> HEISENBERG: I don't believe a word of the whole thing. They must have spent the whole of their £500,000,000 in separating isotopes; and then it's possible. H

> HEISENBERG: I don't believe a word of the whole thing. They must have spent the whole of their £500,000,000 in separating isotopes; and then it's possible. How did Heisenberg know with such an accuracy the budget of the Manhattan project? Wikipedia states that it was $2.2 billion, and the pound/dollar exchange rate during the war was $4.03 for £1, so Heisenberg was less than 10% off. Edit: I think all these discussions must have happened after they heard Truman's speech [1], where he quoted the pricetag of 2 billion dollars. [1] https://millercenter.org/the-presidency/presidential-speeches/august-6-1945-statement-president-announcing-use-bomb https://millercenter.org/the-presidency/presidential-speeche...