The circular windows opened out on the extreme end of the village. Peering between the bars, Simms saw an endless line of Kamalis padding in from the other side of a vine screen, depositing the contents of baskets on a growing pile of black slag. A dozen Kamalis squatted there, pounding pieces of the slag with little flat-nosed hammers. This then was the _Deleon_ Salt industry, the secret of which was so jealously guarded. Abruptly Simms found his gaze focused on a larger conical building he had not noticed before. Even as he stared at its smooth windowless sides, a sound emerged from it. A low drone at first, it rapidly mounted the octaves until it became a high-pitched siren-like shriek. The sound pulsed through the walls of the hut, bludgeoned against the lieutenant's eardrums, seemed to eat into his very brain. Higher and higher it mounted, until presently it had gone beyond the hearing range. But Simms got the impression it was still climbing into the supersonic range. He saw then a native cross the square and head toward his hut, carrying a dish of food. The lieutenant glanced at the old-fashioned lock on the door, and a thought struck him. Feverishly he searched his pockets, drew forth his watch. Made for use on all planets, the timepiece had a magno-shielded case. Quickly Simms unscrewed the back cover. The door creaked open, and the Kamali thrust the dish of food inside. But in the instant before the door clicked into position again, Simms had slipped the watch cover between the latch and the magnetic face plate. The intervening hours until the light outside gradually faded seemed interminable. At length, however the square outside the hut was blanketed in deep gloom. Simms boldly opened the door and emerged onto the street. * * * * * Without a plan of any kind he headed instinctively toward the slag pile and the tower from which that strange vibration had come. He had reached the extreme end of the village when voices reached his ears. Quickly Simms darted into the doorway of a near hut. The men were Halleck and Gately! "Why take chances?" Gately was saying. "We've got all the time in the world, and we might as well give those salts a longer vibration exposure. That way the Earth people who take the stuff won't feel any bad effects for maybe two years." Halleck swore in reply. "You fool," he said. "Don't you realize we're working on counted time. The I.P. men are after me now on Mars and Jupiter. We've got to work fast. Have you convinced the Oligarch?" Gately grunted. "Yes, the whole village sets out on an expedition of war tomorrow night." "You told the Oligarch that neighboring tribes had been tampering with his _Deleon_ mine?" There was growing satisfaction in Halleck's voice. "Sure, I told him. Sterns told him, too, and the fool would be alive now if he'd taken precautions...."