12

A Communication from Britain

James Bryant Conant traveled to London in the winter of 1941 to open a liaison office between the British government and the National Defense Research Council.¹⁴⁰³ Conant was the first American scientist of administrative rank to visit the beleaguered nation following the ad hoc exchanges of the Tizard Mission and he came to count the trip “the most extraordinary experience of my life.” “I was hailed as a messenger of hope,” he writes in his autobiography. “I saw a stouthearted population under bombardment. I saw an unflinching government with its back against the wall. Almost every hour I saw or heard something that made me proud to be a member of the human race.”¹⁴⁰⁴

The Harvard president, who would be forty-seven late in March, was welcomed not only because of his university affiliation or his distinction as a member of the NDRC. He had been an outspoken opponent of American isolationism during the long months of the phony war and was therefore welcomed especially as a sign—with only the Prime Minister dissenting. Churchill was less than delighted at the prospect of lunching with the president of Harvard. “What shall I talk to him about?” he was heard to ask. “He thought you would be an old man with a white beard, exuding learning and academic formality,” Brendon Bracken, Churchill’s aide, told Conant afterward.¹⁴⁰⁵ But braced by the American’s belligerently pro-British views and put at ease by the tweed suit he chose to wear, the Prime Minister eventually warmed over lunch in the bomb-shelter basement at 10 Downing Street, proffering a Churchillian monologue during which he repeated one of his choicer recent coinages: “Give us the tools, and we will finish the job.”

In 1920, at twenty-seven, when Conant was courting the woman he would marry—she was the only child of the Nobel laureate Harvard chemist T. W. Richards, a pioneer in measuring atomic weights—he had shared hopes for a grand future with her that coming from a less able man might have sounded absurd. “I said that I had three ambitions. The first was to become the leading organic chemist in the United States; after that I would like to be president of Harvard; and after that, a Cabinet member, perhaps Secretary of the Interior.”¹⁴⁰⁶ Those may not seem conjoint ambitions, but Conant managed a version of each in turn. He was born of a Massachusetts family that had resided in the state since 1623. After Roxbury Latin and Harvard College he had taken a double Ph.D. under his future father-in-law in organic and physical chemistry. He emerged from the Great War with the rank of major for his work in poison-gas research at Edgewood. In his autobiography, written late in life, he justified his participation:

I did not see in 1917, and do not see in 1968, why tearing a man’s guts out by a high-explosive shell is to be preferred to maiming him by attacking his lungs or skin. All war is immoral. Logically, the 100 percent pacifist has the only impregnable position. Once that is abandoned, as it is when a nation becomes a belligerent, one can talk sensibly only in terms of the violation of agreements about the way war is conducted, or the consequences of a certain tactic or weapon.¹⁴⁰⁷

Like Vannevar Bush, Conant was a patriot who believed in the application of advanced technology to war.

“Conant achieved an international reputation in both natural products chemistry and in physical-organic chemistry,” writes the Ukrainian-born Harvard chemist George B. Kistiakowsky.¹⁴⁰⁸ Natural products include chlorophyll and hemoglobin and Conant contributed to the unraveling of both those vital molecules. His studies also helped generalize the concept of acids and bases, a concept now considered fundamental. If not the leading American organic chemist of his day, he ranked among the leaders. When Caltech tried to lure him away with a large research budget Harvard topped the offer and refused to let him go.

Number two on Conant’s youthful list, the presidency of his alma mater, he won in 1933. He told the members of the Harvard Corporation who approached him that he didn’t want the job, which was apparently a prerequisite, but would serve if elected. He was forty at the time of his election. He created the modern Harvard of eminent scholarship and publish-or-perish, up-or-out.

Conant’s third ambition achieved approximate fulfillment after the war in high, though less than cabinet-rank, appointment; his long span of voluntary government service began with the NDRC.

In England in the late winter of 1941 he met with the leaders of the British government, had an audience with the King, picked up an honorary degree at Cambridge and walked the Backs afterward to see the crocuses in bloom, made room for the NDRC mission among hostile U.S. military and naval attaches, lunched with Churchill again. His mission in Britain was diplomatic rather than technical. He discussed gas warfare and explosives manufacture but was unable to share in the intense exchange of information on radar because he knew very little about electronics. But although he was familiar with the work on uranium and it fell within his official NDRC responsibilities, secrecy and his “strong belief in the ‘need to know’ principle” kept Conant from learning what the British had learned about the possibility of a bomb.¹⁴⁰⁹

He met a “French scientist” at Oxford, probably Hans von Halban, who complained of inaction on uranium-heavy water research. “Since his complaints were clearly ‘out of channels,’ I quickly terminated the conversation and forgot the incident.” That reaction was understandable: Conant could hardly know what security arrangements the British might have made with the Free French. But he also shied from Lindemann. They were lunching alone at a London club. “He introduced the subject of the study of the fission of uranium atoms. I reacted by repeating the doubts I had expressed and heard expressed at NDRC meetings.” Lindemann brushed them aside and pounced:

“You have left out of consideration,” said [Lindemann], “the possibility of the construction of a bomb of enormous power.” “How would that be possible?” I asked. “By first separating uranium 235,” he said, “and then arranging for the two portions of the element to be brought together suddenly so that the resulting mass would spontaneously undergo a self-sustaining reaction.”

Remarkably, the chairman of the chemistry and explosives division of the NDRC adds that, as late as March 1941, “this was the first I had heard about even the remote possibility of a bomb.” Nor did he pursue the matter. “I assumed, quite correctly, that if and when Bush wished to be in touch with the atomic energy work in England, he would do so through channels involving Briggs.” No wonder the Hungarian conspirers continued to tear their hair.

*   *   *

Then for the first time a ranking American physicist joined the debate whose voice could not be ignored. Even before Seaborg and Segré confirmed the fissibility of plutonium, Ernest Lawrence had measured the prevailing American skepticism and conservatism against the increasing enthusiasm of his British friends and responded with characteristic fervor. Ralph H. Fowler, Ernest Rutherford’s widower son-in-law, had visited Berkeley during the 1930s and attended picnics and weekend parties with the inventor of the cyclotron. Fowler was British scientific liaison officer in Washington now and from that close vantage he urged Lawrence to get involved. So did Mark 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.¹⁴¹⁰ He launched it on March 17 when he met with Karl Compton and Alfred Loomis at MIT.¹⁴¹¹

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.”¹⁴¹²

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.¹⁴¹³

By threatening to push Ernest Lawrence out into the cold with the emigrès 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.”¹⁴¹⁴ Bainbridge immediately contacted Briggs and suggested he send someone over to represent the United States in uranium matters.¹⁴¹⁵

Beneath Bush’s organizational bristle lay genuine perplexity. “I am no atomic scientist,” he writes candidly; “most of this was over my head.”¹⁴¹⁶ 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.”¹⁴¹⁷ 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.”¹⁴¹⁸ 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.”¹⁴¹⁹ 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.¹⁴²⁰

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 protégé 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.”¹⁴²¹ 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.”¹⁴²²

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.¹⁴²³ He scattered X rays with a graphite block and caught them and measured their wavelengths Moseley-style with a calcite-crystal X-ray spectrograph. He found that the X rays scattered by the graphite came out with wavelengths longer than their wavelengths going in: as if a shout bounced off a distant wall came back bizarrely deepened to a lower pitch. If X rays—light—were only a motion of waves, then their wavelengths would not have changed; Compton had in fact demonstrated in 1923 what Einstein had postulated in 1905 in his theory of the photoelectric effect: that light was wave but also simultaneously particle, photon. An X-ray photon had collided elastically with an electron, as billiard balls collide, had bounced off and thereby given up some of its energy. The calcite crystal revealed the energy loss as a longer wavelength of X-ray light. Arnold Sommerfeld hailed the Compton effect—elastic scattering of a photon by an electron—as “probably the most important discovery which could have been made in the current state of physics” because it proved that photons exist, which hardly anyone in 1923 yet believed, and demonstrated clearly the dual nature of light as both particle and wave.¹⁴²⁴

The subtle experimenter lost his subtlety when he shifted from doing science to proselytizing for God. Rigor slipped to Chautauqua logic and he perpetrated such howlers as the notion that Heisenberg’s uncertainty principle somehow extends beyond the dimensions of the atom into the human world and confirms free will. Bohr heard Compton’s Free Will lecture when he visited the United States in the early 1930s and scoffed. “Bohr spoke highly of Compton as a physicist and a man,” a friend of the Danish laureate remembers, “but he felt that Compton’s philosopohy was too primitive: ‘Compton would like to say that for God there is no uncertainty principle. That is nonsense. In physics we do not talk about God but about what we can know. If we are to speak of God we must do so in an entirely different manner.’ ”¹⁴²⁵

In 1941 war work had already been kind to Arthur Compton’s brother, moving Karl to national prominence within the science community and winning an important secret laboratory for MIT. Arthur wanted as much or more. There was the problem of pacifism, his mother’s Mennonite creed and a course much discussed at that time in American vestries, a churchly counterpart to isolationism:

In 1940, my forty-eighth year, I began to feel strongly my responsibility as a citizen for taking my proper part in the war that was then about to engulf my country, as it had already engulfed so much of the world. I talked, among others, with my minister in Chicago. He wondered why I was not supporting his appeal to the young people of our church to take a stand as pacifists. I replied in this manner: “As long as I am convinced, as I am, that there are values worth more to me than my own life, I cannot in sincerity argue that it is wrong to run the risk of death or to inflict death if necessary in the defense of those values.”¹⁴²⁶

Arthur Compton was ready, then, “a short time later,” when Bush and the National Academy asked him to serve.

