No one was quite sure what time it was, but the sky that had been gray all day now was streaked with purple, so we guessed there was about an hour of daylight left. By that point the six of us city folks had been floating down West Virginia's Cacapon River for a good five hours, maybe longer, to judge by the blue of our fingernails.

We were fighting cold and hunger and a touch of fear. According to our calculations we should have long since reached the bridge where we'd left our cars. A couple of hours earlier someone on shore had estimated we were only half a mile from it.

To pass the time we fantasized about what we'd have for dinner: we hadn't eaten for eight hours. We tried singing, then whistling. I began composing headlines.

"How about, 'The Longest Half Mile'?" I asked Hilly, who was floating on my right.

"How about Cacapon Claims Six as Tubing Escapade Turns to Tragedy'?" he said.

The Cacapon meanders for some 50 miles throught West Virginia's panhandle, merging with the Potomac near the tiny town of Great Cacapon. It languishes past a farm where I had camped this late August weekend with Hilly, a Congressional systems analyst; Jonathan, a book editor; Kitty, a transportation planner; Geoff, a government engineer, and Nelda, a production manager.

In order to "take our last plunge into the season," as Jonathan put it, we decided to spend Sunday tubing down to the river's mouth. We estimated the trip to be five miles, about the same distance as the road that wound into Great Cacapon by a different route Floating on car-tire innertubes purchased from a gas station in town, we figured the trip would take two or three hours.

Sunday dawned cloudy so we delayed until afternoon hoping for sunshine. Jonathan and Nelda whiled away the time improvising flow-through beer bags; Kitty jogged five miles; the rest of us washed the breakfast dishes. Although clouds still hung low over the river, in early afternoon we decided to go ahead. After dropping two cars at the take-out point, a bridge just outside town, we set seat on the river.

During the first hour we got a sense of the river's rhythm. Stretches of slow-moving water, where we had to kick and paddle, alternated with narrower places where the water surged over rocks, whirling our tubes down small rapids as we clung tightly.

In one of these shallow riffles, Hilly's tube scraped over some jagged rocks. A stream of tiny bubbles rose, and moments late the tube exploded. "I'm not sure," he quipped, scrambling to his feet holding a handful of tattered tube, "but I think I have a leak."

While we were considering the predicament, Providence intervened. There were three slightly saggy tubes abandoned on the shore around the next bend. We eased our consciences by leaving a bouple of beers.

The river slowed to a crawl for the next mile or two and we had to paddle constantly to make any progress. The unaccustomed exertion began to take its toll on everyone but marathoner Kitty, who still looked fresh. Jonathan began to complain of rubber burn on the inside of his elbow. A half-hour drizzle made things all the jollier.

Waterlogged and goosepimply, we kept paddling. With a brambly shoreline and no cabins or roads in sight we had no choice.

We came to a cottage with a couple eating dinner on the porch. They hollered back that it was just after 5, that we were about half a mile from the dam and that the bridge was another half-mile. Cheered, we paddled hard, singing dam and fish songs.

We reached the dam about 6 o'clock, hoisted tubes and portaged through ankledeep mud. Then we floated backwards to watch the water cascade over the dam and revel in the strange beauty of the cliffs towering over us.

We longed for the dry clothes waiting at the bridge. Certain we had gone a half-mile, Hilly declared that the bridge was "just around the bend."

One bend and no bridge late, he assured us it was "around the next bend." Many bends later, after we had exhausted our interest in singing, whistling, headline writing and, especially, tubing, we floated up to a low, one-lane crossover. This dinky contraption hardly deserved to be called a bridge. It was clearly not the one where we had parked. But, as we ducked under it, we each had the same sinking thought: this was the bridge we had been told was just below the dam. We had no idea how much farther our bridge was and no way to find out.

After that it was every tuber for him or her self. Eager to outrace the darkness, we went as fast as legs and arms would allow. I was seated on a bulbous, unevenly-inflated tube and brought up the rear. Shivering in the cool evening air. I started to wonder what the signs of hypothermia were and what, if anything, I could do about it.

Then I wondered why we had never looked at a map before starting out: with its twists and turns, the river was easily twoice as long as we had estimated.

As the distance widened between myself and the others, more morose thoughts followed: would anyone even notice if my tube hit a submerged rock and slowly fizzled out of sight? But Geoff waited for me to catch up and traded his fast, sleek model for my misshapen dud.

The sky turned from gray to blue-black; clouds framed a sliver of moon. the river, wet-benign by day, had become wet-scary. If we stayed on the river we eventually would float under the bridge. But there were unseen rocks, unknown depths and rapids, perhaps snakes. After seven hours even Kitty was exhausted.

The alternative as to get out and walk, but the steep bank, thick with bushes, trees and poision ivy, seemed hardly better.

Trying to think of something cheerful to say, Geoff and I paddled on in silence. We were beginning to catch up to the others, who seemed to be grouping near shore, when we heard the cry, "Cows!"

In the moonlight we made out the ghostly shapes in a field. Where there were cows, there must be people. Civilization!

A path led to some farm buildings. Our tubes bumping against our sides, our shoes squishing with water, we trudged single file. Several yards ahead, Hilly froze. "Deer," he whispered. Straining, we could make out a large shadowy shape, which Geoff immediately identified as a horse. Hilly's citified mistake broke the tension that had been building for hours.

Past the dark farm buildings we continued down a lane by the river to a gate Hilly and Nelda remembered having seen while looking for a place to park.

The bridge and cars were but a brisk walk away. The six of us with bathing suits and innertubes in the black of night must have been a sight to the drivers who sped by.

We were loading the tubes when Geoff had a better idea. With the awl of a Swiss Army knife he stabbed his tube, which gasped and collapsed on the gravel. One by one the rest of us offered our tubes for ritual sacrifice. Nelda's was last, but instead of handing it over to Geoff, she took the knife.

"I want to do the honors myself," she said.