It was not, however, the crack of doom. When Joe stared out the window by the head of his cot, he saw gray-red dawn breaking over the landing field. There were low, featureless structures silhouetted against the sunrise. As the crimson light grew brighter, Joe realized that the angular shapes were hangars. Improbable crane poles loomed above them. One was in motion, handling something he could not make out, but the noise that had awakened him was less, now. It seemed to circle overhead, and it had an angry, droning, buzzing quality that was not natural in any motor he had ever heard before. Joe shivered, standing at the window. It was cold and dank in the dawn light at this altitude, but he wanted to know what that completely unbelievable roar had been. A crane beam by the hangars tilted down, slowly, and then lifted as if released of a great weight. The light was growing slowly brighter. Joe saw something on the ground. Rather, it was not quite on the ground. It rested on something on the ground. Suddenly that unholy uproar began again. Something moved. It ran heavily out from the masking dark of the hangars. It picked up speed. It acquired a reasonable velocity--forty or fifty miles an hour. As it scuttled over the dimly lighted field, it made a din like all the boiler factories in the world and all the backfiring motors in creation trying to drown each other's noise out--and all of them being very successful. It was a pushpot. Joe recognized it with incredulity. It was one of those utterly ungainly creations that were built around one half of the sidewall of the Shed. In shape, its upper part was like the top half of a loaf of bread. In motion, here, it rested on some sort of wheeled vehicle, and it was reared up like an indignant caterpillar, and a blue-white flame squirted out of its tail, with coy and frolicsome flirtings from side to side. The pushpot lifted from the vehicle on which it rode, and the vehicle put on speed and got away from under it with frantic agility. The vehicle swerved to one side, and Joe stared with amazed eyes at the pushpot, some twenty feet aloft. It had a flat underside, and a topside that still looked to him like the rounded top half of a loaf of baker's bread. It hung in the air at an angle of about forty-five degrees, and it howled like a panic-stricken dragon--Joe was getting his metaphors mixed by this time--and it swung and wobbled and slowly gained altitude, and then suddenly it seemed to get the knack of what it was supposed to do. It started to circle around, and then it began abruptly to climb skyward. Until it began to climb it looked heavy and clumsy and wholly unimpressive. But when it climbed, it really moved!