The review committee met immediately with some of Briggs’ associates in Washington. A week later, May 5, 1941, it met again in Cambridge to hear from other Uranium Committee members and from Bainbridge. “There followed,” writes Compton, “two weeks spent in discussing the military possibilities of uranium with others who were actively interested.”¹⁴²⁷ Compton worked quickly to complete a seven-page report and delivered it to Jewett on May 17.

The report began with the statement that the committee was concerned with “the matter of possible military aspects of atomic fission” and listed three of those possibilities: “production of violently radioactive materials . . . carried by airplanes to be scattered as bombs over enemy territory,” “a power source on submarines and other ships” and “violently explosive bombs.” Radioactive dust would need a year’s preparation after “the first successful production of a chain reaction,” which meant “not earlier than 1943.” A power source would need at least three years after a chain reaction. Bombs required concentrating U235 or possibly making plutonium in a chain reaction, so “atomic bombs can hardly be anticipated before 1945.”

And that was that: no mention of fast-neutron fission, or critical mass, or bomb assembly mechanisms. The bulk of the report discussed “progress toward securing a chain reaction” and considered uranium-graphite, uranium-beryllium and uranium-heavy water systems. The committee proposed giving Fermi all the money he needed for his intermediate experiment and beyond. It also, more originally, discovered and emphasized the decisive long-range challenge of the new field:

It would seem to us unlikely that the use of nuclear fission can become of military importance within less than two years. . . . If, however, the chain reaction can be produced and controlled, it may rapidly become a determining factor in warfare. Looking, therefore, to a struggle which may continue for a decade or more, it is important that we gain the lead in this development. That nation which first produces and controls the process will have an advantage which will grow as its applications multiply.

Bush was in the process of reorganizing government science when he received the NAS report. The NDRC, empowered equally with the military laboratories and the National Advisory Committee for Aeronautics, had served for research but lacked the authority to pursue engineering development. Bush proposed a new umbrella agency with wide authority over all government science in the service of war, the Office of Scientific Research and Development. Its director—Bush—would report personally to Roosevelt. Bush prepared to move up to the OSRD by calling in Conant to take over the NDRC.^{1428, 1429} “And only after it was clear that I should shortly have a new position,” writes Conant, “did Bush begin to take me into his confidence as he pondered on what to do with the Briggs Committee.”¹⁴³⁰ Against the background of his British experience Conant told Bush his reaction to Compton’s report was “almost completely negative.”

Jewett had delivered the report to Bush with a cover letter calling it “authoritative and impressive,” but privately he cautioned Bush that he had “a lurking fear” that the report “might be over-enthusiastic in parts and not so well balanced.”^{1431, 1432} Jewett also passed it to several senior colleagues for comment, including the 1923 Nobel laureate in physics, Robert A. Millikan of Caltech, and sent their comments along to Bush in early June. Bush responded with exasperation compounded with astonishing confusion about the developments in Britain:

This uranium business is a headache! I have looked over Millikan’s comments, and it is quite clear that he wrote them without realizing the present situation. The British have apparently definitely established the possibility of a chain reaction with 238[sic],which entirely changes the complexion of the whole affair. Millikan bases his comments on the conviction that only 235 holds promise. This is natural, since he has not been brought in touch with recent developments which the British have told us about in great confidence.¹⁴³³

He agreed that the work “ought to be handled in a somewhat more vigorous form,” but he was still profoundly skeptical of its promise:

Even if the physicists get all that they expect, I believe that there is a very long period of engineering work of the most difficult nature before anything practical can come out of the matter, unless there is an explosive involved, which I very much doubt.

The OSRD director was not yet convinced despite new word of plutonium’s remarkable fissibility. Segrè and Seaborg had continued working through the spring of 1941 to determine the man-made element’s various cross sections. On Sunday, May 18, having finally prepared a sample thin enough for accurate measurement, they calculated plutonium’s cross section for slow-neutron fission at 1.7 times that of U235. When Lawrence heard the news on Monday, says Seaborg, he swung into action:

We told Lawrence about our definitive demonstration yesterday of the slow neutron fissionability of 94²³⁹ and he was quite excited. He immediately phoned the University of Chicago to give the news to Arthur H. Compton. . . . Compton made an immediate attempt to phone (unsuccessfully) and then sent a telegram to Vannevar Bush. . . . In his telegram Compton indicated that the demonstration . . . greatly increases the importance of the fission problem since the available material [i.e., U238 transmuted to plutonium] is thus increased by over 100 times. . . .¹⁴³⁴ He said that Alfred Loomis and Ernest Lawrence accordingly have requested him to urge anew the vital importance of pushing the [uranium-graphite] work at Columbia.

*   *   *

Whenever the U.S. program bogged down in bureaucratic doubt Hitler and his war machine rescued it. That summer’s massive escalation, code-named Operation Barbarossa, was the opening of the Eastern Front at dawn on the morning of Sunday, June 22, a surge eastward with 164 divisions, including Finnish and Rumanian components, toward Blitzkrieg invasion of the USSR. The Führer’s ambitious intention, declared with emphasis in a secret directive six months earlier, was “to crush Soviet Russia in a quick campaigneven before the conclusion of the war against England.”¹⁴³⁵ Hitler meant to push all the way to the Urals before winter and commandeer the Soviet Union’s industrial and agricultural base; by July Panzers had crossed the Dnieper and were threatening Kiev.

The effect on Conant of his London experiences and the widening war was paradoxically to increase his skepticism of the program he had just accepted assignment to administer:

What worried me about Compton’s first report, I told Bush, was the assumption that achieving a chain reaction was so important that a large expenditure of both money and manpower was justified. To me, the defense of the free world was in such a dangerous state that only efforts which were likely to yield results within a matter of months or, at most, a year or two were worthy of serious consideration. In that summer of 1941, with recollections of what I had seen and heard in England fresh in my mind, I was impatient with the arguments of some of the physicists associated with the Uranium Committee whom I met from time to time. They talked in excited tones about the discovery of a new world in which power from a uranium reactor would revolutionize our industrialized society. These fancies left me cold. I suggested that until Nazi Germany was defeated all our energies should be concentrated on one immediate objective.¹⁴³⁶

Having experienced the London Blitz, Conant had developed a siege mentality; Bush, as Conant points out, “was faced with a momentous decision as to priorities.” Both men wanted a hard, practical assessment. They decided Compton’s report needed an injection of common sense in the form of engineering expertise. Compton discreetly retired from the line; W. D. Coolidge, the General Electric scientist, temporarily took his place. Conant added an engineer from Bell Laboratories and another from Westinghouse and early in July the enlarged committee reviewed the first review.

Briggs was a convincing witness. By then he had received the April 9 minutes of a MAUD technical subcommittee meeting where Peierls reported that cross-section measurements confirmed the feasibility of a fastneutron bomb. Briggs had also just learned from Lawrence that plutonium had a cross section for fast fission some ten times that of U238.¹⁴³⁷ Lawrence even submitted a separate report on element 94 that emphasized for the first time in U.S. official deliberations the importance of fast fission over slow. But Briggs was still preoccupied with a slow-neutron chain reaction for power production and so was the second NAS report. “In the summer of 1941,” John Dunning’s associate Eugene Booth remembers, “Briggs visited us in the basement of Pupin at Columbia to see our experiment for the separation of U235 by [gaseous] diffusion of uranium hexafluoride. He was interested, blessed us, but sent us no money.”¹⁴³⁸

The American program was in danger for its life that summer, Compton thought: “The government’s responsible representatives were . . . very close to dropping fission studies from the war program.”¹⁴³⁹ He believed the program was saved because of Lawrence’s proposal to use plutonium to make a bomb. The fissibility of 94 may have convinced Compton. It was not decisive for the government’s responsible representatives. They were hard men and needed hard facts. Those began to arrive. “More significant than the arguments of Compton and Lawrence,” writes Conant, “was the news that a group of physicists in England had concluded that the construction of a bomb made out of uranium 235 was entirely feasible.”¹⁴⁴⁰

The British had been trying all winter and spring to pass the word. In July they tried again. G. P. Thomson had assembled a draft final report for the MAUD Committee to consider on June 23, the day after Barbarossa exploded across the Balkans and eastern Poland. Charles C. Lauritsen of Caltech, a respected senior physicist, was beginning work for the NDRC developing rockets and happened to be in London conferring with the British at the time of the MAUD draft. The committee invited him to attend its July 2 meeting at Burlington House. Lauritsen listened carefully, took notes and afterward talked individually with eight of the twenty-four physicists now attached to the work.¹⁴⁴¹ When he returned to the United States the following week he immediately reported the MAUD findings to Bush. “In essence,” says Conant, “he summarized the ‘draft report.’ ”¹⁴⁴² The physicists Lauritsen had interviewed had all pushed for a U.S.-built gaseous-diffusion plant.

