17

The Evils of This Time

The bombs James Bryant Conant speculated about early in 1945 were crude designs of uncertain yield. The previous October he had traveled out to Los Alamos to ascertain their prospects. To Vannevar Bush he reported that the gun method of detonation seemed “as nearly certain as any untried new procedure can be.”²¹¹² The availability of a uranium gun bomb, which Los Alamos expected would explode with a force equivalent to about 10,000 tons of TNT, now depended only on the separation of sufficient U235. Implosion looked far more questionable; intensive work was just then getting under way following Oppenheimer’s August reorganization of the laboratory. Conant estimated the yield of the first implosion design, whether lensed or not, “as an order of magnitude only” at about 1,000 tons TNT equivalent. That was so relatively modest a result that he invited Bush to consider the gun bomb strategic and the implosion bomb tactical.

For the past three years Bush and Conant had concentrated their efforts entirely on these first crude bombs. Now they were interested in improvements. During the summer of 1944, Conant says, on an earlier inspection trip to Los Alamos, he and Bush had found leisure and privacy to discuss “what the policy of the United States should be after the war was over.”²¹¹³ As a result they had sent Secretary of War Henry L. Stimson a joint memorandum on September 19 that independently raised some of the issues Niels Bohr had raised with Franklin Roosevelt in August, in particular that “the progress of this art and science is bound to be so rapid in the next five years in some countries that it would be extremely dangerous for this government to assume that by holding secret its present knowledge we should be secure.”^{2114, 2115} They did not see the bomb’s complementarity, but did see that whatever control arrangement the United States and Great Britain devised—they favored a treaty—would somehow have to include the Soviet Union; if the Soviets were not informed, as Bush told Conant, the exclusion would lead “to a very undesirable relationship indeed on the subject with Russia.”²¹¹⁶

Roosevelt had returned from Hyde Park troubled that Felix Frankfurter and Bohr had somehow breached Manhattan Project security, Bush and perhaps Conant had talked to Bohr and the two administrators had submitted to Stimson at his request a more detailed proposal incorporating Bohr’s ideas. In doing so they had explicitly recommended that the United States sacrifice some portion of its national sovereignty in exchange for effective international control, understanding as they did so that they would have to answer vigorous opposition:

In order to meet the unique situation created by the development of this new art we would propose that free interchange of all scientific information on this subject be established under the auspices of an international office deriving its power from whatever association of nations is developed at the close of the present war. We would propose further that as soon as practical the technical staff of this office be given free access in all countries not only to the scientific laboratories where such work is contained, but to the military establishments as well. We recognize that there will be great resistance to this measure, but believe the hazards to the future of the world are sufficiently great to warrant this attempt.²¹¹⁷

But how great in fact were the hazards? That was something else Conant traveled to Los Alamos in October to find out. If the argument for allowing the nation’s military establishments to be inspected depended on the dangers of a thermonuclear explosive, it was speculative and therefore weak: the thermonuclear was still only an idea on paper that might not work. How much could fission weapons be improved? How much destructiveness of either kind might a bomber—or, as Bush and Conant briefed Stimson, “a robot plane or guided missile”—eventually visit upon the cities of the world?²¹¹⁸

What Conant learned first of all was that others had already begun to ask the same questions. The technological imperative, the urge to improvement even if the objects to be improved are weapons of mass destruction, was already operating at Los Alamos. Under intense pressure to produce a first crude weapon in time to affect the outcome of the war, people had found occasion nevertheless to think about building a better bomb. Conant reported to Bush:

By various methods that seem quite possible of development within six months after the first bomb is perfected, it should be possible to increase the efficiency . . . in which case the same amount of material would yield something like 24,000 Tons TNT equivalent. Further developments along this same line hold a possibility of producing a single bomb with such amounts of materials and such efficiencies as to run this figure up to several hundred thousand Tons TNT equivalent, or even perhaps a million Tons TNT equivalent. . . . All these possibilities reside only in perfecting the efficiency of the use of elements “25”[U235] and “49” [Pu239]. You will thus see that a considerable “super” bomb is in the offing quite apart from the use of other nuclear reactions.²¹¹⁹

A million tons TNT equivalent was devastation indeed—the world war then raging would consume a total of about three million tons of explosives by its end—but Edward Teller, Conant found, had already dismissed such improvements as picayune:

It seems that the possibility of inciting a thermonuclear reaction involving heavy hydrogen is somewhat less now than appeared at first sight two years ago. I heard an hour’s talk on this subject by the leading theoretical man at L.A. The most hopeful procedure is to use tritium (the radioactive isotope of hydrogen made in a pile) as a sort of booster in the reaction, the fission bomb being used as the detonator and the reaction involving the atoms of liquid deuterium being the prime explosive. Such a gadget should produce an explosive equivalent to 100,000,000 Tons of TNT, which in turn should produce Class B damage over an area of 3,000 square miles!

This last real super bomb is probably at least as distant now as was the fission bomb when you and I first heard of the enterprise.

The thermonuclear was something of a Rorschach test. If it could be made to work at all it was, like a fire, potentially unlimited; to build it larger you only piled on more heavy hydrogen. As Los Alamos paid less attention to Teller’s Super his projection of its destructive potential grew moregrandiose.

Robert Oppenheimer also commited himself at that time to exploring the thermonuclear—after the war was won—in a letter to Richard Tolman on September 20, 1944. “I should like,” he emphasized, “ . . . to put in writing at an early date the recommendation that the subject of initiating violent thermonuclear reactions be pursued with vigor and diligence, and promptly.” A way station on the road to a full-scale thermonuclear might be a boosted fission bomb with a small charge of heavy hydrogen confined possibly within the core of an implosion device:

In this connection I should like to point out that [fission] gadgets of reasonable efficiency and suitable design can almost certainly induct significant thermonuclear reactions in deuterium even under conditions where these reactions are not self-sustaining. . . . It is not at all clear whether we shall actually make this development during the present project, but it is of great importance that such . . . gadgets form an experimentally possible transition from a simple gadget to the super and thus open the possibility of a not purely theoretical approach to the latter.²¹²⁰

(In fact not deuterium but tritium proved to be the necessary ingredient of a boosted fission bomb, and such weapons were not developed until long after the end of the war.)

Alluding then to the larger consequences that Bohr had revealed, Oppenheimer emphasized once more the urgency he attached to the pursuit of an H-bomb: “In general, not only for the scientific but also for the political evaluation of the possibilities of our project, the critical, prompt, and effective exploration of the extent to which energy can be released by thermonuclear reactions is clearly of profound importance.”

Working against the clock to build weapons that might end a long and bloody war strained life at Los Alamos but also heightened it.²¹²¹ “I always pitied our Army doctors for their thankless job,” comments Laura Fermi:²¹²²

They had prepared for the emergencies of the battlefields, and they were faced instead with a high-strung bunch of men, women, and children. Highstrung because altitude affected us, because our men worked long hours under unrelenting pressure; high-strung because we were too many of a kind, too close to one another, too unavoidable even during relaxation hours, and we were all [as Groves had warned his officers not entirely tongue-in-cheek] crackpots; high-strung because we felt powerless under strange circumstances, irked by minor annoyances that we blamed on the Army and that drove us to unreasonable and pointless rebellion.

They made the best of it. Mici Teller waged pointed rebellion saving the backyard trees to preserve a playground for her son. “I told the soldier in his big plow to leave me please the trees here,” one of her friends remembers her recounting, “so Paul could have shade but he said, ‘I got orders to level off everything so we can plant it,’ which made no sense as it was planted by wild nature and suits me better than dust. The soldier left, but was back next day and insisted he had more orders ‘to finish this neck of the woods.’ So I called all the ladies to the danger and we put chairs under the trees and sat on them.²¹²³ So what could he do? He shook his head and went away and has not come again.” Contrariwise, to clear a ski area on the hill to the west of the mesa, George Kistiakowsky wrapped the trees with half-necklaces of plastic explosive and thus noisily but efficiently cut them down. “Then we scrounged equipment to build a rope tow and it became a nice little ski slope,” he recalls.²¹²⁴

The Fermis moved to Los Alamos in September 1944 and requested one of the less coveted fourplex apartments rather than the Ranch School faculty cottage that had been prepared for them, to make a point about social snobbery. The Peierls, Rudolf and energetic Genia—Otto Frisch’s dish-drying coach in Birmingham—lived below. The mix of birthplaces and citizenships was typical of the Hill: Peierls a German Jew, his wife a Russian, both with British citizenship; Laura Fermi still nostalgic for Rome but she and her husband new American citizens as of July. “Oppie has whistled,” Fermi would announce with a yawn when the morning siren sounded. “It is time to get up.”²¹²⁵ The Italian laureate directed a new operation, F (for Fermi) Division, a catchall designed to take advantage of his versatility as both theoretician and experimentalist. One of the groups he caught was Teller’s. “That young man has imagination,” the forty-three-year-old Italian emigré told his wife drolly of the thirty-six-year-old Hungarian. “Should he take full advantage of his inventiveness, he will go a long way.”²¹²⁶ Teller stayed up late at night working out ideas and playing the piano and hardly ever appeared in the Tech Area before late morning.

“Parties,” remembers Fuze Development group leader Robert Brode’s articulate wife Bernice, “both big and brassy and small and cheerful, were an integral part of mesa life. It was a poor Saturday night that some large affair was not scheduled, and there were usually several of them. . . . On [Saturday nights] we raised whoopie, on Sundays we took trips, the rest of the week we worked.”²¹²⁷ Single men and women sponsored dorm parties fueled with tanks of punch made potent with mixed liquors and pure Tech Area grain alcohol and invited wall-to-wall crowds. The singles removed all the furniture from their dormitory common rooms to make areas for dancing and by unwritten rule kept their upstairs doors open through the night.

Square dancing evolved as a natural Saturday evening activity in that Southwestern setting. (“Everybody was wearing Western clothes—jeans, boots, parkas,” Stanislaw Ulam’s French wife Françoise remembers noticing with surprise when she and her husband arrived on the Hill. “There was a feeling of mountain resort, in addition to army camp.”²¹²⁸) The dances were first held in Deke Parsons’ living room, then the theater, then Fuller Lodge, finally expanding to crowd the large mess hall. Eventually even the Fermis attended with their daughter Nella to learn the vigorous reels. Long after mother and daughter had been persuaded from the sidelines Fermi sat unbudging, mentally working out the steps. When he was ready he asked Bernice Brode, one of the leaders, to be his partner. “He offered to be head couple, which I thought most unwise for his first venture, but I couldn’t do anything about it and the music began. He led me out on the exact beat, knew exactly each move to make and when. He never made a mistake, then or thereafter, but I wouldn’t say he enjoyed himself. . . . He [danced] with his brains instead of his feet.”²¹²⁹

Theater sometimes supplied a Saturday alternative. At a performance of Arsenic and Old Lace Robert Oppenheimer surprised and delighted the audience by appearing powdered sepulchrally white with flour as the first of the crowd of corpses emerging from the cellar in the last act. Donald Flanders, tall and bearded, known as Moll, Computation group leader in the Theoretical Division, wrote a comic ballet, Sacre du Mesa, set to George Gershwin music. Despite his beard and his lack of ballet training Flanders danced the part of General Groves. Samuel Allison’s son Keith appeared as Oppenheimer, dancing on a large table wearing suitably casual clothes and a pork-pie hat. “The main stage prop,” Bernice Brode notes, “was a mechanical brain with flashing lights and noisy bangs and sputters, which did consistently wrong calculations, for example, 2 + 2 = 5. In the grand but hectic finale, the wrong calculations were revealed as the real sacred mystery of the mesa.”²¹³⁰

Kistiakowsky preferred less formally intellectual entertainment:

I played a lot of poker with important people like Johnny Von Neumann, Stan Ulam, etc. . . . When I came to Los Alamos I discovered that these people didn’t know how to play poker and offered to teach them. At the end of the evening they got annoyed occasionally when we added up the chips. I used to point out that if they had tried to learn violin playing, it would cost them even more per hour. Unfortunately, before the end of the war, these great theoretical minds caught on to poker and the evening’s accounts became less attractive from my point of view.²¹³¹

And Robert Wilson, Cyclotron Program group leader, who served on the advisory Town Council, discovered even more elemental activities on the Hill despite security screening before employment and roving military police:

Of the many problems that were presented to us during my term of office, the most memorable was when the M.P.’s who guarded the site chose to place one of our women’s dorms off-limits. They recommended that we close the dorm and dismiss the occupants. A tearful group of young ladies appeared before us to argue to the contrary. Supporting them, a determined group of bachelors argued even more persuasively against closing the dorm. It seems that the girls had been doing a flourishing business of requiting the basic needs of our young men, and at a price.²¹³² All understandable to the army until disease reared its ugly head, hence their interference. By the time we got that matter straightened out—and we did decide to continue it—I was a considerably more learned physicist than I had intended to be a few years earlier when going into physics was not all that different from taking the cloth.

Married or single, the occupants of Post Office Box 1663 were young and healthy; they produced so many babies that Groves ordered either the reservation commander or the laboratory director—both versions of the story survive—to staunch the flood. Oppenheimer, if Oppenheimer it was, refused the duty. With justification: his wife Kitty bore him a second child, a daughter, Katherine, called Toni, on December 7, 1944. So many people wanted to see the boss’s baby that the hospital identified the crib with a sign and lines formed to file past the nursery window.

Crowded together behind a fence, Hill families worried about epidemic disease. A pet dog that had bitten several children turned up rabid and pet owners debated angrily with parents about which category of dependent should be kept on a leash. More frightening was the sudden death of a young chemist, a group leader’s wife, from an unidentified form of paralysis. Fearing an outbreak of poliomyelitis, doctors closed the schools, put Santa Fe off limits and ordered all children indoors.

