Something of the man's intensity, his enthusiasm, communicated itself to the professor. His blue eyes came alight. "It is conceivable!" he declared. "Not likely. But conceivable." He gripped the fragment of glass which Mark held. "Yes! We shall try it! If it works, we can--" He stopped short. His face fell. "We can what?" he finished. "Another time mirror will not help us bring Elaine back--" His companion interrupted fiercely: "How do we know? There's always a chance we'll think of something, isn't there? And it's a cinch we won't accomplish anything just sitting here." "But--" "The least we can do is try!" They worked like madmen in the hours that followed, heedless of the wedding guests who came and went from the house in bewildered knots. Unmindful of gashed fingers, Mark fitted the slivers of mirror together, while Professor Duchard tested and analyzed and figured at his side. And then-- "I have it!" shouted the savant triumphantly. "I have the formula!" "Then we can construct another mirror?" Some of the old man's elation dropped away. He shook his head. "Not yet. We know only the _effect_ we want. But how to achieve it--" He shrugged. Experiments. More experiments. Hours of experiments, with Mark and the professor hovering over an electric crucible bubbling with molten glass. Hours of failure. At last the old scientist straightened, his face haggard with weariness. "It is no use," he said sadly. "I have exhausted my knowledge, and to no avail." He turned away, shoulders sagging. Stumbled toward the door. The next instant Mark's voice rose in a scream. "_Look out!_" Instinctively, without so much as a backward glance, the old man lunged forward. Even as he did so, he felt something jerk at his ankle. His leg came out from under him. He pitched to the floor. _Crash!_ The crucible was falling, jerked from its place atop the lab bench! The electric cable which supplied its current was twisted about the professor's ankle, somehow unconsciously caught by his foot as he worked. Molten glass burst out of the pot in a white-hot wave. Slopped over the composition floor in a steaming river. Engulfed table legs and radiator pipes alike. And then, like a writhing snake, the high tension line from which the crucible cable stemmed was whipping down, torn loose by the jar of the professor's leap! Down it came! Struck the floor once. Lashed against the glass-engulfed radiator pipes, bare wires flashing. A ball of purple fire exploded at the contact point, while the cable jerked and twisted like a living thing. The laboratory was suddenly permeated with ozone's peculiar odor. "Look out!" cried Mark again. * * * * * But already Professor Duchard had jerked his foot free of the crucible line. He shrank back under the long bench, away from the writhing cable. An instant later the current went dead. The crackling ball of purple fire evaporated into thin air.