Among the boulders, as it neared the Kwembly, it accumulated more and more water ice, and the progress grew more complicated. The ammonia dissolved water for a time, the mixture flowing away as the composition entered the liquid range. Then the stream would stop and build up, as Benj had pictured it, like hot wax on a candle, solidifying temporarily from addition of ammonia. Then it would slump away again as underlying ice reacted with the mixture.

It finally reached the hole which had been melted along the Kwembly’s starboard side, where the human beings could watch once more. By this time the “stream” was a complex network of alternate liquid, solid, and slush perhaps two miles across. The solid, however, was losing out. While there were still no clouds this far downstream, the air was nearly saturated with ammonia: saturated, that is, with respect to a pure liquid-ammonia surface. The ammonia vapor pressure needed for equilibrium over an ammonia-water mixture is lower; so condensation was taking place on the mostly-water and low-ammonia ice. As it reached the appropriate composition for liquefaction its surface flowed away and exposed more solid to the vapor. The liquid tended to solidify again as it absorbed still more ammonia vapor, but its motion also gave it access to more water ice.

The situation was a little different in the space under the Kwembly’s hull, but not greatly so. Where liquid touched ice the latter dissolved and slush appeared; but more ammonia diffusing from the free surface at the side melted it again. Slowly, slowly, minute after minute, the grip of the ice on the huge vehicle relaxed so gently that neither the human beings watching with fascination from above nor the two Mesklinites waiting in their dark refuge could detect the change, and the hull floated free.

By now the entire river bed was liquid, with a few surviving patches of slush. Gently, very unlike the flood of a hundred hours or so before when three million square miles of water-snow had been touched by the first ammonia fog of the advancing season, a current began to develop. Imperceptibly to all concerned, the Kwembly moved with that current:

imperceptibly because there was no relative motion to catch the eyes of the human beings, and no rocking or pitching to be felt by the hidden Mesklinites.

The seasonal river, which drains the great plateau where the Kwembly had been caught, slices through a range of hills, for Dhrawn respectable mountains; the range extends some four thousand miles northwest-southeast. The Kwembly had gone parallel to this range for most of its length before the flood. Dondragmer, his helmsmen, his air scouts, and indeed most of the crew had been quite aware of the gentle elevation to their left, sometimes near enough to be seen from the bridge and sometimes only a pilot’s report.

The flood had carried the cruiser through a pass near the southeastern end of this range to the somewhat lower and rougher regions close to the edge of Low Alpha before she had grounded. This first flood was a rough, rather hesitant beginning of the new season as Dhrawn approached its feeble sun and the latitude of the sub-stellar belt shifted. The second was the real thing, which would only end when the whole snow plain was drained, more than an Earth year later. The Kwembly’s first motions were smooth and gentle because she was melted free so slowly; then they were smooth and gentle because the liquid supporting her was syrupy with suspended crystals; finally, with the stream fully liquid and up to speed, it was smooth because it was broad and deep. Beetchermarlf and Takoorch may have been slightly dazed by decreasing hydrogen pressure, but even if they had been fully alert the slight motions of the Kwembly’s hull would have been masked by their own shifting on the flexible surface that supported them.

Low Alpha is not the hottest region on Dhrawn, but the zone-melting effects which tend to concentrate any planet’s radioactive elements have warmed it to around the melting point of water ice in many spots, over two hundred Kelvin degrees hotter than Lalande 21185 could manage unassisted. A human being could live with only modest artificial protection in the area, if it were not for the gravity and pressure. The really hot area, Low Beta, is forty thousand miles to the north; it is Dhrawn’s major climate-control feature.

The Kwembly’s drift was carrying it into regions of rising temperature, which kept the river fluid even though it was now losing ammonia to the air. The course of the stream was almost entirely controlled by the topography, rather than the other way around; the river was geologically too young to have altered the landscape greatly by its own action. Also, much of the exposed surface of the planet in this area was bed rock, igneous and hard, rather than a covering of loose sediment in which a stream could have its own way.

About three hundred miles from the point at which she had been abandoned, the Kwembly was borne into a broad, shallow lake. She promptly but gently ran aground on the soft mud delta where the river fed into it. The great hull naturally deflected the currents around it, and set them to digging a new channel alongside. After about half an hour she tilted sideways and slid off into the new channel, righting herself as she floated free. It was the rocking associated with this last liberation which caught the attention of the helmsmen and induced them to come out for a look around.

It would be untrue to say that Benj recognized Beetchermarlf at first glance. As a matter of fact, the first of the caterpillar like figures to emerge from the river and clamber up the hull was Takoorch. However, it was the younger helmsman’s name which echoed from four speakers on Dhrawn.

One of these was on the Kwembly’s bridge and went unheard. Two were in Dondragmer’s encampment a few hundred yards from the edge of the broad, swift river which now filled the valley. The fourth was in Reffel’s helicopter, parked close beside the bulk of the Gwelf.

The flying machines were about a mile west of Dondragmer’s camp; Kabremm would go no closer, not wanting to take the slightest chance of repeating his earlier slip. He would probably not have moved at all from the site where Stakendee had found him if the river had not risen. For one thing, he had been fog-bound and had no wish to fly at all. Reffel had been even less eager to move. However, there had been no choice, so Kabremm had allowed his craft to float upward on its own lift until it was in clear air. Reffel hovered as close to the other machine’s running lights as he dared. Once above the few yards of ammonia droplets, they could navigate, and had flown toward Dondragmer’s lights until the dirigible’s commander had decided they were close enough. Letting the Gwelf come to the attention of the men in orbit above would have been an even more serious mistake than the one he had made already; Kabremm was still trying to decide what he was going to say to Barlennan about that the next time they met.

Both he and Reffel had also spent some uncomfortable hours before concluding, from the lack of appropriate comment, that Reffel had shuttered his vision set quickly enough after coming within sight of the Gwelf.

In any event, Dondragmer and Kabremm had at last achieved almost direct communication, and had been able to coordinate what they would say and do if there were any further repercussions from Easy’s recognition. One load was off the captain’s mind. However, he was still taking steps connected with that mistake.

The cry of “Beetch!” in Benj’s unmistakable voice distracted him from one of these steps. He had been checking over his crew for people who looked as much as possible like Kabremm. The job was complicated by the fact that he had not seen the other officer for several months. Dondragmer had not yet had time to visit the Gwelf Kabremm would come no closer to the camp for any reason, and Dondragmer had never known him particularly well anyway. His plan was to have all crewmen who might reasonably be mistaken for the Esket’s first officer appear unobtrusively and casually but frequently in the field of view of the vision sets. Anything likely to undermine the certainty of Easy Hoffman that she had seen Kabremm was probably worth trying.