Bottomside, we positioned the cage near to the unit, which we found still standing, exhibiting no visible signs of damage, and we halted the illuminated DC a couple of fathoms up and off to the east We were indeed on the edge of a steep cliff. While Paul inspected the sonic-broadcast unit, I moved nearer and flashed my light downward.

Jutting rocky pinnacles and twisting crevices ... Reflexively, I drew back from the edge of the abyss, turned my light away. I returned and watched Paul work.

It took him ten minutes to disconnect the thing and free it from its mountings. Another five saw it secured and rising on its lines.

A bit later, in the periodic sweep of our beams, we caught sight of the replacement unit on the way down. We swam up to meet it and guided it into place. This time, Paul let me go to work. I indicated by pantomime that I wanted to, and he wrote on his slate: GO AHEAD SEE WHAT YOU REMEMB.

So I fastened it in place, and this took me about twenty minutes. He inspected the work, patted me on the shoulder, and nodded. I moved to connect the systems then, but stopped to glance at him. He indicated that I should go ahead.

This only took a few minutes, and when I was finished I had a certain feeling of satisfaction thinking of that light going on again on the big board back at the station. I turned around to indicate that the job was done and that he could come admire my work.

But he was no longer with me.

For a few seconds I froze, startled. Then I began shining my light around.

No, no. Nothing ...

Growing somewhat panicky, I moved to the edge of the abyss and swept downward with the light Luckily, he was not moving very quickly. But he was headed downward, all right. I took off after him as fast as I could move.

Nitrogen narcosis, deepwater sickness, or rapture of the deep does not usually hit at depths above 200 feet. Still, we were at around 170, so it was possible, and he certainly seemed to be showing the symptoms.

Worrying then about my own state of mind, I reached him, caught him by the shoulder, turned him back. Through his mask, I could see the blissful expression that he wore.

Taking him by the arm and shoulder, I began drawing him back with me. For several seconds he accompanied me, offering no resistance.

Then he began to struggle. I had anticipated this possibility and shifted my grips into a kansetsu-waza position, but quickly discovered that judo is not exactly the same underwater, especially when a tank valve is too near your mask or mouthpiece. I had to keep twisting my head away, pulling it back. For a time, it became impossible to guide him that way. But I refused to relinquish my grip. If I could just hold him a while longer and did not get hit by narcosis myself, I felt that I had the advantage. After all, his coordination was affected as well as his thinking.

I finally got him to the DC, a wild antenna of bubbles rising from his air hose by then, as he had spat out his mouthpiece and there was no way I could get it back in without letting go. Still, it might have been one of the reasons he became easier to manage near the end there. I don't know.

I stuffed him into the lighted chamber, followed, and got the hatch sealed. He gave up about then and began to sag. I was able to get his mouthpiece back into place, and then I threw the pull-up switch.

We began to rise almost immediately, and I wondered what Barthelme and Davies were thinking at that moment.

They got us up very quickly. I felt a slight jarring as we came to rest on the deck. Shortly afterward, the water was pumped out. I don't know what the pressure was up to, or down to, at that point, but the communicator came alive and I heard Bartheleme's voice as I was getting out of my gear.

We'll be moving in a few minutes, he said. What happened, and how serious is it?

Nitrogen narcosis, I'd say. Paul just started swimming out and down, struggled with me when I tried to bring him back.

Were either of you hurt?

No, I don't think so. He lost his mouthpiece for a little while. But he's breathing okay now.

What shape is he in otherwise?

Still rapturing, I'd guess. Sort of collapsed, drunken look to him.

All right. You might as well get out of your gear ...

I already have.

... and get him out of his.

Just starting.

We'll radio ahead and have a medic hop out and be waiting at the dispensary, just in case. Sounds like what he really needs most is the chamber, though. So we'll just take it slow and easy in getting him back to surface pressure. I'm making an adjustment right now ... Do you have any rapture symptoms yourself?

No.

Okay, there. We'll leave it at this setting for a little while ... Is there anything else I should know?

Not that I can think of.

All right, then. I'm going forward to radio for the doctor. If you want me for anything, whistle into the speaker. That should carry.

Right.

I got Paul out of his rig then, hoping he would start coming around soon. But he didn't. He just sat there, slouched, mumbling, eyes open but glassy. Every now and then he smiled.

I wondered what was wrong. If the pressure was indeed diminished, the recovery should have been almost instantaneous. Probably needed one more step, I decided.

But could he have been down much earlier that morning, before the workday began?

Decompression time does depend upon the total amount of time spent underwater during about a twelve-hour period, since you are dealing with the total amount of nitrogen absorbed by the tissues, particularly the brain and spinal cord. Might he have been down looking for something, say, in the mud, at the base of a broken mast, amid the wreckage of a certain old vessel? Perhaps down for a long while, searching carefully, worried? Knowing that he had shore duty today, that there should be no more nitrogen accumulated during this workday? Then, suddenly, an emergency, and he has to chance it. He takes it as easy as possible, even encouraging the new man to go ahead and finish up the job. Resting, trying to hang on ...

It could well be. In which case, Barthelme's decompression values were off. The time is measured from surface to surface, and the depth is reckoned from the deepest point reached in any of the dives. Hell, for all I knew he might have visited several caches spotted at various points along the ocean's bottom.

I leaned over, studied the pupils of his eyes, catching his attention, it seemed, in the process. How long were you down this morning? I asked.

He smiled. Wasn't, he said.

It doesn't matter what was involved. It's your health we're worried about now ... How long were you down? What depths?

He shook his head. Wasn't, he said.

Damn it! I know you were! It was the old wreck, wasn't it? That's maybe twenty fathoms. So how long? An hour? Were you down more than once?

Wasn't down! he insisted. Really, Mike! I wasn't.

I sighed, leaned back. Maybe, possibly, he was telling the truth. People are all different inside. Perhaps his physiology was playing some other variation of the game than the one I had guessed at It had been so neat, though. For a moment, I had seen him as the supplier of the stones and Frank as the fence. Then I had gone to Frank with my find, Frank had mentioned this development to him, and Paul, worried, had gone off while the station slept to make certain that things were still where they were supposed to be. His tissues accumulated a lot of nitrogen during his frantic searching, and then this happened. It certainly struck me as logical. But if it were me, I would have admitted to having been down. I could always come up with some lie as to the reason later.

Don't you remember? I tried again.

He commenced an uninspired stream of curses, but lost his enthusiasm before a dozen or so syllables. His voice trailed off, then, Why don't you b'lieve me, Mike? I wasn't down ...