The Crystal Ray BY RAYMOND GALLUN _By the Author of "The Space Dwellers"_ [Illustration: RAYMOND GALLUN] _The greatest advances in science will come during the next hundred years, when our understanding of the different forms of rays emitted by various strange materials is better developed. The past century witnessed the discovery of X-rays, as well as the emanation rays of radium and others. Only very recently a new ray, the cosmic ray, has been announced as a very potent factor in our lives. That many more materials found to emit powerful rays will be discovered, some of them with deadly and altogether unexpected qualities, is a foregone conclusion. The present story deals with such instrumentalities and, incidentally, the author has built a marvelous stirring story which cannot fail to impress you._ [Transcriber's Note: This etext was produced from Air Wonder Stories November 1929. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] A mid-afternoon sun of the stirring war year 2141 A.D. shone upon a small battle flier which was speeding southward at an altitude of fifteen miles. It was a two-seated outfit, cigar-shaped and made of an aluminum alloy. On the shining metal of its body were painted several red, white and blue stars--the insignia of the United States; mounted on its prow were two dangerous looking automatic guns. Beneath the body of the machine was a convex, hollow sheet of metal containing a substance which neutralized gravity when acted upon by the electromagnetic waves sent out by the power stations throughout the western hemisphere; this device, the Whitley gravitational screen, supported the craft in the air. Hissing jets of gas ejected at the stern were driving the machine through the thin atmosphere at a velocity of nearly a thousand miles an hour. A faint wake of bluish vapor trailed behind like the tail of a comet. In the flier were two men wearing the oxygen masks and metal armor necessary at extreme altitudes; attired in this fantastic garb they looked for all the world like a pair of goblins from some distant planet. As members of the U. S. Scout Squadron Number Five, both had done their bit in the seemingly hopeless battle of Caucasian nations against the yellow men of Asia. Holding the controls was George Calhoun, the ace who had to his credit more than sixty aerial victories, including the bombing of two great battleships of the skies. Joseph Pelton, his companion, who in peace time had devoted all his spare moments to science, was not so successful a fighter; but he had participated in many hazardous struggles.