Before the Fallout

by Diana Preston

  A few days later Bohr learned from informants that the Germans planned to deport "undesirable aliens." Realizing that this meant Jewish refugees in Copenhagen, he warned those of his staff who were at risk, helped them contact the Danish underground, who would assist them to flee to Sweden, and gave them money. He expected at any moment to be arrested himself. In fact, as emerged at the Nuremberg war crimes trials, the Germans had intended to seize him the day they declared martial law. They had, however, changed their mind, fearing that it would attract too much attention. They decided, instead, to arrest Bohr during a general roundup of Denmark's Jews.

  Bohr hurriedly destroyed his papers. He also dissolved in acid the gold Nobel medals that James Franck and Max von Laue had left with him for safekeeping. They lived out the war in an innocent-looking bottle on a cluttered shelf, and the gold was later retrieved and recast. On 29 September Mar-grethe Bohr's brother-in-law brought the news Bohr had been expecting. According to a contact in the German diplomatic corps, Berlin had ordered the deportation of Niels and his brother Harald to Germany. Bohr knew that he and Margrethe had to leave at once. Friends arranged for a boat to take them to Sweden and promised to send their sons after them.

  Copenhagen was under strict nighttime curfew. Anyone out on the streets after the deadline was shot on sight. The Bohrs therefore had to try to reach a beach undetected while it was still daylight. In the late afternoon they walked down a still-crowded street, carrying only a small bag. A scientist friend, standing on the corner, gave Bohr a surreptitious nod—the signal that everything was in place for the escape. The Bohrs made their way to fields beyond the city and hid in a shack until dark. They were supposed to make their escape at 9 p.m. However, as Margrethe Bohr recalled, when the time came the Nazis "had come out so that we had to wait until late in the night." When at last the coast was literally clear, the Bohrs hurried down to the beach. It was, Margrethe remembered, "very dramatic"—"you had to throw yourself down to the ground not to be seen." They clambered gratefully aboard a small motorboat waiting to take them out to the fishing boat that would carry them to Sweden.

  Safely arrived near Malmo, Margrethe waited for their sons while Bohr hurried to Stockholm. His mission was to plead for Denmark's Jews, who, he knew, were about to be rounded up and shipped to concentration camps. The neutral Swedish government, which had tried unsuccessfully to intercede on behalf of Norway's Jews, agreed to help and broadcast a formal announcement offering sanctuary to Danish Jews. This offer prompted one of the most honorable and courageous acts of the war. The Danish underground assembled a fleet of small boats and ferried their Jewish countrymen to safety in Sweden. The dangerous shuttle operation saved nearly 6,000. The Nazis were able to deport only 472 Jews, many elderly, helpless, and living in old people's homes. One of Niels Bohr's aunts was among them. She did not survive.

  The rest of Bohr's family reached Sweden safely. Margrethe and their younger sons would remain there for the rest of the war, but within weeks Bohr received a telegram from Lord Cherwell, inviting him to England. This time he accepted. On 6 October 1943 a British Mosquito fighter bomber—painted in civilian livery, unarmed, and flown by two civilians to avoid violating Swedish neutrality—landed in Stockholm. The only available space for the large-framed Bohr was in the empty bomb bay, which had been specially padded to take a passenger. He was equipped with flying suit, parachute, and a set of distress flares and told that if the Luftwaffe attacked the plane, the pilot would open the bomb-bay doors, jettisoning Bohr, who was to parachute into the sea and send up the flares. He was also given a helmet fitted with headphones, which was the only means the crew had of communicating with him.

  To avoid attack, particularly from Luftwaffe bases in Norway, the Mosquito at first flew at very high altitude. The pilot instructed Bohr to turn on his oxygen supply, but unfortunately Bohr's helmet was too small for his gigantic cranium. The headphones did not cover his ears, and he never heard the order. He lost consciousness; but as the Mosquito descended he began to revive, and by the time it landed in Scotland he was conscious once more.

