Tarzan now found himself in a short, dark corridor which presently opened into a wider and lighter one along which innumerable, unladen slaves were moving in the same direction that his guard now escorted him. He noticed that the floor of the corridor had a constant downward gradient and that it turned ever to the right, forming a great spiral leading downward into the earth. The walls and ceiling were timbered and the floor paved with flat stones, worn smooth by the millions of sandaled feet that had passed over them. At sufficiently frequent intervals candles were set in niches in the left-hand wall, and, also at regular intervals, other corridors opened out of it. Over each of these openings were more of the strange hieroglyphics of Minuni. As Tarzan was to learn later, these designated the levels at which the tunnels lay and led to circular corridors which surrounded the main spiral runway. From these circular corridors ran the numerous horizontal tunnels leading to the workings at each level. Shafts for ventilation and emergency exit pierced these tunnels at varying distances, running from the surface to the lowest levels of the quarry. At almost every level a few slaves turned off into these lateral tunnels which were well lighted, though not quite as brilliantly as the spiral. Shortly after they had commenced the descent, Tarzan, accustomed from infancy to keen observation, had taken note of the numbers of tunnel entrances they passed, but he could only conjecture at the difference in the depths of the levels into which they opened. A rough guess placed them at fifteen feet, but before they reached the thirty-sixth, into which they turned, Tarzan felt that there must be an error in his calculations, for he was sure that they could not be five hundred and forty feet below the earth's surface with open flames and no forced ventilation. The horizontal corridor they now entered after leaving the spiral curved sharply to the right and then back to the left. Shortly afterward it crossed a wide, circular corridor in which were both laden and unladen slaves, beyond which were two lines, those laden with rock moving back in the direction from which Tarzan had come, while others, bearing lumber moved in the same direction that he did. With both lines there were unladen slaves. After traversing the horizontal tunnel for a considerable distance they came at last upon the working party, and here Tarzan was turned over to the Vental, a warrior who, in the military organizations of the Minunians, commands ten men. "So this is the giant!" exclaimed the Vental. "And we are not to work him too hard." His tone was sneering and disagreeable. "Such a giant!" he cried. "Why, he is no larger than I and they are afraid to let him do any work into the bargain. Mark you, he will work here or get the lash. Kalfastoban permits no sluggards," and the fellow struck his chest vauntingly.