Ramon and Navarro, as by pre-arrangement, had already begun to move to the other end of the island. Now they stopped abruptly when they heard the cry ash.o.r.e, a cry now taken up by the shouting of many more angry voices.

Ramon said: 'I think Senor Hamilton must have been up to something. I also think we'd better wait a little.'

The two men crouched on the island sh.o.r.e, rifles at the ready, and peered out across the channel. The bulky outline of Hamilton's launch and the two canoes he was towing were now visible not thirty yards from where they were. Not as visible, but still distinct enough to be unmistakable, were the shadowy forms of canoes putting out from the village in pursuit.

Ramon shouted: 'As close to the island as you can. We'll cover you.'

Hamilton glanced over his shoulder. The nearest of half a dozen canoes was already less than thirty yards away. Two men stood in the bows, one with a blowpipe to his mouth, the other pulling back the string of his bow.

Hamilton crouched as low as possible in the boat, glancing almost desperately to his right. He could now see both Ramon and Navarro and he could see that they had their rifles levelled. The two shots came simultaneously. The warrior with the blowpipe toppled backwards in the canoe: the one with the drawn bow pitched into the water, his arrow hissing harmlessly into the river.

'Quickly,' Hamilton called. 'Join the others.'

Ramon and Navarro loosed off a few more shots, more for the sake of discouragement than with the intent of hitting anything, then began to run. Thirty seconds later they rejoined the remainder of the party at the downstream end of the island, all looking anxiously upriver.

Hamilton was struggling, unsuccessfully, to bring his unwieldy trio of boats ash.o.r.e: it looked as if he would miss the tip of the island by feet only.

Ramon and Navarro handed over their rifles, plunged into the river, seized the bows of the motor-launch and turned it into the sh.o.r.e. There were no orders given, no shouts for haste: such were needless. Within seconds all the equipment and pa.s.sengers were aboard the motor-launch, the boat pushed off and paddles distributed. They cast frequent and apprehensive glances astern but there was no cause for concern. The canoes, unmistakably, were dropping behind. There was going to be no pursuit.

Smith said, not even grudgingly: 'That was rather well managed, Hamilton. And now?'

'First we bail out. There should be three cooking pans floating around somewhere. Then we move out into the middle of the river -- just in case they've sent some sharp-shooters down the left bank. There's going to be a full moon shortly, the skies are cloudless so we might as well carry on. Kellner and Hiller must be distinctly worried about us by this time.'

Tracy said: 'Why the two empty canoes?'

'I told you yesterday evening that there were falls about fifty miles below the town. That's why we had to airlift the hovercraft beyond them.

The falls are about twenty miles farther on now. We'll have to make a portage there and it would be impossible to make it with this elephant.

When we get there and have emptied her we'll give her a shove over the edge. Maybe she'll survive, the falls are only fifteen feet.'

Some little time later the now bailed-out motor-launch glided gently down the centre of the river, six men at the paddles but not exerting themselves; the current bore them along. The newly risen moon gleamed softly on the brown water. It was a peaceful scene.

Five hours later, as Hamilton guided the launch into the left bank, the pa.s.sengers could distinctly hear the sound of the falls ahead, no Niagara roar, but unmistakably falls. They made the bank and tied up to a tree. The portage was not more than a hundred yards. First all the equipment, food and personal luggage were carried down, then the two canoes, and just in case the motor-launch should survive its fall, the three cooking utensils for bailing as well.

Hamilton and Navarro climbed into a canoe and reached a spot where the white water ended about a hundred feet below the foot of the falls and paddled gently to maintain position. Both men were looking upriver towards the falls beyond which, they knew, Ramon was at work.

For half a minute there was only the brown-white smoothness of the Rio da Morte sliding vertically downwards. Then the bows of the motor-launch came in sight, appeared to hesitate, until suddenly the entire boat was over and plunging down. There was a loud smack and a considerable cloud of spray as the launch first entered the water then disappeared entirely. All of ten seconds elapsed before it reappeared. But reappear it did, and, remarkably, right side up.

The launch, so full of water that there were only about four inches of freeboard left, drifted sluggishly downstream until Hamilton got a line aboard. With no little difficulty he and Navarro towed it to the left bank and tied up. Bailing operations commenced.

The brightly illuminated hovercraft lay anch.o.r.ed in mid-river.

Navigation, deck and cabin lights were on. Kellner and Hiller were already close to despair because the expected arrivals were already fifteen hours late and it hardly seemed likely that if they hadn't arrived by that time that they would be arriving at all. They had no cause for worry as far as they themselves were concerned. They had only to continue downriver till they came to the junction with the Araguaia and some form of civilisation. Both men were prepared to wait indefinitely and both for the same unexplained reason: they had faith in Hamilton's powers of survival. And so Kellner had his hovercraft lit up like a Christmas tree. He was taking no chances that the helicopter would bypa.s.s him in the darkness.

He and Hiller, both men with their machine-pistols immediately and constantly ready to hand, stood on the brief after-deck between the fans, ears always straining for the first faint intimation of the rackety clamour of the Sikorsky. But it was his eyes that gave Kellner the answer he was waiting for, not his ears. He peered upriver, peered more closely, then switched on and trained the hovercraft's powerful searchlight.

