2. The Germans advance

Having taken Czechoslovakia virtually by British and French invitation in 1938 and 1939, having then launched the Second World War on 1 September 1939 with an attack on Poland that included the terror bombing of Warsaw, the Germans briefly halted. Some in the West dubbed the winter of 1939—40 the time of the ‘phony war’. But the Blitzkrieg started again that spring. On 9 April, three weeks after Italy had entered the war on the side of Germany, the Germans invaded Denmark and Norway. The shocked Danes capitulated almost immediately, though their resistance to Nazi oppression from that moment forward was among the most vigorous in Europe. The Norwegians fought back, and received some poorly organized help from the British. King Haakon escaped his country, the government of Neville Chamberlain fell in part as a result of its blundering efforts in Norway (to be replaced by a Conservative government formed by Winston Churchill), and Norway’s resisters finally surrendered in early June. Meanwhile, on 10 May the Germans invaded the Netherlands, Luxembourg, and Belgium. Overwhelmed, the Luxembourgers surrendered almost immediately, the Dutch five days after the German bombing of Rotterdam that killed 30,000. The Belgians held out for nearly three weeks before capitulating; Dunkirk was evacuated in late May and early June. On 5 June the Nazis struck France, which surrendered after seventeen days. Even as Fascist armies moved against North Africa, Eastern Europe, and the Balkans that summer, the Battle of Britain began in earnest. Churchill rallied his people. The American president, Franklin Delano Roosevelt, sent Churchill his sympathy and as much aid as he could muster through his own office or with the limited support of a cautious Congress.

The fall of Norway meant that the great factory at Vemork, owned by the firm Norsk Hydro, was in German hands. Norsk Hydro produced heavy water, in which two atoms of deuterium replace the two hydrogen atoms: D2O. (Deuterium is an isotope of hydrogen, heavier because it carries one extra neutron.) Heavy water was known to be a moderator of a potential chain reaction—that is, it slows projectile neutrons so as to make them more likely to strike uranium nucleii. Norsk Hydro produced far more heavy water than anyone else in the world, and the Germans quickly commandeered the plant. The previous March, under cover of the phony war but fearing the worst, Frederic Joliot had instigated the purchase of 185 kilograms of heavy water from Norsk Hydro and brought it to Paris in twelve aluminum canisters. When the Germans breached the French front in June, Joliot spirited the heavy water to Bank of France vaults in the center of the country, thence to a death-row prison cell at Riom (the doomed convicts carried the water into the cell themselves), and finally to a British coal ship called the Broompark, which sailed from Bordeaux with the water and a load of industrial diamonds and safely reached England later that summer. It thus followed the many scientists who had left the continent for Britain over the previous seven years—and, as we shall see, it carried two others.5

The Shinkolobwe uranium, piled in Oolen, escaped too. In the spring of 1939, the physicist G. P. Thomson, of the Imperial College of Science and Technology in London, asked officials to obtain for him a ton of uranium oxide, for experimental purposes. Thomson’s request ultimately reached his rector, Sir Henry Tizard, who also chaired the Research Department of the Royal Air Force. Thomson got his ton of UO2, while Tizard was concerned enough by the request to call a meeting with the Belgian ambassador to Britain and two officials of the Union Miniere du Haut Katanga—the Briton Lord Stonehaven, and Edgar Sengier, the Belgian who managed the Shinkolobwe mine for the company. Tizard asked that the British be granted an option to buy all the uranium ore that would be mined at Shinkolobwe; he evidently did not know about the pile of uranium ore already in Belgium. The Belgians refused. As the meeting broke up, Tizard said to Sengier: ‘Be careful, and never forget that you have in your hands something that may mean a catastrophe to your country and mine if this material were to fall into the hands of a possible enemy.’6

Several days later, back in Brussels, Sengier heard much the same warning from Joliot. At that point, worried, he packed the Oolen ore, over 1,200 tons worth, into 2,000 steel drums marked ‘Uranium Ore, Product of the Belgian Congo’, trucked it to port at Antwerp, and placed it on two ships bound for Staten Island, New York. Sengier then tried several times without success to interest the Americans in the ore. (On 18 September 1942, the day after General Leslie Groves took charge of the US atomic bomb project, Groves’s deputy, Kenneth Nichols, found Sengier at Union Miniere’s New York City office. ‘I’ve been waiting for you to come,’ Sengier told Nichols. If the Americans wanted his uranium, they could have it. Nichols and Sengier scribbled an agreement on a piece of paper—the ore was sold for the low price of $1.60 per pound—and within the week it was on its way to American laboratories.7)

Thus did the raw material for a possible atomic bomb come into the hands of Germany, Great Britain, and the United States. To some extent, heavy water and especially uranium followed the best-equipped physics labs and physicists imaginative enough to use them. But not entirely, for Niels Bohr’s small country had no uranium, and the Soviet Union at first appeared to lack the ore that Peter Kapitsa and his colleagues might have put to use. Neither did the Japanese have a source of uranium, even as their scientists experimented with fission and their military spread Japanese authority over the East Asian mainland. Whether Japan would have been able to build atomic bombs had it found a Chinese Joachimsthal or a Malayan Shinkolobwe will always remain a matter for speculation; Germany, after all, had uranium and heavy water but did not, as we shall see, come close to making a bomb. There were in fact many reasons why the Japanese failed to acquire an atomic bomb. The story of the Japanese nuclear project is a tale of a road not taken, or several roads, with critical implications for the world during the 1940s and after.8

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