizational bristle lay genuine perplexity. “I am no atomic scientist,” he writes candidly; “most of this was over my head.” As he saw the situation that April, “it would be possible to spend a very large amount of money indeed, and yet there is certainly no clear-cut path to defense results of great importance lying open before us at the present time.” But he felt the increasing pressure — Lawrence's prodding, Bainbridge's confirmation of British progress — and reached out now for help.
“It was Bush's strategy,” writes the American experimental physicist Arthur Compton, Karl's younger brother, “as co-ordinator of the nation's war research, to use the National Academy [of Sciences] as the court of final appeal for important scientific problems.” On a Tuesday in mid-April, after meeting with Briggs, Bush wrote Frank B. Jewett, the senior Bell Telephone engineer who was president of the National Academy. Briggs had heard from Bainbridge and alerted Bush; Bush and Briggs, “disturbed,” had conferred. “The British are apparently doing fully as much as we are, if not more, and yet it seems as though, if the problem were of really great importance, we ought to be carrying most of the burden in this country.” Bush wanted “an energetic but dispassionate review of the entire situation by a highly competent group of physicists.” The men chosen ought to have “sufficient knowledge to understand and sufficient detachment to cold bloodedly evaluate.”
At a regular Washington meeting of the National Academy the following Friday Jewett, Bush and Briggs recruited their review group. They put Lawrence on the committee and the recently retired director of the research laboratory at General Electric, a physical chemist named William D. Coolidge. Then they sought out Arthur Compton, a Nobel laureate and professor of physics at the University of Chicago, and proposed he head the review. Compton humbly questioned his “fitness for the task” and jumped at the chance.
Arthur Holly Compton was the son of a Presbyterian minister and professor of philosophy at the College of Wooster in Wooster, Ohio. Compton's Mennonite mother was dedicated to missionary causes and had been the 1939 American Mother of the Year. He followed his older brother Karl into science and surpassed him in achievement but preserved the family piety as well. “Arthur Compton and God were daily companions,” notes Leona Woods, Enrico Fermi's young protege at the University of Chicago. She judged Compton nevertheless “a fine scientist and a fine man… He was remarkably handsome all his life and athletically spare and strong.” Fermi had concluded, writes Woods, that “tallness and handsomeness usually were inversely proportional to intelligence,” but “he excepted Arthur Compton… whose intelligence he respected enormously.”
Compton's physics was first-rate, as Fermi's respect implies. He graduated from the College of Wooster and took his Ph.D. at Princeton. In 1919, the first year of the program, he was appointed a National Research Council fellow and used the appointment to study under Rutherford at the Cavendish. The difficult work he began there — examining the scattering and absorption of gamma rays — led directly to the discovery of what came to be called the Compton effect, for which he won the Nobel Prize.
In 1920, Compton writes, he accepted a professorship at Washington University in St. Louis, “a small kind of place,” to get out of the mainstream of physics so that he could concentrate on his scattering studies, which he was then extending from gamma rays to X rays. He scattered X rays with a graphite block and caught them and
