Hiroshima_ The World's Bomb - Andrew J. Rotter [40]
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