"He proposed to construct a tubular car or cage which would traverse the almost eight thousand miles in only four hours—more than twenty four hours less than the time required for a trip to the Antipodes by stratosphere plane.
"His argument for the success of the undertaking lay, not so much in the time saved on the trip, but in the novelty of the method of travel, and its value for giving people a taste of what weightless travel in space ships would be like. His imagination capitalized on the fact that Man is always on the alert for some new and strange way of cheating his perambulatory equipment of its needed exercise.
"Before advancing his proposition, he'd had his engineers draw up complete plans and specifications of the proposed cage and the necessary auxiliary equipment.
"The cage itself was to be a zeppelin-shaped projectile—But come, the Diamvator itself is due in five minutes."
Andrews arose and led the way to the terminal gate, and for the next few minutes Randall unobtrusively strolled around the circumference of the Earth-Tube, examining its massive steel barrier. He completed his circuit and was peering timidly through the steel lattice, when a long-drawn "whoooosh" and a metallic click sounded from the black depths.
He turned inquiringly to Andrews, who hastened to explain. "Closing of the air-locks," he said. "You see, the air is only partially exhausted from the Earth-Tube, so that the Diamvator will be held from the Tube sidewall during its free fall. Thus it does not attain the full acceleration of a freely falling body in a vacuum by a great deal. Consequently it does not approach its full pendular ascent from the Earth's center against gravitation.
"It lacks 'falling' to the surface of the Earth by over ten thousand feet, so some means had to be provided for propelling the Vator on up to the surface. To accomplish this, automatic air-locks were installed in the tube almost three hundred miles from either end, with other locks every few miles from there to the surface.
"When the Vator has passed a lower lock, both that one and the lock above it close, and air is admitted under high pressure below the Vator and exhausted above it, thus pushing the car up to the surface, where it is grasped and held by interlocking steel arms—"
Andrews was interrupted by a second "whoooosh" as the upper lock opened, followed immediately by the appearance of the bullet-shaped nose of the Diamvator.