deviations from hydrodynamic theory were the result of the speed of the chemical reactions themselves. To control the reaction, calculations down to the microsecond level were needed. Section 8 was drawn into the investigation of shaped charges, whose mechanism was explained by Taylor and James Tuck in 1943. Manhattan Project At the Manhattan Project's Los Alamos Laboratory, research into implosion had been proceeding under Seth Neddermeyer, but his division had worked with cylinders and small charges, and had produced only objects that looked like rocks. Their research was accorded a low priority, owing to expectations that a gun-type nuclear weapon design would work for both uranium-235 and plutonium, and implosion technology would not be required. In September 1943, the Los Alamos Laboratory's director, Robert Oppenheimer, arranged for von Neumann to visit Los Alamos and investigate implosion with a fresh set of eyes. After reviewing Neddermeyer's studies, and discussing the matter with Edward Teller, von Neumann suggested the use of high explosive in shaped charges to implode a sphere, which he showed could not only result in a faster assembly of fissile material than was possible with the gun method, but greatly reduce the amount of material required. The prospect of more efficient nuclear weapons impressed Oppenheimer, Teller and Hans Bethe, but they decided that an expert on explosives was required. Kistiakowsky's name was immediately suggested, and he was brought into the project as a consultant in October 1943. Kistiakowsky was initially reluctant to come, "partly because", he later explained, "I didn't think the bomb would be ready in time and I was interested in helping to win the war". At Los Alamos, he began reorganizing the implosion effort. He introduced techniques such as photography and X-rays to study the behavior of shaped charges. The former had been extensively employed by the ERL, while the latter had been described in papers by Tuck, who also suggested using three-dimensional explosive lenses. As with other aspects of the Manhattan Project, research into explosive lenses followed multiple lines of inquiry simultaneously because, as Kistiakowsky noted, it was "impossible to predict which of these basic techniques will be the more successful." Kistiakowsky brought with him to Los Alamos a detailed knowledge of all the studies into shaped charges, of explosives like Composition B, and of the procedures used at the ERL in 1942 and 1943. Increasingly, the ERL itself would be drawn into the implosion