The British government would not officially transmit the final MAUD Report to the United States government until early October, but the committee approved it on July 15 (and thereupon promptly disbanded) and by then Bush had been passed a copy of the Thomson draft, which embodied the essential findings. The MAUD Report differed from the two National Academy studies as a blueprint differs from an architect’s sketch.¹⁴⁴³ It announced at the outset:

We have now reached the conclusion that it will be possible to make an effective uranium bomb which, containing some 25 lb of active material, would be equivalent as regards destructive effect to 1,800 tons of T.N.T. and would also release large quantities of radioactive substances. . . . A plant to produce 2¼ lb (1 kg) per day [of U235] (or 3 bombs per month) is estimated to cost approximately £5,000,000. . . . In spite of this very large expenditure we consider that the destructive effect, both material and moral, is so great that every effort should be made to produce bombs of this kind. . . . The material for the first bomb could be ready by the end of 1943. . . . Even if the war should end before the bombs are ready the effort would not be wasted, except in the unlikely event of complete disarmament, since no nation would care to risk being caught without a weapon of such destructive capabilities.

Of conclusions and recommendations the report offered, crisply, three:

(  i) The committee considers that the scheme for a uranium bomb is practicable and likely to lead to decisive results in the war.

( ii) It recommends that this work continue on the highest priority and on the increasing scale necessary to obtain the weapon in the shortest possible time.

(iii) That the present collaboration with America should be continued and extended especially in the region of experimental work.

“With the news from Great Britain unofficially in hand,” Conant concludes in a secret history of the project he drafted in 1943, “ . . . it became clear to the Director of OSRD and the Chairman of NDRC that a major push along the lines outlined was in order.”¹⁴⁴⁴

They still did not immediately organize that push. Nor was Conant, to his postwar recollection, yet convinced that a uranium bomb would work as described. British research and considered judgment had at least proposed a clear-cut program ofmilitarydevelopment. Bush took it to Vice President Henry Wallace, his White House sounding board, who was the only scientist in the cabinet, a plant geneticist who had developed several varieties of hybrid corn. “During July,” writes Conant, “Bush had a discussion with Vice President Wallace about the question of spending a large amount of government money on the uranium program.”¹⁴⁴⁵ After which Bush apparently decided to wait for official transmittal of the final MAUD Report.

“If each necessary step requires ten months of deliberation,” Leo Szilard had complained to Alexander Sachs in 1940, “then obviously it will not be possible to carry out this development efficiently.”¹⁴⁴⁶ The American program was moving faster now than that, but not by much.

*   *   *

While Lawrence and Compton championed plutonium that summer, a big, rawboned, war-battered Austrian hiding out within the German physics establishment tried to keep the fissile new element out of sight. He was an old friend of Otto Frisch:

Fritz Houtermans and I had met in Berlin, but in London [before the war] I saw a lot more of that impressive eagle of a man, half Jewish as well as a Communist who had narrowly escaped the Gestapo. His father had been a Dutchman, but he was very proud of his mother’s Jewish origin and liable to counter anti-semitic remarks by retorting “When your ancestors were still living in the trees mine were already forging cheques!” He was full of brilliant ideas.¹⁴⁴⁷

Houtermans had taken a Ph.D. in experimental physics at Göttingen but was strong in theory. One of his brilliant ideas, developed in the late 1920s at the University of Berlin with a visiting British astronomer, Robert Atkinson, concerned the production of energy in stars. Atkinson was familiar with recent estimates by his older colleague Arthur Eddington that the sun and other stars burn at temperatures of 10 million and more degrees and have life spans of billions of years—a prodigious and unexplained expenditure of energy. On a walking tour near Göttingen in the summer of 1927 the two men had wondered if nuclear transformations of the sort Rutherford was producing at the Cavendish might account for the enduring stellar fires. They quickly worked out a basic theory, as Hans Bethe later described it, “that at the high temperatures in the interior of a star, the nuclei in the star could penetrate into other nuclei and cause nuclear reactions, releasing energy.”¹⁴⁴⁸ The energy would be released when hot (and therefore fast-moving) hydrogen nuclei collided with enough force to overcome their respective electrical barriers and fused together, making helium nuclei and giving up binding energy in the process. With George Gamow, Houtermans and Atkinson later named these eventsthermonuclear reactions because they proceeded at such high temperatures.

In 1933 Houtermans emigrated to the Soviet Union, “but fell victim,” writes Frisch, “to one of Stalin’s purges and spent a couple of years in prison; his wife with two small children managed to escape and get to the U.S.A. When Hitler made his temporary pact with Stalin in 1939 it included an exchange of prisoners, and Houtermans was handed back to the Gestapo.” Max von Laue, whom Frisch celebrates as “one of the few German scientists with the prestige and courage to stand up against the Nazis,” managed to free Houtermans and arranged for him to work with a wealthy German inventor, Baron Manfred von Ardenne, who had studied physics and who maintained a private laboratory in Lichterfelde, outside Berlin.^{1449, 1450} Von Ardenne was pursuing uranium research independently of Heisenberg and the War Office; to raise funds for the work he had approached the German Post Office, which commanded a large and largely unused budget for research. The Minister of Posts, imagining himself handing Hitler the decisive secret weapon of the war, had funded the building of a million-volt Van de Graaff and two cyclotrons, all under construction in 1941. Until they came on line Houtermans turned his attention to theory.

By August he had independently worked out all the basic ideas necessary to a bomb. He discussed them in a thirty-nine-page report, “On the question of unleashing chain reactions,” that considered fast-neutron chain reactions, critical mass, U235, isotope separation and element 94. Houtermans emphasized making 94. “Every neutron which, instead of fissioning uranium-235, is captured by uranium-238,” he wrote, “creates in this way a new nucleus, fissionable by thermal neutrons.”¹⁴⁵¹ He discussed his ideas privately with von Weizsäcker and Heisenberg, but he saw to it that the Post Office kept his report in its safe secure from War Office eyes. He had learned to cooperate for survival in the Soviet Union, where the NKVD—the KGB of its day—had knocked out all his teeth and kept him in solitary confinement for months. But in Germany as in the USSR he withheld as much information as he dared. His private endorsement of 94, to be transmuted by chain reaction from natural uranium, probably contributed to the neglect of isotope separation in Germany. After the summer of 1941 the German bomb program depended entirely on uranium and Vemork heavy water.

*   *   *

The British, at least, knew where they were going. Tizard was skeptical of the MAUD Report and doubted that a bomb could be produced before the end of the war. Lindemann—he was Lord Cherwell now, a baron, courtesy of his friend the P.M.—did not. Cherwell had followed the MAUD work carefully. He respected Thomson; Simon was an old friend; Peierls had read his grunts correctly after all. He trusted their judgment and set to work to reduce the lengthy report to a memorandum for Churchill. Churchill liked his documents held to half a page. So important was this one that Cherwell allowed it to run on for two and a half pages. He thought research should continue for six months and then face further review. He thought an isotope-separation plant should be erected not in the United States but in England—despite manpower shortages and the risk of German bombing—or “at worst” in Canada. In that conclusion he differed from the MAUD Committee.¹⁴⁵² “The reasons in favor [of an English location],” he wrote, “are the better chance of maintaining secrecy . . . but above all the fact that whoever possesses such a plant should be able to dictate terms to the rest of the world. However much I may trust my neighbor and depend on him, I am very much averse to putting myself completely at his mercy. I would, therefore, not press the Americans to undertake this work.” His summation narrowed the odds but decisively raised the stakes:

People who are working on these problems consider the odds are ten to one on success within two years. I would not bet more than two to one against or even money. But I am quite clear that we must go forward. It would be unforgivable if we let the Germans defeat us in war or reverse the verdict after they had been defeated.

Churchill received Cherwell’s recommendation on August 27. Three days later he minuted his military advisers, alluding ironically to the effects of the Blitz: “Although personally I am quite content with the existing explosives, I feel we must not stand in the path of improvement, and I therefore think that action should be taken in the sense proposed by Lord Cherwell.”¹⁴⁵³

The British chiefs of staff concurred on September 3.

*   *   *

Mark Oliphant helped goad the American program over the top. “If Congress knew the true history of the atomic energy project,” Leo Szilard said modestly after the war, “I have no doubt but that it would create a special medal to be given to meddling foreigners for distinguished services, and Dr. Oliphant would be the first to receive one.”¹⁴⁵⁴ Conant in his 1943 secret history thought the “most important” reason the program changed direction in the autumn of 1941 was that “the all-out advocates of a head-on attack on the uranium problem had become more vocal and determined” and mentioned Oliphant’s influence first of all.¹⁴⁵⁵

Oliphant flew to the United States in late August—he considered the Pan-American Clipper through Lisbon too slow and usually traveled by unheated bomber—to work with his NDRC counterparts on radar. But he was also charged with inquiring why the United States was ignoring the MAUD Committee’s findings. “The minutes and reports . . . had been sent to Lyman Briggs . . . and we were puzzled to receive virtually no comment. . . . I called on Briggs in Washington, only to find that this inarticulate and unimpressive man had put the reports in his safe and had not shown them to members of his Committee.” Oliphant was “amazed and distressed.”¹⁴⁵⁶

He met then with the Uranium Committee. Samuel K. Allison was a new committee member, a talented experimentalist, a protégé of Arthur Compton at the University of Chicago. Oliphant “came to a meeting,” Allison recalls, “ . . . and said ’bomb’ in no uncertain terms. He told us we must concentrate every effort on the bomb and said we had no right to work on power plants or anything but the bomb. The bomb would cost twenty-five million dollars, he said, and Britain didn’t have the money or the manpower, so it was up to us.” Allison was surprised. Briggs had kept the committee in the dark. “I thought we were making a power source for submarines.”¹⁴⁵⁷

In desperation Oliphant reached out to the most effective champion he knew in the United States. He wired Ernest Lawrence: “I’ll even fly from Washington to meet at a convenient time in Berkeley.”¹⁴⁵⁸ At the beginning of September he did.