No new cases appeared, the danger abated with the continuation of cold weather and work and play resumed. “I don’t think I shall ever again live in a community where so many brains were,” comments Edwin McMillan’s wife Elsie, Ernest Lawrence’s sister-in-law, “nor shall I ever live in a community so confined that visitors expected us to fight with each other. We didn’t have telephones, we didn’t have the bright lights, but I don’t think I shall ever live in a community that had such deep roots of cooperation and friendship.”²¹³³

Some reserved Sundays for church and hobbies; others devoted the day to outings. The Oppenheimers maintained magnificent riding horses and rode regularly on Sunday morning but only once in three years found time for an overnight excursion. Kistiakowsky bought one of Oppenheimer’s quarter horses and refreshed himself trailing in the mountains after his late Saturday poker nights; the Army stabled the private animals along with the remuda it kept for the mounted MP’s who patrolled the mesa fences. Emilio Segrè found excellent fly-fishing. “The streams are full of big trouts,” he announced happily to newcomers. “All you have to do is throw in a line and they bite you, even if you are shouting.”²¹³⁴ Fermi took up angling, says Segrè, “but he went about it in a peculiar way.²¹³⁵ He had tackle different from what anyone else used for trout fishing, and he developed theories about the way fish should behave. When these were not substantiated by experiment, he showed an obstinacy that would have been ruinous in science.” Fermi insisted on fishing for trout with worms, arguing that the condemned creatures should be offered an authentic final meal, not the dry flies of tradition. Segrè made a point of reviewing the subtleties of trout fishing with his old friend. “Oh, I see, Emilio,” Fermi eventually countered, “it is a battle of wits.”²¹³⁶

Mountain climbing had long been a Hans Bethe hobby. He and Fermi, among others, sometimes scaled Lake Peak across the Rio Grande in the Sangre de Cristos, one of Bethe’s admiring group leaders remembers, to “sit there in the sunshine” at 12,500 feet “discussing physics problems. This is how many discoveries were made.”²¹³⁷ Leona Marshall, who moved with Fermi to Los Alamos, recalls less Olympian hours with “nothing to do but admire the view and gasp for breath.”²¹³⁸

Equally strenuous excursions went out to area landmarks. Genia Peierls and Bernice Brode determined to find the Stone Lions, prehistoric lifesized twin effigies of crouching mountain lions carved in tuff, reported beside a ruined pueblo on a distant mesa. They gathered up a carload of Navy ensigns and another of young bachelors from the British mission and drove within ten miles of their goal, then set out walking, Genia Peierls leading the way in tennis shoes without socks: “Best for stones, best for bunions.” Lunch at two in the afternoon by a cool canyon stream encouraged the weary ensigns to drop anchor, but Mrs. Peierls had cowed the young British mission men from similar protest. “OK, we proceed to Stone Lions without U. S. Navy. All aboard.” More hiking, crossing desert country from mesa to mesa, the Rio Grande below. The American woman was impressed with the Stone Lions; not so the Russian. “House cats only, my dear, not well made and maybe not even old.” “On the way back,” Bernice Brode recalls, “the young men . . . looked out over the wide expanse of the desert region and the ribbon of water shining in the setting sun. One of them, dark and slim, wearing tortoise shell rimmed glasses, spoke in his soft voice with a slight German accent. ‘I have not seen New York, nor Chicago, but I have seen the Stone Lions.’ He smiled pleasantly as we walked on. His name was Klaus Fuchs.” Penny-in-the-slot Fuchs, Genia Peierls nicknamed him, because the quiet, hardworking emigré theoretician only spoke when spoken to.²¹³⁹

On a hike through Frijoles Canyon with the Fermis, Niels Bohr stopped to admire a skunk, an animal unknown to Europeans, but it chose not to instruct the vigorous Dane in the pungency of its defenses. Bears sometimes appeared on the trails, prompting warnings in the daily bulletin: “Remember that these are not tame bears like those in Yellowstone Park.”²¹⁴⁰ A family cat turned up with a suppurating jaw; the Hill’s Army veterinarian recognized the bone necrosis as a sign of radiation poisoning from Tech Area contamination and kept the animal alive to observe its unusual symptomatology, about which not much was yet known. Its tongue swelled and its hair fell out in patches; its heartsick owner eventually asked that the animal be destroyed.

A low-power radio station began broadcasting to Hill residents on Christmas Eve, 1943, drawing on several fine collections of classical records, including Oppenheimer’s; the few New Mexicans beyond the Hill who could receive the station’s signals were puzzled that announcers never introduced live performers by their last names. The “Otto” who occasionally played classical piano selections was Otto Frisch. A golf course opened in June 1944. Men and women fielded baseball, softball and basketball teams. The Army divided up the old Ranch School truck garden east of Fuller Lodge into victory-gardening plots but had no water to spare for irrigation.

Life was rougher for construction workers, machinists, soldiers and WAC’s: minimal barracks, jerrybuilt dormitories, muddy trailer courts. Hillbilly construction families invited once in the interest of authenticity to the square dancing at the mess hall arrived drunk and nearly caused a riot; thereafter a man in uniform guarded the door. Hans Bethe recalls that one wild machinist late in the war, when the laboratory took what help it could find, slit a fellow worker’s throat “from cover to cover.”²¹⁴¹ The Indians from San Ildefonso and other pueblos and ranches in the area lived better for their work on the Hill as cleaning women and maintenance men. The hand-coiled black pottery of Maria Martinez soon graced many Los Alamos apartments.

In winter a pall of coal smoke hung over the mesa. The men the Army assigned to service the apartment furnaces stoked them so hot that apartment walls sometimes sizzled. Los Alamos sat high and dry surrounded by pine forests, and fire worried everyone. The main machine shop in the Tech Area caught fire one night early in 1945; Eleanor Jette remembers watching her husband Eric, Metal Reduction group leader in the Chemistry and Metallurgy Division, standing with Oppenheimer and the Hill commanding officer on the fire escape of the administration building grimly overseeing the firefighters. “Jesus,” she heard someone say, “let’s be thankful it isn’t D building. That place is as hot as seven million dollars. Every time it gets too hot for them to work, they slap on another coat of paint.” Her husband worked in D building; she did not know he worked with plutonium but understood that “hot” meant radioactive. “Damn,” he told her when she asked. “You mustn’t be upset. We’re so careful it’s fantastic.”²¹⁴² A fire in the plutonium-handling areas would be a major disaster; after the machine-shop fire Groves ordered a fireproof plutonium works built with steel walls and a steel roof and filtering systems for both incoming and outgoing air.

Robert Oppenheimer oversaw all this activity with self-evident competence and an outward composure that almost everyone came to depend upon. “Oppenheimer was probably the best lab director I have ever seen,” Teller repeats, “because of the great mobility of his mind, because of his successful effort to know about practically everything important invented in the laboratory, and also because of his unusual psychological insight into other people which, in the company of physicists, was very much the exception.”²¹⁴³“He knew and understood everything that went on in the laboratory,” Bethe concurs, “whether it was chemistry or theoretical physics or machine shop. He could keep it all in his head and coordinate it. It was clear also at Los Alamos that he was intellectually superior to us.”²¹⁴⁴ The Theoretical Division leader elaborates:

He understood immediately when he heard anything, and fitted it into the general scheme of things and drew the right conclusions. There was just nobody else in that laboratory who came even close to him. In his knowledge. There was human warmth as well. Everybody certainly had the impression that Oppenheimer cared what each particular person was doing. In talking to someone he made it clear that that person’s work was important for the success of the whole project. I don’t remember any occasion at Los Alamos in which he was nasty to any person, whereas before and after the war he was often that way. At Los Alamos he didn’t make anybody feel inferior, not anybody.²¹⁴⁵

Yet Oppenheimer felt inferior himself, had always felt for the actions of his life, as he confessed many years afterward, “a very great sense of revulsion and of wrong.” At Los Alamos for the first time he seems to have found alleviation of that loathing. He may have discovered there a process of self-analysis anchored in complementarity that served him more comprehensively later in his life: “In an attempt to break out and be a reasonable man, I had to realize that my own worries about what I did were valid and were important, but that they were not the whole story, that there must be a complementary way of looking at them, because other people did not see them as I did.²¹⁴⁶ And I needed what they saw, and needed them.” Certainly he found the more traditional alleviation of losing himself in work.

Whatever his burden of morale and work in those years, Oppenheimer also carried his full share of private pain. He was kept under constant surveillance, his movements monitored and his rooms and telephones bugged; strangers observed his most intimate hours. His home life cannot have been happy. Kitty Oppenheimer responded to the stress of living at isolated Los Alamos by drinking heavily; eventually Martha Parsons, the admiral’s daughter, took over the duties of social leadership on the Hill. Army security officers hounded the director of the central laboratory of the nation’s most important secret war project mercilessly; at least one of them, Peer de Silva, was convinced Oppenheimer was a Soviet spy. They interrogated him frequently, fishing for the names of people he knew or believed to be members of the Communist Party, hoping to trip him up. He invented circumstances and volunteered the names of friends to protect his own, indiscretions that would return in time to haunt him.²¹⁴⁷

During the first Los Alamos summer he heard from Jean Tatlock, the unhappy woman he had loved before he met his wife. Loyally, even though she had been and still might be a Communist and he knew himself to be spied upon, he went to her; an FBI document coldly summarizes a security man’s peepshow version of that meeting:

On June 14, 1943, Oppenheimer traveled via Key Railway from Berkeley to San Francisco on the evening of June 14, 1943, where he was met by Jean Tatlock who kissed him. They dined at the Xochimilcho Cafe, 787 Broadway, San Francisco, then proceeded at 10:50 P.M. to 1405 Montgomery Street and entered a top floor apartment. Subsequently, the lights were extinguished and Oppenheimer was not observed until 8:30 A.M. next day when he and Jean Tatlock left the building together.²¹⁴⁸

In January 1944 Jean Tatlock committed suicide. “I wanted to live and to give and I got paralyzed somehow,” her suicide note said.²¹⁴⁹ It was a paralysis of the spirit Oppenheimer seemingly had to resist in himself.

Planning began in March 1944 for a full-scale test of an implosion weapon. Sometime between March and October Oppenheimer proposed a code name for that test.²¹⁵⁰ The first man-made nuclear explosion would be a historic event and its designation therefore a name that history might remember. Oppenheimer coded the test and the test site Trinity. Groves wrote him in 1962 to find out why, speculating that he chose the name because it is common to rivers and peaks in the American West and would be inconspicuous.

“I did suggest it,” Oppenheimer responded, “but not on [that] ground. . . .²¹⁵¹ Why I chose the name is not clear, but I know what thoughts were in my mind. There is a poem of John Donne, written just before his death, which I know and love. From it a quotation:

As West and East

In all flatt Maps—and I am one—are one,

So death doth touch the Resurrection.”

The poem was Donne’s “Hymne to God My God, in My Sicknesse,” and among its subtleties it construes a complementarity that parallels the complementarity of the bomb that Bohr had recently revealed to Oppenheimer. (“Bohr was deeply in this,” Bethe testifies, “and this was his real interest, and Bohr had long conversations with Oppenheimer which brought Oppenheimer into this at a very early stage. Oppenheimer was very much indoctrinated by Bohr’s ideas of international control.”²¹⁵²) That dying leads to death but might also lead to resurrection—as the bomb for Bohr and Oppenheimer was a weapon of death that might also end war and redeem mankind—is one way the poem expresses the paradox.

“That still does not make a Trinity,” Oppenheimer’s letter to Groves goes on, “but in another, better known devotional poem Donne opens, ‘Batter my heart, three person’d God;—.’ Beyond this, I have no clues whatever.”²¹⁵³ Nor must Groves have had; but the fourteenth of Donne’s Holy Sonnets equally explores the theme of a destruction that might also redeem:

Batter my heart, three person’d God; for you

As yet but knocke, breathe, shine, and seeke to mend;

That I may rise, and stand, o’erthrow mee, and bend

Your force to breake, blowe, burn and make me new.

I, like an usurpt towne, to another due,

Labour to admit you, but Oh, to no end;

Reason, your viceroy in mee, mee should defend,

But is captiv’d, and proves weake or untrue.

Yet dearly I love you, and would be loved faine,

But am betroth’d unto your enemie:

Divorce me, untie, or breake that knot againe,

Take mee to you, imprison me, for I

Except you enthrall me, never shall be free,

Nor ever chaste, except you ravish me.

That is poetry perhaps martial enough, ardent enough and sufficiently fraught with paradox to supply a code name for the first secret test of a millennial force newly visited upon the world.

Oppenheimer did not doubt that he would be remembered to some degree, and reviled, as the man who led the work of bringing to mankind for the first time in its history the means of its own destruction.²¹⁵⁴ He cherished the complementary compensation of knowing that the hard riddle the bomb would pose had two answers, two outcomes, one of them transcendent. Such understanding justified the work at Los Alamos if anything did, and the work in turn healed the split between self and overweening conscience that hurt him.²¹⁵⁵ He had long recognized the possibility of such a convalescence and evoked it explicitly in the epistle on discipline he wrote his brother Frank in 1932 that concluded in Pauline measure: “Therefore I think that all things which evoke discipline: study, and our duties to men and to the commonwealth, war, and personal hardship, and even the need for subsistence, ought to be greeted by us with profound gratitude; for only through them can we attain to the least detachment; and only so can we know peace.”²¹⁵⁶ At Los Alamos, if only for a time, he located that detachment in duties to men and to the commonwealth that Bohr was teaching him to believe might be worthy, not macabre. He was not the first man to find himself in war.

*   *   *

To develop implosion Los Alamos had to develop diagnostics, ways to see and to measure events that began and ended in considerably less time than the blink of an eye. The iron pipes Seth Neddermeyer imploded could be studied by aiming a high-speed flash camera down their bores, but how could the physicists of G Division observe the shaping of a detonation wave as it passed through solid blocks of high explosives, or the compression of the metal sphere which those explosives completely surrounded? They were competent research scientists who had been working within narrow technological constraints for a year and a half; diagnostics demanded imagination and they brought all their frustrated creativity to the task.

X-raying was a reliable approach; the Ordnance Division had already used X rays to study the behavior of small spherical arrangements of explosives. X rays reveal differences in density—dense bone casts a darker shadow than lighter flesh—and since the detonation wave of a developing implosion changed the density of the explosive material as it burned its way through, X rays could make that wave visible. But adapting X-ray diagnostics to implosion studies on an increasing scale meant protecting fragile X-ray equipment from the repeated blasts of as much as two hundred pounds of high explosives at a time. That challenge the physicists met by the unorthodox expedient of mounting their implosion tests between two closely spaced blockhouses with the X-ray unit in one building and the radiography equipment in the other, accessible to the test event through protected ports. Ultimately flash X-ray equipment—high-current X-ray tubes that pulsed as rapidly as every ten-millionth of a second—proved most useful for detonation-wave studies.

The behavior of a test unit’s HE shell was easier to study with X rays and high-speed photography than was the compression of its denser metal core. For following the metal core as it squeezed to less than half its previous volume Los Alamos developed several different diagnostic methods and used them in complement.

One method set the test unit within a magnetic field and measured changes in field configuration as the metal sphere compressed. Since HE is essentially transparent to magnetism, this method allowed the physicists eventually to study full-scale assemblies. It gave reliable measure of shock waves reflected from the core and of the troublesome detonation-wave intersections that caused jets and spalling.

Carefully spaced prearranged wires contacted by the metal sphere as it imploded supplied information not only about the timing of the implosion but also about material velocities at various depths within the core. That provided direct, quantitative data which the Theoretical Division could use to check how well its hydrodynamic theory fit the facts. The Electric Method group began by measuring the high-explosive acceleration of flat metal plates. Early in 1945 it adapted its techniques to partial spheres and eventually to spheres surrounded by HE lens systems with only one lens removed to access the necessary wires.

Duplicated at another test site, the blockhouse arrangement that served to protect ordinary X-ray equipment also served to shield the most unusual diagnostic method the scientists devised: firing pulsed X rays from a betatron through scale-model implosion units into a cloud chamber and photographing the resulting ionization tracks with a stereoscopic camera.¹ The betatron method needed an ingenious timing circuit to trigger in quick but precise sequence the explosive charge, the betratron X-ray pulse, the expansion of the diaphragm of the cloud chamber that made the ionization tracks visible as droplets in the fog and the camera shutters that photographed them.