  Bohr was flown on to London, where James Chadwick was waiting to greet him. Since 1940 Bohr had been cut off from information about British and American progress on atomic research. He was amazed by what he soon learned-—especially that Enrico Fermi had achieved a self-sustaining chain reaction. Bohr was assigned an office near the London headquarters of the Directorate of Tube Alloys, where he was joined by his son, Aage, as his assistant. Bohr spent the next few months visiting laboratories across the country and bringing himself up to speed. The reality of a nuclear bomb disturbed as well as fascinated him, and he already foresaw that it could, in the future, prompt an arms race.

  The British tried to persuade Bohr to go to the United States as part of their team under the Quebec Agreement. Bohr, who had close personal ties with America as well as Britain, was reluctant to be affiliated with any particular camp. To meet his concerns and to allow him the requisite degree of independence, he was appointed as "Consultant to the British Directorate of Tube Alloys." His brief was to review the work under way in the United States and decide how he could best assist the common goal.

  Aage and Niels Bohr

  Niels and Aage Bohr sailed for the New World under their assumed names of Nicholas and James Baker. However, the FBI agents who met them as they disembarked were horrified to see "NIELS BOHR" written in large black letters on "Nicholas Baker's" suitcase. General Groves accompanied them on the long train journey from Chicago to Lamy, New Mexico—the nearest station to Los Alamos. To keep the Danes' presence on the train secret, Groves ordered their meals to be served in their compartment. He was chagrined to discover that on both mornings of the long journey the Bohrs breakfasted in the dining car. Groves found the journey stressful in other ways. During their hours of confinement he found Bohr hard to understand. The morning after they reached Los Alamos, Oppenheimer noticed that the general seemed below par and asked him what the matter was. Groves replied, "I've been listening to Bohr."

  There were, of course, many at Los Alamos only too eager to listen to Bohr. One evening at Oppenheimer's house, Bohr addressed a small group of European scientists about conditions in Denmark and about his escape. It made a deep impression. As Emilio Segre recalled, "For many of us this was the first eyewitness account of what was really happening in a Nazi-occupied country. . . . the account left us depressed and worried, and more determined than ever that the bomb should be ready at the earliest date possible."

  · · ·

  Segre would have been relieved to know of the increasing practical difficulties confronting Germany's scientists. During the summer of 1943 British night bombing attacks on Germany had achieved a new intensity in an operation code-named "Gomorrah." Aided by the first use of "window"—strips of aluminum foil—designed to confuse German radar when released from bombers—the Royal Air Force had targeted Hamburg. On the night of 27 July the blast of their high-explosive bombs, combined with incendiaries, created a firestorm. Fires merged, sucking air into the center, where the oxygen was burned out. One pilot simply muttered, "Those poor bastards." Another crewman recalled, "It was as if I was looking into what I imagine an active volcano to be." Eight square miles of the city were reduced to ashes. Some victims were caught in melting asphalt as they tried to escape. In a raid that lasted only forty-three minutes, forty-two thousand people were killed, including more civilians than died in all German raids on London. Fearing such Allied attacks on Berlin, Albert Speer ordered Germany's research institutes to seek new and safer homes outside the capital.*

  Heisenberg did not share Speer's anxiety. Though forced on one occasion to flee through the burning streets of Berlin, shoes smoldering with phosphorus, he believed that his reactor experiments in a concrete bunker in the "Virus House" were well protected. Nevertheless, reflecting that maintaining essential supplies of electricity and water in Berlin might not be possible for much longer, he decided gradually to relocate the Ka
iser Wilhelm Institute for Physics to Hechingen, a small town in southwest Germany. Not only was it quite close to Urfeld in the Bavarian Alps, where he had recently moved his family permanently, but, he reckoned, if the worst should come, Hechingen was more likely to fall to invading western Allies than Russians advancing from the east. By the end of 1943 he had sent a third of his institute—those not essential to the fission work—south under Max von Laue as assistant director.

  Heisenberg meanwhile continued his work in the Virus House, undeterred by the nighttime wail of the air-raid sirens and the crump of exploding Allied bombs.

