"Of course. Yes."

Javan said cheerfully, "You heat the water. No pressure in the world can stop water from turning to steam at a temperature of more than 374° C. And the steam forces the sea water out through a one-way valve."

"Another weak point," said Demerest. "I suppose so. It's never failed yet. The water in the lock is being pushed out now. When hot steam starts bubbling out the valve, the process automatically stops and the lock is fun of overheated steam."

"And then?"

"And then we have a whole ocean to cool it with. The temperature drops and the steam condenses. Once that happens, ordinary air can be let in at a pressure of one atmosphere and then the door opens."

"How long must we wait?"

"Not long. If there were anything wrong, there'd be sirens sounding. At least, so they say. I never heard one in action."

There was silence for a few minutes, and then there was a sudden sharp clap and a simultaneous jerk.

Javan said, "Sorry, I should have warned you. I'm so used to it I forgot. When the door opens, a thousand atmospheres of pressure on the other side forces us hard against the metal of Ocean-Deep. No electromagnetic force can hold us hard enough to prevent that last hundredth-of-an-inch slam."

Demerest unclenched his fist and released his breath. He said, "Is everything all right?"

"The walls didn't crack, if that's what you mean. It sounds like doom, though, doesn't it? It sounds even worse when I've got to leave and the air lock fills up again. Be prepared for that."

But Demerest was suddenly weary. Let's get on with it, he thought. I don't want to drag it out. He said, "Do we go through now?"

"We go through."

The opening in the 'scaphe wall was round and small; even smaller than the one through which they had originally entered. Javan went through it sinuously, muttering that it always made him feel like a cork in a bottle.

Demerest had not smiled since he entered the 'scaphe. Nor did he really smile now, but a comer of his mouth quirked as he thought that a skinny Moon-man would have no trouble.

He went through also, feeling Javan's hands firmly at his waist, helping him through.

Javan said, "It's dark in here. No point in introducing an additional weakness by wiring for lighting. But that's why flashlights were invented."

Demerest found himself on a perforated walk, its stainless metallic surface gleaming dully. And through the perforations he could make out the wavering surface of water.

He said, "The chamber hasn't been emptied."

"You can't do any better, Mr. Demerest. If you're going to use steam to empty it, you're left with that steam, and to get the pressures necessary to do the emptying that steam must be compressed to a~ut one-third the density of liquid water. When it condenses, the chamber remains one-third full of water-but it's water at just one-atmosphere pressure… Come on, Mr. Demerest."

John Bergen's face wasn't entirely unknown to Demerest. Recognition was immediate. Bergen, as head of Ocean-Deep for nearly a decade now, was a familiar face on the TV screens of Earth-just as the leaders of Luna City had become familiar.

Demerest had seen the head of Ocean-Deep both flat and in three dimensions, in black-and-white and in color. Seeing him in life added little.

Like Javan, Bergen was short and thickset; opposite in structure to the traditional (already traditional?) Lunar pattern of physiology. He was fairer than Javan by a good deal and his face was noticeably asymmetrical, with his somewhat thick nose leaning just a little to the right.

He was not handsome. No Moon-man would think he was, but then Bergen smiled and there was a sunniness about it as he held out his large hand.

Demerest placed his own thin one within, steeling himself for a hard grip, but it did not come. Bergen took the hand and let it go, then said, "I'm glad you're here. We don't have much in the way of luxury, nothing that will make our hospitality stand out, we can't even declare a holiday in your honor-but the spirit is there. Welcome!"

"Thank you," said Demerest softly. He remained unsmiling now, too. He was facing the enemy and he knew it. Surely Bergen must know it also and, since he did, that smile of his was hypocrisy.

And at that moment a clang like metal against metal sounded deafeningly and the chamber shuddered. Demerest leaped back and staggered against the wall.

Bergen did not budge. He said quietly, "That was the bathyscaphe unhitching and the waterclap of the air lock filling. Javan ought to have warned you."

Demerest panted and tried to make his racing heart slow. He said, "Javan did warn me. I was caught by surprise anyway."

Bergen said, "Well, it won't happen again for a while. We don't often have visitors, you know. We're not equipped for it and so we fight off all kinds of big wheels who think a trip down here would be good for their careers. Politicians of all kinds, chiefly. Your own case is different of course."

Is it? thought Demerest. It had been hard enough to get permission to make the trip down. His superiors back at Luna City had not approved in the first place and had scouted the idea that a diplomatic interchange would be of any use. ("Diplomatic interchange" was what they had called it.) And when he had overborne them, there had been Ocean-Deep's own reluctance to receive him.

It had been sheer persistence alone that had made his present visit possible. In what way then was Demerest's case different?

Bergen said, "I suppose you have your junketing problems on Luna City, too?"

"Very little," said Demerest. "Your average politician isn't as anxious to travel a half-million-mile round trip as he is to travel a ten-mile one."

"I can see that," agreed Bergen, "and it's more expensive out to the Moon, of course…In a way, this is the first meeting of inner and outer space. No Ocean-man has ever gone to the Moon as far as I know and you're the first Moonman to visit a sub-sea station of any kind. No Moon-man has ever been to one of the settlements on the continental shelf."

"It's a historic meeting, then," said Demerest, and tried to keep the sarcasm out of his voice.

If any leaked through, Bergen showed no sign. He rolled up his sleeves as though to emphasize his attitude of informality (or the fact that they were very busy, so that there would be little time for visitors?) and said, "Do you want coffee? I assume you've eaten. Would you like to rest before I show you around? Do you want to wash up, for that matter, as they say euphemistically?"

For a moment, curiosity stirred in Demerest; yet not entirely aimless curiosity. Everything involving the interface of Ocean-Deep with the outside world could be of importance. He said, "How are sanitary facilities handled here?"

"It's cycled mostly; as it is on the Moon, I imagine. We can eject if we want to or have to. Man has a bad record of fouling the environment, but as the only deep-sea station, what we eject does no perceptible damage. Adds organic matter." He laughed.

Demerest filed that away, too. Matter was ejected; there was therefore ejection tubes. Their workings might be of interest and he, as a safety engineer, had a right to be interested.

"No, he said, "I don't need anything at the moment. If you're busy-"

"That's all right. We're always busy, but I'm the least busy, if you see what I mean. Suppose I show you around. We've got over fifty units here, each as big as this one, some bigger-"

Demerest looked about. Again, as in the 'scaphe, there were angles everywhere, but beyond the furnishings and equipment there were signs of the inevitable spherical outer wall. Fifty of them!