Again the visiscreen glowed, this time with the image of the Director of Precautions, who reported, "I, Melsit, have inspected the Time Visor, Experimental Permit No. 445,826, and find it to contain no dangerous elements." "It is well," said the Master, releasing the elevator lock, "Technician Heidkamp may bring it to my Presence, accompanied by two of the Guard. Remain in communication." A bell rang softly as the elevator rose into view. Technician Heidkamp, a man whose gray, lined face and desolate eyes belied his middle-age, gave the salute, then entered wheeling before him a cabinet whose glass panels revealed an intricacy of tubes and wiring in interlacing spirals. Behind him came the giant Guards, watchful and impassive. The Master watched, smiling secretly as he exulted in his power over Heidkamp. It was small pleasure to have the right of life and death over the workers who toiled in the depths of the city, but here was one of the great minds of all time, whom the Master could crush out of existence like an insect. The Master's eyes sparkled as he acknowledged the salute of the Technician. From the top of the cabinet Heidkamp lifted the separate eyepiece, its control buttons showing white against the ruby case, and laid it on the Master's desk. Again he saluted. "Your Excellency, a year ago you commanded me to construct a machine through which, for your amusement, you could view the past. Night and day I have labored, and now I offer to you the Time Visor through which you may view one small segment of the past--that time when the world, long tottering on the brink of disaster, spread too late the wings of war, and hurled itself to its long ruin. From this high place you may see the towers of Manhattan once more piled against the southern sky, in the midst of that vast ancient web of bridges, highways and villages, with its great harbor filled with the shipping that the War of the Wings has since destroyed. Look downward, and you may follow hour by hour the simple life of the old village of Nyack where our city now stands. Or you may carry it to the ends of the earth, and view the whole crowded world of those other days. "The instrument is adjusted to your Excellency's eyes. The lower button regulates the magnification, now set at three diameters. Your Excellency, you have long possessed the present and the future. It is my honor now to offer you the past." Heidkamp paused, his face glowing with the impersonal exultation of the born scientist.