The fifth successful method G Division developed varied the betatron method by incorporating an intense source of gamma radiation within the core itself. The source, radioactive lanthanum extracted from among fission products of the Oak Ridge air-cooled pile, gave the method its name: RaLa. Not a cloud chamber but alignments of rugged ionization chambers served to register the changing patterns of radiation from the RaLa cores as they compressed. Since no one knew at first how extensively the radiolanthanum would contaminate the test site, Luis Alvarez, who coordinated the first experiment, borrowed two tanks from the Army’s Dugway Proving Ground in Utah to use as temporary blockhouses. He recalls spectacular results:

I was sitting in the tank when the first explosion went off. George Kistiakowsky was in one tank and I was in the other. We were looking through the periscopes and all that happened was that it blew a lot of dust in our eyes.²¹⁵⁷ And then—we hadn’t thought about this possibility at all—the whole forest around us caught on fire. These pieces of white-hot metal went flying off into the wild blue yonder setting trees on fire. We were almost surrounded.

Implosion lens development had begun the previous winter, says Bethe, when John von Neumann “very quickly designed an arrangement which was obviously correct from the theoretical point of view—I had tried and failed.”²¹⁵⁸ Now in the fall and winter of 1944–45 Kistiakowsky had to make the theoretical arrangement work.

An optical lens takes advantage of the fact that light travels at different velocities in different media. Light traveling through air slows when it encounters glass. If the glass curves convexly, as a magnifying glass is curved, the light that encounters the thicker center must follow a longer path than the light that encounters the thinner edges. The effect of these differing path lengths is to direct the light toward a focal point.

The implosion lens system von Neumann designed was made up of truncated pyramidal blocks about the size of car batteries. The assembled lenses formed a sphere with their smaller ends pointing inward. Each lens consisted of two different explosive materials fitted together—a thick, fast-burning outer layer and a shaped slow-burning solid inclusion that extended to the surface of the face of the block that pointed toward the bomb core:

The fast-burning outer layer functioned for the detonation wave as air around an optical lens functions for light. The slower-burning shaped inclusion functioned as a magnifying glass, directing and reshaping the wave. A detonator would ignite the fast-burning explosive. That material would develop a spherical detonation wave. When the apex of the wave advanced into the apex of the inclusion, however, it would begin burning more slowly. The delay would give the rest of the wave time to catch up. As the detonation wave encountered and burned through the inclusion it thus reshaped itself from convex to concave, from a spherical wave expanding from a point to a spherical wave converging on a point, emerging fitted to the convex curve of the spherical tamper. Before the reshaped wave reached the tamper it passed through a second layer of solid blocks of fast-burning explosive to add to its force. The heavy natural-uranium tamper then served to smooth out any minor irregularities as the spherical shock wave compressed it passing through to the plutonium core.

Kistiakowsky would apologize after the war for a research program “too frequently reduced to guesswork and empirical shortcuts” because the field had been grossly neglected.²¹⁵⁹ “Prior to this war the subject of explosives attracted very little scientific interest,” he wrote in an introduction to a technical history of X Division’s work, “these materials being looked upon as blind destructive agents rather than precision instruments; the level of fundamental knowledge concerning detonation waves—and strong shock waves induced by them in the adjacent non-explosive media—was distressingly low.”²¹⁶⁰ To support its experiments X Division expanded an explosives-casting site a few miles south of Anchor Ranch, constructing roughhewn earth-sheltered timber buildings because hauling in concrete would have delayed the work.

Not until mid-December 1944 did a lens test look promising; the eighteen 5-kilogram bombs Groves told George Marshall he hoped to have on hand by the second half of 1945 he also thought might explode so inefficiently that each would be equivalent to no more than 500 tons of TNT, down from the 1,000 tons Conant had heard estimated in October.

Kistiakowsky had to fight once more with Parsons before he won the field. “So much pessimism was developing about our ability to build satisfactory lenses,” he recalls, “that Captain Parsons began urging (and he was not alone in this) that we give up lenses completely and try somehow to patch up the non-lens type of implosion.”²¹⁶¹ Kistiakowsky thought that alternative hopeless. Early in 1945 Groves came out to monitor the debate. In the end Oppenheimer took Kistiakowsky’s side and decided for lenses. Parsons’ Ordnance Division then restricted its work to the uranium gun, Little Boy, and to engineering the weapons for the battlefield. X and G Divisions worried about implosion.

Finishing the high-explosive castings by machining them was the most dramatic innovation Kistiakowsky introduced. He wanted to shape the HE components entirely by machining from solid pre-cast blocks but lacked sufficient time to develop and build the elaborate remote-controlled machinery the innovative technology would have required. He settled instead for precision casting with machine finishing and used his limited supply of machinists primarily to turn out the necessary molds. Molds gave him “the greatest agony,” he remembers; the HE components of the bomb totaled “something in the nature of a hundred or so pieces, which had to fit together to within a precision of a few thousandths of an inch on a total size of five feet and make a sphere. So we had to have very precise molds.”²¹⁶² Eventually mold procurement paced Fat Man’s testing and delivery.

But even with the necessary molds on hand, casting HE was far from simple, another technology that had to be learned by trial and error. In February 1945 Kistiakowsky chose an explosive called Composition B to serve as the fast-burning component of Fat Man’s lenses and a mixture he had commissioned from a Navy research laboratory, Baratol, for the slow-burning component.²¹⁶³ Composition B was poured as a hot slurry of wax, molten TNT and a non-melting crystalline powder, RDX, that was 40 percent more powerful than TNT alone. Baratol slurried barium nitrate and aluminum powder with TNT, stearoxyacetic acid and nitrocellulose:

We learned gradually that these large castings, fifty pounds and more each, had to be cooled in just certain ways, otherwise you get air bubbles in the middle or separations of solids and liquids, all of which screwed up the implosion completely. So it was a slow process. The explosive was poured in and then people sat over that damned thing watching it as if it was an egg being hatched, changing the temperature of the water running through the various cooling tubes built into the mold.²¹⁶⁴

The wilderness reverberated that winter to the sounds of explosions, gradually increasing in intensity as the chemists and physicists applied small lessons at larger scale. “We were consuming daily,” says Kistiakowsky, “something like a ton of high performance explosives, made into dozens of experimental charges.”²¹⁶⁵ The total number of castings, counting only those of quality sufficient to use, would come to more than 20,000. X Division managed more than 50,000 major machining operations on those castings in 1944 and 1945 without one explosive accident, vindication of Kistiakowsky’s precision approach. A RaLa test on February 7, 1945, showed definite improvement in implosion symmetry. On March 5, after a strained round of conferences, Oppenheimer froze lens design. However scarce plutonium might be, no one doubted that Fat Man would have to be tested at full scale before a military weapon could be trusted to work.

*   *   *

A problem small in scale but difficult of solution was the initiator, the minuscule innermost component of the bombs.²¹⁶⁶ The chain reaction required a neutron or two to start it off. No one wanted to trust a billion dollars’ worth of uranium or several hundred million dollars’ worth of plutonium to spontaneous fission or a passing cosmic ray. Neutron sources had been familiar laboratory devices for more than a decade, ever since James Chadwick bombarded beryllium with alpha particles from polonium and broke the elusive neutral particle free in the first place. In his early lectures at Los Alamos Robert Serber had discussed using a radium-beryllium source in a gun bomb with the radium attached to one piece of core material and the beryllium to the other, arranged to smash together when the gun was fired and the two core components mated to complete a critical assembly. Radium released dangerous quantities of gamma radiation, however, and Edward Condon noted in the Los Alamos Primer that “some other source such as polonium . . . will probably prove more satisfactory.”²¹⁶⁷ Polonium emitted copious quantities of alpha particles energetic enough to knock neutrons from beryllium but very little gamma radiation.

The challenge of initiator development was to design a source of sufficient neutron intensity that released those neutrons only at the precise moment they were needed to initiate the chain reaction. In the case of the uranium gun that requirement would be relatively easy to meet, since the alpha source and the beryllium could be separated with the bullet and the target core. But the implosion bomb offered no such convenient arrangement for separation and for mixing. Polonium and beryllium had to be intimately conjoined in Fat Man at the center of the plutonium core but inert as far as neutrons were concerned until the fraction of a microsecond when the imploding shock wave squeezed the plutonium to maximum density. Then the two materials needed instantaneously to mix.

Polonium, element 84 on the periodic table, was a strange metal. Marie and Pierre Curie had isolated it by hand from pitchblende residues (at backbreaking concentrations of a tenth of a milligram per ton of ore) in 1898 and named it in honor of Marie Curie’s native Poland. Physically and chemically it resembled bismuth, the next element down the periodic table, except that it was a softer metal and emitted five thousand times as much alpha radiation as an equivalent mass of radium, which caused the ionized, excited air around a pure sample to glow with an unearthly blue light.

Po210, the isotope of polonium that interested Los Alamos, decayed to lead 206 with the emission of an alpha particle and a half-life of 138.4 days. The range of Po210’s alphas was some 38 millimeters in air but only a few hundredths of a millimeter in solid metals; the alphas gave up their energies ionizing atoms along the way and finally came to a stop. That meant the polonium for an initiator could be safely confined within a sandwich of metal foils. Sandwiching the foils in turn might be concentric shells of light, silvery beryllium. The entire unit need be no larger than a hazelnut.

“I think I probably had the first idea [for an initiator design],” Bethe remembers, “and Fermi had a different idea, and I thought mine was better for once, and then I was the chairman of a committee of three to watch the development of the initiator.”²¹⁶⁸Segregating the Po210 from the beryllium was straightforward. Making sure the two elements mixed thoroughly at the right instant was not, and the primary difference between initiator designs—many were invented and tested during the winter of 1944–45—was their differing mixing mechanisms. A quantity of Po210 equivalent in alpha activity to 32 grams of radium, thoroughly mixed with beryllium, would produce some 95 million neutrons per second, but that would be no more than nine or ten neutrons in the brief ten-millionth of a second when they would be useful in an imploding Fat Man to start the chain reaction; therefore the mixing had to be certain and thorough. Initiator design has never been declassified, but irregularities machined into the beryllium outer surface that induced turbulence in the imploding shock wave probably did the job: the Fat Man initiator may have been dimpled like a golf ball.

To supply ten neutrons to initiate a chain reaction men labored for years. Bertrand Goldschmidt, a French chemist who had once been Marie Curie’s personal assistant and who came to the United States after the invasion of France to work with Glenn Seaborg at the Met Lab, extracted the first half-curie of initiator polonium from old radon capsules at a New York cancer hospital (polonium is a daughter product of radium decay). Quantity production required using scarce neutrons from the Oak Ridge air-cooled pile to transmute bismuth one step up the periodic table to Po. Charles A. Thomas, research director for the Monsanto Chemical Company, a consultant on chemistry and metallurgy, took responsibility for purifying the Po, for which purpose he borrowed the indoor tennis court on his mother-in-law’s large and securely isolated estate in Dayton, Ohio, and converted it to a laboratory.

Thomas shipped the Po on platinum foil in sealed containers, but another nasty characteristic of polonium caused shipping troubles: for reasons never satisfactorily explained by experiment, the metal migrates from place to place and can quickly contaminate large areas. “This isotope has been observed to migrate upstream against a current of air,” notes a postwar British report on polonium, “and to translocate under conditions where it would appear to be doing so of its own accord.”²¹⁶⁹ Chemists at Los Alamos learned to look for it embedded in the walls of shipping containers when Thomas’ foils came up short.

Initiator studies proceeded in G Division at a test site established in Sandia Canyon, one mesa south of the Hill. The Initiator group drilled blind holes in large turbine ball bearings—screwballs, the experimenters called them—inserted test initiators and plugged the holes with bolts.²¹⁷⁰ After imploding the screwballs they recovered the remains and examined them to see how well the Po and Be had mixed. Mixing, unfortunately, could not be a conclusive measure of effectiveness. Bethe’s committee selected the most promising design on May 1, 1945, but only a full-scale test culminating in a chain reaction could prove definitively that the design worked.

*   *   *

Progress toward a Japanese atomic bomb, never rapid, slowed to frustration and futility across the middle years of the Pacific war. After the Imperial Navy had bowed out of atomic energy research Yoshio Nishina had continued patriotically to pursue it even though he privately believed that Japan in challenging the United States had invited certain disaster.²¹⁷¹ On July 2, 1943, Nishina had met with his Army liaison, a Major General Nobuuji, to report that he had “great expectations” for success.²¹⁷² He noted that the Air Force had asked him to study uranium as a possible aircraft fuel, as an explosive and as a source of power, and he had recently received a request for assistance from another Army laboratory, which had contributed 2,000 yen to his expenses. Nobuuji promptly discouraged such consultations. “The main point,” Nishina agreed, “is to complete the project as rapidly as possible.” His calculations, he told Nobuuji, indicated that 10 kilograms of U235 of at least 50 percent purity should make a bomb, although cyclotron experiments would be necessary to determine “whether 10 kg. will be sufficient, or whether it will require 20 kg. or even 50 kg.” He wanted help finishing his 60-inch cyclotron:²¹⁷³

The 250-ton, 1.5 meter accelerator is ready for operation except for certain components which are unavailable as they are being used in the construction of munitions. If this accelerator is completed we believe we can accomplish a great deal. At this moment the U.S. plans to construct an accelerator ten times as great but we are unsure as to whether they can accomplish this.

The previous March Nishina had discarded as impractical under wartime conditions in Japan all methods of isotope separation except gaseous thermal diffusion. Otto Frisch had tried gaseous thermal diffusion (differing from Philip Abelson’s liquid thermal diffusion) at Birmingham early in 1941 and proved it inadequate for separating uranium isotopes, but Nishina had no knowledge of that secret work. The Riken team had designed a thermal column much like the laboratory-scale column Abelson had built at the Naval Research Laboratory in Washington: of concentric 17-foot pipes, the inner pipe heated to 750°F—electrically heated in the Riken configuration—and the outer pipe cooled with water.

Nishina did not meet again with Nobuuji until seven months later, in February 1944, when he reported difficulty producing uranium hexafluoride. His team had managed to develop a method for generating elemental fluorine but had not yet been able to combine the gas with uranium using an old and inefficient process that Abelson in the United States had discarded before he began his thermal-diffusion studies. Nishima also had a problem with his diffusion column that Abelson would have appreciated: it leaked. “To achieve an airtight system,” Nishina told Nobuuji, “we used [sealing] wax and finally achieved our goal. Solder could not be used because of the corrosive properties of the fluorine.” He was “in the middle of developing this [hexafluoride-generating] process but can see the end in sight.” His 1.5-meter cyclotron was now in operation but only at low energy; his explanation for that compromise comments pointedly on the condition of the Japanese industrial economy by 1944:

We have been unable to obtain any superior, high-frequency-generating vacuum tubes . . . for the cyclotron. . . . As a result of this constraint, the low operating voltages limit the population of neutrons we can produce. . . . In order to liberate many high-energy neutrons, a high-voltage vacuum tube is required. But, unfortunately, they are difficult to acquire.

