"Mark: this is not an ordinary mirror. That is what I mean! It denies every law of optics! Glass as full of waves and ripples as this apparently is should return hideously distorted reflections. Yet it does not do so!" "But what--" "We shall see. Come on! Bring the mirror to my laboratory." Hesitating only long enough to throw a tablecloth across the face of the glass, the old man hurried out. Mark strode along in his wake, the heavy mirror in his arms. Together, they left the house and followed the bricked path to the little laboratory structure located at the far end of the lot. "Set it down here, in this rack," the professor instructed, indicating an easel-like arrangement in one corner. He himself wheeled a strange electrical apparatus into position in front of the glass. Then took up a position behind a large glass screen, and motioned Mark to join him. "What are you going to do?" "You shall see!" * * * * * The white-haired savant threw a switch. The laboratory's lights went out. He pressed a button on the control board of the apparatus behind which they stood. Leaned forward eagerly, peering through the glass screen at the mirror. Manipulated dials and levers. An inexplicable excitement gripped Mark. He had a sudden, unshakable conviction that he and the professor were on the verge of incredible discoveries. Discoveries that would lead him to an explanation of the strange coma that held Elaine in its grim sway. His brown eyes fastened on the mirror. The next instant they went wide with astonishment. The glass screen behind which he and the professor were standing was clearly reflected. But it was merely an opaque surface! Neither he nor the scientist could be seen behind it! As if reading his mind, Professor Duchard gave vent to a little laugh. "'One-way' glass," he explained. "It permits vision in only one direction." Then the humor went out of his voice. "We may thank God that science developed it before we are through." Again he leaned forward, his eyes on the mirror. An instant later he leveled a quivering forefinger. "_Look!_" There, in the semi-darkness where stood the looking-glass, a weird figure was beginning to glow! Tension flooded through Mark's veins. His fingers knotted into fists. His eyes strained to catch the thing which grew upon the mirror's surface. Slowly, like some wizard's evil phantasmagoria, the glowing lines came together. Took form. Painted a figure-- _The figure of the woman in the mirror!_ "That's her!" he cried excitedly. "That's the woman we saw reflected instead of Elaine!" Professor Duchard snapped off the machine beside him. He turned on the lights. Swung around to face his daughter's fiance. His face was grey. Grim lines of worry etched deep into the flesh. "So that is it!" he said. "That is what he has done to her!"