not blamed himself for abandoning the cruiser, even though the flood had been such an anticlimax. It had been the most reasonable decision at the time and with the available knowledge. By the time the actual nature of the new flood had been clear, and it was obvious that they could have remained in the cruiser with perfect safety, it had been impossible to get back. Being a Mesklinite, the captain had wasted no time on thoughts of the “if only” variety. He had known when he left his vehicle that the chances of getting back were rather small, and when she had drifted downstream intact instead of a shattered ruin they had grown smaller. Not quite to zero, perhaps, but not large enough to take seriously any more. Now suddenly they had expanded again. The Kwembly was not only usable, but his helmsmen were alive and aboard her. Something might be done, if … “Benj!” Dondragmer spoke as his thoughts reached this point. “Will you please get your technical men to determine as closely as they can just how far from us the Kwembly is now? It is perfectly possible for Beetchermarlf to drive her alone, though there are other problems in the way of general maintenance which will keep him and Takoorch busy. However, they should be able to manage. In any case, we must find out whether the distance involved is fifty miles or a thousand. I doubt the latter, since I don’t think this river could have carried them so far in twelve hours, but we’ll have to know. Get your people at it, and please tell Barlennan what is happening.” Benj obeyed quickly and efficiently. He was no longer overtired, worried, and resentful. With the abandonment of the Kwembly twelve hours before he had given up hope for his friend’s life and had left the communication room to get some long overdue sleep. He had not expected to be able to accomplish this, but his own body chemistry had fooled him. Nine hours later he had returned to his regular duties in the aerology laboratory. It had been chance alone which had brought him back to the screens within a few minutes of the helmsmen?s emergence. He had been sent by McDevitt to collect general data from the other cruisers, but had lingered for a few minutes to watch at the Kwembly station. The weather man had come to depend heavily on Benj’s knowledge of the Mesklinite language. The sleep, and the sudden discovery that Beetchermarlf was alive after all, combined to dispose of Benj’s lingering resentment of Dondragmer’s policy. He acknowledged the captain’s request, called his mother to take his place, and headed for the laboratory decks as rapidly as his muscles would take him up the ladders. Easy, who had also had some sleep, reported Benj’s departure and her own presence to Dondragmer, briefed Barlennan as requested, and switched back to the captain with a question of her own. “That’s two of your missing men. Do you think there is still any chance of finding your helicopter pilots?” Dondragmer almost slipped on his answer, carefully as he picked his words. He knew, of course, where Reffel was, since messengers had been passing steadily between the camp and the Gwelf, but Kervenser, to his disappointment, had not been seen by the crew of the dirigible or anyone else. His disappearance was perfectly genuine, and the captain now regarded his chances for survival as even lower than those of the Kwemb/y pair an hour before. It was safe, of course, to talk about this; his slip consisted of failing to mention Reffel at all. The Stennish forms equivalent to “him” and “them” were as distinct as the human ones, and several times Dondragmer caught himself using the former when talking about his lost pilots. Easy seemed not to notice, but he wondered afterward. “It is hard to judge. I have not seen either one. If he went down in the area now flooded it is hard to see how they could be alive now. It is very unfortunate, not only because of the men themselves but because with even one of the helicopters we might be able to transfer more men to the Kwembly and get her back here more easily. Of course, most of the equipment could not be carried that way; on the other hand, if it turns out that the two men cannot bring the cruiser back here for any reason, having one of the fliers could make a great difference to them. It is a pity that your scientists cannot locate the transmitter which Reffel was carrying, as they can the one on the Kwembly.”
