WHEN they see him do such things as use an entire box of matches to light a single pipeful of tobacco, his compatriots say that Professor Niels Bohr lives in some vague atomic world of his own. Because so few Danes comprehend his work, they like to think of Dr. Bohr as a kindly prototype of the absent-minded professor, and sometimes they forget that, in addition to being in the van in developments in his field of research, this greatest of Danes quotes poetry, reads detective novels as well as the classics, was once an outstanding athlete, and has always taken an active interest in world politics.
In 1942 Dr. Bohr was secretly invited west to help with a new project in America. Having taught or worked with nearly every leading nuclear physicist in the world, he must have known what that project was, but he felt at the time that he would be more useful in Copenhagen, evaluating reports sent him by the Danish military attaché in Berlin, and generally keeping an eye on Nazi scientific developments. The Germans hardly bothered with him at all; they did not understand the professor. For the same reason they kept away from his 10-million-volt cyclotron, an apparatus that incorporated, among other things, an electro-magnet with a 35-ton iron core. But had the Nazis staged a surprise raid on Jacobsen House, the home provided for Dr. Bohr by the Carlsberg Brewery’s scientific foundation, they would have found his desk cluttered with damning memoranda. In his quiet way, Dr. Bohr was helping to organize the movement of many refugees out of Denmark.
Neither Professor Bohr nor the Resistance knew it, but in August, 1943, a special Gestapo agent was sent to Copenhagen to arrest the physicist. Incredible as it may seem, this German was reluctant to act before calling in a Nazi specialist in nuclear physics, and Bohr was still free in October. Then, more worried that he might somehow be forced into serving the Germans, the Allied authorities sent Bohr a second, more im perative invitation. The professor at once burned all his papers on refugee movements, and through Dr. Lindstrøm-Lang, a scientist in his staff, made plans to take Mrs. Bohr, their three sons, and their families to Sweden. None of the Resistance people who were to help get him away knew why Bohr was being evacuated, but they guessed it was because he had some Jewish ancestors.
In south Copenhagen, near the Sound, there is an area known as ‘Music City’ because all its streets are named after famous composers. There, one night early in October, Dr. Lindstrøm-Lang took the physicist and his wife, and the professor’s famous brother, mathematician Harald Bohr, and his wife. They waited with some other refugees in a house on Mozartvej, and later were led through back streets to a small quay where a fishing boat, the Søstjernen, lay tied.
An air raid alert had just sounded and searchlights raked the moonless sky. Niels Bohr was shown into the cramped cabin with some other passengers, but several of the refugees had to be hidden among the herring boxes on the boat’s deck. While Christian Hansen, the fisherman owner of the craft, fidgeted with the small, one-cylinder diesel engine, there was some rifle fire on shore. The refugees whispered tensely together, wondering if their flight had been discovered. On deck, Hansen nervously cursed over his engine when it refused to start.
The shooting continued for some minutes and then died away, and the passengers sighed in relief as they heard the engine throb into life, making the entire boat shudder as she nosed out on to the choppy water.
The least perturbed person on board was Niels Bohr; despite the lurching, he dozed for six hours until Hansen cut the engine and the fishing boat drifted. They had only come as far as the middle of the Sound, and again the passengers tensed when they heard low voices call out from a larger boat closing rapidly with them. Why, they wondered, if a patrol ship had inter cepted them, did Søstjernen not veer off and try to make a quick run for Sweden?
Men from the larger vessel stepped across to the deck of Søstjernen and ordered the passengers to gather their things and come on to the other boat—she was crewed by Danish Resistance men. When the last of the refugees had been transhipped, Hansen returned to Copenhagen, rather proud that his craft with the name that meant ‘The Starlight’ had carried a most Stellar passenger.
The Danes across the Sound had made elaborate preparations for Professor Bohr’s arrival, but the customs official who met the boat had not been told to expect the physicist. Sleepily tugging on his clothes as the refugees entered his office, the Swede asked for the people’s names, and when he heard ‘Niels Bohr’, he embarrassedly jerked the straps of his braces over his shoulders. The others would have to await routine question ing, he said, but Professor Bohr was free to catch the next train to Stockholm.
