On April 12, 1935, five days after the second atomic bomb test explosion had concluded.
Arthur looked at the strikingly different sets of data on his desk and turned to Albert Einstein with some surprise, unable to resist asking, "Is this the atomic bomb data you tested a few days ago?"
"Yes, Your Majesty," Einstein nodded, seemingly having anticipated Arthur's astonishment.
"The first set of data is from our first test of the gun-type atomic bomb, while the second and third sets are from our improved uranium-235 bomb and plutonium-239 bomb, respectively," Einstein explained.
"The improved uranium-235 atomic bomb reached an explosive yield of 3,200 tons TNT equivalent, and the utilization rate of the nuclear material is at least 10%? The plutonium-239 atomic bomb had an explosive yield of 5,000 tons, with a nuclear material utilization rate of at least 15%?" Arthur had never imagined that the data from the second nuclear weapon test would differ so greatly from the first.