A powerless but impa.s.sively manned motor-launch and two canoes had just appeared in line ahead round a bend in the Rio da Morte.

CHAPTER SEVEN.

The hovercraft's cabin was luxuriously furnished although on a necessarily small scale. The bar was splendidly if selectively equipped and, at the moment, well patronised. Most of the pa.s.sengers from the wrecked helicopter gave the impression of having escaped from the jaws of death. The atmosphere was relaxed, almost convivial, and the spirit of the departed Heffner did not appear to hover over the company.

Hamilton said to Kellner. 'Any trouble during the night?'

'Not really. A couple of canoe-loads of Indians approached us just after midnight. We turned the searchlight on them and they turned and headed back for sh.o.r.e.'

'No shooting?'

'None.'

'Good. Now, the big question tomorrow is the rapids that the Indians call the Hoehna.'

'Rapids?' Kellner said. 'There are no rapids shown on the chart.'

'I daresay. Nevertheless, they're there. Never been through them myself although I've seen them from the air. Don't look anything special from up there, but then nothing ever does. Much experience with rapids?'

'A fair bit,' Kellner said. 'Nothing that a boat hasn't navigated though.'

'I'm told boats have made it through the Hoehna.'

'So where's the problem? A hovercraft can navigate rapids that no boat made by man could ever hope to.'

Serrano said: 'Knowing you, Senor Hamilton, I thought you would have had us on our way by this time. A clear night. Bright moon. A beautiful night for sailing. Or is it "flying" in one of those machines?'

'We need a good night's rest, all of us. It's going to be a hard day tomorrow. The Hoehna rapids are less than a hundred miles away. How long to get there, Kellner?'

"Three hours. Less, if you want.'

'One does not navigate rapids by night. And only a madman goes there in the hours of darkness. Because of the h.o.r.ena, you see.'

Tracy said: 'The h.o.r.ena? Another Indian tribe?'

'Yes.'

'Like the Chapate?'

'They're not at all like the Chapate. The h.o.r.ena are the Roman lions, the Chapate the Christians. The h.o.r.ena put the fear of living death into the Chapate.'

'But you said the Muscias --'

'Ah! The Muscias are to the h.o.r.ena what the h.o.r.ena are to the Chapate.

Or so they say. Goodnight!'

'Rapids!' Ramon called out. 'Rapids ahead!'

In the two and a half hours since the hovercraft's dawn departure the Rio da Morte, though flowing at a rate of about fifteen knots, had been almost gla.s.sily calm and, although visibility had been poor because of fairly heavy rain, no problems had been encountered. But now conditions had dramatically altered. At first indistinctly through the now sheeting rain, but then suddenly, frighten-ingly, and all too vividly rocks could be seen, some jagged, some curved, thrusting up from the river bed. For as far as the eye could see hundreds of them spanned the entire width of the river with white-veined, seething water coursing down between them.

The hovercraft, throttled back to a point where directional control could just be maintained, was almost at once into this white and seething cauldron.

When Kellner had said that he had some little experience of navigating rapids he had been doing himself less than justice. As far as the untrained observer could see, he was masterly. He was positively dancing a jig at the controls. He no longer had the throttle pulled back but kept altering it between half and full ahead which, considering their speed, might have seemed foolhardy, but wasn't. By doing this and by ignoring the air ducts and maintaining the cushion pressure as high as possible he could all the more easily avoid making violent course alterations which would have slewed the hovercraft broadside and into disaster. Instead, he was deliberately aiming for and riding his hovercraft over the less fearsome rocks in his pat,..; Even here he had to be selective, searching out the more rounded rocks and avoiding the jagged ones which, at that speed, would have ripped even the abnormally tough ap.r.o.n skirts, leading to the collapse of the cushion and turning the hovercraft into a boat which would then have foundered in short order. One moment he was jerking the pitch control back, putting power on the left fan, then if this proved insufficient, applying right rudder to give him directional stability while only seconds later he had to reverse the procedure. His task was made harder by the fact that even the high-speed windscreen wipers were capable only intermittently of clearing the spray and rain.

Kellner said to Hamilton who was seated beside him: 'Tell me again about all those boats that were supposed to navigate the Hoehna.'

'I guess I must have been misinformed.' Further back in the hovercraft no-one spoke because all their energies were concentrated on hanging on to their seats. The general effect of the motion was that of a roller-coaster -- except that this roller-boaster, unlike the fairground type, also shook violently from side to side.

Up front, Kellner said: 'Do you see what I see?'

Some fifty yards ahead the river appeared to come to an abrupt end. They were obviously approaching a waterfall of sorts.

'Unfortunately. What are you going to do about it?'

'Funny.'

The hovercraft was being swept helplessly along to what was indeed a waterfall. The drop in the river level must have been at least ten feet.

Kellner was doing the only thing he could do -- trying to keep the hovercraft on a perfectly straight course.