Sweden was then full of German espionage agents, and to avoid attracting their attention the Danes did not arrange private transport to Stockholm for the professor. But when Dr. Bohr climbed aboard his railway carriage a little later, he was followed by a man who kept at a distance and afterwards made no effort on the train to introduce himself to the physicist. All night this man remained alertly on watch outside Dr. Bohr’s compartment. When the professor alighted at central station in Stockholm, this man again followed closely behind him. As Bohr lumbered past the ticket gate a round-faced, genial-looking gentleman in civilian clothes stepped forward and winked at the man who had been following the professor. The round-faced man then went up to the physicist and introduced himself smartly: ‘Lieutenant-Colonel Gyth, Danish Military intelligence, sir. We have a car for you outside.’
While they were driving through the city the officer explained that final arrangements had been made to fly Bohr to England that night. ‘Oh, but I have some imperative business here before I go,’ Dr. Bohr said.
Gyth then told him that special guards would be with him at all times, and that the Germans must not know that the professor was in Sweden. Bohr agreed that this was a good idea.
The following day the entire Bohr family reached Stockholm except one of the professor’s sons who, after an anxious delay owing to transport difficulties, arrived several days later. As part of Colonel Gyth’s elaborate security arrangements, Professor Bohr did not live with his family in Stockholm but was allowed to visit them each day; he was moved between the homes of several eminent Danes in Stockholm each night.
Professor Bohr decided that, before leaving for England, he would make use of his notoriety to coax high-ranking Swedes to get their Government to protest formally to the Germans about the treatment of Danish jews. Bohr wanted the Germans told that Danish Jews would be given shelter in the neutral country. To this end, he had several talks with the Swedish Foreign Minister. This official, however, was reluctant to take any action, and because of this Bohr did not feel himself free to leave for England.
During their discussions with the professor Ebbe Munck and other prominent free Danes were disturbed to learn that the professor had forgotten quite a few papers in Jacobsen House. What did the papers concern? Were they secret scientific matters, details of refugee movements, or evaluations of intelligence data? Frankly, Bohr confessed, he could not really remember.
So far, the Germans had not searched Jacobsen House in Copenhagen, but they were likely to do so at any time, so some action had to be taken quickly. Ebbe Munck used his secret communication lines with Denmark to get word to Dr. Lindstrøm-Lang who, quite blithely, went to the Bohr home inside the grounds of the Carlsberg Brewery and asked the housekeeper to show him into Dr. Bohr’s solarium study. There Lingstrøm-Lang scooped up all the notes he could find that had been scribbled by the professor, and these were dis patched in a suitcase to Stockholm. Dr. Bohr, still making his appeal to the Swedish Government, found time to go through the mass of notes. To tell the truth, he admitted, he could read none of them and they might have meant anything!
After several days, realizing that the Swedish Foreign Minister was not likely to help him have a protest made to the Germans, Dr. Bohr decided to go to higher authority and called on the Swedish Crown Prince.
Meanwhile, having learned that the physicist was in Sweden, the German Embassy there contacted Copenhagen. The Gestapo men who were sent to search Jacobsen House carried away only stacks of innocuous newspaper cuttings which the pro fessor had saved.
In a later conversation with the Danes in Stockholm Dr. Bohr remembered that he had forgotten a bottle of heavy water in his home. To the Danes, of course, this meant nothing in 1943, and Bohr made no attempt to explain to them what it was; he only said that it was rare and might be important. In any case, he supposed the Germans had found it by then.
Again the Danes contacted Copenhagen and told the Resistance to get the bottle of heavy water from the Bohr home. The house was no longer under German surveillance because the Nazis had ransacked it so thoroughly, and a Resistance agent had no trouble calling on the Bohr housekeeper. Did she know where the professor had left a bottle of something called heavy water? Had the Germans found it?
The woman led the man into the house, but instead of taking him into Dr. Bohr’s laboratory, she directed him into her kitchen. Then she went to the larder and reached in among some beer bottles. One bottle held about a quarter of a litre of heavy water. This was sent to Sweden—the last heavy water in Denmark. Probably it would, in any case, have been of little use to the Germans, for they already had taken about twenty tons of the liquid from the Rukan power station in Norway before it was blown up by British saboteurs.