Lawrence drove Oliphant up the hill behind the Berkeley campus to the site of the 184-inch cyclotron where they could talk without being overheard. Oliphant rehearsed the MAUD Report, which Lawrence had not yet seen. Lawrence in turn proclaimed the possibility of electromagnetic separation of U235 in converted cyclotrons and the virtues of plutonium. “How much I still admire the way in which things are done in your laboratory,” Oliphant would write him after their meeting. “I feel quite sure that in your hands the uranium question will receive proper and complete consideration.”^{1459, 1460} Back in his office Lawrence called Bush and Conant and arranged for Oliphant to see them. From Oliphant he collected a written summary of the secret British report.

In Washington Conant took Oliphant to dinner and listened with interest. Bush met him in New York and gave him a barely courteous twenty minutes. Neither administrator admitted to knowledge of the MAUD Report. “Gossip among nuclear physicists on forbidden subjects,” Conant characterizes Oliphant’s peregrinations in his secret history.¹⁴⁶¹

Oliphant also stopped by to talk to Fermi. He found the Italian laureate more cautious than ever, “non-committal about the fast-neutron bomb and not altogether happy about the Bohr-Wheeler theory of fission.”¹⁴⁶²

Before or after his meetings in Washington and New York Oliphant visited William D. Coolidge, the temporary chairman who produced the second NAS report, at General Electric in Schenectady. That visit at least stirred something like indignation. Coolidge immediately wrote Jewett of Oliphant’s news, emphasizing for pure U235 “that the chain reaction in this case would take place thru the direct action of fast neutrons. . . . This information, so far as I know, was not available in this country until after the National Academy Committee had sent in its second report. I think that Oliphant’s story should be given serious consideration.”¹⁴⁶³ Information had indeed been available in the United States—at least the MAUD minutes, including Peierls’ April 9 statement—but Briggs had locked it away for safekeeping. Oliphant returned to Birmingham wondering if he had made any impression at all.

Lawrence was already moving. He called Arthur Compton in Chicago after Oliphant left Berkeley. “Certain developments made him believe it would be possible to make an atomic bomb,” Compton paraphrases the conversation. “Such a bomb, if developed in time, might determine the outcome of the war. The activity of the Germans in this field made it seem to him a matter of great urgency for us to press its development.”¹⁴⁶⁴ It was no more than Szilard had argued two years earlier. Lawrence was scheduled to speak in Chicago on September 25. Conant would be in town to receive an honorary degree. Compton proposed to invite both men together to his home. Lawrence could then press the NDRC chairman directly.

*   *   *

Following his decision for political commitment at the Pan American Scientific Conference, Edward Teller had continued teaching at George Washington University but sought work in fission research. In March 1941, with Merle Tuve as one of their sponsors, the Tellers swore allegiance to the United States and became American citizens. Hans Bethe, who was teaching at Columbia for the spring term on temporary leave from Cornell, took the oath the same month. At the end of the term Bethe recommended that Columbia invite Teller to replace him. To work more closely with Fermi and Szilard—and to adjudicate their disputes, which he did with sensitivity—Teller accepted and moved to Manhattan, to an apartment on Morningside Drive.

In the midst of experiment Fermi found time to theorize. He and Teller had lunch at the University Club one pleasant day in September. Afterward, walking back to Pupin—“out of the blue,” Teller says—Fermi wondered aloud if an atomic bomb might serve to heat a mass of deuterium sufficiently to begin thermonuclear fusion.¹⁴⁶⁵ Such a mechanism, a bomb fusing hydrogen to helium, should be three orders of magnitude as energetic as a fission bomb and far cheaper in terms of equivalent explosive force. For Fermi the idea was a throwaway. Teller found it a surpassing challenge and took it to heart.

Teller liked to break new ground. When he understood something theoretically he usually moved on without waiting for experimental confirmation. He understood the atomic bomb. He moved on to consider the possibility of a hydrogen bomb. He made extensive calculations. They were disappointing. “I decided that deuterium could not be ignited by atomic bombs,” he recalls.¹⁴⁶⁶ “Next Sunday, we went on a walk. The Fermis and the Tellers.¹⁴⁶⁷ And I explained to Enrico why a hydrogen bomb could never be made. And he believed me.” For a while, Teller even believed himself.

Enrico Fermi and Edward Teller were not, however, the first to conceive of using a nuclear chain reaction to initiate a thermonuclear reaction in hydrogen. That distinction apparently belongs to Japanese physicist Tokutaro Hagiwara of the faculty of science of the University of Kyoto. Hagiwara had followed world fission research and had conducted studies of his own. In May 1941 he lectured on “Super-explosive U235,” reviewing existing knowledge.^{1468, 1469} He was aware that an explosive chain reaction depended on U235 and understood the necessity of isotope separation: “Because of the potential application of this explosive chain reaction a practical method of achieving this must be found. Immediately, it is very important that a means of manufacturing U-235 on a large scale from natural uranium be found.” He then discussed the linkage he saw between nuclear fission and thermonuclear fusion: “If by any chance U-235 could be manufactured in a large quantity and of proper concentration, U-235 has a great possibility of becoming useful as the initiating matter for a quantity of hydrogen. We have great expectations for this.”

But before the Japanese or the Americans could build a hydrogen bomb they would have to build an atomic bomb. And in neither country was major support yet secure.

*   *   *

“It was a cool September evening,” Arthur Compton remembers. “My wife greeted Conant and Lawrence as they came into our home and gave each of us a cup of coffee as we gathered around the fireplace. Then she busied herself upstairs so the three of us might talk freely.”¹⁴⁷⁰

Lawrence spoke with passion. He was “very vigorous in his expression of dissatisfaction with the U.S. program,” writes Conant. “Dr. Oliphant had seen him during the summer and by recounting the British hopes had further fired Lawrence’s zeal for more action in this whole field.”¹⁴⁷¹ Conant knew all about the British hopes, knew talk was cheap and chose to play the devil’s advocate, easily gulling Compton, who thought his arguments turned the tide:

Conant was reluctant. As a result of the reports so far received he had concluded that the time had come to drop the support of nuclear research as a subject for wartime study. . . . We could not afford to spend either our scientific or our industrial effort on an atomic program of highly questionable military value when every ounce of our strength was needed for the nation’s defense.

I rallied to Lawrence’s support. . . .

Conant began to be convinced.¹⁴⁷²

“I could not resist the temptation,” says the Harvard president, “to cut behind [Lawrence’s] rhetoric by asking if he was prepared to shelve his own research programs.”¹⁴⁷³ Compton cranks Conant’s challenge to high melodrama:

“If this task is as important as you men say,” [Conant] remarked, “we must get going. I have argued with Vannevar Bush that the uranium project be put in wraps for the war period. Now you put before me plans for making a definite, highly effective weapon. If such a weapon is going to be made, we must do it first.¹⁴⁷⁴ We can’t afford not to. But I’m here to tell you, nothing significant will happen on such a job as this unless we get into it with everything we’ve got.”

He turned to Lawrence. “Ernest, you say you are convinced of the importance of these fission bombs. Are you ready to devote the next several years of your life to getting them made?”

 . . . The question brought Lawrence up with a start. I can still recall the expression in his eyes as he sat there with his mouth half open. Here was a serious personal decision. . . . He hesitated only a moment: “If you tell me this is my job, I’ll do it.”

Back in Washington Conant briefed Bush on what he calls “the results of the involuntary conference in Chicago to which [I] had been exposed.”¹⁴⁷⁵ The two administrators decided to order up a third National Academy report, enlarging Compton’s committee this time to include W. K. Lewis, a chemical engineer with an outstanding reputation for estimating the potential success at industrial scale of laboratory processes, and Conant’s Harvard colleague George B. Kistiakowsky, the resident NDRC explosives expert.

Tall, big-boned, boisterous, with a flat Slavic face and abiding selfconfidence, Kistiakowsky had volunteered at eighteen for the White Russian Army and fought in the Russian Revolution. “I grew up in a family in which the question of civil rights, human freedom, was an important one,” he told an interviewer late in life. “My father was a professor of sociology and wrote articles and books on the subject and got into trouble with the Czar’s regime, very substantial trouble. Mother was also politically oriented. I think both of them went through a short period of being Marxists and then rejected it. That’s why I really joined the anti-Bolshevik armies in ‘18. It was certainly not because I loved Czarism. Of course, I got completely disgusted with the White Army long before it was all over.” Kistiakowsky escaped to Germany and took his doctorate at the University of Berlin in 1925. He might have stayed, but his professor advised him to look elsewhere. “He told me that if I wanted to go into an academic career I should emigrate; I would never get a job in Germany—’Here you will always be a Russian.’ ”¹⁴⁷⁶ Princeton accepted the Ukrainian chemist on a fellowship and soon hired him for its faculty. Then Harvard discovered and courted him. In 1930 he moved, becoming professor of chemistry in 1938.

