The two men moved quickly along the deck, their padded soles soundless on the metal plates. A white midnight sky hung across the dark surface of the lagoon, a few stationary clumps of cumulus like sleeping galleons. The low night sounds of the jungle drifted over the water; occasionally a marmoset gibbered or the iguanas shrieked distantly from their eyries in the submerged office blocks. Myriads of insects festered along the water-line, momentarily disturbed as the swells rolled in against the base, slapping at the canted sides of the pontoon.

One by one Kerans began to cast off the restraining lines, taking advantage of the swells to lift the loops off the rusting bollards. As the station slowly pivoted away he looked up anxiously at the dark bulk of the base. Gradually the three nearside blades of the helicopter came into view above the top deck, then the slender tail rotor. He paused before releasing the last line, waiting for Bodkin to give the all-clear from the starboard bridge.

The tension on the line had doubled, and it took Kerans several minutes to work the metal loop up the curving lip of the bollard, the successive swells giving him a few inches of slack as the station tilted, followed a moment later by the base. Above him he could hear Bodkin whispering impatiently-they had swung right around into the narrow interval of water behind them and were now face on to the lagoon, the single light in Beatrice's penthouse burning on its pylon. Then he cleared the lip and lowered the heavy cable into the slack water three feet below, watching it cleave back towards the base.

Freed of its attendant burden, and with its centre of gravity raised by the helicopter on its roof, the huge drum rolled over a full five degrees from the vertical, then gradually regained its balance. A light in one of the cabins went on, then flicked off again after a few moments. Kerans seized the boathook on the deck beside him as the interval of open water widened, first to twenty yards, then to fifty. A low current moved steadily through the lagoons, and would carry them back along the shore to their former mooring.

Holding the station off from the buildings they skirted, now and then crushing the soft fern trees sprouting through the windows, they soon covered two hundred yards, slowing as the current diminished around the curve, and finally lodged in a narrow inlet about a hundred feet square in size.

Kerans leaned over the rail, looking down through the dark water at the small cinema theatre twenty feet below the surface, its flat roof luckily uncluttered by elevator-heads or fire escapes. Waving to Bodkin on the deck above, he stepped in through the laboratory and made his way past the specimen tanks and sinks to the companionway leading down to the float.

Only one stop-cock had been built into the base of the float, but as he turned the handwheel a powerful jet of cold foaming water gushed up around his legs. By the time he returned to the lower deck, to make a final check of the laboratory, water was already spilling ankle-deep through the scuppers, sluicing among the sinks and benches. He quickly released the marmoset from its fume cupboard and pushed the bushy-tailed mammal through one of the windows. The station went down like an elevator, and he waded waistdeep to the companionway and climbed up to the next deck where Bodkin was exultantly watching the windows of the adjacent office blocks rise into the air.

They settled about three feet below deck level, on a flat keel with a convenient access point by the starboard bridge. Dimly below they could hear trapped air bubbling from the retorts and glassware in the laboratory, and a frothy stain spread across the water from a submerged window by one of the reagent benches.

Kerans watched the indigo bubbles fade and dissolve, thinking of the huge semi-circle of programme charts sinking below the water as he left the laboratory, a perfect, almost vaudevillian comment on the biophysical mechanisms they sought to describe, and which perhaps symbolised the uncertainties that lay ahead now that he and Bodkin had committed themselves to remaining behind. They were now entering the _aqua incognita_, with only a few ruleof-thumb principles to guide them.

From the typewriter in his cabin Kerans took a sheet of paper, pinned it firmly to the door of the galley. Bodkin appended his signature to the message, and the two men went out on to the deck again and lowered Kerans' catamaran into the water.

Paddling slowly, the outboard shipped, they glided off across the black water, soon disappearing among the dark blue shadows along the edge of the lagoon.

As the down-draught from its blades fanned furiously across the swimming pool, tearing at the striped awning of the patio, the helicopter circled deafeningly over the penthouse, plunging and diving as it searched for a landing point. Kerans smiled to himself as he watched it through the plastic vanes over the lounge windows, confident that the tottering pile of kerosene drums he and Bodkin had pyramided over the roof would safely deter the pilot. One or two of the drums toppled down on to the patio and splashed into the pool, and the helicopter veered away and then came in more slowly, hovering steadily.