By summer Nishina’s group had manufactured some 170 grams of uranium hexafluoride—in the United States hex was now being produced by the ton—and in July attempted a first thermal separation.²¹⁷⁴ Gauges at the top and bottom of the column, intended to measure a difference in pressure—showing that separation was taking place—indicated no difference at all. “Well, don’t worry,” Nishina told his team.²¹⁷⁵ “Just keep on with it, just keep giving it more gas.”²¹⁷⁶

He reconvened with Nobuuji on November 17, 1944, to report that “since February of this year there has not been a great deal of progress.” He was losing as much as half his hexafluoride to corrosion effects:

We thought the materials we had used to make this apparatus for working with the [hexafluoride] were made of impure metals. Therefore we next used the most highly-refined metals available for the system. However, they were still eaten away. It was therefore necessary to reduce the pressure of the system . . . to compensate for this erosion.

The cyclotron was operating at higher but not yet full power; Nishina was using it, he told Nobuuji, “to assay the concentrated, separated material.” Significantly missing from the November 17 conference report is any mention of measurable separation of U235 from U238. Nishina’s staff had understood for more than a year that he did not believe his country could build an atomic bomb in time to affect the outcome of the war.²¹⁷⁷ Whether he continued research out of loyalty, or because he thought such knowledge would be valuable after the war, or to win support for his laboratory and deferment from military service for his young men, the bare record does not reveal. On the occasion of the November 17 conference he once again complained of the lack of sufficiently powerful vacuum tubes for his cyclotron and told Nobuuji, contrary to the evidence of experiment, that the Riken’s efforts at isotope separation were “now at a midpoint in their practical solution.” Nobuuji might have been more helpful if he had understood even the most basic facts of the work. An exchange between the two men late in the meeting indicates the military liaison was as innocent of nuclear physics as a stone:

Nobuuji: If uranium is to be used as an explosive, 10 kg is required. Why not use 10 kg of a conventional explosive?

Nishina: That’s nonsense.

A B-29, specially modified, first dropped an atomic bomb—a dummy Thin Man—at Muroc Army Air Force Base in California on March 3, 1944. Restrained by sway-bracing, a bomb hung singly in the B-29’s bomb bay from a single release, and the first series of tests ended ignominiously that season when a release cable loosened and dumped one onto closed bomb-bay doors at 24,000 feet. “The doors were then opened,” a technical report notes, “and the bomb tore free, considerably damaging the doors.”²¹⁷⁸ A second series of tests in June went better. Word that Fat Man would be heavier than previously estimated encouraged Norman Ramsey’s Delivery group to replace the original bomb-release mechanism, which had been modified from a standard glider tow release, with a sturdier British Lancaster bomber design.

Lessons learned, the Air Force began modifying seventeen more B-29’s at the Glenn L. Martin plant in Omaha, Nebraska, in August; that month the service prepared to train a special group to deliver the first atomic bombs. The 393rd Bombardment Squadron, then based at Fairmont, Nebraska, in training for Europe, would form the nucleus of the new organization. Late in August Henry H. (“Hap”) Arnold, the commanding general of the U.S. Army Air Forces, approved the assignment of an Illinois-born lieutenant colonel, Paul W. Tibbets, twenty-nine years old, to be group commander.

Tibbets may well have been the best bomber pilot in the Air Force. He had led the first B-17 bombing mission from England into Europe, had carried Dwight Eisenhower to his Gibraltar command post before the invasion of North Africa and had led the first bomber strike of that invasion. More recently he had been test-piloting the B-29, which in 1944 was just beginning to come on line, working with the physics department of the University of New Mexico in Albuquerque to determine how well the new bomber could defend itself against fighter attack at high altitude. He was a man of medium height and stocky build with dark, wavy hair and a widow’s peak, full-faced and square-jawed, a pipe smoker. His father was a candy wholesaler in Florida and a disciplinarian from whom Tibbets probably acquired his reserved perfectionism; he was closer to his mother, the former Enola Gay Haggard of Glidden, Iowa. He had chosen an Air Force career, he told a postwar interviewer, after his mother had supported him in that choice against his father’s opposition:

When I was in college, studying to be a doctor, I realized that I had always wanted to fly. In 1936, my desire to do something about it reached the point where a family showdown on the subject developed. During the discussion, a few tempers flared, but my mother never said a word. In the end, still undecided, I got her off to the side and asked her what she thought. Despite the things that had been said on the subject, and the fact that most of the people in the discussion had included the statement, “You’ll kill yourself in an airplane,” Mother said, quite calmly and with positive assurance, “You go ahead and fly. You will be all right.”²¹⁷⁹

So far he had been, and now he had won a new assignment. He flew to Second Air Force headquarters in Colorado Springs at the beginning of September 1944 to report to commanding Major General Uzal Ent. An aide installed him in the general’s anteroom. An officer came out, introduced himself, took Tibbets aside and asked him if he had ever been arrested. Tibbets considered the situation and decided to answer honestly to this stranger that he had been, as a teenager in North Miami Beach, caught in flagrante delicto in the backseat of a car with a girl. Lieutenant Colonel John Lansdale, Jr., who was responsible to Groves for atomic bomb intelligence and security, knew about the arrest and had questioned Tibbets to test his honesty. Now he led him into Ent’s office. Norman Ramsey and Deke Parsons were waiting there. “I’m satisfied,” Lansdale said.²¹⁸⁰ The physicist and the Navy officer briefed Tibbets on the Manhattan Project and the Muroc bombing tests. Lansdale cautioned him at length on security. After the three men left, Ent specified Tibbets’ assignment. “You have to put together an outfit and deliver this weapon,” the pilot remembers the Second Air Force commander saying. “We don’t know anything about it yet. We don’t know what it can do. . . . You’ve got to mate it to the airplane and determine the tactics, the training, and the ballistics—everything. These are all parts of your problem. This thing is going to be very big. I believe it has the potential and possibility of ending the war.”²¹⁸¹ The delivery program within the Air Force had been codenamed Silverplate, Ent told him. If Tibbets needed anything, he had only to use that magic word; Arnold had accorded it the highest priority in the service.

The Air Force chose Wendover Field, Utah, as home base for the new organization.²¹⁸² Tibbets flew to Utah early in September, looked the base over and liked what he saw. It was sited between low mountain ranges on the desert salt flats in gritty and secure isolation 125 miles west of Salt Lake City near the Utah-Nevada border; the flat basin, the sink of an ancient and enormous freshwater lake of which the Great Salt Lake is a brackish remnant, offered miles of desolation for bombing practice. Pioneers bound for California had suffered the crossing once—their wagon ruts could still be viewed nearby. The 393rd moved to Wendover in September and with the addition of troop-carrier and other support components became the 509th Composite Group. In October it began receiving its new B-29’s.²¹⁸³

A Boeing product, the B-29 was a revolutionary aircraft, the first intercontinental bomber. It was conceived in the late 1930s by ambitious officers within what was then still the Army Air Corps as the vehicle of their vision of wars fought at great distance by strategic air power. As early as September 1939 they proposed its use from bases in the Philippines, Siberia or the Aleutians in the event of war against Japan.²¹⁸⁴ It was the world’s first pressurized bomber and at 70,000 pounds the heaviest production bomber ever built, 135,000 pounds loaded, a weight that required an 8,000-foot runway to lumber airborne. In appearance it was a sleek, polished-aluminum tube 99 feet long intersected by huge 141-foot wings—two B-29’s would fill a football field—with a classic sinusoidal tail nearly three stories tall. Four Wright 18-cylinder radial engines that each developed 2,200 horsepower propelled it at altitude at 350 miles per hour maximum speed—it cruised at 220—and it was designed to fly a 4,000-mile mission with up to 20,000 pounds of bombs, though 12,000 pounds was nearer its operational load. It could cruise above 30,000 feet, out of range of flak and of most enemy fighters. Turbosuperchargers boosted engine power; outsized 16.5-foot propellers turned more slowly than those of any other aircraft; wing flaps, the world’s largest, adjusted a fifth of wing area to adapt the high-speed, long-range, low-drag wing for takeoff and landing.

On the ground the B-29 rested level on three point landing gear: retractable wheels at the nose and under each wing. The plane’s eleven-man crew occupied two pressurized sections within the five joined sections of the fuselage; tandem bomb bays fore and aft of the wings separated the nose section from the waist and tail, and to pass back from the nose to the waist required crawling through a pressurized one-man tunnel. The standard B-29 crew counted pilot, copilot, bombardier, flight engineer, navigator and radio operator in the nose section, three gunners and a radar operator in the waist and another gunner in the tail. Because electrical wiring was less vulnerable to battle damage than pneumatic or hydraulic tubing, the aircraft systems with the exception of the hydraulic wheel brakes operated entirely on electric motors, more than 150 in all, with a gasolinepowered donkey engine in the rear fuselage supplying current on the ground. Analog computers ran a central gun-control system, but all the guns were stripped from 509th bombers except the 20-millimeter cannon in the tail.

If the B-29’s engines were powerful they were also notoriously susceptible to fires. To improve their horsepower-to-weight ratio Wright had used magnesium for their crankcases and accessory housings. Engine cooling was inadequate and exhaust valves tended to overheat and stick; an engine would then sometimes swallow a valve and catch fire. If the fire reached the magnesium, a metal commonly used in incendiary bombs, the engine would usually burn through the main wing spar and peel off the wing. To prevent such disasters Boeing improved engine cooling but the basic design fault persisted; there was no time to develop a new power plant if the aircraft was to serve the war for which it was invented. (One Delivery group physicist remembers skimming along at Wendover for miles after takeoff, mowing sagebrush, to cool the engines before climbing to altitude.²¹⁸⁵)

Once at altitude the flight crews of the 509th practiced bombing runs, bombardiers aiming from above 30,000 feet through their Norden bombsights at progressively smaller target circles limed on the ground. Crews that had flown in cloudy Europe wondered why they were training in visual bombing; an odd evasive maneuver instructed them at least in the explosive potential of the unknown weapon they would carry. Tibbets briefed no one on the atomic bomb but directed his crews to nose their aircraft over into a sharp 155-degree diving turn immediately after bomb release. Diving the huge bombers rapidly increased their airspeed; by perfecting the maneuver the crews could escape ten miles from the delayed explosion, “safe from destruction” by a bomb of 20,000 tons TNT equivalent, writes Groves, “by a factor of two.”²¹⁸⁶ Before they practiced their diving turns they dropped bombs of concrete and bombs filled with HE. These crudely riveted Fat Man imitations, painted bright orange for visibility, they called Pumpkins. The 509th worked hard; the winter wind howled over the Wendover reservation, trapping tumbleweeds on the barbed-wire fences; crews careened into Salt Lake City on weekends to blow out. Tibbets opened their mail, bugged their telephones, had them followed and shipped off those who broke security to the secure but miserable Aleutians for the duration of the war.²¹⁸⁷ He held authority over 225 officers and 1,542 enlisted men. With his silverplated requisitions he commandeered from around the world the best pilots, bombardiers, navigators and flight engineers he could find.

One of them, Captain Robert Lewis of Brooklyn, New York, stocky and blond, twenty-six years old, an abrasive but gifted pilot whom Tibbets had personally trained, had spent part of the summer of 1944 at Grand Island, Nebraska, teaching a senior officer with hundreds of combat hours behind him to fly B-29’s. Thus checked out, Major General Curtis LeMay rode a C-54 to India late in August to take over the 20th Bomber Command, based in India with forward airfields in China from which it was attempting with fewer than two hundred B-29’s to bomb Japan. The bombers had to ferry their own fuel and ordnance from India to China over the Himalayas before each mission—seven supply flights for each bombing strike, up to twelve gallons burned for each one gallon delivered. “It didn’t work,” LeMay writes in his autobiography. “No one could have made it work. It was founded on an utterly absurd logistic basis. Nevertheless, our entire Nation howled like a pack of wolves for an attack on the Japanese homeland.”²¹⁸⁸

Curtis LeMay was a wild man, hard-driving and tough, a bomber pilot, a big-game hunter, a chewer of cigars, dark, fleshy, smart. “I’ll tell you what war is about,” he once said bluntly—but he said it after the war—“you’ve got to kill people, and when you’ve killed enough they stop fighting.”²¹⁸⁹ Through most of the war he seems to have held to the preference for precision bombing over area bombing that had distinguished the U.S. Air Force from the British since Churchill’s and Cherwell’s intervention of 1942. Sometimes in Europe precision bombing had served, though never decisively. Over Japan, so far, it had failed. And failure was LeMay’s bete noire.

His father had been a failure, an odd-job drifter, forever moving his family around. The LeMays lived all over Ohio, in Pennsylvania, out in the wilds in Montana, in California. Curtis Emerson LeMay, born in Columbus, Ohio, in 1906, was the first of seven children. The two memories of early childhood he chooses to offer in his autobiography are linked. Of first seeing an airplane and chasing it madly: “I wanted not only the substance of the mysterious object, not only that part I could have touched with my hands. I wished also in vague yet unforgettable fashion for the drive and speed and energy of the creature.”²¹⁹⁰ And of compulsively running away from home: “truancy” that “bordered on mania,” his mother told him.²¹⁹¹ “I had to grow older,” LeMay writes, “and be burdened with a lot of responsibilities, and begin to nourish ambition—I had to do these things before I could manage to control my temper and discipline my activities.”²¹⁹²

He delivered telegrams and packages and boxes of candy. He delivered newspapers, sold newspapers, wholesaled newspapers to delivery boys, supporting himself and sometimes his family: “When the grocer hesitates about putting that latest basket of groceries on the bill, then you’d better be ready to come up with cash in hand. Very early in life I was convinced bitterly of this necessity. . . . The larder was a vague mystery which Pop didn’t bother to penetrate.”²¹⁹³ LeMay resented the missing childhood but moved on. He paid his own way through Ohio State by working nights at a steel foundry. ROTC in college led to the Ohio National Guard because the Guard had higher priority on Army flying-school enrollments than the Army Reserve. He won his wings in 1929 and never looked back: mess officer, navigation officer, General Headquarters navigator, B-10’s, B-17’s. In England in 1943 and 1944 he worked night and day to improve precision bombing. He won quick promotion.

Arnold sent him to the Pacific because he needed someone who could get the job done:

General Arnold, fully committed to the B-29 program all along, had crawled out on a dozen limbs about a thousand times, in order to achieve physical resources and sufficient funds to build those airplanes and get them into combat. . . . So he finds they’re not doing too well. He has to keep juggling missions and plans and people until the B-29s dodo well. General Arnold was absolutely determined to get results out of this weapons system.²¹⁹⁴

The B-29 had to be used, that is, successfully used, or men who had staked their careers and their convictions would be shamed, resources squandered that might have aided elsewhere in the war, lives lost futilely and millions of dollars wasted. The justification recurs.

The first B-29 to arrive in the Marianas landed on Saipan on October 12, 1944. Brigadier General Haywood S. Hansell, Jr., assigned to lead the 21st Bomber Command, flew it. As Arnold’s chief of staff Hansell had helped formulate the doctrine of precision bombing and believed strongly in its central premise—that wars could be won by selectively destroying the enemy’s key industries of war.^{2195, 2196} A stream of new bombers followed the new commander out to the Marianas; the first U.S. aircraft to fly over Tokyo since the Doolittle raid of 1942 was a B-29 on November 1 soaring high and light on a photoreconnaissance mission. A French journalist living in Tokyo at the time, Robert Guillain, remembers his sense of anticlimax:

The city waited. Millions of lives were suspended in the silence of the radiant autumn afternoon. For a moment, antiaircraft fire shook the horizon with a noise of doors slamming in the sky. Then—nothing: the all-clear was sounded without sight of a plane. The radio announced that a single B-29 had flown over the capital without dropping any bombs.