Conant had been among those who lured Kistiakowsky from Princeton to Harvard. He valued highly his friend and fellow chemist’s opinion. “When I retailed to him the idea that a bomb could be made by the rapid assembly of two masses of fissionable material, his first remark was that of a doubting Thomas. ‘It would seem to be a difficult undertaking on a battlefield,’ he remarked.” But it was Kistiakowsky’s judgment that finally convinced Conant, as British hopes and physicists’ entreaties had not:

A few weeks later when we met, his doubts were gone. “It can be made to work,” he said. “I am one hundred percent sold.”

My doubts about Briggs’ project evaporated as soon as I heard George Kistiakowsky’s considered verdict. I had known George for many years. . . . I had asked him to be head of the NDRC division on explosives. . . . I had complete faith in his judgment. If he was sold on Arthur Compton’s program, who was I to have reservations?¹⁴⁷⁷

Oliphant convinced Lawrence, Lawrence convinced Compton, Kistiakowsky convinced Conant. Conant says Compton’s and Lawrence’s attitudes “counted heavily with Bush.” But “more significant” was the MAUD Report, which G. P. Thomson, now British scientific liaison officer in Ottawa, officially transmitted to Conant on October 3.¹⁴⁷⁸ On October 9, without waiting for the third National Academy of Sciences review, Bush carried the report directly to the President.

Franklin Roosevelt, Henry Wallace and the director of the OSRD met that Thursday at the White House. In a memorandum Bush wrote to Conant the same day he makes it clear that the MAUD Report was the basis for the discussion: “I told the conference of the British conclusions.”¹⁴⁷⁹ He told the President and the Vice President that the explosive core of an atomic bomb might weigh twenty-five pounds, that it might explode with a force equivalent to some eighteen hundred tons of TNT, that a vast industrial plant costing many times as much as a major oil refinery would be necessary to separate the U235, that the raw material might come from Canada and the Belgian Congo, that the British estimated the first bombs might be ready by the end of 1943. Bush tried to explain that an atomic bomb plant would produce no more than two or three bombs a month but doubted if the President took in that “relatively low yield.” He emphasized that he was basing his statements “primarily on calculation with some laboratory investigation, but not on a proved case” and therefore could not guarantee success.

Bush was presenting, essentially, British calculations and British conclusions. Such a presentation made it appear that Britain was further advanced in the field than America. The discussion therefore shifted to the question of how the United States was attached or might attach itself to the British program. “I told of complete interchange with Britain on technical matters, and this was endorsed.” Bush explained that the “technical people” in Britain had also formulated policy—had proposed that the government develop the atomic bomb as a weapon of war—and had passed their formulations along directly to the War Cabinet. In the United States, Bush said, an NDRC section and an advisory committee considered technical matters and only he and Conant considered policy.

Policy was the President’s prerogative. As soon as Bush exposed it to view Roosevelt seized it. Bush took that decision to be the most important outcome of the meeting and put it emphatically first in his memorandum to Conant. Roosevelt wanted policy consideration restricted to a small group (it came to be called the Top Policy Group). He named its members: Vice President Wallace, Secretary of War Henry L. Stimson, Army Chief of Staff George C. Marshall, Bush and Conant. Every man owed his authority to the President. Roosevelt had instinctively reserved nuclear weapons policy to himself.

Thus at the outset of the U.S. atomic energy program scientists were summarily denied a voice in deciding the political and military uses of the weapons they were proposing to build. Bush accepted the usurpation happily. To him it was simply a matter of who would run the show. It left him on top and inside and he put it to use immediately to shoulder the physics community into line. Within hours, as he wrote Frank Jewett in November, he had “emphasized to Arthur Compton and his people the fact that they are asked to report upon the techniques, and that consideration of general policy has not been turned over to them as a subject.”^{1480, 1481}

Significantly, Bush associated the reservation of policy with relief from criticism: “Much of the difficulty in the past has been due to the fact that Ernest Lawrence in particular had strong ideas in regard to policy, and talked about them generally. . . . I cannot. . . . bring him into the discussions, as I am not authorized by the President to do so.” He applied just this test—silence on policy—to measure Lawrence’s and Compton’s loyalty: “I think [Lawrence] now understands this, and I am sure that Arthur Compton does, and I think our difficulties in this regard are over.”

A scientist could choose to help or not to help build nuclear weapons. That was his only choice. The surrender of any further authority in the matter was the price of admission to what would grow to be a separate, secret state with separate sovereignty linked to the public state through the person and by the sole authority of the President.

Patriotism contributed to many decisions, but a deeper motive among the physicists, by the measure of their statements, was fear—fear of German triumph, fear of a thousand-year Reich made invulnerable with atomic bombs. And deeper even than fear was fatalism. The bomb was latent in nature as a genome is latent in flesh. Any nation might learn to command its expression. The race was therefore not merely against Germany. As Roosevelt apparently sensed, the race was against time.

There are indications in Bush’s memorandum that Roosevelt was concerned less with a German challenge than with the long-term consequences of acquiring so decisive a new class of destructive instruments. “We discussed at some length after-war control,” Bush wrote Conant, “together with sources of raw material” (sources of raw material were then believed to be few and far between; whoever commanded them might well, it seemed, monopolize the bomb). Roosevelt was thinking beyond developing bombs for the war that the United States had not yet entered. He was thinking about a military development that would change the political organization of the world.

Bush, who was a successful administrator partly because he knew the limits of his charter, then suggested that a “broader program”—industrial production—ought to be handled when the time came by some larger organization than the OSRD. Roosevelt agreed. Summarizing his assignment, Bush told the President he understood he was to expedite in every possible way the necessary research but was “not [to] proceed with any definite steps on this expanded plan until further instructions from him. . . . He indicated that this was correct.” The money, the President told him, “would have to come from a special source available for such an unusual purpose and . . . he could arrange this.”

The United States was not yet committed to building an atomic bomb. But it was committed to exploring thoroughly whether or not an atomic bomb could be built. One man, Franklin Roosevelt, decided that commitment—secretly, without consulting Congress or courts. It seemed to be a military decision and he was Commander in Chief.

*   *   *

Bush and Conant proceeded to order up from Arthur Compton a third NAS review. Compton asked Samuel Allison for the name of someone who could help him calculate the critical mass of U235. Allison had been corresponding with Enrico Fermi on the subject of carbon absorption cross sections and recommended him highly. Compton “called on Fermi in his office at Columbia University.¹⁴⁸² Stepping to the blackboard he worked out for me, simply and directly, the equation from which could be calculated the critical size of a chain-reacting sphere. He had at his fingertips the most recent experimental values of the constants. He discussed for me the reliability of the data. . . . Even the most conservative estimate showed that the amount of fissionable metal needed to effect a nuclear explosion could hardly be greater than a hundred pounds.”¹

Compton moved on to Harold Urey’s office to look into isotope separation. Urey was the recognized world leader in the field as a result of his Nobel Prize-winning work with hydrogen isotopes; he had directed isotope separation studies for the Uranium Committee and the Naval Research Laboratory since the beginning. He personally investigated chemical separation of U235 (which turned out to be impossible given the chemical compounds of the day) and separation by centrifuge. Estimating that a centrifuge plant that would produce one kilogram of U235 per day would require 40,000 to 50,000 yard-long centrifuges and would cost about $100 million, he had recently contracted with Westinghouse in the name of the Uranium Committtee for a prototype unit.

Urey was initially skeptical of gaseous barrier diffusion. He and John Dunning were not compatible, perhaps because they were both enthusiasts, and only when centrifuge development was well under way, in late 1940, did Urey turn his attention to the process that Dunning and Eugene Booth were working hard at their own expense to develop. They had chosen gaseous diffusion at dinner one evening in 1940 on their way home from a trip to Schenectady by systematically ruling out other methods as unsuitable for large-scale production, much as Peierls and Simon had done.¹⁴⁸³ They were interested in nuclear power, Booth remembers, not bomb-making. “Our reasons for pursuing the isotope separation path toward power production were simple and general. If a chain reaction became possible with normal uranium, a smaller and probably cheaper power plant could be made with enriched uranium.”¹⁴⁸⁴

Dunning and Urey produced a joint appraisal of the gaseous-diffusion process in November 1940. Dunning’s barrier material at the time was fritted glass—partially fused and therefore porous silica, the material from which porcelain is made—which uranium hexafluoride was likely to corrode.¹⁴⁸⁵ They estimated that a gaseous-diffusion plant would involve some five thousand separate barrier tanks—“stages”—but made no attempt to determine cost and power requirements.

By the autumn of 1941, without official support, Dunning and Booth had nevertheless made significant progress. They had switched to brass barriers from which the zinc had been etched (brass is an alloy of copper and zinc; etching away the zinc made the material porous). In November, the month after Compton’s visit, they would successfully enrich a measurable quantity of uranium with their equipment.