Sweden’s Crown Prince received Dr. Bohr graciously and got his Government to send the protest to the Germans about the Danish Jews. Could he, Dr. Bohr’s compatriots then asked him, now leave for England? No, he said, not yet. The Swedish protest would mean nothing, Bohr realized, unless it was made public, and he again visited the Crown Prince to explain this to him and ask his help. The protest, the first official action Sweden took against the Germans during the war, was finally published in Swedish newspapers, and Bohr said he was now ready to depart for England.
The escape would by no means be easy. Stockholm aerodrome was used by the Luftwaffe as well as by British aircraft, and the flight to England would be risky. A pair of Mosquito bombers landed in Stockholm every day and departed every night for Britain, a single passenger in a specially constructed seat in the bomb bay of each aircraft. This was how Bohr was to be taken to England, and on the night set for his evacuation the physicist was escorted to the aerodrome by a secretary from the Danish Legation.
Bohr, dressed in warm clothes, was helped into the tight bomb bay, strapped into the seat, and given a flying helmet, headphones, and an oxygen mask. The secretary wished him good-bye, and the aeroplane taxied down the runway. The secretary watched the take-off, then decided he would wait at the aerodrome for a while before returning to his home in the city. Half an hour later the Mosquito landed again at the field; engine trouble had forced it back. Dr. Bohr would have to wait until the next night to get to England.
The Germans dared take no direct action against Bohr while he was in Sweden, but they were looking everywhere for him, hoping to prevent his leaving. A naturalized Swede, German by birth, reported to Nazi espionage agents in Stockholm that he had seen Bohr at the aerodrome. At the time the Danes did not know of this security leak. Whether it was a result of the information the Germans received is not known—but one of the two Mosquito bombers that left Stockholm the following night never reached England.
On this next evening Bohr was again strapped into a Mosquito’s bomb bay and the aircraft took off. This time it did not return.
As the Mosquito climbed toward a safe flying altitude the pilot switched on the intercom and told the professor and the navigator to turn on their oxygen gear. The aircraft continued to climb to between 27,000 and 30,000 feet. A little while later, looking at his instruments, the pilot became alarmed. Something was very wrong. Dr. Bohr’s oxygen equipment was not working. The pilot was now very concerned, but his orders were not to turn back, and while they were in the air there was no way to get to the passenger’s seat in the bomb bay.
The only thing to do was to keep on toward Britain. However, after passing over Jutland the pilot dived, and from then they flew on at a much lower altitude.
When the plane at last touched down, its worried pilot rushed under the fuselage to open the bomb bay. The physicist was slumped over in his seat, his eyes shut. Aware of the effects of high-altitude flying without proper oxygen, the pilot was very much afraid that his precious passenger might be dead, or, if still alive, that his brain cells would be seriously damaged.
However, when the airman tapped him, Bohr awakened. He had, he said, slept through the entire flight. He had been unable to fit his headphones down over his flying helmet and had not heard the instruction to use his oxygen mask. With it still in his lap, he had dozed.
After some months in Britain, Professor Bohr was taken to America where, for about a year and a half, he worked on the atomic bomb project. During this time he was kept under security guard and was not allowed to use his own name. His colleagues on the Los Alamos project did their best to keep other people from knowing who the famous Dane was, but many stories have been told about the problems American security officers had in guarding the physicist. According to one story, Bohr was taken to New York City to consult with some scientists, and when walking down the street one day he encountered a lady from Copenhagen. ‘Why, hello, Dr. Bohr!’ she said. ‘I didn’t know you were in America.’
‘I’m very sorry,’ Bohr said, for once mindful of security regulations, ‘but you’re mistaken. My name isn’t Bohr.’
‘Oh, but you’re Niels Bohr. I knew you in Copenhagen.’
‘I’m very sorry, madam,’ the professor replied, ‘I’m not Niels Bohr.’ Then his eyes brightened. ‘But how are you, Mrs. Hansen?’