That seemed a reprieve and for a time only reconnaissance missions disturbed the ill-defended city. “One day the visitor finally appeared, flying at 35,000 feet,” Guillain continues; “he even left his signature chalked on the blue sky: a line of pure white like some living thing that seemed to nose an almost imperceptible silver fly ahead of it.” Back in the Marianas Hansell was teaching his men to navigate together, to fly in formation; they had trained in the United States only as individual crews.

Hansell received his first target directive on November 11. The Joint Chiefs of Staff had approved it and it reflected their conviction that bombing and naval blockade alone could not bring the Pacific war to a timely end. In September the Combined Chiefs—British and American together—had established a planning date for the end of the war: eighteen months after the defeat of Germany. The U.S. Joint Chiefs judged an invasion of the Japanese home islands essential to achieve that goal. The target directive Hansell received therefore gave first priority to the precision bombing of the Japanese aircraft industry (to cripple Japanese air defenses before an American invasion), second priority to supporting Pacific operations (MacArthur was even then reoccupying the Philippines, returning as he had promised he would) and third priority to testing the efficacy of area incendiary attacks. These priorities, putting precision bombing first, suited Hansell’s own.

His crews flew their first raid on Japan from Saipan on November 24. Their target was the Musashi aircraft engine factory north of Tokyo ten miles from the Imperial Palace. A hundred planes began the mission. Seventeen aborted; six were unable to release their bombs. Flak was heavy and the target buried in undercast. But totally unexpected at the high altitude at which the bombers flew was a 140-mile-per-hour wind. They were blown with it over the target and their ground speed was therefore nearly 450 mph, impossible for the bombardiers. As a result only twenty-four planes managed to bomb the factory area—the rest scattered their loads over the docks and warehouses around Tokyo Bay—and only sixteen bombs hit the target. “I did not anticipate the extremely high wind velocities above thirty thousand feet,” Hansell said later, “and they came as a very disagreeable surprise.”²¹⁹⁷ The Air Force had discovered the jet stream.

LeMay was then still working with his 20th Bomber Command out of India and China. Supporting the indifferent military campaigns of Chiang Kai-shek was an activity he abhorred but was sometimes forced to perform. For six months Claire Chennault, the leathery Texan who headed the U.S. air staff assigned to the Nationalist Chinese Army, had been promoting the bombing of Hankow, the riverside city on the Yangtze five hundred miles inland from Shanghai from which Japan supplied its Asian mainland armies. With a renewed Japanese drive in interior China in November Chennault pressed for a Hankow attack. LeMay resisted diverting his command from Japanese home-island targets; the Joint Chiefs had to compel his participation. B-24’s and B-25’s were also massing for the strike; Chennault particularly wanted LeMay to load his aircraft with incendiaries and bomb from 20,000 feet rather than from above 30,000 feet in order to sow a denser pattern. LeMay reserved one aircraft in five for high explosives. Seventy-seven B-29’s took part in the raid on December 18 and burned the Hankow river district down; fires raged out of control for three days. The lesson was not lost on Washington, nor on LeMay.

At Los Alamos the same week Groves, Parsons, Conant, Oppenheimer, Kistiakowsky, Ramsey and several other leaders met in Oppenheimer’s office to discuss preparing Pumpkins—they called them blockbusters—for Tibbets’ 509th Composite Group.²¹⁹⁸ The first Fat Man design, the 1222, had already been changed because it had proved so difficult to assemble—assembly required inserting, threading nuts onto and tightening more than 1,500 bolts—and redesign meant the loss of about 80 percent of the tooling work done at the Pacific Aviation Company in Los Angeles through the autumn. The first unit of a new, simpler design, the 1291, would be ready in three days, on December 22. “Captain Parsons said that the blockbuster production for the 1291 gadget between 15 February and 15 March would require a minimum of 30 blockbusters,” the minutes of the meeting report, “so that each B-29 could drop at least two. . . . An additional 20 blockbusters should be produced for H.E. testing. . . . Following that, 75 units should be produced for overseas shipment.”²¹⁹⁹

Groves wanted none of it. He wanted no dummy 1291’s drop-tested outside the continental United States and he saw no reason to build 75 Pumpkins for overseas target practice for Tibbets’ crews. It was the end of 1944 and he was feeling the pressure of accumulating Manhattan Project delays: “General Groves indicated that too much valuable time was being taken from other problems to devote time to the blockbuster program.” Conant asked how long the blockbuster program would have to continue; Parsons answered combatively that it would have to continue as long as Tibbets’ group operated so that 509th crews could maintain their bombing skills. He relented to reveal that “Colonel Tibbets’ Group expected to reach peak combat training by 1 July.”

Since Parsons had not succeeded in person in convincing Groves of the importance of bomb-assembly and bombing practice he wrote the general a forceful memorandum on the day after Christmas. There were major differences, he pointed out, between the “gun gadget” and the “implosion gadget,” particularly in terms of final assembly:

It is believed fair to compare the assembly of the gun gadget to the normal field assembly of a torpedo, as far as mechanical tests are involved. . . . The case of the implosion gadget is very different, and is believed comparable in complexity to rebuilding an airplane in the field. Even this does not fully express the difficulty, since much of the assembly involves bare blocks of high explosives and, in all probability, will end with the securing in position of at least thirty-two boosters and detonators, and then connecting these to firing circuits, including special coaxial cables and high voltage condenser circuit. . . . I believe that anyone familiar with advance base operations . . . would agree that this is the most complex and involved operation which has ever been attempted outside of a combined laboratory and ammunition depot.

Parsons’ simple and compelling point: the assembly team as well as the bombardiers needed practice. Groves relented; Tibbets got his Pumpkins.

More conventional bombs were falling regularly now on Japan, if not yet to devastating effect. Robert Guillain, the French journalist, remembers the first night raid over Tokyo at the end of November:

Suddenly there was an odd, rhythmic buzzing that filled the night with a deep, powerful pulsation and made my whole house vibrate: the marvelous sound of the B-29s passing invisibly through a nearby corner of sky, pursued by the barking of antiaircraft fire. . . . I went up on my terrace roof. . . . The B-29s caught in the sweeping searchlight beams went tranquilly on their way followed by the red flashes of ack-ack bursts which could not reach them at that altitude. A pink light spread across the horizon behind a near hill, growing bigger, bloodying the whole sky. Other red splotches lit up like nebulas else-where on the horizon.²²⁰⁰ It was soon to be a familiar sight. Feudal Tokyo was called Edo, and the people there had always been terrified by the frequent accidental fires they euphemistically called “flowers of Edo.” That night, all Tokyo began to blossom.

While Parsons and Groves were debating Pumpkins, Lauris Norstad, who had succeeded Hansell in Washington as Hap Arnold’s chief of staff when Hansell moved to the Marianas, passed along word to his predecessor that a trial fire raid on Nagoya, Japan’s third-largest city, was an “urgent requirement.” Hansell resisted. “With great difficulty,” he wrote Norstad, he had “implanted the principle that our mission is the destruction of primary targets by sustained and determined attacks using precision bombing methods both visual and radar” and he was “beginning to get results.” Ironically, he feared that area bombing would slacken his crews’ hard-won skills. Norstad sympathized but insisted that Nagoya was only a test, “a special requirement resulting from the necessity of future planning.”²²⁰¹ Nearly one hundred of Hansell’s B-29’s flew incendiaries to Nagoya, at the southern end of the Nobi Plain two hundred miles southwest of Tokyo, on January 3, 1945, and started numerous small fires that resisted coalescing.

In three months of hard flying, taking regular losses, Hansell had managed to destroy none of his nine high-priority targets. His determination not to rise to the bait Washington was offering—Billy Mitchell, the Air Force’s earliest strategic champion, had pointed out the vulnerability of Japanese cities to fire as long ago as 1924—doomed his command. Norstad flew out to Guam to relieve Hansell of duty on January 6. Curtis LeMay arrived from China the next day. “LeMay is an operator,” Norstad told Hansell, “the rest of us are planners. That’s all there is to it.”²²⁰² As if to encourage the new commander to independence, Hap Arnold suffered a major heart attack on January 15 and withdrew for a time to Miami sunshine to heal.

LeMay officially took command on January 20. He had 345 B-29’s in the Marianas and more arriving. He had 5,800 officers and 46,000 enlisted men. And he had all Hansell’s problems to solve: the jet stream; the terrible Japanese weather, seven days of visual bombing a month with luck and not much weather prediction because the Soviets refused to cooperate from Siberia, whence the weather came; B-29 engines that overheated and burned out while straining up the long climb to altitude; indifferent bombing:

General Arnold needed results. Larry Norstad had made that very plain. In effect he had said: “You go ahead and get results with the B-29. If you don’t get results, you’ll be fired. If you don’t get results, also, there’ll never be any Strategic Air Forces of the Pacific. . . . If you don’t get results it will mean eventually a mass amphibious invasion of Japan, to cost probably half a million more American lives.”²²⁰³

LeMay set his crews to intensive training. They were beginning to get radar units and he saw to it that they were able at least to identify the transition from water to land. He ordered high-altitude precision strikes but experimented with firebombing as well; 159 tons on Kobe on February 3 burned out a thousand buildings. Not good enough: “another month of indifferent operations,” LeMay calls February:²²⁰⁴

When I summed it all up, I realized that we had not accomplished very much during those six or seven weeks. We were still going in too high, still running into those big jet stream winds upstairs. Weather was almost always bad.

I sat up nights, fine-tooth-combing all the pictures we had of every target which we had attacked or scouted. I examined Intelligence reports as well.

Did actually very much in the way of low-altitude flak exist up there in Japan? I just couldn’t find it.

There was food for thought in this.

There was food for thought as well in two compelling February horrors. One occurred halfway around the world, in Europe, where LeMay had flown so often before. The other began nearby. The hardbitten general from Ohio who despised failure and was failing in Japan could not have avoided learning in detail of both.

The European event was the bombing of Dresden, the capital of the German state of Saxony, on the Elbe River 110 miles south of Berlin, famous for its art and its graceful and delicate architecture. In February 1945 the Russian front advanced to less than eighty miles to the east; refugees streamed west from that deadly harrowing and into the Saxon city. Lacking significant war industry, Dresden had not been a bombing target before and was essentially undefended. It counted in its suburbs 26,000 Allied prisoners of war.

Winston Churchill instigated the Dresden raid.²²⁰⁵ The Secretary of State for Air responded to a phone call from the Prime Minister sometime in January with tactical proposals; the P.M. countered as testily as he had countered in the matter of Niels Bohr:

I did not ask you last night about plans for harrying the German retreat from Breslau. On the contrary, I asked whether Berlin, and no doubt other large cities in East Germany should not now be considered especially attractive targets. I am glad that this is “under consideration.” Pray report to me tomorrow what is going to be done.²²⁰⁶

Dresden’s number thus came up. On the cold night of February 13, 1,400 Bomber Command aircraft dropped high explosives and nearly 650,000 incendiaries on the city; six planes were lost. The firestorm that ensued was visible two hundred miles away. The next day, just after noon, 1,350 American heavy bombers flew over to attack the railroad marshaling yards with high explosives but found nine-tenths cover of cloud and smoke and bombed a far larger area, encountering no flak at all.

The American novelist Kurt Vonnegut, Jr., was a young prisoner of war in Dresden at the time of the attack. He described his experience to an interviewer long after the war:

The first fancy city I’d ever seen. A city full of statues and zoos, like Paris. We were living in a slaughterhouse, in a nice new cement-block hog barn. They put bunks and straw mattresses in the barn, and we went to work every morning as contract labor in a malt syrup factory. The syrup was for pregnant women. The damned sirens would go off and we’d hear some other city getting it—whump a whump a whumpa whump. We never expected to get it. There were very few air-raid shelters in town and no war industries, just cigarette factories, hospitals, clarinet factories. Then a siren went off—it was February 13, 1945—and we went down two stories under the pavement into a big meat locker. It was cool there, with cadavers hanging all around. When we came up the city was gone. . . . The attack didn’t sound like a hell of a lot either. Whump. They went over with high explosives first to loosen things up, and then scattered incendiaries. . . . They burnt the whole damn town down. . . .²²⁰⁷

Every day [afterward] we walked into the city and dug into basements and shelters to get the corpses out, as a sanitary measure. When we went into them, a typical shelter, an ordinary basement usually, looked like a streetcar full of people who’d simultaneously had heart failure. Just people sitting there in their chairs, all dead. A fire storm is an amazing thing. It doesn’t occur in nature. It’s fed by the tornadoes that occur in the midst of it and there isn’t a damned thing to breathe. We brought the dead out. They were loaded onto wagons and taken to parks, large, open areas in the city which weren’t filled with rubble. The Germans got funeral pyres going, burning the bodies to keep them from stinking and from spreading disease. One hundred thirty thousand corpses were hidden underground.

Nearer at hand Curtis LeMay could see the intensity and ferocity of Japanese resistance increasing as American forces fought their way toward the home islands. The latest hellhole was Iwo Jima—Sulfur Island—a mass of volcanic ash and rock only seven square miles in area with a dormant volcano at one end, Mount Suribachi, that had risen from the sea within historic times.²²⁰⁸ Miasmic with sulfur fumes, a steam of rotten eggs, Iwo lacked fresh water but supported two airfields from which Japanese fighter-bombers departed to attack LeMay’s B-29’s shining on their hardstands on Guam, Saipan and Tinian. It was nine hundred miles closer to Tokyo than the Marianas and its radar outposts gave Honshu antiaircraft batteries and defensive fighter units ample warning when B-29’s dispatched for strategic assault passed overhead.

The Japanese understood the island’s strategic position and had prepared for months, often under bombardment from U.S. Navy and Air Force planes, to defend it. Fifteen thousand men turned Iwo Jima into a fortress of bunkers, ditches, trenches, 13,000 yards of tunnels, 5,000 pillboxes and fortified cave entrances, vast galleys and wards built into Suribachi, blockhouses with thick concrete walls. The emplacements were armed with the largest concentration of artillery the Japanese had assembled anywhere up to that day: coastal defense guns in concrete bunkers, fieldpieces of all calibers shielded in caves, rocket launchers, tanks buried in the sand up to their turrets, 675-pound spigot mortars, long-barreled anti-aircraft guns cranked down parallel to the ground. The Japanese commander, Lieutenant General Tadamichi Kuribayashi, taught his men a new strategy: “We would all like to die quickly and easily, but that would not inflict heavy casualties. We must fight from cover as long as we possibly can.”²²⁰⁹ His soldiers and marines, increased in strength now to more than 21,000, would no longer throw away their lives in banzai charges. They would resist to the death. “I am sorry to end my life here, fighting the United States of America,” Kuribayashi wrote his wife. “But I want to defend this island as long as I can.”²²¹⁰ He expected no rescue. “They meant to make the conquest of Iwo so costly,” says William Manchester, who fought not this battle but the next one, Okinawa, “that the Americans would recoil from the thought of invading their homeland.”²²¹¹

Washington secretly considered sanitizing the island with artillery shells loaded with poison gas lobbed in by ships standing well offshore; the proposal reached the White House but Roosevelt curtly vetoed it.²²¹² It might have saved thousands of lives and hastened the surrender—arguments used to justify most of the mass slaughters of the Second World War, and neither the United States nor Japan had signed the Geneva Convention prohibiting such use—but Roosevelt presumably remembered the world outcry that had followed German introduction of poison gas in the First World War and decided to leave the sanitizing of Iwo Jima to the U.S. Marines.

