They turned about, began to retrace their steps. Larry marked carefully the corridor which led to the control turret. He would not forget it, nor how to reach it. And as they walked he caught Sandra's eye for a brief moment. Harg did not see the swift wink that passed between them, nor the way Sandra's hands clenched before her in a delighted gesture of approbation.... But he did see, and gloried in, the amazement mirrored in the eyes of Sandra and Larry when at last they stepped into the chamber which housed the Time-warping machine. It was a huge structure, its inner chamber alone being large enough to house a battalion of men. But its core was small, being an oddly shaped, angular object spinning endlessly on a bar of crystalline material. Displaying all the vanity Larry had hoped for, the little scientist pointed to the twirling object first, then at a great, banked keyboard like that of some gigantic organ. "The end product of man's genius," he boasted vaingloriously, "for a thousand millenia! The machine which can span Time. You do not comprehend the object which spins upon the bar, no? I fear it is beyond your puny concept, friends from an unenlightened age. It is a tesseract; the infinite cube of four dimensions. Your eyes see but a cross section of its fullness, which is beyond seeing. Yet I, Harg-Ofortu, conceived and built it! * * * * * "These banks control the ages that Have-Been and the ages that are Yet-to-Be. Through their relays are disrupted the world-line of any given thing at any given time. I would demonstrate, but terrific power is expended each time I bring a new object from the past; I would not now waste power to convince such savages as you. "Yet by pressing a button--so--and deflecting a lever--so!--I can, if I will, bring across the negation or Time-that-Was-Not creatures like yourselves from any period of time. The ages in which I angle are clearly marked here; the position on this sphere called 'Earth' from which I draw my experiments I determine by means of this mapped globe." He paused, smirking with pride, so blinded with self-glory that he did not even notice the studiousness of Sandra's and Larry's eyes. But when he spoke again, it was to say words that dragged Larry back to earth with a start. "And it will interest you to know, Sandra Day, that a great tribute is shortly to be paid to you." Sandra said, "A--a tribute?" A faint shadow flickered across the diminutive one's face. "A recent disturbance," he proclaimed, "amongst slaves whom we call the 'Underlings' has wakened in us, the Masters, recognition that for too many generations we have allowed our brains to expand whilst our bodies failed in strength.