I listened, with a shudder thrilling me; and I know that every man in the room must have felt the same. A queer thrilling shudder, as though the very sound itself were physically affecting me with its vibrations. It was very soft, now at first; and I was only hearing the faint, radio echo of it; yet upon my senses it laid a singularly weird, uncanny feeling of the diabolical. * * * * * The minutes passed. As the plane flew northward, the crimson stain in the sky seemed spreading. And the whine increased; grew louder, resolved itself now into a myriad undertones. Cries, muffled, faint, aerial, yet somehow clear; screams, checked and then begun again; a low, tiny throbbing--a myriad unearthly sounds, weirdly abnormal, like nothing I had ever heard before, all blended as undertones to the one great whine. The crimson radiance, screaming into the night! Light and sound intermingled. Was this some strange weapon of a strange science which the invaders from Xenephrene had brought to attack us? There was something deadly in the aspect of that crimson radiance. And something equally lethal in the gruesome sound which split the night around it. My thoughts were whirling in this fashion when I heard the muttered words of the man next to me--murmuring to the man on his other side, "That's weird! Vanderstuyft says that the girl from Xenephrene can see and hear below the human scale! This is it--the infra-red made visible, and its sounds brought up to our human ears! Weird--" Some one else was asking: "Is that light and that sound their weapon? Where's the Robinson plane?" And the War Secretary said: "Hush! He's there--ahead. We're mounting." Nothing but sky again. A blood-red, night sky. The stars gleamed like crimson jewels through the radiance. Then again, the Davis plane leveled. We saw now that the invaders evidently were encamped in a snowy stretch of what had been comparatively open country. The houses which once were there, lay now under mounds of snow. A blank rolling landscape; fences, roads, all gone beneath the billowing blanket of white; the trees only were left, stark black sticks in patches. In an oval, perhaps a mile across its greatest diameter, the red beam stood up into the sky. A barrage of crimson--not light, but sound! It throbbed and screamed and whined its defiance! The two planes circled the radiance, some ten thousand feet up, and several miles away. The Davis plane fired a shell; we heard the dull muffled report, saw a yellow glare where it struck the red beam and harmlessly exploded. But it struck low, where perhaps the sound-vibrations were too intense. The planes mounted higher. We could see Robinson's ahead and above us! He was closer to the crimson barrage. Trying to climb over it--to drop a bomb.