  *Passengers on the bomber spent the sixteen-hour flight in the bomb bay, lying in the freezing cold on a rough mattress resting on the bomb doors. They had to wear full flying gear, including oxygen mask, helmet, and parachute. It was impossible to read because the plane was blacked out. Sometimes people lost their head in the cold, noisy darkness. Oliphant recalled a man who, thrashing about in a panic, inflated his life jacket and passed out. As Oliphant struggled to help him, the rip cord of the man's parachute caught on something, filling the bay with rippling silk.

  *The pronunciation and spelling of Fuchs's name was a source of difficulty and embarrassment to English-speakers. Even his fellow German Rudolf Peierls signed one letter addressed to "Dear Fucks."

  *Sir John Colville, Churchill's private secretary, related that Air Marshal Harris had shown Churchill a film of the bombing raids on Hamburg and elsewhere, expecting praise for his efforts. When the lights came up, Colville saw tears running down Churchill's face, and he (Churchill) said, "Are we beasts that we should be doing these things?" However, Churchill's views on what we would now call "weapons of mass destruction" varied with his mood and the progress of the war. Later, when the German flying bombs were falling on Britain in July 1944, he wrote a memo to his military chiefs of staff: "I want you to think very seriously over the question of using poison gas. I would not use it unless it could be shown that (a) it was life or death for us, or (b) that it would shorten the war by a year. It is absurd to consider morality on this topic when everybody used it in the last war without a word of complaint from the moralists or the Church. On the other hand, in the last war the bombing of open cities was regarded as forbidden. Now everybody does it as a matter of course. It is simply a question of fashion changing as she does between long and short skirts for women." Churchill, of course, on reflection concluded that gas should not be used.

  EIGHTEEN

  HEAVY WATER

  SINCE THE RAID on the Vemork heavy water plant in February 1943, Knut Haukelid had been living a precarious existence, organizing resistance groups in the mountains. It had, as he later wrote, been very hard surviving in the wilds of the Hardanger Plateau: "Snow and cold had been our constant companions and we had carried danger with us wherever we went." Reports that the Germans had immediately started to rebuild the plant perturbed him. Predictably, they had taken precautions against further assault, bricking up doors and windows up to the first-floor level and fortifying entrances with double doors, through which only one person at a time was admitted after scrutiny through a peephole. In addition, they had trebled the guard, floodlit the entire area, and laid new minefields. A further commando raid seemed out of the question.

  In the United States General Groves worried about Germany's continued capacity to manufacture heavy water. He was also angered by Britain's attitude toward the problem. Before the Gunnerside attack, the head of the Directorate of Tube Alloys, Wallace Akers, had told him that the British were planning to raid Vemork but had revealed no details of how or when. Groves had only learned the outcome from a translation of an article published in the Swedish Svenska Dagbladet on 14 March 1943 reporting that all the apparatus, machines, and facilities for the production of heavy water had been blown up.

  Groves's annoyance grew as the weeks passed and the British still refused to disclose exactly what had happened. He even suggested to his superiors that the U.S. government should buy the information if that was the only way. He was particularly concerned that the plant had not been knocked out permanently. When the British finally furnished sparse details of the raid, claiming that the plant would not be fully effective for more than twelve months, he was unconvinced. A message to London from the Norwegian resistance on 8 July 1943 that the plant was expected to reach full production again by 15 August, which was passed on to him, proved him right.

  Groves convinced Vannevar Bush and the army chief of staff, General George C. Marshall, that the plant had to be bombed from the air. The British at first resisted, arguing that casualties among Norwegian civilians would be heavy, but, seeing no other way, bowed to American pressure. On 1 c. November 1943, 388 B-17S and B-24S of the U.S. Eighth Air Force took off from English airfields, some to make diversionary raids around Oslo, the remainder to target the heavy water complex. Anticipating just such attacks, the Germans had installed antiaircraft batteries and stretched cables from mountain to mountain to hinder low-flying aircraft. As a result, the air assault failed. Only two bombs hit the Norsk-Hydro plant. The heavy water cells were undamaged, but twenty-two Norwegians were killed by stray bombs.

