Perry staggered toward the inert form which lay there. Rod, his head swathed in bandages, was completely unrecognizable. His features were covered. "Gas, same as hit me?" Wilcox asked the girl. "No," she whispered. "Some kind of beam of concentrated heat waves. It's his eyes, mostly." "How long was he out there?" Perry questioned. "What I mean is, how long did he stay in action before he got hurt?" "About two hours, I think," the girl responded. "He helped with the first civilian wounded, managing to stay clear of the gas himself. There was an explosion afterward. And out of the hole blown in the ground the machines--they're like strange robots--began to emerge. That was at ten o'clock the night before last. Mr. Murgatroyd was brought in at eleven o'clock, so he must have been active for half an hour after the explosion." Perry had heard enough. He bent over the bed of his friend and touched his shoulder. "Hey, Rod!" he called. "Hey, this is Perry! Wake up, you old son-of-a-gun!" Perry's vision was misted. Murgatroyd groaned and stirred. When he spoke, however, he seemed lucid, his mind clearing after the long siege of unconsciousness, caused by his head injury. "Hello, fella," he muttered, turning his face toward the sound of Perry's voice as though trying to peer through the bandages that covered his damaged eyes. "Rod," the young man whispered. "I want you to concentrate--try to remember. We've got a big job that's our personal concern. But it's more than that. It's a danger concerning the whole country--maybe the whole world. Just what kind of an enemy is out there, Rod? Those robots. What are they? Is anybody controlling them? Or do they think for themselves? Do you know anything about them, Rod? Anything at all?" The old Scotch-American's lips moved, almost hidden in the swathing of cloth. "I guess it should--be all right," he said at last. "I guess it's kind of--funny. Machines--think? Some might, but these--don't. They can do things--perfectly. Like a machine that rifles a gun barrel or predicts the tides. They're made that way. But these robots are just refined machines--acting almost human, sure! They'd almost fool you. "They see, they hear--in a way. They come toward you, aiming and firing explosive slugs, or sending out beams of concentrated heat. But we stopped a few of those robots with shells. Just adding-machine stuff inside, Perry. Cams and rods and wires, like our inventors would build, only a lot more wonderful and complicated. No soul could be in that, Perry. No real consciousness. No ambition.... "Professor Vince had the wrecks hauled off--copped them for examination. I guess he knows a lot now, Perry. He tried to talk me into giving him your camera, with the pictures you took down in the bore, too, Perry. But I sent the camera to the rear with one of our men....