Thus, water seeped into Source Victoria through microtubes, much the same way it seeped into a beach, and air wafted into it silently down the artfully skewed exponential horns of those thrusting calla lilies, each horn a point in parameter space not awfully far from some central ideal. They were strong enough to withstand typhoons but flexible enough to rustle in a breeze. Birds, wandering inside, sensed a gradient in the air, pulling them down into night, and simply chose to fly out. They didn't even get scared enough to shit.

The lilies sprouted from a stadium-sized cut-crystal vase, the Diamond Palace, which was open to the public. Tourists, aerobicizing pensioners, and ranks of uniformed schoolchildren marched through it year in and year out, peering through walls of glass (actually solid diamond, which was cheaper) at various phases of the molecular disassembly line that was Source Victoria. Dirty air and dirty water came in and pooled in tanks. Next to each tank was another tank containing slightly cleaner air or cleaner water. Repeat several dozen times. The tanks at the end were filled with perfectly clean nitrogen gas and perfectly clean water.

The line of tanks was referred to as a cascade, a rather abstract bit of engineer's whimsy lost on the tourists who did not see anything snapshot-worthy there. All the action took place in the walls separating the tanks, which were not really walls but nearly infinite grids of submicroscopic wheels, ever-rotating and many-spoked. Each spoke grabbed a nitrogen or water molecule on the dirty side and released it after spinning around to the clean side. Things that weren't nitrogen or water didn't get grabbed, hence didn't make it through. There were also wheels for grabbing handy trace elements like carbon, sulfur, and phosphorus; these were passed along smaller, parallel cascades until they were also perfectly pure. The immaculate molecules wound up in reservoirs. Some of them got combined with others to make simple but handy molecular widgets. In the end, all of them were funneled into a bundle of molecular conveyor belts known as the Feed, of which Source Victoria, and the other half-dozen Sources of Atlantis/Shanghai, were the fountainheads.