Hal Clement - Noise

“Good, because I think you’ll have to go last. Keo and I probably won’t be noticed in armor, especially if we don’t go together, but people will see and remember you. You have one of your note cases ashore? Good. Keo will go first, I’ll follow in about ten minutes, you wait at least twenty more, then head back to the ship with your case—I hope there’s just one? Or at least not more than you can carry? Good. We’ll hope no one wonders; maybe the fact that you took cases with you on other trips will keep them from wondering—”

“They’re not all traders, I noticed,” Hoani couldn’t help remarking. “I get the impression that most of them wouldn’t know what I was doing. They just wouldn’t care, except for congenital loafers, and there don’t seem to be many of those on this world.” Wanaka may not have interpreted the remark as a slur; at least, she let it pass. She put just one more question set.

“Did you notice whether the watch on the other ships were clearing hail while you were?”

“They weren’t.”

“Had they done it before you came? Were their decks clear?”

Mike strained his memory. “Yes. They were. Maybe that’s why the watch was there this time.”

“And why not before? What’s changed since then?”

“We’re farther south. I don’t know what else.”

“There are fewer storms farther south, and a bigger change in buoyancy after a storm, because the basic surface salinity is greater the farther one gets from the tropical rain belt. It increases away from the equator, at least until we get to the neighborhood of the ice cap, where I suppose melting dilutes it again.” She paused, eyed the man thoughtfully, then seemed to make a decision.

“Mike, you didn’t think these folks were making a wave come in at just the right time, did you?”

“I—oh. Of course. No. They must change the city’s buoyancy. They can raise and lower it. Not very far either way, I’d guess, but two or three meters anyway. I must be twins; I couldn’t be that stupid all by myself. You know, whoever is handling the buoyancy tanks right now must be very, very uptight.”

To Mike’s relief, he had gotten slightly ahead of Wanaka.

“Why?”

“Because the tanks must be big enough to lower or raise the city far enough to be useful even when all its normal floating ice is present. Right now, letting them fill too full could submerge everything—and if the sea gets to the air lock there’ll be more than buoyancy tanks getting filled. I’m sure they must have some emergency way to forestall that, but they won’t like to use it, any more than you’d like to see all of Muamoku’s floats submerged.”

Wanaka nodded slowly. Mike had an alarming thought.

“Captain, you wouldn’t try to—”

“Of course I wouldn’t. In the first place, I wouldn’t kill anyone, let alone a whole city. In the second, whatever happens to get Mata back to sea will have to happen with all four of us aboard. I’m simply assuming that Hinemoa won’t let us go, which is pretty obvious, you must admit.”

Mike was somewhat relieved that she had put the first and second items in that order, but said nothing. He had little chance, actually; there was a knock at the coral door. Mike was closest to it, and opened it at Wanaka’s nod. As they had expected, it was ’Ao. As they had not, it was also Hinemoa and Eru.

Wanaka as usual controlled her expression perfectly. Mike hoped that his own was less readable to the native. The latter spoke at once.

“Captain, how many children can you carry?”

“Why—well, for how long?”

“With good luck, about two days. With bad, indefinitely.”

“ Mata can feed and breathe about four more of ’Ao’s mass without overloading oxygen and food equipment, I’d say. I’m guessing, because this far south our leaf doesn’t get as much power. Why?”

“We’re launching in just under two hours, carrying as many childen as we can.”

“Why? Or would you rather not say?”

“I’d rather not, but I will. We’re making an emergency drop of the bottom kilometer of the city shaft, so as to float higher. We’re getting close to the ice cap. We have to reach it to get more ice, but from here on south the ocean gets less salty because of the melting cap, so we’ll be settling. There’s no saying just how far. We can’t lift any higher without the drop because of melting loss—Mike must have noticed when they showed him the city chart that there was a lot less than a tenth of the volume above water.”

Mike made no comment since he had in fact failed to notice this, but Hinemoa wasn’t asking for confirmation and anyway he was busy translating. She went on, “We can’t risk settling far, so some weight has to go, and we’ve already dropped all our regular ballast. What’s come in on the last few loads hasn’t been processed into slugs we can handle rapidly, and even if we added yours, which I hope you realize is still yours, there wouldn’t be enough to make a difference. Once we’ve made the drop there’ll be no way to get the ships off, assuming it does lift us as far as it should. We’re launching as many people as we can, and if we don’t lose the city, hoping to take them back in a couple of days when we’ve started to gather cap ice. The times this happened before we came through all right, but we’re not taking chances.”

“Of course,” agreed the captain.

“So get your people aboard pronto. Eru wants to go with you if you’re willing. Other children are being selected and siblings separated, and will come along. You can take three besides Eru, you say.”

Mike was not a hero by instinct, but there are some things a civilized adult can’t, and some things he or she simply must, do. He answered without translating for or consulting with the captain.

“Add three more to Mata ’s load. They won’t use more food or air than I do, and I’m not important in handling Mata .”

Hinemoa showed no expression. “Good. We can use your muscle here. Since Eru is going, my husband and I will stay, of course. Captain, you and your crew get to your ship and prepare for launch. Your other passengers will be brought to the harbor.” Mike translated the order and reported his offer. Wanaka showed no surprise, either. Keo gripped his hand briefly but said nothing.

“The tricky part will be submerging just enough for launch,” was Hinemoa’s parting remark. “If we don’t overshoot on that, there shouldn’t be any trouble later. We’ll get ready for the drop, then sink just enough—we hope—to let the fleet off, and immediately let go of the shaft segment. Don’t wait for orders or warning; go out with the spill. In a minute or two after that you’ll know whether a standby or a hunt for another city is in order.” She gestured to Mike to follow her, and left.

Fortunately there was no need to descend nineteen kilometers, or even to the bottom of the ice part of the city. In another large cavern a few hundred meters below the city model dozens of washers, presumably of some variety of coral, obviously not ice for several reasons, nearly covered the ice floor. Each was about five meters across. The floor was more than usually reinforced with coral also, to what depth Mike could only guess; he had no way of telling how much of the twenty-kilometer shaft’s weight was counteracted by buoyancy, though obviously it couldn’t all be. The ice part—mushroom cap of the model—clearly had to be at the top.

Each washer supported a half-meter-thick rod, apparently of the same material. The top of each of these was threaded, with a huge capstan shaped like a wing nut keeping it in place.

Four of the “nuts” were pointed out to the crew of men standing by. One of these said loudly, “Those are the ones to unwind. We have to get them off all the way; the actual release is remotely controlled and is down at the separation point. These are simply safety backups.” Mike wondered for a moment why he was explaining this to natives as well as to him, then realized these were probably a group selected for muscle rather than a permanent emergency crew. The work started, with six men at each side of each wing nut.