He watched her face. She swallowed. What he'd said was largely without meaning. Actually, it wasn't even right. The evidence so far was that the nerves of smell were more sensitive than the optic nerves or the auditory ones, while nerves to bundles of muscle were less sensitive still. But Lockley wasn't concerned with accuracy just now. He wanted to reassure Jill. Then his eyes widened suddenly and he stared past her. He'd been speaking feverishly out of emotion, while a part of his mind stood aside and listened. And that detached part of his mind had heard him say something worth noting. He stood stock-still for seconds, staring blankly. Then he said very quietly, "You made me think, then. I don't know why I didn't, before. The terror beam does scatter a little, like a searchlight beam in thin mist. It's scattered by ions, like light by mist-droplets. That's right!" He stopped, thinking ahead. Jill said challengingly, "Go on!" Again what he'd said had little meaning to her, but she could see that he believed it important. "Why, a searchlight beam is stopped by a cloud, which is many mist-droplets in one place. It's scattered until it simply doesn't penetrate!" Lockley suddenly seemed indignant at his own failure to see something that had been so obvious all along. "If we could make a cloud of ions, it should stop the terror beam as clouds stop light! We could--" Again he stopped short, and Jill's expression changed. She looked confident again. She even looked proud as she watched Lockley wrestling with his problem, unconsciously snapping his fingers. "Vale and I," he said jerkily, "had electronic base-measuring instruments. Some of their elements had to be buried in plastic because otherwise they ionized the air and leaked current like a short. If I had that instrument now--No. I'd have to take the plastic away and it couldn't be done without smashing things." "What would happen," asked Jill, "if you made what you're thinking about?" "I might," said Lockley. "I just possibly might make a gadget that would create a cloud of ions around the person who carried it. And it might reflect some of the terror beam and refract the rest so none got through to the man!" Jill said hopefully, "Then tonight we go into a deserted town and steal the things you need...." Lockley interrupted in a relieved voice, "No-o-o-o. What I need, I think, is a cheese grater and the pocket radio. And there should be a cheese grater in the house." He listened at the barn door gap, and then went out. Presently he was back. He had not only a cheese grater but also a nutmeg grater. Both were made of thin sheet metal in which many tiny holes had been punched, so that sharp bits of torn metal stood out to make the grating surface. Lockley knew that sharp points, when charged electrically, make tiny jets of ionized air which will deflect a candle flame. Here there were thousands of such points.