"The simple truth," Winthrop told him. "We reviewed the data and reached an inescapable conclusion. Bert, when it came, the disarranged circuitry cut into the anti-gravity mechanism and landed it safely, as we suspected. Had it been wired properly, something forward would have been awakened. I'm sure of that! "The math explained the autopilot/computer, the anti-gravity mechanism, the reactor, the fission bomb--and _something sinister_! "The history book--not comic book--showed where the ship originated, and it also showed clearly who launched it. The math is based on fourteen symbols. The invaders in the history book have seven-fingered hands, the pastoral folk five!" Steadily Winthrop returned the general's stare. "I shouldn't have said 'ship'! It wasn't designed for passengers or crew. We thought the forward portion wasn't described. But it was--in the same equations that explained the reactor and the fission bomb! "We use fission bombs to detonate fusion bombs. The _missile's_ warhead contains a fusion bomb which the math proves would have caused a spontaneous carbon chain reaction which would almost instantaneously have wiped out the Earth! Through a technician's error it came to Earth a dud. Its launchers will never know that. It will be _back where it belongs_ twenty times quicker than the light now leaving Sol--and it's no longer a dud!" They all were silent then. _You licked it_, Winthrop told himself, _when you armed the greatest bomb_. Verification of classification came almost nine years later. Then a flareup of near-nova intensity was noted in Sirius, the finest photographs being obtained by Englander in New Palomar Observatory on Pluto.