At last the party had crossed the great hall, and stopped beside a large doorway. The officer halted for a moment, and gestured toward two of his men, who remained, while the others walked quickly away. The diminished party stepped through the doorway into a small room whose walls were lined with copper, and an instant later, as the officer pushed a small button, there was a low hiss of escaping air, and a copper grating sprang quickly up across the opening of the elevator. He touched another button, and there was the familiar sinking feeling as the car rose, a low hum seeming to come from its base. The elevator rose swiftly through a very considerable distance--up--up, endlessly. "They must have some wonderfully strong cables here on Venus!" Morey exclaimed. "The engineers of Terrestrial buildings have been wondering for some time how to get around the difficulty of shifting elevators. The idea of changing cars doesn't appeal to me, either--but we must have risen a long way!" "I should say so--I wonder how they do it. We've been rising for a minute and a half at a very fair clip--there we are; end of the line--I want to look at this car!" Arcot stepped over to the control board, looked at it closely, then stepped out and peered down between the car and the shaft as the copper grating fell, simultaneously pulling down with it the door that had blocked off the hallway. "Come here, Morey--simple system at that! It would be so, of course. Look--they have tracks, and a regular trolley system, with cog rails alongside, and the car just winds itself up! They have a motor underneath, I'll bet, and just run it up in that way. They have never done that on Earth because of the cost of running the car up without too much power. I think I see the solution--the car has electro-dynamical brakes, and descending, just slows itself down by pumping power into the line to haul some other car up. This is a mighty clever scheme!" As Arcot straightened, the officer beckoned to him to follow, and started down the long corridor which was lined on either side with large doorways, much like a very exotic earthly office building. Passing through a long series of branching corridors they at last reached one that terminated in a large office, into which the young officer led them. Snapping to attention, he spoke briefly and rapidly, saluted and retired with his two men. The man before whom the Terrestrians stood was a tall, kindly-faced old gentleman. His straight black hair was tinged with bluish gray, and the kindly face bore the lines of age, but the smiling eyes, and the air of sincere interest gave his countenance an amazingly youthful air. It was warm and friendly despite its disconcerting blueness. He looked curiously, questioningly at the two men before him, looked at their hands, his eyes widening in surprise; then he stepped quickly forward, and extended his hand, at the same time looking toward Arcot.