They began landing on Saturday, February 19, at 9 A.M., after weeks of naval barrage and bombing. A less well-defended foe would have been pulverized by that battering; the Japanese dug in on Iwo Jima were only groggy from the long disturbance of their sleep. The Navy ferried the marines to shore in amphtracs, gave them over to the deep and treacherous black pumice of the beaches and ran out to reload. The Japanese commanded Suribachi, the high ground; they had zeroed in on every point of consequence on the flat island and now stood back to fire. On the beaches, says Manchester, men were more often killed by artillery than by bullets:

The invaders were taking heavy mortar and artillery fire. Steel sleeted down on them like the lash of a desert storm. By dusk 2,420 of the 30,000 men on the beachhead were dead or wounded. The perimeter was only four thousand yards long, seven hundred yards deep in the north and a thousand yards in the south. It resembled Doré’s illustrations of the Inferno. Essential cargo—ammo, rations, water—was piled up in sprawling chaos. And gore, flesh, and bones were lying all about.²²¹³ The deaths on Iwo were extraordinarily violent. There seemed to be no clean wounds; just fragments of corpses. It reminded one battalion medical officer of a Bellevue dissecting room. Often the only way to distinguish between Japanese and marine dead was by the legs; Marines wore canvas leggings and Nips khaki puttees. Otherwise identification was completely impossible. You tripped over strings of viscera fifteen feet long, over bodies which had been cut in half at the waist. Legs and arms, and heads bearing only necks, lay fifty feet from the closest torsos. As night fell the beach reeked with the stench of burning flesh.

After that first awful night, when the Japanese might have squandered themselves in counterattacks but chose instead to hold fast to their defensive redoubts, the leaders of the invasion understood that they would pay with American lives for every foot of the island they captured. Kuribayashi’s final order to his men demanded of them the same sacrifice: “We shall infiltrate into the midst of the enemy and annihilate them,” he exhorted.²²¹⁴ “We shall grasp bombs, charge the enemy tanks and destroy them. With every salvo we will, without fail, kill the enemy. Each man will make it his duty to kill ten of the enemy before dying!” Slow, cruel fighting continued for most of a month. In the end, late in March, when shell and fire had changed the very landscape, victory had cost 6,821 marines killed and 21,865 wounded of some 60,000 committed, a casualty ratio of 2 to 1, the highest in Marine Corps history. Of Japanese defenders, 20,000 died on Iwo Jima; only 1,083 allowed themselves to be captured.

That so many were dying to protect his B-29 crews when their results were inconsequential to the war catalyzed LeMay to radical departure. The deaths had to be justified, the debt of death repaid.

One more incendiary test, 172 planes over Tokyo on February 23, produced the best results of any bombing so far, a full square mile of the city burned out. But LeMay had long known that fire would burn down Japan’s wooden cities if properly set. Proper setting, not firebombing itself, was the problem he struggled to solve.

He studied strike photographs. He reviewed intelligence reports. “The Japanese just didn’t seem to have those 20- and 40-millimeter [antiaircraft] guns,” he remembers realizing. “That’s the type of defense which must be used against bombers coming in to attack at a low or medium altitude. Up at twenty-five or thirty thousand feet they have to shoot at you with 80- or 90-millimeter stuff, or they’re never going to knock you down. . . . But 88-millimeter guns, if you come in low, are impotent. You’re moving too fast.”²²¹⁵

Low-altitude firebombing had other important advantages. Flying low saved fuel coming and going from the Marianas: the B-29’s could carry more bombs. Flying low put less strain on the big Wright engines: fewer aircraft would have to abort or ditch. LeMay added in another variable and proposed to bomb at night; his intelligence sources indicated that Japanese fighters lacked airborne radar units. With little or no light flak or fighter cover Tokyo would be nearly defenseless. Why not, then, LeMay reasoned, take out B-29 guns and gunners and further increase the bomb load? He decided to leave the tail gunner as an observer and pull the rest.²²¹⁶

He discussed his plan with only a few members of his staff. They worked out a target zone, a flat, densely crowded twelve square miles of workers’ houses adjacent to the northeast corner of the Imperial Palace in central Tokyo. Even two decades after the war LeMay felt the need to justify the site as in some sense industrial: “All the people living around that Hattori factory where they make shell fuses. That’s the way they disperse their industry: little kids helping out [at home], working all day, little bits of kids.”²²¹⁷The U.S. Strategic Bombing Survey notes frankly that 87.4 percent of the target zone was residential, and LeMay goes on to more candid admission later in his autobiography:²²¹⁸

No matter how you slice it, you’re going to kill an awful lot of civilians. Thousands and thousands. But, if you don’t destroy the Japanese industry, we’re going to have to invade Japan. And how many Americans will be killed in an invasion of Japan? Five hundred thousand seems to be the lowest estimate. Some say a million.²²¹⁹

 . . . We’re at war with Japan. We were attacked by Japan. Do you want to kill Japanese, or would you rather have Americans killed?

A little later in the war a spokesman for the Fifth Air Force would point out that since the Japanese government was mobilizing civilians to resist invasion, “the entire population of Japan is a proper military target.”²²²⁰

Onto the proper military target of working-class Tokyo LeMay decided to drop two kinds of incendiaries. His lead crews would carry M47’s, 100-pound oil-gel bombs, 182 per aircraft, each of which was capable of starting a major fire. Behind those crews his major force would sow M69’s, 6-pound gelled-gasoline bombs, 1,520 per aircraft. He eschewed magnesium bombs because those more rigid weapons smashed all the way through the tile roofs and light wooden floors of Japanese houses and buried themselves ineffectually in the earth. LeMay also remembers including a few high explosives in the mix to demoralize the firemen.

He delayed seeking approval of his plan until the day before the raid was scheduled to go, taking responsibility for it himself and determined to risk the gamble. Norstad approved on March 8 and alerted the Air Force public relations staff to the possibility of “an outstanding strike.”²²²¹ Arnold was informed the same afternoon.²²²² LeMay’s crews were stunned to hear they would fly their sorties unarmed at staggered levels between five and seven thousand feet. “You’re going to deliver the biggest firecracker the Japanese have ever seen,” LeMay told them.²²²³ Some of them thought he was crazy and considered mutiny. Others cheered.

From Guam first, from Saipan next and then from Tinian 334 B-29’s took off for Tokyo in the late afternoon of March 9. They were loaded with more than 2,000 tons of incendiaries.

They flew toward a city that an Associated Press correspondent who knew it well had described in 1943 in a best-selling book as “grim, drab and grubby.”²²²⁴ Freed from Japanese detention in Manila and then in Shanghai, Russell Brines had brought home a message about the people he had lived among before the war and whose language he spoke:

“We will fight,” the Japanese say, “until we eat stones!” The phrase is old; now revived and ground deeply into Japanese consciousness by propagandists skilled in marshaling their sheeplike people. . . . [It] means they will continue the war until every man—perhaps every woman and child—lies face downward on the battlefield. Thousands of Japanese, maybe hundreds of thousands, accept it literally. To ignore this suicide complex would be as dangerous as our pre-war oversight of Japanese determination and cunning which made Pearl Harbor possible. . . .²²²⁵

American fighting men back from the front have been trying to tell America this is a war of extermination. They have seen it from foxholes and barren strips of bullet-strafed sand. I have seen it from behind enemy lines. Our picture coincides. This is a war of extermination. The Japanese militarists have made it that way.²²²⁶

The fighting men of the Navy and the Air Force had seen particular evidence of Japanese doggedness that autumn and winter in the appearance of kamikazes, planes loaded with high explosives and deliberately flown to ram ships. Between October and March young Japanese pilots, most of them barely qualified university students, sacrificed themselves in some nine hundred sorties. Navy fighters and antiaircraft guns shot most of the kamikazes down. About four hundred U.S. ships were hit and only about one hundred sunk or severely damaged in a fleet of thousands, but the attacks were alien and terrifying; they served to confirm for Americans the extent of Japanese desperation even as they further depleted Japan’s waning air defenses.

LeMay’s pathfinders arrived first over Tokyo a little after midnight on March 10. On the district of Shitamachi on the flatlands east of the Sumida River where 750,000 people lived crowded into wood-and-paper houses they marked a diagonal of fire and then crossed it to ignite a gigantic, glowing X. At 0100 the main force of B-29’s came on and began methodically bombing the flatlands. The wind was blowing at 15 miles per hour. The bombers carried their 1,520 M69’s in 500-pound clusters that broke apart a few hundred feet above the ground. Main-force intervalometers—the bomb-bay mechanisms that spaced the release of the clusters—had been set for 50-foot intervals. Each planeload then covered about a third of a square mile of houses. If only a fifth of the incendiaries started fires, that was one fire for every 30,000 square feet—one fire for every fifteen or twenty closely spaced houses. Robert Guillain remembers a deadlier density:

The inhabitants stayed heroically put as the bombs dropped, faithfully obeying the order that each family defend its own house. But how could they fight the fires with that wind blowing and when a single house might be hit by ten or even more of the bombs . . . that were raining down by the thousands? As they fell, cylinders scattered a kind of flaming dew that skittered along the roofs, setting fire to everything it splashed and spreading a wash of dancing flames everywhere.²²²⁷

By 0200 the wind had increased to more than 20 miles per hour. Guillain climbed to his roof to observe:

The fire, whipped by the wind, began to scythe its way through the density of that wooden city. . . . A huge borealis grew. . . . The bright light dispelled the night and B-29’s were visible here and there in the sky. For the first time, they flew low or middling high in staggered levels. Their long, glinting wings, sharp as blades, could be seen through the oblique columns of smoke rising from the city, suddenly reflecting the fire from the furnace below, black silhouettes gliding through the fiery sky to reappear farther on, shining golden against the dark roof of heaven or glittering blue, like meteors, in the searchlight beams spraying the vault from horizon to horizon. . . .²²²⁸ All the Japanese in the gardens near mine were out of doors or peering up out of their holes, uttering cries of admiration—this was typically Japanese—at this grandiose, almost theatrical spectacle.

Something worse than a firestorm was kindled in Tokyo that night. The U.S. Strategic Bombing Survey calls it a conflagration, begun when the high wind heeled over the pillar of hot and burning gases that the fires had volatilized and convection had carried up into the air:

The chief characteristic of the conflagration . . . was the presence of a fire front, an extended wall of fire moving to leeward, preceded by a mass of preheated, turbid, burning vapors. The pillar was in a much more turbulent state than that of [a] fire storm, and being usually closer to the ground, it produced more flame and heat, and less smoke. The progress and destructive features of the conflagration were consequently much greater than those of [a] fire storm, for the fire continued to spread until it could reach no more material. . . . The 28-mile-per-hour wind, measured a mile from the fire, increased to an estimated 55 miles at the perimeter, and probably more within.²²²⁹ An extended fire swept over 15 square miles in 6 hours. Pilots reported that the air was so violent that B-29s at 6,000 feet were turned completely over, and that the heat was so intense, even at that altitude, that the entire crew had to don oxygen masks. The area of the fire was nearly 100 percent burned; no structure or its contents escaped damage. The fire had spread largely in the direction of the natural wind.

A bombardier who flew through the black turbulence above the conflagration remembers it as “the most terrifying thing I’ve ever known.”^{2230, 2231}

In the shallower canals of Shitamachi, where people submerged themselves to escape the fire, the water boiled.

The Sumida River stopped the conflagration from sweeping more than 15.8 square miles of the city. The Strategic Bombing Survey estimates that “probably more persons lost their lives by fire at Tokyo in a 6-hour period than at any [equivalent period of] time in the history of man.” The fire storm at Dresden may have killed more people but not in so short a space of time. More than 100,000 men, women and children died in Tokyo on the night of March 9-10, 1945; a million were injured, at least 41,000 seriously; a million in all lost their homes. Two thousand tons of incendiaries delivered that punishment—in the modern notation, two kilotons. But the wind, not the weight of bombs alone, created the conflagration, and therefore the efficiency of the slaughter was in some sense still in part an act of God.

Hap Arnold sent LeMay a triumphant telex: CONGRATULATIONS. THIS MISSION SHOWS YOUR CREWS HAVE GOT THE GUTS FOR ANYTHING.²²³² Certainly LeMay did; having gambled and succeeded, he quickly pushed on. His B-29’s firebombed Nagoya on March 11; firebombed Osaka by radar on March 13; firebombed Kobe on March 16—stocks of M69’s were running low and M17A1 clusters of 4-pound magnesium thermite bombs, less effective, had to be substituted; firebombed Nagoya again on March 18. “Then,” says LeMay, “we ran out of bombs. Literally.”²²³³ In ten days and 1,600 sorties the Twentieth Air Force burned out 32 square miles of the centers of Japan’s four largest cities and killed at least 150,000 people and almost certainly tens of thousands more.²²³⁴ “I consider that for the first time,” LeMay wrote Norstad privately in April, “strategic air bombardment faces a situation in which its strength is proportionate to the magnitude of its task. I feel that the destruction of Japan’s ability to wage war lies within the capability of this command.”²²³⁵ He had found a method, LeMay had begun to believe, whereby the Air Force might end the Pacific war without invasion.

*   *   *

At Oak Ridge guests removed their shoes before entering a house. Hiring was still increasing on the muddy Tennessee reservation and construction continuing, challenges to the meager ground cover that a Tennessee Eastman employee was moved to immortalize anonymously in verse:

In order not to check in late,²²³⁶

I’ve had to lose a lot of weight,

From swimming through a fair-sized flood

And wading through the goddam mud.

I’ve lost my rubbers and my shoes

Perpetually I have the blues

My spirits tumble with a thud

Because of all this goddam mud.

It’s in my system so that when

I cut my finger now and then

Instead of bleeding just plain blood

Out pours a stream of goddam mud.

Mud measured progress: Ernest Lawrence’s calutrons, built at such great expense, had begun enriching uranium. A minimum of 100 grams per day—3.5 ounces—of 10 percent U235 came through the Alpha racetracks beginning in late September 1944.²²³⁷ But poor planning for chemical recovery of that feed from the Beta tanks wasted some 40 percent of it, as Mark Oliphant reported to James Chadwick from Oak Ridge early in November: “This loss or hold-up . . . has resulted in a very serious delay in the production of material for the first weapon. . . .²²³⁸ The chemistry, viewed as a whole, I believe to present an appalling example of lack of coordination, of inefficiency, and bad management.”

