‘ -53- ’ associated scientists thenselves knew up to the close of 1942. much of the subsequent findings as well. It in fact tells In any caso, from the end of 192 it was only two and onc-half years before we had the bonb, Tho Smyth Report reveals among other things that five distinct and separate processes for producing fissicnable materials were pursued, and that all were successful, These involved four processes for the separation of the U-235 isotope from the nore common forms of uranium and one basic process for the production of plutonium. One of the isotope separation processes, the so-called "Ncontrifuge process," was nevcr pushed beyond the pilct plant stage, but it was successful as far as it was pursucd. It was droppcd when the gaseous diffusion and clectromagnétic methods of isotope separation promised assured success 49 The thermal diffusion process was restricted to a small plant. But any of these | processes would have sufficeoc to produce the fissionable naborials for the bomb. Each of these processes presented probloms for which generally multiple rather than singic solutions were discovered. Each of them, furthermore, is described in the report in fairly revealing though general terms. probably reveals enough Finally, the report to indicatc to the careful reader which of the processes presents the fewest problems and offers the nost profitable yicld. Another nation wishing to produce the bomb cafimenfine its efforts to that one proccss fe eB fs o t. about the bomb itself tc give one a good idca of its basic character. Superficially at lcast, the problem of bomb design seems a bottleneck, since the same bomb is required to handic the matcrials produced by any of the five processes mentioned above, But that is like saying that waile gascline can be produced in several diffcroant ways, only one kind of engine can utilize it effectively. The bomb is gadgetry, and it is a commonplace in the history of technology that mechanical devices of radically different cesign have been perfected to achieve a comion end. The machine gun has several variants See Smyth Report, chaps. vii-xi, also paragraph 5.21.