“You’re not the first to feel that way,” agreed Easy. The matter had been brought up shortly after Reffel’s disappearance. “I don’t know enough about the machines to tell why the signal strength depends on the picture brightness; I always thought a carrier wave was a carrier wave; but that seems to be it. Either Reffel’s set is in total darkness or it has been destroyed. “I see your life-support equipment is set up and working.” The last sentence was not entirely an effort of Easy’s to change the subject; it was her first good look at the equipment in question, and she was genuinely curious about it. It consisted of scores, perhaps over a hundred, of square transparent tanks covering altogether a dozen square yards, each about a third full of liquid, with the nearly pure hydrogen which constituted Mesklinite air bubbling through it. A power unit operated the lights which shone on the tanks, but the pumps which kept the gas circulating were muscle-driven. The vegetation which actually oxidized the saturated hydrocarbons of Mesklinite biological waste and gave off free hydrogen was represented by a variety of unicellular species corresponding as nearly as might be expected to terrestrial algae. They had been selected for edibility, though not, as Easy had been given to understand, for taste. The sections of the support equipment which used higher plants and produced the equivalent of fruit and vegetables were too bulky to move from the cruiser. Easy did not know how the non-gaseous items in the biological cycle were gotten into and out of the tanks, but she could see the charging of air suit cartridges. This was a matter of muscle-driven pumping again, squeezing hydrogen into tanks which contained slugs of porous solid. This material was another strictly non-Mesklinite product, a piece of molecular architecture vaguely analogous to zeolite in structure, which adsorbed hydrogen on the inner walls of its structural channels and, within a wide temperature range, maintained an equilibrium partial pressure with the gas which was compatible with Mesklinite metabolic needs. Dondragmer answered Easy’s remark. “Yes, we have just about enough food and air. The real problem is what to do. We have saved very little of your planetological equipment; we can’t carry on your work. Conceivably we might make our way back to the Settlement on foot, but we’d have to carry the life-support material by stages. That would mean setting up a camp only a few miles from here, transferring the equipment, recharging the air cartridges after cycling has resumed, and then repeating the process indefinitely. Since the distance to the settlement is about thirty thousand, excuse me, in your numbers about twelve thousand, of your miles, it would take us years to get there: that’s no metaphor, nor do I mean your short years. If we’re to be any further use to your project, we really must get the Kwembly back here.” Easy could only agree, though she could see an alternative which the captain had not mentioned. Of course, Aucoin would disapprove, or would he, under the circumstances? A trained and efficient exploring crew represented quite an investment, too. That might be a useful line to follow. It was several more minutes before Benj returned with his information, and incidentally with a following of interested scientists. “Captain,” he called, “the Kwembly is still moving, though not very fast, something like twenty cables an hour. She is located, or was six minutes ago, 310.71 miles from your transmitter, in our figures. In your numbers and units that?s 233,750 cables. There?s a small error if there?s much difference in elevation. That?s great circle distance; we don?t have too good an idea of the length of the river, though they have about twenty position readings taken along it since your ship started drifting, so there?s a rough river map up in the lab.? “Thank you,” came the captain’s answer in due course. “Are you in verbal contact with the helmsmen yet?”
“Not yet, but they’ve gone inside. I’m sure they’ll find the communicator on the bridge pretty soon, though I suppose there are other places they’d want to check first. The air must be pretty low in their suits.” This was perfectly correct. It took the helmsmen only a few minutes to ascertain that the cruiser was deserted, and to note that much of the life-support equipment was gone; but this left them with the need to check the air now aboard for contamination with oxygen from outside. Neither of them knew enough basic chemistry to invent a test, and neither was familiar with the routine ones used by Borndender and his colleagues. They were considering the rather drastic procedure of testing by smell when it occurred to Beetchermarlf that a communicator might have been left aboard for scientific reasons, and that the human beings might be of help. There was none in the laboratory, but the bridge was the next most likely spot, and Beetchermarlf’s voice was on its way up to the station some ten minutes after the helmsmen had come aboard. Benj postponed greetings when he heard Beetchermarif’s question, and relayed it at once to Dondragmer. The captain called his scientists and outlined the situation, and for over half an hour the relay was very busy: Borndender explained things, and Beetchermarlf repeated the explanations, then went to the lab to examine material and equipment, then came back to the bridge to make sure of some minor point … Eventually both parties in the conversation felt sure that the instructions had been understood. Benj, at its pivot point, was nearly sure. He knew enough physics and chemistry himself to judge that nothing was likely to blow up if Beetch made a mistake; his only worry was that his friend might perform the tests sloppily and so miss a dangerous amount of oxygen. Was the risk simply one of poisoning, or did hydrogen-oxygen mixtures present other dangers? He wasn’t quite sure; hydrogen-oxygen mixtures have other qualities. He remained rather tense until Beetchermarlf returned to the bridge with the report that both tests were complete. The catalyst which disposed of free oxygen by accelerating its reaction with ammonia was still active, and the ammonia-vapor concentration in the ship’s air was
