And as he gazed, earth and moon swept into view. The latter was almost hidden behind one of two disc-like machines that hung between the earth and Henshaw’s viewpoint. The doctor caught a glimpse of a great brassy reflecting surface, a central apparatus resembling a solar engine, and tremendous tentacles that held a huge building in their grasp. Then machines, earth and moon had swept past the window and only the stars appeared. When he turned, he found the Russian beside him, looking over his shoulder. “Are we--rotating?” Henshaw asked, his disbelief turned to awe. “Yes,” Godonoff nodded, “the centrifugal force of our rotation is what gives the effect of gravity in the car.” As Godonoff spoke, earth, moon and the great machines again swept into view and this time, Henshaw was able to secure a better view of them. He saw that the building in the grasp of the foremost machine was really the Woolworth, and that the farther one held the Eiffel Tower in its arms. The machines swept out of view, but in a few minutes appeared again. Godonoff began proudly to explain them. “That brass surface reflects the greater part of the sun’s rays. Although space is intensely cold, when the rays strike directly on anything, they heat it up to a remarkable degree. As you see, we reflect most of the heat from the machine’s surface; what we need is absorbed by the solar engine in the center. Note the curved mirrors which reflect the heat to the central cylindrical steam boiler. The steam generated runs the turbines that generate electricity to heat and operate the whole machine. “See that green globe in the middle of the machine?” he continued as the machines swung past again, “that’s the helium fluoride. An electric current is passed through it, when we first leave the earth, but, after a good speed is secured, our inertia carries us on.” “What are those two searchlight beams?” asked Henshaw. “They are not light beams, Doctor. They are hollow cones of gas, lit up by the sun. The helium fluoride is not a stable substance; it slowly decomposes into its elements. The resulting gases are forced through pipes and through the boiler of the solar engine, where the heat expands them and drives them at high pressure through the nozzles you see. The recoil of the resulting jets is used for steering the disc.” Henshaw turned back into the room, his eyes dazed by the view of the rapidly revolving heavens. “That door,” he said, pointing, “it leads to outer space?” The Russian eyed him narrowly and then nodded. “I suppose you’ve bolted it,” Henshaw went on smilingly, “so that I can’t leap out into space and take my secret with me?” “Oh, no,” Godonoff answered. “It was locked when we left the earth, and I’ve just left it that way. I’ll unlock it, but don’t think it can be opened. With fifteen pounds of air pressure on this side and a vacuum on the other, wild horses couldn’t open it.”