"In a sense, the trouble here is that there's a swamp underground, made by irrigation. It slides. It's really a swamp upside down. On Soris II we had a very odd problem, only the swamp was right-side-up there. We'd several hundred square miles of swamp that could be used if we could drain it. We built a soil-dam around it. You know the trick. You bore two rows of holes twenty feet apart, and put soil-coagulant in them. It's an old, old device. They used it a couple of hundred years ago back on Earth. The coagulant seeps out in all directions and ... well ... coagulates the dirt. Makes it water-tight. It swells with water and fills the space between the soil-particles. In a week or two there's a water-tight barrier, made of soil, going down to bedrock. You might call it a coffer-dam. No water can seep through. On Soris II we knew that if we could get the water out of the mud inside this coffer-dam, we'd have cultivable ground." Sandringham said skeptically: "But it called for ten years' pumping, eh? When mud doesn't move, pumping isn't easy!" "We wanted the soil," said Hardwick. "And we didn't have ten years. The Soris II colony was supposed to relieve population-pressure on another planet. The pressure was terrific. We had to be ready to receive some colonists in eight months. We had to get the water out quicker than it could be pumped. And there was another problem mixed up with it. The swamp vegetation was pretty deadly. It had to be gotten rid of, too. So we made the dam and ... well ... took certain measures and then we irrigated it. With water from a nearby river. It was very ticklish. But we had dry ground in four months, with the swamp-vegetation killed and turning back to humus." "I ought to read your reports," said Sandringham dourly. "I'm too busy, ordinarily. But I should read them. How'd you get rid of the water?" Hardwick told him. He felt uncomfortable about it. The telling required eighteen words. "Of course," he added, "we did pick a day when there was a strong wind from the right quarter." Sandringham stared at him. Then he said vexedly: "But how does that apply here? It was sound enough, though I'd never have thought of it. But what's it got to do with the situation here?" "This ... swamp, you might say," said Hardwick, "is underground. But there's forty feet, on an average, of soil on top." He explained painstakingly what difference that made. It took him three sentences to make the difference clear. Sandringham leaned back in his chair. Hardwick scratched the dog, somewhat embarrassed. Sandringham thought concentratedly. "I do not see any possible chance," said Sandringham distastefully, "of doing it any other way. I would never have thought of that! But at least ninety per cent of the people on this island, Civilian and Survey together, will die if we don't do something. So we will do this. But I'm taking it out of your hands, Hardwick." Hardwick said nothing. He waited.