Barnes drew a deep breath.
"I thought that was it, sir," he said shakily. "I mean—that the whole island would start sliding."
"The ground's a bit more water-soaked down here," Bordman said. "Inland the bottom-soil's not nearly as fluid as here. But I'd hate to have a really heavy rainfall right now!"
Barnes' mind jerked back to the Sector Chief's office.
"The drumming would set off the ship-fuel?"
"Among other things," said Bordman. "Yes." Then he said abruptly: "How good are you at precision measurements? I've messed around on swamp-planets. I know a bit too much about what I ought to find, which is not good for accuracy. Can you take these bottles and measure the rate of sedimentation and plot it against salinity?"
"Y-yes, sir. I'll try."
"If we had soil-coagulants enough," said Bordman, "we could handle that damned upside-down swamp the civilians have so carefully made here. But we haven't got it! The freshened sea-water they've been irrigating with is practically mineral-free! I want to know how much mineral content in the water would keep the swamp-mud from acting like wet soap. It's entirely possible that we'd have to make the soil too salty to grow anything, in order to anchor it. But I want to know!"
Barnes said uncomfortably:
"Wouldn't you—wouldn't you have to put the minerals in irrigation-water to get them down to the swamp?"