A copy of Oliphant’s complaint went to Groves, who must have acted quickly; the troubleshooting Australian physicist could report to the general two weeks later that “the output from the beta tracks has shown an abrupt and very satisfying upward trend.” In his letter to Chadwick, Oliphant had noted a Beta output of only 40 grams per day; now “an output of about 90 grams per day [has] been reached and there [is] reason for believing that this level would be maintained, or even increased, during the coming months.” He concluded optimistically that “there is now a definite hope that continued effort on the part of the operating company and others will lead early in the New Year to a plant output of the order of that expected.”²²³⁹

As of January 1945 on any given day about 85 percent of some 864 Alpha calutron tanks operated to produce 258 grams—9 ounces—of 10 percent enriched product; at the same time 36 Beta tanks converted the accumulated Alpha product to 204 grams—7.2 ounces—per day of 80 percent enriched U235, sufficient enrichment to make a bomb. James Bryant Conant calculated in his handwritten history notes on January 6 that a kilogram of U235 per day would mean one gun bomb every six weeks.^{2240, 2241} It follows that the gun bomb required about 42 kilograms—92.6 pounds, about 2.8 critical masses—of U235.²²⁴² Without further improvement the calutrons alone could produce that much material in 6.8 months, and Conant noted after conferring with Groves that “it looks as if 40-45 kg . . . will be obtained by July 1.” Ernest Lawrence’s monumental effort had succeeded; every gram of U235 in the one Little Boy that should be ready by mid-1945 would pass at least once through his calutrons.

Conant also contrasted his assumptions of June 1944 with his assumptions at the beginning of the new year to draw up a problematic balance sheet: while he had previously “believed a few bombs might do the trick” of ending the war, at the beginning of 1945 he was “convinced many bombs will now be required (German experience).” The German experience was probably the determined German resistance that was prolonging the war in Europe, particularly the counteroffensive through the Ardennes known as the Battle of the Bulge that had begun in mid-December and still threatened Allied lines at the time of Conant’s notes. It was partly Allied frustration with such continuing resistance that would lead in another month to the atrocity of the Dresden bombing.

Houdaille-Hershey was finally delivering satisfactory barrier tubes for the K-25 gaseous-diffusion plant. Union Carbide had scheduled barrier delivery to take advantage of K-25’s organization as a cascade; as individual tanks, called converters, arrived, workers hooked them into the system and tested them for leaks in atmospheres of nitrogen and helium with the portable mass spectrometers that Alfred Nier had designed. When a stage was leakproof and otherwise ready it could be operated without further delay, and the first stage of the enormous K-25 cascade was charged with uranium hexafluoride on January 20, 1945. Enrichment by gaseous barrier diffusion in the most advanced automated industrial plant in the world had begun. It would proceed efficiently with only normal maintenance for decades.

The pipes in Philip Abelson’s scaled-up thermal-diffusion plant, S-50, leaked so badly they had to be welded, which delayed production, but all twenty-one racks had begun enriching uranium by March. Juggling the different enrichment processes to produce maximum output in minimum time then became a complex mathematical and organizational challenge. Lieutenant Colonel Kenneth D. Nichols, Groves’ talented and long-suffering assistant, worked out the scheduling. Based on Nichols’ schedule Groves decided in mid-March not to build more Alpha calutrons, as Lawrence had proposed, but to construct instead a second gaseous-diffusion plant and a fourth Beta plant. Though he certainly expected his atomic bombs to end the war, Groves seems to have justified the new construction by the Joint Chiefs’ conservative estimate that the Pacific war would end eighteen months after the European; his new plants could not be completed before February 15, 1946, he explained in his proposal, but “on the assumption that the war with Japan will not be over before July, 1946, it is planned to proceed with the additions to the two plants unless instructions to the contrary are received.”²²⁴³ Perhaps he was simply being prudent.

Early in 1945 Oak Ridge began shipping bomb-grade U235 to Los Alamos. Between shipments Groves took no chances with a substance far more valuable gram for gram than diamonds. Although the Army had condemned all the land and ejected the original inhabitants from the Clinton reservation area, at the dead end of a dusty reservation back road cattle grazed in a pasture beside a white farmhouse.²²⁴⁴ A concrete silo towered over the road, which was sheltered by a steep bluff. From the air the scene resembled any number of small Tennessee holdings, but the silo was a machine-gun emplacement, the farm was manned by security guards, and built into the side of the bluff a concrete bunker shielded a bank-sized vault completely encircled with guarded walkways. In this pastoral fortress Groves stored his accumulating grams of U235. Armed couriers transported it as uranium tetrafluoride in special luggage by car to Knoxville, where they boarded the overnight express to Chicago. They passed on the luggage the next morning to their Chicago counterparts, who held reserved space on the Santa Fe Chief. Twenty-six hours later, in midafternoon, the Chicago couriers debarked at Lamy, the stranded desert way station that served Santa Fe. Los Alamos security men met the train and completed the transfer to the Hill, where chemists waited eagerly to reduce the rare cargo to metal.

Plutonium production at Hanford depended as much on chemical separation as it did on chain-reacting piles. The chemistry was Glenn Seaborg’s, spectacularly scaled up a billionfold directly from his team’s earlier ultramicrochemical work. The plutonium in the slugs irradiated in the Hanford piles emerged mixed to the extent of only about 250 parts per million with uranium and highly radioactive fission products. Carrier chemistry—the fractional crystallization of Marie Curie and Otto Hahn—was therefore required to help the scant plutonium along. The man-made metal is extremely poisonous if ingested but only mildly radioactive. To make it safe to handle it also needed to be purified to less than 1 part in 10 million of fission products. And because the pile slugs developed such a burden of radioactivity, all but the final chemical processing had to be carried out by remote control behind thick shielding.²²⁴⁵

Seaborg’s team developed two separation processes to take advantage of the different chemistries of plutonium’s several different valence states. One process used bismuth phosphate as a carrier; the other used lanthanum fluoride. Bismuth phosphate, scaled up directly from Met Lab experiments, served the primary purpose of uranium and fission-product decontamination. Lanthanum fluoride, applied at pilot scale at Oak Ridge, then concentrated the plutonium from the large volume of solution in which it was suspended.

Hanford was the largest plant Du Pont had ever constructed and operated; not least among its facilities were the chemical separation buildings. “Originally eight separation plants were considered necessary,” writes Groves, “then six, then four. Finally, with the benefit of the operating experience and information obtained from the Clinton semi-works, we decided to build only three, of which two would operate and one would serve as a reserve.” For safety the plants went up behind Gable Mountain ten miles southwest of the riverside piles. Each building was 800 feet long, 65 feet wide and 80 feet tall, poured-concrete structures so massive the workers called them Queen Marys; the British ocean liner of that name was only a fifth again as long.²²⁴⁶ The Queen Marys were essentially large concrete boxes, says Groves, containment buildings “in which there were individual cells containing the various parts involved in the process equipment. To provide protection from the intense radioactivity, the cells were surrounded by concrete walls seven feet thick and were covered by six feet of concrete.”

Each Queen Mary contained forty cells, and each cell’s lid, which could be removed by an overhead crane that rolled the length of the building’s long canyon, weighed 35 tons. Irradiated slugs ejected from a production pile would be stored in pools of water 16.5 feet deep to remain until the most intense and therefore short-lived of their fission-product radioactivities decayed away, the water glowing blue around them with Cerenkov radiation, a sort of charged-particle sonic boom. The slugs would then move in shielded casks on special railroad cars to one of the Queen Marys, where they would first be dissolved in hot nitric acid. A standard equipment group occupied two cells: a centrifuge, a catch tank, a precipitator and a solution tank, all made of specially fabricated corrosion-resistant stainless steel. The liquid solution that the slugs had become would move through these units by steam-jet syphoning, a low-maintenance substitute for pumps. There were three necessary steps to the separation process: solution, precipitation and centrifugal removal of the precipitate. These would repeat from equipment group to equipment group down the canyon of the separation building. The end products would be radioactive wastes, stored on site in underground tanks, and small quantities of highly purified plutonium nitrate.

Once the Queen Marys were contaminated with radioactivity no repair crews could enter them. Equipment operators had to be able to maintain them entirely by remote control. The operators trained at Du Pont in Delaware, at Oak Ridge and on mockups at Hanford, but the engineer in charge, Raymond Genereaux, sought more authoritative qualification. And found it: he required his operators, one hundred of whom arrived at Hanford in October 1944, to install the process equipment into the first completed separation building by remote control, pretending the canyon was already radioactive. They did, awkwardly at first but with increasing confidence as practice improved their remote-manipulation skills.

“When the Queen Marys began to function,” Leona Marshall remembers, “dissolving the irradiated slugs in concentrated nitric acid, great plumes of brown fumes blossomed above the concrete canyons, climbed thousands of feet into the air, and drifted sideways as they cooled, blown by winds aloft.”²²⁴⁷ B-pile slugs traveled by rail into the 221-T separation plant beginning on December 26, 1944. “The yields in the first plant runs . . . ranged between 60 and 70 per cent,” Seaborg notes proudly, and “reached 90 per cent early in February 1945.”²²⁴⁸ Lieutenant Colonel Franklin T. Matthias, Groves’ representative at Hanford, personally carried the first small batch of plutonium nitrate by train from Portland to Los Angeles, where he turned it over to a Los Alamos security courier. Thereafter shipments—small subcritical batches in metal containers in wooden boxes—traveled in convoy by Army ambulance via Boise, Salt Lake City, Grand Junction and Pueblo to Los Alamos.

Bertrand Goldschmidt, the French chemist who worked with Glenn Seaborg, puts the Manhattan Engineer District at the height of its wartime development in perspective with a startling comparison. It was, he writes in a memoir, “the astonishing American creation in three years, at a cost of two billion dollars, of a formidable array of factories and laboratories—as large as the entire automobile industry of the United States at that date.”²²⁴⁹

*   *   *

One of the mysteries of the Second World War was the lack of an early and dedicated American intelligence effort to discover the extent of German progress toward atomic bomb development. If, as the record repeatedly emphasizes, the United States was seriously worried that Germany might reverse the course of the war with such a surprise secret weapon, why did its intelligence organizations, or the Manhattan Project, not mount a major effort of espionage?

Vannevar Bush had raised the question of espionage with Franklin Roosevelt at their crucial meeting on October 9, 1941, when Bush apprised the President of the MAUD Report, but the OSRD director got no satisfactory answer, probably because the United States was not yet a belligerent. Groves in his memoirs passes the buck to the existing intelligence agencies—Army G-2, the Office of Naval Intelligence and the Office of Strategic Services, the forerunner of the CIA—and attributes the inadequacy of their information to “the unfortunate relationships that had grown up among [them].”²²⁵⁰ Why he failed to confront the issue himself until late 1943, when George Marshall asked him directly to do so, he chooses not to say. One reason was certainly security, a Groves obsession; in order to know what to look for, intelligence agents would have to be briefed on at least isotopeseparation technologies and nuclear-fission research, which would mean that any agent captured or turned might well give American secrets away. When Groves finally did take responsibility for intelligence gathering he picked scientific personnel who had not worked within the Manhattan Project and authorized paramilitary operations to advance only into areas already occupied. That at least is how he intended his intelligence unit to operate; in practice it frequently claimed its prizes in the no-man’s-land between fighting fronts, by hook or by crook.

The unit Groves authorized in late 1943 somehow acquired the name Alsos, Greek for “grove” and thus obscurely revealing; the brigadier thought to have it renamed, “but I decided that to change it . . . would only draw attention to it.”²²⁵¹ To head the Alsos mission he chose Lieutenant Colonel Boris T. Pash, a former high school teacher turned Army G-2 security officer, FBI trained, who had made himself notorious in domestic intelligence circles for his flamboyant investigation of Communist activities among members of the staff of Ernest Lawrence’s Berkeley laboratory. Pash, trim and Slavic, with rimless glasses and light, thin hair, spoke Russian fluently and was a great hunter of Communists. His background helps explain why: his Russian emigré father was the Metropolitan—senior bishop—of the Eastern Orthodox Church in North America. It was Pash who had interrogated Robert Oppenheimer about his Communist affiliations while a clandestine recording device in the next room preserved the physicist’s damaging evasions on blank sound motion picture film; he concluded without hard evidence that Oppenheimer was a Communist Party member gone underground and possibly a spy. Whatever Groves thought of Pash’s Red-baiting, he chose him to head Alsos because he delivered the goods: “his thorough competence and great drive had made a lasting impression on me.”²²⁵²

Pash set up a base in London in 1944 as the Allied armies pushed through France after the Normandy invasion. He then crossed the Channel with a squad of Alsos enlisted men and wheeled toward Paris by jeep. “The ALSOS advance party joined the 102nd U.S. Cavalry Group on Highway 188 at Orsay,” a contemporary military intelligence report notes. The American force stopped outside Paris—Charles de Gaulle had persuaded Franklin Roosevelt to allow the Free French to enter the city first—but Pash decided to improvise: “Colonel Pash and party then proceeded to cut across-country to Highway 20 and joined second elements of a French armored division.²²⁵³ The ALSOS Mission then entered the City of Paris 0855 hrs., 25 August 1944. The party proceeded to within the city in the rear of the first five French vehicles to enter, being the first American unit to enter Paris.” The five French vehicles were tanks. In his unarmored jeep Pash drew repeated sniper fire. He dodged among the back streets of Paris and by the end of the day had achieved his goal, the Radium Institute on the Rue Pierre Curie. There he settled in for the evening to drink celebratory champagne with Frédéric Joliot.

Joliot knew less about German uranium research than anyone had expected. Pash moved his base to liberated Paris and began following up promising leads. One of the most significant pointed to Strasbourg, the old city on the Rhine in Alsace-Lorraine, which Allied forces began occupying in mid-November. Pash found a German physics laboratory installed there in a building on the grounds of Strasbourg Hospital. His scientific counterpart on the Alsos team was Samuel A. Goudsmit, a Dutch theoretical physicist and Paul Ehrenfest protégé who had studied criminology and had previously worked at the MIT Radiation Laboratory. Goudsmit followed Pash to Strasbourg, began laboriously examining documents and hit the jackpot. He recalls the experience in a postwar memoir:

It is true that no precise information was given in these documents, but there was far more than enough to get a view of the whole German uranium project. We studied the papers by candlelight for two days and nights until our eyes began to hurt. . . . The conclusions were unmistakable. The evidence at hand proved definitely that Germany had no atom bomb and was not likely to have one in any reasonable form.²²⁵⁴

But paper evidence was not good enough for Groves; as far as he was concerned, he could close the books on the German program only when he had accounted for all the Union Minière uranium ore the Germans had confiscated when they invaded Belgium in 1940, some 1,200 tons in all, the only source of untraced bomb material available to them during the war with the mines at Joachimsthal under surveillance and the Belgian Congo cut off.

Pash had already liberated part of that supply, some 31 tons, from a French arsenal in Toulouse where it had been diverted and secretly stored. Moving into Germany with the Allied armies after they crossed the Rhine late in March he acquired a larger force of men, two armored cars mounted with .50-caliber machine guns and four machine-gun-mounted jeeps and began tracking the German atomic scientists themselves. “Washington wanted absolute proof,” Pash remembers, “that no atomic activity of which it did not know was being carried on by the Nazis. It also wanted to be sure that no prominent German scientist would evade capture or fall into the hands of the Soviet Union.”²²⁵⁵ Alsos moved through Heidelberg and picked up Walther Bothe, whose laboratory contained Germany’s only functioning cyclotron. Documents there pointed to Stadtilm, near Weimar, as the location of Kurt Diebner’s laboratory. The small town proved to have become the central office of the German atomic research program as well, and although Werner Heisenberg and his group from the Kaiser Wilhelm Institutes had moved to southern Germany to escape Allied bombing and the advancing Russian and Allied armies, there was a small amount of uranium oxide at Stadtilm to reward Pash’s search.

