Bert wrote instructions for me while the others were getting out of the place.

“When we’re all gone and the door is sealed, the room will be pumped down to surface pressure. A green light will flash over the table when it’s down, but you’ll know anyway — you’ll be able to open your tank. When you can get out, go over to the table and get onto it. Fasten the straps around your body and legs. It doesn’t matter whether your arms are free or not. When you’re tight to the table, press the red signal button you can see from here.” He indicated the button to me. ‘It’s within reach of your right hand, you see. A container of sleeping medicine will be delivered by one of the hands. Drink it and relax. Nothing more can be done while you’re conscious.”

“Why not?”

“You’ll have to be plugged into a heart-lung machine during the change. Don’t worry. It’s been done many times before. Once you’re out of that tank and onto the table, the only unusual problem you offer will have been solved. All right?”

“I see. All right.” He put down his pad and swam out through the ponderous lock, which swung slowly shut. I hadn’t seen any special dogs or clamps on it, but it opened out into the corridor and wouldn’t need any. With its area, once the pressure started down in the room nothing much short of an earthquake could open it.

I could tell when the pumps started; the whole place quivered, and the vibration carried through to the tank very easily. I spent some time estimating the work that would have to be done to empty a room of this volume against a one-mile head of sea water and a little more in wondering how the mysterious fluid that was replacing water would behave when the pressure came down. If it had a high vapor pressure there would be a purging job on top of the pumping one — no, not necessarily, come to think of it; the stuff must be physiologically harmless, so probably the vapor could be left in the room. Of course if it were flammable it might make trouble when they put oxygen in for me to breathe. Well, they were used to that problem and had been for decades. I needn’t worry about it.

In spite of all the free energy which seemed to be around, it took nearly half an hour to empty the place. The liquid level went down steadily. The surface, when it appeared, remained smooth. There was no boiling or other special behavior. It might as well have been water. They took no pains to get the last of it out; there were several puddles on the rather uneven floor when the light flashed.

I wasted no time opening the tank; I’d been in it for a long time and couldn’t get out too fast. My ears hurt for a moment as the hemispheres fell apart; pressures had not been perfectly matched, but the difference wasn’t enough to be serious. Once out I slowed down. My arms and legs were badly cramped, and I found it almost impossible for a few moments to walk even as far as the table. I spent several minutes working the kinks out of my limbs before I took the next step.

The table was comfortable. Anything I could have stretched out on, including the stone floor, would have been comfortable just then. I fastened the broad, webbed strap about my waist and chest, then of course found I couldn’t reach down to the ones for my legs. I undid the first set,

took care of my legs, refastened the upper strap and finally was ready to push the signal switch.

As promised, one of the mechanical hands promptly extended toward me with a beaker of liquid and a flexible tube to let me drink it lying down. I followed orders, and that’s all I remember about the process.

I woke up with a reasonably clear head. I was lying on a bunk in a small room that contained two other beds and nothing much else. No one else was around.

Someone had removed my clothes, but they were folded in a sort of hybrid, offspring of a laundry basket and a letter rack near the head of the bunk. Another similar affair held a pair of trunks such as I had seen worn by many of the men around my tank. After a moment’s thought I put on the trunks; my other garments weren’t made for swimming. I got out of the bunk and stood on the floor, though my head felt a little funny.

It occurred to me that I had no business feeling enough weight to let me stand, under the circumstances; I was presumably immersed in a liquid denser than water, and therefore denser than my body. A thought crossed my mind; I rummaged in the pockets of my old clothes, found a jack-knife, and let go of it.

Sure enough, it fell past my face. I was standing on the ceiling, as were the bunks.

I tried swimming after the knife, which had come to rest a couple of feet out of reach on the floor/ceiling. It was quite an effort, though not by any means impossible. It: was obvious why the people I had seen wore the ballast belts. I didn’t see any of those around, though, for the moment at least, I’d have to walk if I wanted to go anywhere. This promised to be rather inconvenient too, since the liquid was fairly viscous, though less so than water. Also, the architecture wasn’t designed for walkers; one of the doors to the room was in a wall and fairly accessible, but the other was in the floor — that is, the floor toward which my head was now pointing and on which my jackknife had come to rest. Under the circumstances I decided to wait until Bert or someone showed up with ballast and swim fins.

The decision was helped by the fact that I still didn’t feel quite myself, even aside from the difference of opinion between my eyes and my semicircular canals as to which way was up and which was down. As a matter of fact, the canals couldn’t seem to make up their minds at all on the matter, and it suddenly occurred to me that some surgery must have been done there as well. They could not possibly have been left full of air — or could they? How strong was bone, and how well surrounded by it were the canals, anyway?

I felt around and found several places on my neck and around my ears where the smooth plastic of surgical dressing covered the skin, but that didn’t prove much. It had been obvious all along that some work around the ears would be necessary.

I felt no desire to breathe; they must have slipped a supply of their oxygen-food into me sometime during the procedure. I wondered how long it would last.

It suddenly occurred to me that I was very much in the power of anyone who chose to exercise it, since I hadn’t the faintest idea where to get more of the stuff. That was something I’d have to discuss with Bert very shortly.

I tried forcing myself to breathe. I found I could squeeze liquid slowly out of my lungs and get it back equally slowly, but it hurt and made me feel even dizzier than being right side up and upside down simultaneously. The liquid went into my windpipe; I could feel it, but there was no tendency to cough. I still think that must have been one of the trickiest parts of the conversion procedure, considering the nerve and muscle activity which coughing involves.

The presence of liquid in my windpipe, expected at it was, raised another question. I certainly couldn’t talk, and I didn’t know the sign language which appeared to be standard here — didn’t even know the spoken language on which it was presumably based. I had a long job ahead of me if I were to communicate with the local inhabitants. Maybe it would be better to bypass ‘any such effort; if I could find out all I needed to know from Bert, language lessons would be a waste of time.

I could hear, though. The sounds were almost strange, though some might have been the hum of high-speed motors or generators. There were whistles, thus, whines — nearly everything there is a word for, but none of it exactly similar to anything familiar, and one particular class of noise completely missing. The gabble of speech which drenches every other inhabited part of Earth was totally lacking.