"A very violent electrical discharge went out from it then. A blue light seemed to flash all around the horizon at no great distance and my speaker blew out. I have turned on the spare. I do not know whether my sender is functioning--" The spare speaker cut in abruptly at that moment: "It is. Stay where you are and observe. A squadron is coming." * * * * * Then the voice broke off, because a new sound was coming from the speaker. It was a voice that was unhuman and queerly horrible and somehow machine-like. Hoots and howls and whistles came from the speaker. Wailing sounds. Ghostly noises, devoid of consonants but broadcast on a wave-length close to the G.C. band and therefore produced by intelligence, though unintelligible. The unhuman hoots and wails and whistles came through for nearly a minute, and stopped. "Stay on duty!" snapped the G.C. speaker. "That's no language known on earth. Those are Martians!" Thorn looked up to see Sylva standing by the Watch-plane door. Her face was pale in the growing darkness outside. "Beginning duty sir," said Thorn steadily, "I report that I have with me Miss Sylva West, my fiancee, in violation of regulations. I ask that her family be notified." He snapped off the lights and went with her. The red rocket-ship had landed in the very next valley. There was a glare there, which wavered and flickered and died away. "Martians!" said Thorn in fine irony. "We'll see when the Watch planes come! My guess is Com-Pubs, using a searchlight! Nervy!" The glare vanished. There was only silence, a curiously complete and deadly silence. And Thorn said, suddenly: "There's no wind!" There was not. Not a breath of air. The mountains were uncannily quiet. The air was impossibly still, for a mountain-top. Ten minutes went by. Twenty. The detector-whistles shrilled. "There's the Watch," said Thorn in satisfaction. "Now we'll see!" And then, abruptly, there was a lurid flash in the sky to northward. Two thousand feet up and a mile away, the unearthly green blaze of a hexynitrate explosion lit the whole earth with unbearable brilliance. "Stop your ears!" snapped Thorn. * * * * * The racking concussion-wave of hexynitrate will break human eardrums at an incredible distance. But no sound came, though the seconds went by.... Then, two miles away, there was a second gigantic flash.... Then a third.... But there was no sound at all. The quiet of the hills remained unbroken, though Thorn knew that such cataclysmic detonations should be audible at twenty miles or more. Then lights flashed on above. Two--three--six of them. They wavered all about, darting here and there.... Then one of the flying searchlights vanished utterly in a fourth terrific flash of green. "The watch planes are going up!" said Thorn dazedly. "Blowing up! And we can't hear the explosions!" Behind him the G.C. speaker barked his call. He raced to get its message.