cities spread upon them together with the new controlled auto-farms. Only the smaller rivers and streams continued to flow until they reached a predesignated flow force. Then they vanished, spilling down into tunnels and flowing for hundreds of miles along subterranean aqueducts into great storage reservoirs beneath the surface of the land and protected from the drain of the sun and wind. From these, each precious drop of water was rationed upwards to meet the increasing needs of the people. And still there was never enough.

It was still snowing when Troy and Alec awoke in the morning. The snows had drifted over both the domes on the windward side. They cooked a quick breakfast and then Alec began stowing the camp gear into its compact containers. Troy took a small hand shovel and crawled out through the double opening of the front dome and tunneled his way up out of the snow. Twin plumes of vapor rose through the snow that curved in gentle hummocks over the buried domes. The tall engineer shoveled a short path to the downed spruce and cleared the way into the shelter where the Sno cars waited. He removed the protecting boughs and shoveled a short ramp out of the trough to the surface of the snow.

The temperature had risen during the night and the snow had changed from the crystal dry powder of the night before to fluffy, gentle flakes, falling in a steady curtain through the trees. Troy opened the side hatch of the bubble canopy of his Sno car and climbed in. He slid into the single bucket seat and with a flick of his finger set the tiny reaction motor into operation. Moments later heat filled the bubble and a cloud of steam moisture flared from the thrust pipes.

The ten-foot-long tapered Snow car sat on twin broad-planted skis in front with a single retractable wheel raised between them for snow travel. At the wider rear, another pair of short, broad ski blades rested on the surface of the snow on either side of a wide, continuous track assembly. A pair of handle bars, much like an early-day motorcycle, extended into the bubble from the front fork. The grips were studded with additional control buttons. Troy pressed one and the two rear skis rose on outrigger arms like a small catamaran to allow the Sno car to sink a couple of inches back onto the gripper track.

As the weight of the vehicle shifted to the track assembly it automatically diverted the tiny nuclear engine output from jet thrust to gear box drive. Troy settled himself in the seat and increased the power. The track started to turn and the Sno car glided slowly out from under the protecting branches and churned up the slight ramp to the top of the snow pack. He turned the front skis and plowed to a halt beside the tunnel into the domes.

Alec emerged with one of the camp kits and handed it up to his partner, then went to the shelter for his own Sno car. Troy stowed the kit in the carrier and dismounted and began digging snow away from the domes. Alec's Sno car pulled up alongside and the chunky engineer vanished once more into the domes to emerge with his own kit. Then he joined Troy in the digging operation. Fifteen minutes later, both domes were collapsed and stowed in the carriers. The men boarded their vehicles.

Inside the warm bubble canopies, air circulators kept the plastic free of condensation. Outside, the snow glanced off the treated surface, keeping it clear.

"Lead off, Dr. Patterson," Troy called out over the car radio.

Alec increased power and the track of his Sno car dug into the soft surface, then caught and the vehicle moved forward and into the trees. Troy fell into line behind the other vehicle as they drove down the gentle slope towards the snow-covered access trail another mile below them on the side of the mountain.

Out of the trees and onto the trail, both drivers shifted gears, dropping rear skis to the more solid pack of the trail and sending jets of steam shooting out from the thrust tubes of the Sno cars. Troy dropped back to stay out of Alec's vapor cloud as they now glided smoothly and easily along the trail. A bright red metal pole, topped by a small housing and antenna came into view on the side of the road. The tube went down through the snow and deep into the soil of the mountain side. Inside, electrostats read soil moisture at depths up to thirty feet and transmitted the information on automatic or demand signal.

Ahead, the vapor cloud from Alec's Sno car vanished as the trail dipped down the side of the mountain and the driver cut his thrust to let the momentum carry him on the twin set of skis. Troy gunned his car for a final burst of speed then cut rear drive and dropped swoopingly down the grade, whipping along in Alec's tracks. The trail curved sharply ahead and Troy gently manipulated the front fork skis into a snowplow to cut speed. His fingers rested lightly on the pressure switch that would open small scoops on the under surfaces of all skis for additional braking power. As a final resort, the engine thrust could be shifted from rear to forward reaction to bring him to a complete stop and even send the car backwards.

The Sno car whipped around and down the trail. As the roadway swung to the south slope of the range, the track in the fresh snow cut by the lead vehicle turned dark gray and then almost black. When the present storm had ended and before new snow fell again, the south slopes would again be stained with clouds of black, mono-molecular film, gushing out in clouds behind spray jets of the survey planes. Each successive layer was treated, lessening the evaporative surface effects of the sun upon the south slopes and holding as much of the moisture-giving snow to the earth for controlled runoff. A pair of fresh elk-tracks came down the side of the mountain and cut across the trail and Troy braked to peer through the trees for a glimpse of the animals. But they had vanished, frightened by the sudden intrusion of the men.

A half hour later and four thousand feet lower, the trail joined a wider and more traveled road. Alec turned onto the road and increased speed. A few minutes later, the Sno cars flashed by a sign reading "Elk City—4 miles." Alec cut speed and waited for Troy to pull alongside, then the two cars glided slowly to the edge of the wilderness community. At the outskirts of the little town the snow on the road came to an abrupt end. Chemically-treated paving kept the roadways warm and bare of snow. Ahead, the pavement into town was wet and glistening and even falling snow had stopped. Rear skis were again retracted and the front wheels lowered for non-snow driving and then the two vehicles rumbled slowly into Elk City.

They came to a halt at the ranger station and dismounted.

"Let's call for a taxi and then go for a cup of coffee and another bite," Troy said. "I'm starved again."

"You and that hollow stomach to match your head," Alec grunted.

They entered the ranger station. Behind the counter, one of the four rangers on permanent duty at the station was transferring a radar storm plot onto a weather chart. He glanced up as the two men entered.

"Back so soon," he commented. "That was a quick trip. Get the job done?"

"Neither rain, snow or sun stops the Division of Agriculture in its appointed rounds," Troy said flippantly. "Harry, call Spokane and tell 'em we're ready for a pickup, please."

The ranger reached for a mike. "Spokane Region," he called, "this is Elk City station."

"This is Spokane," came the reply.

"Your two snow boys are here," Harry said, "looking for a lift. Can you send a 'copter after them?"

"Affirmative, Elk City," Spokane communicator replied. "We'll pick them up in about forty-five minutes."

"Thanks, Harry," Troy said. "We're going to take a walk uptown and get something to eat. If the chopper should get here sooner, tell him we'll be right back."

"O.K.," the ranger said, "but there's a pot of coffee on the stove in the kitchen if you want to save yourself the walk."

Alec grimaced. "I had