Compton traveled next to Princeton to see Eugene Wigner, who had been working closely with Fermi. Wigner clarified for Compton the difference between fast- and slow-neutron fission. He endorsed the uraniumgraphite system Fermi was developing as a method for producing 94. “He urged me,” writes Compton, “almost in tears, to help get the atomic program rolling. His lively fear that the Nazis would make the bomb first was the more impressive because from his life in Europe he knew them so well.”¹⁴⁸⁷

Back in Chicago Compton talked to Glenn Seaborg, who had come east from Berkeley at Compton’s request. Seaborg was confident he could devise a large-scale, remote-controlled technology for separating 94 chemically from uranium.

Armed with this new round of information Compton called a meeting of his committee for October 21 in Schenectady.¹⁴⁸⁸ He prepared for the meeting by writing a draft report. A letter came from Lawrence saying he wanted to bring along Robert Oppenheimer: “I have a great deal of confidence in Oppie, and I’m anxious to have the benefit of his judgment in our deliberation.”¹⁴⁸⁹ Conant had scolded Lawrence at Compton’s fireside when he learned that Lawrence had asked Oppenheimer, still an outsider, for help with theory, but now Lawrence’s request was granted.¹⁴⁹⁰

A dispute between Lawrence and Oppenheimer about what Lawrence called the theoretician’s “leftwandering activities” almost excluded him from the atomic bomb project.¹⁴⁹¹ Oppenheimer, married now to the former Katherine Puening, known as Kitty, with a six-month-old son, had begun to wish for assignment. “Many of the men I had known went off to work on radar and other aspects of military research,” he testified later. “I was not without envy of them.”¹⁴⁹² He learned the price of admission when he invited Lawrence to an organizational meeting at his elegant new home on Eagle Hill for a professional union, the American Association of Scientific Workers, of which Arthur Compton, among others, was a senior member. Lawrence wanted no part in any “causes and concerns,” as he called political activities, and barred his staff as well: “I don’t think it’s a good idea,” he told them.¹⁴⁹³ “I don’t want you to join it. I know nothing wrong with it, but we’re planning big things in connection with the war effort, and it wouldn’t be right. I want no occasion for somebody in Washington to find fault with us.” Oppenheimer was not so easily put off; he debated Lawrence’s point, arguing that humanity was everyone’s responsibility and that the more fortunate should help “underdogs.” The Nazis came first, Lawrence countered.¹⁴⁹⁴ He told Oppenheimer about Conant’s scolding. Oppenheimer reserved judgment. The October 21 meeting, where he could measure the scientific leaders of the uranium program against his own formidable gifts, changed his mind. “It was not until my first connection with the rudimentary atomic-energy enterprise,” he testifies, “that I began to see any way in which I could be of direct use.”¹⁴⁹⁵ When he saw his way to war work he quickly sacrificed his underdogs, writing Lawrence on November 12:

I . . . assure you that there will be no further difficulties at any time with the A.A.S.W. . . . I doubt very much whether anyone will want to start at this time an organization which could in any way embarrass, divide or interfere with the work we have in hand. I have not yet spoken to everyone involved, but all those to whom I have spoken agree with us: so you can forget it.¹⁴⁹⁶

Lawrence opened the Schenectady meeting by reading Oliphant’s summary of the MAUD Report. Compton followed with a review based on his October travels. Oppenheimer weighed in during the discussion of U235’s critical mass with an estimate of 100 kilograms, 220 pounds, close to Fermi’s estimate of 130,000 grams. “Kistiakowsky,” writes Compton, “explained the great economic advantage of being able to deliver a heavy blow with a bomb carried by a single plane.”¹⁴⁹⁷

But Compton was distressed to discover he could not move the engineers on the review committee—the practical souls Bush had insisted be added to bring the NAS reviews down to earth—to estimate either how much time it would take to build a bomb or how much the enterprise would cost:

With one accord they refused. . . . There weren’t enough data. The fact was that they had before them all the relevant information that existed, and some kind of answer was needed, however rough it might be, for otherwise our recommendation could not be acted upon. After some discussion, I suggested a total time of between three and five years, and a total cost . . . of some hundreds of millions of dollars. None of the committee members objected.

So the American numbers came out of a scientist’s hat, as the British numbers had. Atomic energy was still too new for engineering.

If Compton was distressed by the refusal of commitment, Lawrence was appalled. Within twenty-four hours he mailed the committee chairman a bracing challenge edged with threat:

In our meeting yesterday, there was a tendency to emphasize the uncertainties, and accordingly the possibility that uranium will not be a factor in the war. This to my mind, was very dangerous. . . .¹⁴⁹⁸

It will not be a calamity if, when we get the answers to the uranium problem, they turn out negative from the military point of view, but if the answers are fantastically positive and we fail to get them first, the results for our country may well be tragic disaster. I feel strongly, therefore, that anyone who hesitates on a vigorous, all-out effort on uranium assumes a grave responsibility.

But Compton had already been threatened by an expert, Vannevar Bush, and knew his duty well, though he did not yet know that Bush was already committed to expedition and expansion. He had difficulty estimating “the destructiveness of the bomb.” The calculation “involved problems of gas pressure, specific heats at hitherto unknown temperatures, the transmission of radiations and particles through the material, and forces of inertia.”¹⁴⁹⁹ He asked Gregory Breit for help. Breit was even more obsessed with secrecy than Briggs. “No help was forthcoming,” says Compton, gritting his teeth. He turned then to Oppenheimer. “I had known ‘Oppie’ for some fourteen years and had found him most competent in seeing the essentials of an intricate problem and in interpreting what he saw. So I was glad to get a letter from him with helpful suggestions.”¹⁵⁰⁰ Through the end of October Compton worked on.

*   *   *

At Leipzig in September Werner Heisenberg received the first forty gallons of heavy water from Norsk Hydro and immediately prepared another chain-reaction experiment like the unsuccessful effort at the Virus House in Dahlem the year before: a thirty-inch aluminum sphere filled with alternating layers of heavy water and uranium oxide, more than three hundred pounds of it, arranged around a central neutron source, the sphere itself then immersed in water in a laboratory tank. This time Heisenberg found some increase in neutrons, enough to extrapolate eventual success. The German laureate knew now from the work of von Weizsácker and Houtermans that a sustained chain reaction in natural uranium would breed element 94. “It was from September 1941,” he remarks in consequence, “that we saw an open road ahead of us, leading to the atomic bomb.”¹⁵⁰¹

He decided to talk to Bohr. To what end he thought Bohr might help him he never unambiguously explained. His wife Elisabeth believes “he was lonely in Germany. Niels Bohr had become a father figure to him. . . . He thought that he could talk about anything with Bohr. . . . The advice of an older friend, more experienced in human and political affairs, had always been important to him.” He “saw himself confronted with the spectre of the atomic bomb,” Elisabeth Heisenberg explains, “and he wanted to signal to Bohr that Germany neither would nor could build a bomb. . . . Secretly he even hoped that his message could prevent the use of an atomic bomb on Germany one day. He was constantly tortured by this idea. . . . This vague hope was probably the strongest motivation for his trip.”¹⁵⁰²

Heisenberg and von Weizsäcker attended a scientific meeting in Copenhagen at the end of October, a meeting Bohr routinely boycotted as he boycotted all joint Danish and German activities, to emphasize his refusal to collaborate. He was willing to see Heisenberg, however, and received him, according to the German physicist’s wife, “with great warmth and hospitality.”¹⁵⁰³

Heisenberg saved his crucial conversation for a long evening walk with Bohr through the brewery district around the Carlsberg House of Honor. “Being aware that Bohr was under the surveillance of the German political authorities,” he recalled after the war, “and that his assertions about me would probably be reported to Germany, I tried to conduct this talk in such a way as to preclude putting my life into immediate danger.” Heisenberg remembers asking Bohr if it was right for physicists to work on “the uranium problem” in wartime when there was a possibility that such work could lead to “grave consequences in the technique of war.” Bohr, who had returned from the United States convinced that a bomb was practically impossible, “understood the meaning of the question immediately, as I realized from his slightly frightened reaction.” Heisenberg apparently thought Bohr was privy to American secrets and was reacting guiltily to implicit exposure. But Bohr’s next response suggests that he had been, rather, stunned at Heisenberg’s revelation: he asked Heisenberg if a bomb really was possible. Heisenberg says he answered that a “terrific technical effort” would be necessary, which he hoped could not be realized in the present war. “Bohr was shocked by my reply, obviously assuming that I had intended to convey to him that Germany had made great progress in the direction of manufacturing atomic weapons. Although I tried subsequently to correct this false impression I probably did not succeed. . . . I was very unhappy about the result of this conversation.”¹⁵⁰⁴

Thus Heisenberg’s version of the evening walk. Bohr’s is less detailed. His son Aage, a Nobel laureate in his turn and his father’s successor as director of the Copenhagen institute, summarizes it in a memoir:

The impression that in Germany great military importance was given to [atomic energy research] was strengthened by the visit to Copenhagen in the autumn of 1941 of Werner Heisenberg and C. F. von Weizsäcker. . . . In a private conversation with my father Heisenberg brought up the question of the military applications of atomic energy. My father was very reticent and expressed his scepticism because of the great technical difficulties that had to be overcome, but he had the impression that Heisenberg thought that the new possibilities could decide the outcome of the war if the war dragged on. . . . [Heisenberg’s] account [of the meeting] has no basis in actual events.¹⁵⁰⁵

Robert Oppenheimer, who also had the story direct from Bohr, condenses the meeting to the comment: “Heisenberg and von Weizsäcker came over from Germany, and so did others. Bohr had the impression that they came less to tell what they knew than to see if Bohr knew anything that they did not; I believe that it was a standoff.”¹⁵⁰⁶

The two accounts are not incompatible, but both leave out a crucial fact: that Heisenberg passed to Bohr a drawing of the experimental heavywater reactor he was working to build.¹⁵⁰⁷ If he did so clandestinely he certainly risked his life. If he did so cynically and with Nazi approval to misdirect Allied intelligence he was certainly no longer attached to Bohr as a father figure, as Elisabeth Heisenberg writes. Whatever his intent, it had the wrong effect on Bohr. Elisabeth Heisenberg thinks “Bohr essentially heard only one single sentence: The Germans knew that atomic bombs could be built. He was deeply shaken by this, and his consternation was so great that he lost track of all else.”¹⁵⁰⁸ But Aage Bohr’s and Oppenheimer’s accounts imply a further response from Bohr: indignation, even incredulity, that Heisenberg would think Bohr might be willing in any way, for any reason, to cooperate with Nazi Germany. Heisenberg, in turn, was aghast that Bohr would fail to see and credit his reservations, would not understand, as his wife writes, that his “bond to his country and its people was not tantamount to a bond to the regime.” To the contrary, she adds, “Bohr told Heisenberg that he understood completely that one had to use all of one’s abilities and energies for one’s country in time of war.” Not surprisingly, since it implied Bohr thought the worst of him—that he was willing to work for the Nazis—“Heisenberg was deeply shocked by Bohr’s reply.”¹⁵⁰⁹

The meeting, and especially the drawing Heisenberg passed, gave Bohr more to worry about, but he continued to doubt that any nation could afford sufficient industrial capacity, especially in wartime, to pursue isotope separation. He must have been pained at what he took to be the treachery of a brilliant and formerly devoted protege. Heisenberg for his part found himself, says his wife, in “a state of confusion and despair.”¹⁵¹⁰ Even at risk he had not convinced Bohr of his sincerity nor in any way begun a dialogue to avert possible catastrophe. In the absence of such dialogue he had only managed potentially to alarm Germany’s most powerful enemy further with news of progress in approaching the chain reaction. That news must necessarily accelerate Allied efforts to build a bomb. As Rudolf Peierls writes of this period in Heisenberg’s life, “he had agreed to sup with the devil, and perhaps he found that there was not a long enough spoon.”¹⁵¹¹

*   *   *

Arthur Compton sent draft copies of the third National Academy of Sciences report to Vannevar Bush and Frank Jewett before the weekend of November 1. The new report was brief—six double-spaced typewritten pages (with forty-nine pages of technical appendices and figures)—and finally and emphatically to the point: “The special objective of the present report is to consider the possibilities of an explosive fission reaction with U235” Progress toward separating uranium isotopes, Compton wrote, made renewed consideration urgent (a rationale somewhat less than candid: British progress had spurred the change).^{1512, 1513}

This time the report knew what it was about: “A fission bomb of superlative destructive, power will result from bringing quickly together a sufficient mass of element U235. This seems to be as sure as any untried prediction based upon theory and experiment can be.”¹⁵¹⁴ On the second page an estimate of critical mass elicited for the first time among the three NAS reports a mention of fast fission: “The mass of U235 required to produce explosive fission under appropriate conditions can hardly be less than 2 kg nor greater than 100 kg. These wide limits reflect chiefly the experimental uncertainty in the capture cross-section of U235 for fast neutrons.”¹⁵¹⁵

The NAS estimate of destructiveness was low compared to the MAUD Report estimate, some 30 tons of TNT equivalent per kilogram of U235 (for 25 pounds, 300 tons compared to MAUD’s 1,800 tons), but the American report attempted to compensate for its doubts about the efficacy of an intense energy release from a small amount of matter by emphasizing that the destructive effects on life of a bomb’s radioactivity “may be as important as those of the explosion itself.”¹⁵¹⁶

The centrifuge and gaseous diffusion programs were noted to be “approaching the stage of practical test.”¹⁵¹⁷ Fission bombs might be available “in significant quantity within three or four years.”¹⁵¹⁸ Like its predecessors the report stressed not the German challenge but the long-term prospect: “The possibility must be seriously considered that within a few years the use of bombs such as described here, or something similar using uranium fission, may determine military superiority.¹⁵¹⁹ Adequate care for our national defense seems to demand urgent development of this program.”

In detailed appendices Compton calculated the critical mass of a bomb heavily constrained in tamper at no more than 3.4 kilograms; Kistiakowsky debated whether a fission explosion would be as destructive in terms of energy produced as the explosion of an equivalently energetic mass of TNT and confirmed the feasibility of firing together two pieces of uranium at a speed of several thousand feet per second; and a senior physicist on Compton’s committee reported favorably on the isotope-separation systems then under consideration and recommended “the principle of parallel development,” meaning pursuing them all at once, an expensive way to save time in case one or more failed.

Notably missing from the third report was any mention of the uranium-graphite work going on at Columbia or of plutonium. Compton remembers that a U235 bomb looked “more straightforward and more certain of accomplishment” than a plutonium bomb, but the omission also measures the extent to which Briggs’ judgment of priorities, and Briggs himself, had been set aside.¹⁵²⁰ Bush writing Jewett before he met with Compton had already mentioned “leaving Briggs in charge of a section devoted as it is at the present time to physical measurements”—small potatoes indeed—and constituting “a new group under a full-time head to handle development.” He was considering Ernest Lawrence but still thought Lawrence talked too much: “The matter . . . would have to be handled under the strictest sort of secrecy.¹⁵²¹ This is the reason that I hesitate at the name of Ernest Lawrence.”

If the third and last NAS report only rationalized a previous presidential decision, it at least served to check the British findings independently and to commit the American physics community to the cause. The United States had finally set its wheels to the bomb track. Its inertia was proportional to the juggernaut of its scientific, engineering and industrial might. Acceleration overcoming inertia, it now began to roll.

*   *   *

No document Franklin Delano Roosevelt signed authenticates the fateful decision to expedite research toward an atomic bomb that Vannevar Bush reported in his October 9 memorandum to James Bryant Conant: the archives divulge no smoking gun. The closest the records come to a piece of paper that changed the world is a banality. Bush personally delivered the third National Academy of Sciences report to the President on November 27, 1941. Roosevelt returned it to him two months later with a note on White House stationery written in black ink with a broad-nibbed pen, a note that would communicate only a commonplace of the housekeeping of state secrets except for the authority of its first vernacular expression and the initials it bears:

Text reads: “Jan 19—V.B. OK—returned—I think you had best keep this in your own safe FDR”¹⁵²²

Still orphaned was plutonium, which Lawrence and Compton believed so promising. Compton found his chance to speak for it in early December when Bush and Conant called the members of the Uranium Committee to Washington to announce the reorganization of their work. Harold Urey would develop gaseous diffusion at Columbia, Bush and Conant had decided. Lawrence would pursue electromagnetic separation at Berkeley. A young chemical engineer, Eger V. Murphree, the director of research for Standard Oil of New Jersey, would supervise centrifuge development and look into broader questions of engineering. Compton in Chicago would be responsible for theoretical studies and the actual design of the bomb. “The meeting adjourned,” writes Compton, “with the understanding that we would meet again in two weeks to compare progress and shape our plans more firmly.”¹⁵²³

Bush, Conant and Compton went to lunch at the Cosmos Club on Lafayette Square. There the Chicago physicist spoke up for plutonium. He argued that the advantage of chemical extraction rather than isotope separation made element 94 “a worthy competitor.” Bush was wary. Conant pointed out that the new element’s chemistry was still largely unknown.¹⁵²⁴ Compton recalls their exchange:

“Seaborg tells me that within six months from the time [plutonium] is formed [by chain reaction] he can have it available for use in the bomb,” was my comment.

“Glenn Seaborg is a very competent young chemist, but he isn’t that good,” said Conant.

How good a chemist Glenn Seaborg might be remained to be seen. Compton, Conant remembers, went on to argue that “the construction of a self-sustaining chain reaction [in natural uranium—Fermi’s and Szilard’s project]¹⁵²⁵ would be a magnificent achievement” even if plutonium flunked as bomb material; “it would prove that the measurements and theoretical calculations were correct”:

I never knew whether it was this near-certainty of demonstrating a slow-neutron reaction which settled the matter in Van’s mind, or whether he was impressed with Compton’s faith in the production of a plutonium bomb, against my lack of faith as a chemist. At all events, within a matter of weeks he agreed to Arthur Compton’s setting up at Chicago a highly secret project.

Bush had called the Washington meeting on a weekend to accommodate busy men. They had assembled on Saturday, December 6, 1941. Almost immediately they found themselves busier yet.

