The German army invades Denmark, where Niel Bohr is staying. He has already donated his gold Nobel medal to charity, but he is keeping the two Nobel medals of his German Jewish colleagues Max von Laue (X-ray diffraction) and James Franck (energy quantization). Any gold object is subject to strict restrictions and cannot leave the Reich. Fearing the Germans might find them, he dissolves them (with difficulty due to the large amount of gold) in white spirit and leaves them in the jar in the laboratory. The Germans search the laboratory but ignore the jar of brown liquid, which remains there for the rest of the war. In 1945, Bohr sends the jar to the Royal Swedish Academy of Sciences, explaining what happened. The gold is recovered, and the Nobel Foundation mints two more medals from it, which are returned to the two Germans.