The hovercraft swept over the fall, dipped sharply and plunged downwards at an angle of forty-five degrees. With an explosion of sound and spray, the hovercraft momentarily disappeared save for the stern. Not only the bows but part of the front of the cabin had gone completely under and in that way and at that angle the hovercraft remained for several seconds before it slowly struggled to the surface again, water cascading off its decks. It settled deeper in the water, the effect of partially losing its air cushion when the stern had come completely clear of the water.

The interior of the craft was a scene of appalling confusion. The angle of fall and the stunning impact had catapulted everyone to the deck.

Equipment which had been stored but not lashed aft was now scattered throughout the cabin. To make matters worse, a window had been smashed and hundreds of gallons of water were sloshing about the interior of the cabin. One by one the pa.s.sengers struggled upright. They were bruised, dazed and slightly concussed, but there seemed to be no broken bones.

As the air cushion began to fill again and the water gurgled away through the self-draining ports, they could feel the hovercraft rise slowly to its normal position.

Three times in the next few minutes the hovercraft went through a similar experience, although none of the overfalls were as high as the first time. At last the hovercraft pa.s.sed into an area of smooth, rock-free water, but it was then that another danger manifested itself.

The forested banks gave way to what was at first low rock, which quickly became higher and higher until they were pa.s.sing through what was virtually a cliff-sided canyon. At the same time the river swiftly narrowed to about a third of its original width and the speed of the river and hence that of the hovercraft rapidly more than doubled.

Hamilton and Kellner stared through the windscreens, glanced at each other, then looked forward again. Ahead, the steep-sided river walls fell sharply away, but this promised no surcease. A quarter of a mile ahead a jumble of huge black rocks blocked the river from side to side.

'Bloouy charts!' Kellner said.

'Indeed.'

'Pity, really. These machines are very expensive.'

'Make for the left.'

'Any particular reason?'

'The h.o.r.ena live on the right bank.'

'Left, as the man says.'

The rocks were about three hundred yards away. They appeared to form an impenetrable barrier, no two sufficiently far apart to afford pa.s.sage to the hovercraft.

Hamilton and Kellner looked at each other. Simultaneously they shrugged.

Hamilton turned and faced the rear.

'Hang on tight,' he said. 'We're about to stop very suddenly.' He had no sooner spoken than he realised that his warning had been unnecessary.

They had seen what was coming up. They were already hanging on for dear life.

The rocks were now no more than a hundred yards distant. Kellner was guiding the craft towards the biggest gap between any two of them, the first and the second from the left bank.

For one brief moment it seemed that the hovercraft might just have one chance of making - the pa.s.sage as Kellner arrowed straight for the centre of the gap. The craft's bows pa.s.sed through but that was all: the pa.s.sage was at least eighteen inches narrower than the midships beam of the hovercraft. With a grinding, screeching tearing of metal, the hovercraft came to an abrupt halt, immovably jammed.

Kellner went into reverse and applied maximum power. Nothing happened.

Kellner eased off the fans but kept the engine running to maintain the cushion. He straightened up, muttering to himself, 'Now with an ocean-going tug . . .'

Ten minutes later there was a pile of rucksacks, canvas bags and other improvised luggage containers on deck and Hamilton was securing a rope around his waist. He said: 'It's only twenty feet to that bank but the water's mighty fast so kindly don't let go of the end of that rope.'

It was a danger, but not the only one. Even as he finished speaking there came a sudden grunt and Kellner collapsed to the deck. A dart protruded from the back of his neck. Hamilton swung round.

On the far right bank, less than fifty yards away, stood a group of Indians, ten or twelve in all. Every man had a blowpipe to his mouth.

'h.o.r.ena!' Hamilton shouted. 'Down! Take cover behind the cabin, inside the cabin. Ramon! Navarro!'

Almost immediately, Ramon and Navarro, all humanitarian principles forgotten at the sight of Kellner, were on the cabin roof, stretched out on their elbows, rifles in hand. More darts struck the metal sheathing but none found a target. In three seconds the twins fired six shots. At five hundred yards either man was accurate. At fifty yards they were deadly. One after another, in those few seconds, three h.o.r.ena toppled into the river, three others crumpled and died where they stood, and the others melted away.

Hamilton gazed down in bitterness at the lifeless Kellner. Not for the h.o.r.ena the use of timbo, the poisonous bark of a forest vine which merely stunned: the dart which took Kellner had been tipped with curare.

Hamilton said: 'If it weren't for Kellner we'd all be dead. And now Kellner is dead.' Without another word he jumped into the river. The only danger here was the speed of the water: neither alligators nor piranha ever inhabit rapids.

At first he was swept downstream and had to be hauled back. On the second attempt he succeeded in reaching the bank. He stood there some time, regaining his breath -- the buffeting had been severe -- then undid the rope around his waist and secured it to the bole of a tree.

Another rope was thrown across to him. This he pa.s.sed round a branch and threw back to the hovercraft where, in turn, it was pa.s.sed round a fan bracket and thrown back to Hamilton, forming, in effect, an endless pulley.

The first item of equipment -- Hamilton's own rucksack -- was ferried across, well clear of the water, as was all the rest of the equipment.

The members of the party had to make it the wet way.

CHAPTER EIGHT.