As they walked forward Luhor turned to Mark with a proud smile. "You won't find _that_ type of navigation in the 'Advanced Principles,' eh, Earthman?" "No, indeed not," Mark admitted. "But I still don't understand that braking process!" Luhor pointed to colossal sets of coils, in niches along each side of the vast corridor. "Synchronized magnetic degravitation fields; they arrest mass and speed synchronously, finally stopping the spacer in a graduating net of force. Similar coils to these exist for a mile along the gorge back there, through which we came. Even so it is a very delicate and precise process." They stepped into a grotto so vast as to dwarf anything Mark had ever imagined. It extended for miles, sheltering an entire little city! Mark saw rows of stone dwellings, stream-lined, ultra-modern. From larger buildings came the sounds of blast furnaces and an occasional flash of ruddy glow. Groups of workmen hurried past, glanced curiously at the new arrivals but didn't stop to fraternize. And then Mark saw Carston. Ernest Carston! One of the very highest men among the Tri-Planetary Prison Bureau officials! The surprise stopped Mark Denning in his tracks, but fortunately, thanks to his training, he managed to keep his face impassive as they recognized each other simultaneously. Carston flashed him a quick look that seemed to say, "Later!" Then the newcomers were marching in silence to a spacious building, where they were assigned rooms. The furnishings were simple, but comfortable, and Luhor led them to the rear of the building where the dining-room was located. They ate with the famished eagerness of men who had long subsisted on compressed synthetic rations. Then they were issued cigarettes. To the men who had been doomed on Venus only a few hours previously, it was like awakening in heaven from a nightmare in hell. Through Mark's mind ran an ancient saying: "Eat, drink and be merry, for tomorrow...." IV Standing in the doorway, the girl of the unsmiling blue eyes surveyed the new men silently. Her trim, aloof figure instantly commanded their attention, and their respect as well. "I cannot waste words on you," she said abruptly, "for my time is limited. I know all of your names, so you shall know mine as well, although it will mean nothing to you. I am Cynthia Marnik, but you will address me always as Commander. You will obey me implicitly in all things here. Second to me, you will obey Luhor. "All of you volunteered to come. Now that you're here, you are part of our scheme of things and you will work as hard as you did in the swamp. It is dangerous work, but you will have ample remuneration. Idlers and grumblers will be done away with, I promise you. Your lives were forfeit in the swamp, and that is not altered by your being on Vulcan." She paused as if waiting for objections, but every man was silent.