The machine was huge, but it had an appearance of simple construction. A large rectangular block of what appeared to be a strange black metal was set on end and flanked on each side by two smaller ones. On the top of the large block was set a half-globe of a strange substance, somewhat, Henry thought, like frosted glass. On one side of the large cube was set a lever, a long glass panel, two vertical tubes and three clock-face indicators. The control board, it appeared, was relatively simple. Beside the mass of the five rectangles, on the floor, was a large plate of transparent substance, ground to a concave surface, through which one could see an intricate tangle of wire mesh. Hanging from the ceiling, directly above the one on the floor, was another concave disk, but this one had a far more pronounced curvature. Wires connected the two disks and each in turn was connected to the rectangular machine. "It is a matter of the proper utilization of two forces, electrical and gravitational," proudly explained Dr. White. "Those two forces, properly used, warp the third-dimensional into the fourth. A reverse process is used to return the object to the third. The principle of the machine is--" The old man was about to launch into a lengthy discussion, but Henry interrupted him. A glance at his watch had shown him press time was drawing perilously close. "Just a second," he said. "You propose to warp a third-dimensional being into a fourth dimension. How can a third-dimensional thing exist there? You said a short time ago that only a specified dimension could exist on one single plane." "You have missed my point," snapped Dr. White. "I am not sending a third-dimensional thing to a fourth dimension. I am changing the third-dimensional being into a fourth-dimensional being. I add a dimension, and automatically the being exists on a different plane. I am reversing evolution. This third dimension we now exist on evolved, millions of eons ago, from a fourth dimension. I am sending a lesser entity back over those millions of eons to a plane similar to one upon which his ancestors lived inconceivably long ago." "But, man, how do you know you can do it?" * * * * * The doctor's eyes gleamed and his fingers reached out to press a bell. A servant appeared almost at once. "Bring me a dog," snapped the old man. The servant disappeared. "Young man," said Dr. White, "I am going to show you how I know I can do it. I have done it before, now I am going to do it for you. I have sent dogs and cats back to the fourth dimension and returned them safely to this room. I can do the same with men." The servant reappeared, carrying in his arms a small dog. The doctor stepped to the control board of his strange machine. "All right, George," he said.