The thesis was 'The specific heat of heavy water'. You know, heavy water is the isotope, the D2O, the deuterium isotope of normal water which is H2O, and Eucken was interested in the specific heat, which had to be measured very precisely by five decimals, up to 10-5, because he had developed the water theory, the theory of the structure formation in water. You know, water molecules are dipoles, and so they have a strong interaction which is called hydrogen bond, it's a bond between the positive proton in the H2O molecule and the lone electron pair at the oxygen of the water molecule, and it made these associations via hydrogen bonds. And he wanted to test his theory and needed the isotope effects.
[Q] But the question is, it was post-war, DO2, heavy water...
D2O...
[Q] Excuse me... did he have it? It was forbidden, it was a...
Yes, he still had in his board, he still had about 500 grams of it, but it was a...
[Q] Secret? Treasure?
It was a treasure. I mean he could... well, all right, you couldn't buy it any more, you couldn't get new one, but what you had, you can't do any harm with D2O. D2O plays a role in the atomic reactor, the fast neutrons are slowed down by the deuterium and therefore... But for atomic reactor you needed large amounts of heavy water so you couldn't do anything. No, it was a real scientific problem, but heavy water was expensive at that time.
[Q] And you couldn't buy it?
Oh no, you couldn't buy it, it wasn't available, and if it were available in the States or wherever, it would have been very, very expensive.