  Nevertheless, the attack made the Germans rethink the production of heavy water at Vemork. The risks of further air raids and sabotage were, they decided, too great. They considered manufacturing heavy water in an Italian nitrogen plant and then sending it to Germany for purification but abandoned the idea as too complex. Instead, they decided to ship Vemork's heavy water to Germany and there construct their own heavy water plant. When Norwegian agents passed rumors of this plan to London, the Special Operations Executive on 29 December sent a message to the Norwegian resistance: "We have information that heavy water equipment may be dismantled and sent to Germany. Can you verify this? . . . Can this transport be aborted?"

  The first question was easily answered. The resistance checked with their contacts at the plant and two days later confirmed to London that the Germans were indeed planning to remove all the stocks of heavy water and the key equipment. Furthermore the move was imminent. The second question was more problematic. The Norwegians told London that they could not yet suggest a plan.

  Haukelid and his colleagues managed to discover that the Germans intended to transport the heavy water by rail from Vemork to the northern end of a long, narrow inland lake called Tinnsjo. Here, on Sunday, 20 February 1944, they would load the railcars onto the ferry sailing south down the lake to connect with the railhead at Tinnoset, whence the railcars with their cargo of heavy water would continue their journey to the coast for shipment to Germany. Three weeks before the shipment was due the Norwegians believed they had the answer. Haukelid radioed London that the most reliable solution would be to sink the ferry. Lake Tinnsjo was almost thirteen hundred feet deep, and it would be impossible for the Germans to retrieve the drums from its frigid depths.

  They also warned London that "we must expect reprisals." A special army detachment together with a company of S.S. had been called in to guard the shipment—a sign both of how seriously the Germans regarded the transport and of their likely response if thwarted. Indeed, the resistance were so worried about what the Germans might do to the civilian population that on i c. February they sent a further message, urgently querying whether the importance of the operation justified the potential consequences. London replied the same day. The answer was perhaps tactlessly breezy but also unequivocal: "Matter has been considered. It is thought very important that the heavy water shall be destroyed. Hope it can be done without too disastrous results. Send our best wishes for success in the work. Greetings."

  Haukelid reviewed the options again. Even putting thoughts of reprisals aside, the dangers to innocent passengers aboard the ferry were hard for him to stomach, but there seemed no choice. Disguised as a workman, he made a reconnaissance trip. He carefully timed how long the ferry took to reach the deepest part of the lake. The answer was twenty minutes. He knew that he and his fellow saboteurs would hav
e to be very careful getting to the ferry and boarding it. The Germans were on high alert: "There were more Germans than Norwegians in the whole valley. . . . German police stopped everyone that looked suspicious and checked their identity cards and parcels they carried." On another scouting mission, this time in Rjukan during a local music festival, Haukelid disguised himself as a musician, concealing his machine gun in a violin case like any Chicago gangster.

  On the evening of 19 February, twelve hours before the ferry was due to depart, Haukelid and two companions, Rolf Sorlie and Knut Lier-Hansen, dodged through the shadows down to the landing where the ferry was moored for the night: "The bitterly cold night set everything creaking and crackling; the ice on the road snapped sharply as we went over it. When we came out on the bridge by the ferry station, there was as much noise as if a whole company was on the march." While his comrades covered him, Hauke­lid, encumbered by a sack of explosives and detonators as well as his weapons, crept up the ferry gangplank. To his surprise, all seemed quiet apart from the voices of the crew playing poker belowdecks. The Germans had failed to place guards on the ferry—the most vulnerable link in the whole heavy water transport route.

  Haukelid signaled to Sorlie and Lier-Hansen to follow him aboard. The trio crept below to the third-class accommodation and found a hatchway leading down to the bilges. However, before they could raise the steel hatch they heard footsteps and hastily took cover. It was the ferry watchman. According to Haukelid, they told him they were seeking a suitable place to hide. The man replied that he had several times helped conceal "illicit things" on the ferry and showed them the hatch. While Haukelid and Sorlie climbed down and got busily to work fixing the explosives, Lier-Hansen kept the watchman engaged in conversation.