In the optimistic time of the Crystal Palace, when progress was an article of national faith, it was easy to see the present as ascending toward an even better future; by the 1870s, it seemed to many to be more like exile from a better past.
32.
From memory, I think the most optimistic time estimate was on the order of 4-6 weeks to make enough plutonium for another bomb after that . ( U-235, for the Little Boy design, took longer to make . )-- Anonymous, edited 08 : 49 UTC, February 17, 2008.