The pilot, Sergeant Daley, swung the fuselage around so that the hatch door faced the lounge windows, and the hatless figure of Riggs appeared in the doorway, two of the soldiers holding on to him as he bellowed into an electric megaphone.

Beatrice DahI ran across to Kerans from her observation post at the far end of the lounge, cupping her ears from the din.

"Robert, he's trying to talk to us!"

Kerans nodded, the Colonel's voice completely lost in the engine roar. Riggs finished and the helicopter leaned backwards and soared away across the lagoon, taking the noise and vibration with it.

Kerans put his arm around Beatrice's shoulders, the bare oiled skin smooth under his fingers. 'Well, I think we have a pretty good idea what he was saying."

They went out on to the patio, waving up to Bodkin who had appeared from the elevator-house and was straightening the drums. Below them, on the opposite side of the lagoon, the upper deck and bridge of the scuttled testing station protruded from the water, a flotsam of hundreds of pieces of old note-paper eddying away from it. Standing by the rail, Kerans pointed to the yellow hull of the base moored by the Ritz in the furthest of the three central lagoons.

After a futile attempt to re-float the station, Riggs had set off at noon as planned, sending the cutter over to the apartment house where he assumed the two biologists were hiding. Finding the elevator out of order, his men had refused the alternative of a twenty-storey climb up the stairway-already a few iguanas had made their homes on the lower landings-so Riggs had finally tried to reach them with the helicopter. Baulked there, he was now crashing the Ritz.

"Thank God he's left," Beatrice said fervently. "For some reason be really got on my nerves."

"You made that pretty plain. I'm surprised he didn't take a pot shot at you."

"But, darling, he was insufferable. All that stiff upper lip stuff and dressing for dinner in the jungle-a total lack of adaptability."

"Riggs was all right," Kerans remarked quietly. "He'll probably get by." Now that Riggs had gone he was aware of how dependent he had been on the Colonel's buoyancy and good humour. Without him the morale of the unit would have disintegrated in an instant. It remained to be seen whether Kerans could imbue his own little trio with the same degree of confidence and sense of purpose. Certainly it was up to him to be the leader; Bodkin was too old, Beatrice too self-immersed.

Kerans glanced at the thermo-alarm he wore next to his wristwatch. It was after 3-30, but the temperature was still a hundred and ten degrees, the sun beating against his skin like a fist. They joined Bodkin and went into the lounge.

Resuming the action conference interrupted by the helicopter, Kerans said: "You've got about a thousand gallons left in the roof tank, Bea, enough for three months-or let's say two as we can expect it to get a lot hotter-and I recommend you to close down the rest of the apartment and move into here. You're on the north side of the patio so the elevator-house will protect you from the heavy rains when they come in on the southerly storms. Ten to one the shutters and air-seals along the bedroom walls will be breached. What about food, Alan? How long will the stocks in the deep freeze last?"

Bodkin pulled a distasteful face. 'Well, as most of the lambs' tongues in aspic have been eaten they now consist chiefly of bully beef, so you could say 'indefinitely'. However, if you're actually planning to eat the stuff-six months. But I'd prefer iguana."

"No doubt the iguana would prefer us. All right then, that seems pretty fair. Alan will be over in the station until the level rises, and I'll be holding out at the Ritz. Anything else?"

Beatrice wandered away around the sofa towards the bar. "Yes, darling. Shut up. You're beginning to sound like Riggs. The military manner doesn't suit you."

Kerans threw her a mock salute and strolled over to look at the painting by Ernst at the far end of the lounge, while Bodkin gazed down at the jungle through the window. More and more the two scenes were coming to resemble each other, and in turn the third nightscape each of them carried within his mind. They never discussed their dreams, the common zone of twilight where they moved at night like the phantoms in the Delvaux painting.

Beatrice had sat down in the sofa with her back to him, and shrewdly Kerans guessed that the present unity of the group would not be long maintained. Beatrice was right; the military manner did not suit him, his personality was too passive and introverted, too self-centred. More important, though, they were entering a new zone, where the usual obligations and allegiances ceased to operate. Now that they had made their decision the bonds between them had already begun to fade, and it was not simply for reasons of convenience that they would live apart. Much as he needed Beatrice Dahl, her personality intruded upon the absolute freedom he required for himself. By and large, each of them would have to pursue his or her own pathway through the time jungles, mark their own points of no return. Although they might see one another occasionally, around the lagoons or at the testing station, their only true meeting ground would be in their dreams.