*   *   *

At 7 A.M. Hawaiian time on Sunday, December 7, 1941, near Kahuku Point at the northernmost reach of the island of Oahu, two U.S. Army privates in the process of shutting down the Opana mobile radar station, an aircraft reconnaissance unit which they had manned since 4 A.M., noticed an unusual disturbance on their oscilloscope screen.¹⁵²⁶ They checked and confirmed no malfunction and decided the large merged blur of light “must be a flight of some sort.” Their plotting board indicated a bearing out of the northeast at a distance of 132 miles. More than fifty planes appeared to be involved. One of the men called the information center at Fort Shafter, at the other end of the island, where radar and visual reconnaissance reports were combined on a tabletop map. The lieutenant who took the phone heard the radar operator call the sightings “the biggest . . . he had ever seen.”¹⁵²⁷ The operator did not, however, report his estimate of their number.

Both the Army and the Navy had been warned of imminent danger of Japanese attack. The Japanese had convinced themselves that dominance over East Asia was vital to their survival. The American reaction to militant Japanese expansion into Manchuria and China—as many as 200,000 men, women and children were brutally slaughtered by the Japanese Army in Shanghai in 1937—had been to embargo war materials and freeze Japanese assets in the United States. Aviation fuel, steel and scrap iron went on the embargo list in September 1940 when the Japanese moved into French Indochina with the timid approval of Vichy France. After that the Japanese estimated they could survive no more than eighteen months without access to Asian oil and iron ore. For some time they had prepared for war while continuing to negotiate. Now negotiations had collapsed.

Lieutenant General Walter C. Short, commander of the Army’s Hawaiian Department, received a coded message on November 27 signed in the name of the Chief of Staff—George Marshall—that read in part:

Negotiations with Japan appear to be terminated to all practical purposes with only the barest possibility that the Japanese Government might come back and offer to continue. Japanese future action unpredictable but hostile action possible at any moment. If hostilities cannot, repeat cannot be avoided the United States desires that Japan commit the first overt act. . . . Measures should be carried out so as not, repeat not, to alarm civil population or disclose intent.¹⁵²⁸

Short had at option three levels of alert, escalating from “a defense against sabotage, espionage and subversive activities without any threat from the outside” to full defense against “an all-out attack.” He thought it obvious that the War Department message “was written basically for General Mac-Arthur in the Philippines” and chose the limited sabotage defense, Alert No. 1.¹⁵²⁹

Admiral Husband E. Kimmel, Commander in Chief of the U.S. Pacific Fleet, which was based at Pearl Harbor west of Honolulu on the southern coast of Oahu, received a similar but even more pointed message from the Navy Department a few hours later:

This dispatch is to be considered a war warning. Negotiations with Japan looking toward stabilization of conditions in the Pacific have ceased and an aggressive move by Japan is expected within the next few days. The number and equipment of Japanese troops and the organization of naval task forces indicates an amphibious expedition against either the Philippines, Thai or Kra Peninsula or possibly Borneo. Execute an appropriate defensive deployment preparatory to carrying out the tasks assigned.¹⁵³⁰

Kimmel noted the references to other theaters of potential conflict. When he and Short exchanged messages he noted the “more cautious phrasing” of the Army warning.¹⁵³¹ “Appropriate defensive deployment” meant, he thought, full security measures for ships at sea. A surprise submarine attack seemed possible and he ordered the depth-bombing of any submarines discovered in the waters around Oahu.

The Army lieutenant who took the Opana radar call therefore had no expectation of danger. He looked for a routine explanation of the unusual report and found it. The Army paid radio station KGMB in Honolulu to play Hawaiian music throughout the night whenever it ferried aircraft to the Islands, giving its navigators a signal to seek. The lieutenant had heard such music on the radio that morning on his way to the information center. He decided that the radar must be picking up a flight of B-17’s. The heading plotted at Opanu was the usual direction of approach from California. “Well, don’t worry about it,” the lieutenant told the radar men.¹⁵³²

Pearl Harbor is a shallow, compound basin sheltered inland through a narrow outer channel from the sea. A bulge of land, Pearl City, and a midbasin island, Ford Island, canalize the main anchorage of the harbor into a loop of narrow inlets. In 1941 drydocks, oil storage tanks and a submarine base occupied the harbor’s irregular eastern shore. Seven battleships rode at anchor immediately southeast of Ford Island that Sunday morning: Nevada anchored alone; Arizona inboard of the repair ship Vestal; Tennessee inboard ofWest Virginia; Maryland inboard of Oklahoma; California alone. An eighth battleship, Pennsylvania, wedged naked in drydock nearby.

Lieutenant Commander Mitsuo Fuchida of the Japanese Imperial Navy, thirty-nine years old, who wore a red shirt to disguise from his men any blood he might shed and a white hachimaki tied around his flight helmet brushed with the calligraphic characters for “Certain Victory,” called out “Tora! Tora! Tora!” at 0753 hours as his pilot banked around Barber’s Point southwest of Pearl: “Tiger!” three times invoked to announce to the listening Japanese Navy that his first wave of 183 planes had achieved complete surprise. The 43 fighters, 49 high-level bombers, 51 dive-bombers and 40 torpedo planes he commanded had flown from six carriers holding station 200 miles to the north, carriers formidably escorted by battleships, heavy cruisers, destroyers and submarines that had left Hitokappu Bay on the northern Japanese island of Etorofu on November 25 and sailed blacked out in radio silence across the stormy but empty northern Pacific for almost two weeks to achieve this stunning rendezvous.

The torpedo bombers divided into groups of twos and threes and dived. The aircrews had prepared themselves to ram the battleships if necessary, but nothing restrained their attack. At 0758 the Ford Island command center radioed its frantic message to the world: AIR RAID PEARL HARBOR. THIS IS NOT DRILL. Admiral Kimmel saw the attack begin from a neighbor’s lawn—“in utter disbelief and completely stunned,” the neighbor remembers, “as white as the uniform he wore.” Torpedoes struck a light cruiser and a target ship, a minelayer, another light cruiser, then the battleships: Arizona lifted out of the water; West Virginia washed by a huge waterspout; Oklahoma hit by three torpedoes one after another and immediately listing steeply to port; the bottom blown out ofArizona;three torpedoes into California; two more into West Virginia’, a fourth into Oklahoma that bounced the big ship and rolled it over bottom up; Arizona taking a bomb that detonated its forward explosive stores, ripped the ship apart, killed at least a thousand men and blew high into the air a grisly rain of bodies, hands, legs and heads; a torpedo tearing out Nevada’s port bow. Thick black smoke rolled up to foul the blue Hawaiian morning and in the water, burning, screaming men attempted to swim through a dense scum of burning oil. Japanese fighters and bombers destroyed aircraft on the ground and strafed soldiers and marines pouring out of barracks at Hickam Field and Ewa Field and Wheeler. An hour later a second wave of 167 more attack aircraft deployed to further destruction. The two raids accounted for eight battleships, three light cruisers, three destroyers and four other ships sunk, capsized or damaged and 292 aircraft damaged or wrecked, including 117 bombers. And 2,403 Americans, military and civilian, killed, 1,178 wounded, in unprovoked assaults that lasted only minutes. The following afternoon, Franklin Roosevelt, addressing Congress in joint session, requested and won a declaration of war against not only Japan but Germany and Italy as well.

The man who conceived and planned the surprise attack on Pearl Harbor, Admiral Isoroku Yamamoto, Commander in Chief of the Japanese Combined Fleet, had few illusions about the ultimate success of a war against the United States. He had studied at Harvard and served as a naval attaché in Washington and knew America’s strength. But if war had to come he meant “to give a fatal blow to the enemy fleet” when it was least expected, at the outset. By that act he hoped he could win his country six months to a year during which it might establish its Greater East Asia Co-Prosperity Sphere and dig in.

The torpedoes had been a challenge. Pearl Harbor was only forty feet deep. Torpedoes dropped from planes routinely sank seventy feet or more before bobbing up to attack depth. The Japanese had to reduce that plunge signficantly or bury their weapons in the Pearl mud.

They found in repeated experiments that they could sometimes manage a shallower drop by flying only forty feet above the water and holding down their air speed—the maneuver demanded skilled flying—but further improvement required torpedo redesign, largely by trial and error. As late as mid-October Fuchida’s flyers were still managing no better than sixtyfoot plunges, still far too deep.

A new stabilizer fin, originally designed for aerial stability, saved the mission. Tested during September, it consistently held the torpedo to less than forty feet and steadied it as well. But the pilots still needed aiming practice. Only thirty of the modified weapons could be promised by October 15, another fifty by the end of the month and the last hundred on November 30, after the task force was scheduled to sail.

The manufacturer did better. Realizing the weapons were vital to a secret program of unprecedented importance, manager Yukiro Fukuda bent company rules, drove his lathe and assembly crews overtime and delivered the last of the 180 specially modified torpedoes by November 17. Mitsubishi Munitions contributed decisively to the success of the first massive surprise blow of the Pacific War by the patriotic effort of its torpedo factory on Kyushu, the southernmost Japanese island, three miles up the Urakami River from the bay in the old port city of Nagasaki.¹⁵³³