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Show CROSSING RAYS TO GUIDE THE PILOT French Inventor Ue the Herzian Wave Signals. Purls, France. To mark out an unmistakable un-mistakable truck for air pilots by menus of Uerzlan wave signals is the object of a striking Invention of William Wil-liam Loth, which was recently brought to the attention of the French air ministry. min-istry. It is not a device for sending occasional messages of guidance. The Inventor contends thut It enables an aviator making for an airport to observe ob-serve Instantly, and at any time he likes, whether he Is on the right course. The pilot has no need to call up the aerodrome or to wait until be Is called up. The signals are constantly In the nlr about him and all he has to do Is to put on tbo beodplcc of his listening aparstus and hear them. At his experimental station at Vaux, on the Seine, M. Loth gives practical demonstrations of the simple principle on which the Invention Is based. In clear weather and over moderate distances dis-tances ordinary searchlight Blgnels may be employed Instead of Merzlun waves, and M. Loth shows both. Two "lighthouses," with powerful projectors, are pluced one on each side of the route which the arriving airplane should follow. The projectors project-ors revolve and their beams sweep round In circles. As they are synchronized synchro-nized the pencils of light wheel round nt exnetly Identical speeds. It follows that whenever the beams cross each other they do so at a point equidistant equidis-tant from the two lighthouses. An observer ob-server placed at such a point of Intersection In-tersection sees the flashes of the two lights precisely at the same moment, and not one after the other. The task of the navigator Is simple. As soon as he comes within range he watches out for the lighthouses. . If the flush from the right-hand light readies bim first he knows that he Is on the right of bis proper track and must veer to the left Observing the repenting flashes, he maneuvers until he sees both at the same time. He Is then equidistant from both lighthouses and in the middle of the right road. |