Sound and light were transformed into mechanical action at the banquet of the National Tool Exposition recently to illustrate their possibilities in regulating traffic, aiding the aviator, and performing other automatic functions. A beam of light was thrown on the "eyes" of a mechanical contrivance known as the "telelux," a brother of the "televox," and as the light was thrown on and off it performed mechanical function such as turning an electric switch. The contrivance, which was developed by the Westinghouse Electric and Manufacturing Company, utilizes two photo-electric cells, sensitive to the light beam. One of the cells is a selector, which progressively chooses any one of three operating circuits when light is thrown on it. The other cell is the operator, which opens or closes the chosen circuit, thus performing the desired function. S. M. Kintner, manager of the company's research department, who made the demonstration, also threw music across the room on a beam of light, and light was utilized in depicting the shape and direction of stresses in mechanical materials. [Illustration _"The globe leaped upward into the huge coil, which whirled madly."_] The Fifth-Dimension Catapult A COMPLETE NOVELETTE _By Murray Leinster_ The story of Tommy Reames' extraordinary rescue of Professor Denham and his daughter--marooned in the fifth dimension. FOREWORD This story has no normal starting-place, because there are too many places where it might be said to begin. One might commence when Professor Denham, Ph. D., M. A., etc., isolated a metal that scientists have been talking about for many years without ever being able to smelt. Or it might start with his first experimental use of that metal with entirely impossible results. Or it might very plausibly begin with an interview between a celebrated leader of gangsters in the city of Chicago and a spectacled young laboratory assistant, who had turned over to him a peculiar heavy object of solid gold and very nervously explained, and finally managed to prove, where it came from. With also impossible results, because it turned "King" Jacaro, lord of vice-resorts and rum-runners, into a passionate enthusiast in non-Euclidean geometry. The whole story might be said to begin with the moment of that interview. But that leaves out Smithers, and especially it leaves out Tommy Reames. So, on the whole, it is best to take up the narrative at the moment of Tommy's first entrance into the course of events. CHAPTER I He came to a stop in a cloud of dust that swirled up to and all about the big roadster, and surveyed the gate of the private road. The gate was rather impressive. At its top was a sign. "Keep Out!" Halfway down was another sign. "Private Property. Trespassers Will Be Prosecuted." On one gate-post was another notice, "Live Wires Within." and on the other a defiant placard. "Savage Dogs At Large Within This Fence."