The sun shone, and the land was green, and a seeming of vast tranquility hung over the whole seascape. But the small Survey-personnel recreation-boat moved in toward the shore, and the look of things changed. At a mile, a mass of green that had seemed to be trees growing down to the water's edge became a thicket of tumbled trunks and overset branches where a tree-thicket had collapsed. At half a mile the water was opaque. There were things floating in it: the roof of a house, the leaves of an ornamental shrub, with nearby its roots showing at the surface, washed clean. A child's toy bobbed past the boat. It looked horribly pathetic. There were the exotic planes and angles of three wooden steps, floating in the ripples of the great ocean. "Ignoring the imminent explosion of the fuel-store," said Bordman, "we need to find out something about what has to be done to the soil to stop its creeping. I hope you remembered, Lieutenant, to ask a great many useless questions." "Yes, sir," said Barnes. "I tried to. I asked everything I could think of." "Those boats yonder?" Bordman indicated a boat from which something like a wire basket splashed into the water as he gestured. "A garden-boat, sir," said Barnes. "On this side of the island the sea-bottom slopes so gradually that there are sea-gardens on the bottom. Shellfish from Earth do not thrive, sir, but there are edible sea-plants. The gardeners cultivate them as on land." Bordman reached overside and carefully took his twentieth sample of the sea-water. He squinted, and estimated the distance to shore. "I shall try to imagine someone wearing a diving-mask and using a hoe," he said drily. "What's the depth here?" "We're half a mile out, sir," said Barnes. "It should be about sixty feet. The bottom seems to have about a three per cent grade, sir. That's the angle of repose of the mud. There's no sand to make a steeper slope possible." "Three per cent's not bad!" Bordman looked pleased. He picked up one of his earlier samples and tilted it, checking the angle at which the sediment came to rest. The bottom mud, here, was essentially the same as the soil of the land. But the soil of the land was definitely colloid. In sea-water, obviously, it sank because of the salinity which made suspension difficult. "You see the point, eh?" he asked. When Barnes shook his head, Bordman explained, "Probably for my sins I've had a good deal to do with swamp-planets. The mud of a salt-swamp is quite different from a fresh-water swamp. The essential trouble with the people ashore is that by their irrigation they've contrived an island-wide swamp which happens to be upside down, the swamp at the bottom. So the question is, can it acquire the properties of a salt-swamp instead of a fresh-water swamp without killing all the vegetation on the surface? That's why I'm after these samples. As we go inshore the water should be fresher, on a shallowing shore like this with drainage in this direction."