Pash missed the ore rescue. Groves’ liaison man with the British had been watching a factory at Stassfurt, near Magdeburg in northern Germany, since late 1944, when documents captured in Brussels indicated it might house the balance of the Belgium ore. By early April 1945 the Red Army had advanced too close to that prize to leave it uninspected any longer; Groves arranged to assemble a mixed British and American strike force led by Lieutenant Colonel John Lansdale, Jr., the security officer who had cleared Paul Tibbets, to move in. The team met with the Twelfth Army Group’s G-2 in Gottingen to seek approval for the Stassfurt mission; Lansdale describes the confrontation in a report:

We outlined to him our proposal and advised him that if we found the material we were after we proposed to remove it and that it would be necessary that we act with the utmost secrecy and greatest dispatch inasmuch as a meeting between the Russian armies and Allied armies apparently would soon take place and the area in which the material appeared to be was a part of the proposed Russian zone of occupation. [The G-2] was very perturbed at our proposal and foresaw all kinds of difficulties with the Russians and political repercussions at home. Said he must see the Commanding General.²²⁵⁶

That was calm, no-nonsense Omar Bradley:

He went alone in to see General Bradley, who at that time was in conference with [the] Ninth Army Commander within whose area Stassfurt then was. Both of them gave unqualified approval to our project, General Bradley being reported to have remarked “to hell with the Russians.”

On April 17, led by an infantry-division intelligence officer familiar with the area, Lansdale and his team struck for Stassfurt:

The plant was a mess both from our bombings and from looting by the French workmen. After going through mountains of paper we located the lager or inventory of papers which disclosed the presence of the material we sought at the plant. . . . This ore was fortunately stored above ground. It was in barrels in open sided sheds and had obviously been there a long time, many of the barrels being broken open. Approximately 1100 tons of ore were stored there. This was in various forms, mostly the concentrates from Belgium and about eight tons of uranium oxide.

Lansdale instructed his group to take inventory and went off to Ninth Army headquarters. That organization assigned him two truck companies. He moved on to the nearest railhead within the permanent American zone of occupation but found the commanding officer there too busy evacuating some ten thousand Allied prisoners of war to be able to offer more help than half a dozen men for guard duty. Lansdale improvised, located empty airport hangars nearby where the ore could be stored awaiting shipment out of Germany and arranged to have them cleared of booby traps. Then he returned to Stassfurt:

Many of the barrels in which the material was packed were broken open and the majority of those not broken open were in such a weakened condition that they could not stand transportation.²²⁵⁷ [A British and an American officer] and I took a jeep and scouting around the country found in one small town a paper bag factory which had a large supply of very heavy bags. We later sent a truck and obtained 10,000 of these. We also discovered in a mill a quantity of wire and the necessary implements for closing the bags. By the evening of 19th April we had a large crew busily engaged in repacking the material and that night the movement of the material to [the railhead] started.

Boris Pash in the meantime continued to chase down the German atomic scientists. Alsos documents placed Werner Heisenberg, Otto Hahn, Carl von Weizsäcker, Max von Laue and the others in their organization in the Black Forest region of southwestern Germany in the resort town of Haigerloch.²²⁵⁸ By late April the German front had broken and the French were moving ahead. Pash and his forces, which now included a battalion of combat engineers, got word in the middle of the night and raced around Stuttgart in their jeeps and trucks and armored cars to beat the French to Haigerloch. They drew German fire along the way and returned it. In the meantime Lansdale in London reassembled his British-American team and flew over to follow Pash in. The story is properly Pash’s:²²⁵⁹

Haigerloch is a small, picturesque town straddling the Eyach River. As we approached it, pillowcases, sheets, towels and other white articles attached to flagpoles, broomsticks and window shutters flew the message of surrender.

 . . . While our engineer friends were busy consolidating the first Alsosdirected seizure of an enemy town, [Pash’s men] led teams in a rapid operation to locate Nazi research facilities. They soon found an ingenious set-up that gave almost complete protection from aerial observation and bombardment—a church atop a cliff.

Hurrying to the scene, I saw a box-like concrete entrance to a cave in the side of an 80-foot cliff towering above the lower level of the town. The heavy steel door was padlocked. A paper stuck on the door indicated the manager’s identity.

 . . . When the manager was brought to me, he tried to convince me that he was only an accountant. When he hesitated at my command to unlock the door, I said: “Beatson, shoot the lock off. If he gets in the way, shoot him.”

The manager opened the door.

 . . . In the main chamber was a concrete pit about ten feet in diameter. Within the pit hung a heavy metal shield covering the top of a thick metal cylinder. The latter contained a pot-shaped vessel, also of heavy metal, about four feet below the floor level. Atop the vessel was a metal frame. . . . [A] German prisoner . . . confirmed the fact that we had captured the Nazi uranium “machine” as the Germans called it—actually an atomic pile.

Pash left Goudsmit and his several colleagues behind at Haigerloch on April 23 and rushed to nearby Hechingen. There he found the German scientists, all except Otto Hahn, whom he picked up in Tailfingen two days later, and Werner Heisenberg, whom he located with his family at a lake cottage in Bavaria.

The pile at Haigerloch had served for the KWI’s final round of neutron-multiplication studies. One and a half tons of carefully husbanded Norsk-Hydro heavy water moderated it; its fuel consisted of 664 cubes of metallic uranium attached to 78 chains that hung down into the water from the metal “shield” Pash describes. With this elegant arrangement and a central neutron source the KWI team in March had achieved nearly sevenfold neutron multiplication; Heisenberg had calculated at the time that a 50 percent increase in the size of the reactor would produce a sustained chain reaction.

“The fact that the German atom bomb was not an immediate threat,” Boris Pash writes with justifiable pride, “was probably the most significant single piece of military intelligence developed throughout the war. Alone, that information was enough to justify Alsos.”²²⁶⁰ But Alsos managed more: it prevented the Soviet Union from capturing the leading German atomic scientists and acquiring a significant volume of high-quality uranium ore. The Belgian ore confiscated at Toulouse was already being processed through the Oak Ridge calutrons for Little Boy.

*   *   *

At Los Alamos in late 1944 Otto Frisch, always resourceful at invention, proposed a daring program of experiments. Enriched uranium had begun arriving on the Hill from Oak Ridge. By compounding the metal with hydrogen-rich material to make uranium hydride it had become possible to approach an assembly of critical mass responsive to fast as well as slow neutrons. Frisch was leader of the Critical Assemblies group in G Division. Making a critical assembly involved stacking several dozen 1½-inch bars of hydride one at a time and measuring the increased neutron activity as the cubical stack approached critical mass. Usually the small bars were stacked within a boxlike framework of larger machined bricks of beryllium tamper to reflect back neutrons and reduce the amount of uranium required. Dozens of these critical-assembly experiments had gone forward during 1944. “By successively lowering the hydrogen content of the material as more U²³⁵ became available,” the Los Alamos technical history points out, “experience was gained with faster and faster reactions.”²²⁶¹

But it was impossible to assemble a complete critical mass by stacking bars; such an assembly would run away, kill its sponsors with radiation and melt down. Frisch nearly caused a runaway reaction one day by leaning too close to a naked assembly—he called it a Lady Godiva—that was just subcritical, allowing the hydrogen in his body to reflect back neutrons. “At that moment,” he remembers, “out of the corner of my eye I saw that the little red [monitoring] lamps had stopped flickering.²²⁶² They appeared to be glowing continuously. The flicker had speeded up so much that it could no longer be perceived.” Instantly Frisch swept his hand across the top of the assembly and knocked away some of the hydride bars. “The lamps slowed down again to a visible flicker.” In two seconds he had received by the generous standards of the wartime era a full day’s permissible dose of radiation.

Despite that frightening experience, Frisch wanted to work with full critical masses to determine by experiment what Los Alamos had so far been able to determine only theoretically: how much uranium Little Boy would need. Hence his daring proposal:

The idea was that the compound of uranium-235, which by then had arrived on the site, enough to make an explosive device, should indeed be assembled to make one, but leaving a big hole so that the central portion was missing; that would allow enough neutrons to escape so that no chain reaction could develop.²²⁶³ But the missing portion was to be made, ready to be dropped through the hole so that for a split second there was the condition for an atomic explosion, although only barely so.

Brilliant young Richard Feynman laughed when he heard Frisch’s plan and named it: he said it would be like tickling the tail of a sleeping dragon.²²⁶⁴ The Dragon experiment it became.

At a remote laboratory site in Omega Canyon that Fermi also used, Frisch’s group built a ten-foot iron frame, the “guillotine,” that supported upright aluminum guides. The experimenters surrounded the guides at table level with blocks of uranium hydride. To the top of the guillotine they raised a hydride core slug about two by six inches in size. It would fall under the influence of gravity, accelerating at 32 feet per second/per second. When it passed between the blocks it would momentarily form a critical mass. Mixed with hydride, the U235 would react much more slowly than pure metal would react later in Little Boy. But the Dragon would stir, and its dangerous stirring would give Frisch a measure of the fit between theory and experiment:

It was as near as we could possibly go towards starting an atomic explosion without actually being blown up, and the results were most satisfactory. Everything happened exactly as it should. When the core was dropped through the hole we got a large burst of neutrons and a temperature rise of several degrees in that very short split second during which the chain reaction proceeded as a sort of stifled explosion. We worked under great pressure because the material had to be returned by a certain date to be made into metal. . . .²²⁶⁵ During those hectic weeks I worked about seventeen hours a day and slept from dawn till mid-morning.

The official Los Alamos history measures the significance of Frisch’s Dragon-tickling:

These experiments gave direct evidence of an explosive chain reaction. They gave an energy production of up to twenty million watts, with a temperature rise in the hydride up to 2°C per millisecond. The strongest burst obtained produced 10¹⁵ neutrons. The dragon is of historical importance. It was the first controlled nuclear reaction which was supercritical with prompt neutrons alone.²²⁶⁶

By April 1945 Oak Ridge had produced enough U235 to allow a nearcritical assembly of pure metal without hydride dilution. The little bars arrived at the Omega site packed in small, heavy boxes everyone took pains to set well apart; unpacked and unwrapped, the metal shone silver in Frisch’s workbench light. Gradually it oxidized, to blue and then to rich plum. Frisch had walked in the snow at Kungälv puzzling out the meaning of Otto Hahn’s letters to his aunt; in the basement at Bohr’s institute in Copenhagen he had borrowed a name from biology for the process that made these small exotic bars deadly beyond measure; at Birmingham with Rudolf Peierls he had toyed with a formula and had first seen clearly that no more plum-colored metal than now lay scattered on his workbench would make a bomb that would change the world. At Los Alamos in Southwestern spring, dénouement: he would assemble as near a critical mass of U235 as anyone might ever assemble by hand and not be destroyed.

April 12, Thursday, was the day Frisch completed his critical assembly experiments with metallic U235. The previous day Robert Oppenheimer had written Groves the cheering news that Kistiakowsky had managed to produce implosive compressions so smoothly symmetrical that their numbers agreed with theoretical prediction. April 12 in America was Friday, April 13, in Japan, and on the night of that unlucky day B-29’s bombing Tokyo bombed the Riken. The wooden building housing Yoshio Nishina’s unsuccessful gaseous thermal diffusion experiment did not immediately burn; firemen and staff managed to extinguish the fires that threatened it. But after the other fires were out the building suddenly burst into flame. It burned to the ground and took the Japanese atomic bomb project with it. In Europe John Lansdale was preparing to rush to Stassfurt to confiscate what remained of the Belgian uranium ore; when Groves heard of the success of that adventure later in April he wrote a memorandum to George Marshall that closed the German book:

In 1940 the German Army in Belgium confiscated and removed to Germany about 1200 tons of uranium ore. So long as this material remained hidden under the control of the enemy we could not be sure but that he might be preparing to use atomic weapons.²²⁶⁷

Yesterday I was notified by cable that personnel of my office had located this material near Stassfurt, Germany and that it was now being removed to a safe place outside of Germany where it will be under the complete control of American and British authorities.

The capture of this material, which was the bulk of uranium supplies available in Europe, would seem to remove definitely any possibility of the Germans making use of an atomic bomb in this war.

The day these events cluster around, April 12, saw another book closed: at midday, in Warm Springs, Georgia, while sitting for a portrait, Franklin Delano Roosevelt in the sixty-third year of his life was shattered by a massive cerebral hemorrhage. He lingered comatose through the afternoon and died at 3:35 P.M. He had served his nation as President for thirteen years.

When the news of Roosevelt’s death reached Los Alamos, Oppenheimer came out from his office onto the steps of the administration building and spoke to the men and women who had spontaneously gathered there. They grieved as Americans everywhere grieved for the loss of a national leader. Some also worried about whether the Manhattan Project would continue. Oppenheimer scheduled a Sunday morning memorial service that everyone in and out of the Tech Area might attend.

“Sunday morning found the mesa deep in snow,” Philip Morrison recalls of that day, April 15. “A night’s fall had covered the rude textures of the town, silenced its business, and unified the view in a soft whiteness, over which the bright sun shone, casting deep blue shadows behind every wall. It was no costume for mourning, but it seemed recognition of something we needed, a gesture of consolation. Everybody came to the theater, where Oppie spoke very quietly for two or three minutes out of his heart and ours.”²²⁶⁸ It was Robert Oppenheimer at his best:

When, three days ago, the world had word of the death of President Roosevelt, many wept who are unaccustomed to tears, many men and women, little enough accustomed to prayer, prayed to God.²²⁶⁹ Many of us looked with deep trouble to the future; many of us felt less certain that our works would be to a good end; all of us were reminded of how precious a thing human greatness is.

We have been living through years of great evil, and of great terror. Roosevelt has been our President, our Commander-in-Chief and, in an old and unperverted sense, our leader. All over the world men have looked to him for guidance, and have seen symbolized in him their hope that the evils of this time would not be repeated; that the terrible sacrifices which have been made, and those that are still to be made, would lead to a world more fit for human habitation. . . .

In the Hindu scripture, in the Bhagavad-Gita, it says, “Man is a creature whose substance is faith. What his faith is, he is.” The faith of Roosevelt is one that is shared by millions of men and women in every country of the world. For this reason it is possible to maintain the hope, for this reason it is right that we should dedicate ourselves to the hope, that his good works will not have ended with his death.

Vice President Harry S. Truman of Independence, Missouri, who knew only the bare fact of the Manhattan Project’s existence, said later that when he heard from Eleanor Roosevelt that he must assume the Presidency in Franklin Roosevelt’s place, “I kept thinking, ‘The lightning has struck. The lightning has struck!’ ” Between the Thursday of Roosevelt’s death and the Sunday of the memorial service on the Hill, Otto Frisch delivered to Robert Oppenheimer his report on the first experimental determination of the critical mass of pure U235.²²⁷⁰ Little Boy needed more than one critical mass, but the fulfillment of that requirement was now only a matter of time. The lightning had struck at Los Alamos as well.