“This — is — really — something. Just for the record, young pal, we are in a serious jam, I hope you realize.”
“I don't think so. His wife is against the idea, and he'll let himself get talked out of it — he's a little afraid of the results already.”
“Not the point. It doesn't matter if the whole thing was a practical joke on his part. They're out of sight, in a medium where no current charts exist and the only navigation aids are that sphere's own sonar units. He could find his way back to the core, but how could he find us?”
“Aren't we right under the lock and the station? We came straight down.”
“Don't bet on that. I told you — there are currents. If we made a straight track on the trip down here I'll be the most surprised man inside Luna's orbit. There are twenty million square feet on this mudball. We'd be visible from a radius of maybe two hundred — visible and recognizable, that is, with our lights on. That means they have something like two hundred search blocks, if my mental arithmetic is right, without even a means of knowing when they cover a given one a second time. There is a chance they'd find us, but not a good one — not a good enough one so that we should bet your chance of dodging a couple of weeks of weightlessness on it. When that nut went out of sight, he disposed of us once and for all.”
“I wouldn't call him a nut,” Bresnahan said.
“Why not? Anyone who would leave a couple of people to starve or get loaded with zero-gee symptoms on the odd chance that they might blab his favorite scheme to the public…'
“He's a little unbalanced at the moment, but not a real nut. I'm sure he didn't realize he'd passed the point of no return. Make allowances, Bert; I can. Some of my best friends are married, and I've seen 'em when they first learned a kid was on the way. It's just that they don't usually have this good a chance to get other people in trouble; they're all off the beam for a little while.”
“You're the most tolerant and civilized character I've met, and you've just convinced me that there can be too much of even the best of things. For my money the guy is a raving nut. More to the point, unless we can get ourselves out of the jam he's dropped us into, we're worse than nuts. We're dead.”
“Maybe he'll realize the situation and go back to the station and call for help.”
“There can be such a thing as too much optimism, too. My young friend, he's not going to get to the station.”
“What? Why not?”
“Because the only laser tube not already in the station able to trigger the cobweb launchers is right here on my equipment clip. That's another reason I think he's a nut. He should have thought of that and pried it away from me somehow.”
“Maybe it just means he wasn't serious about the whole thing.”
“Never mind what it means about him. Whatever his intentions, I'd be willing to wait for him to come back to us with his tail between his legs if I thought he could find us. Since I don't think he can, we'd better get going ourselves.”
“Huh? How?”
“Swim. How else?”
“But how do we navigate? Once we're out of sight of the core we'd be there in the dark with absolutely nothing to guide us. These little lights on our suits aren't…'
“I know they aren't. That wasn't the idea. Don't worry; I may not be able to swim in a straight line, but I can get us to the surface eventually. Come on; five miles is a long swim.”
Silbert started away from the glow, and Bresnahan followed uneasily. He was not happy at the prospect of weightlessness and darkness combined; the doses on the trip down, when at least the sphere had been present for some sort of orientation, had been more than sufficient.
The glow of the core faded slowly behind them, but before it was too difficult to see Silbert stopped.
“All right, put your light on. I'll do the same; stay close to me.” Bresnahan obeyed both orders gladly. “Now, watch.”
The spaceman manipulated valves on his suit, and carefully ejected a bubble of air about two feet in diameter. “You noticed that waste gas from the electrolyzers in the diving suits didn't stay with us to be a nuisance. The bubbles drifted away, even when we were at the core,” he pointed out. Bresnahan hadn't noticed, since he wasn't used to paying attention to the fate of the air he exhaled, but was able to remember the fact once it was mentioned.
“That of course, was not due to buoyancy, so close to the core. The regular convection currents started by solar heat at the skin must be responsible. Therefore, those currents must extend all the way between skin and core. We'll follow this bubble.”
“If the current goes all the way, why not just drift?”
“For two reasons. One is that the currents are slow — judging by their speed near the skin, the cycle must take over a day. Once we get away from the core, the buoyancy of this bubble will help; we can swim after it.
“The other reason is that if we simply drift we might start down again with the current before we got close enough to the skin to see daylight.
“Another trick we might try if this takes too long is to have one of us drift while the other follows the bubble to the limit of vision. That would establish the up-down line, and we could swim in that direction for a while and then repeat. I'm afraid we probably couldn't hold swimming direction for long enough to be useful, though, and it would be hard on the reserve air supply. We'd have to make a new bubble each time we checked. These suits have recyclers, but a spacesuit isn't built to get its oxygen from the surrounding water the way that diving gear is.”
“Let's just follow this bubble,” Bresnahan said fervently.
At first, of course, the two merely drifted. There simply was no detectable buoyancy near the core. However, in a surprisingly short time the shimmering globule of gas began to show a tendency to drift away from them.
The direction of drift was seldom the one which Bresnahan was thinking of as “up” at the moment, but the spaceman nodded approval and carefully followed their only guide. Bresnahan wished that his training had given him more confidence in instrument readings as opposed to his own senses, but followed Silbert hopefully.
8
The fourteen hours he spent drifting weightless in the dark made an experience Bresnahan was never to forget, and his friends were never to ignore. He always liked crowds afterward, and preferred to be in cities or at least buildings where straight, clearly outlined walls, windows, and doors marked an unequivocal up-and-down direction.
Even Silbert was bothered. He was more used to weightlessness, but the darkness he was used to seeing around him at such times was normally pocked with stars which provided orientation. The depths of Rain-drop provided nothing. Both men were almost too far gone to believe their senses when they finally realized that the bubble they were still following could be seen by a glow not from their suits' lights.
It was a faintly blue-green illumination, still impossible to define as to source, but unmistakably sunlight filtered through hundreds of feet of water. Only minutes later their helmets met the tough, elastic skin of the satellite.
It took Silbert only a few moments to orient himself. The sun and the station were both visible — at least they had not come out on the opposite side of the satellite — and he knew the time. The first and last factors were merely checks; all that was really necessary to find the lock was to swim toward the point under the orbiting station.
“I don't want to use the sonar locator unless I have to,” he pointed out. “There is sonar gear on the sphere. I should be able to get us close enough by sighting on the station so that the magnetic compass will work. Judging by where the station seems to be, we have four or five miles to swim. Let's get going.”
“And let's follow the great circle course,” added Bresnahan. “Never mind cutting across inside just because
