What Professor Strong said proved to be true. In less than half an hour they saw the whitecaps forming on the lake behind them. The wind came and went in fitful gusts, and then of a sudden came a blow that was little short of a hurricane.

“We’re going to catch it now!” shouted Mark. “Just hear how it whistles!”

“Hold fast, all of you!” came from Professor Strong.

“We are holding fast,” answered Darry, who was clinging to the stern sheets with might and main.

The sail had long since been taken in and Salvador stood at his rudder, doing his best to keep the craft up to the wind. But this was no easy task for the wind was veering around rapidly.

“Gracious, it’s down on us for keeps!” shouted Frank, a moment later. “Look at that!”

He bobbed his head forward and looking the other boys made out a low wall of white foam moving on them with incredible swiftness. There was a strange humming in the air and the sky became blacker than ever.

In a twinkling the squall was on them in all its fury, sending the sloop headlong into the foam. The boys could see nothing and held their breath in awful suspense. Hockley fairly shivered with terror, but none of the others noted this, being too busy caring for their own safety.

As the sloop veered around, the boiling foam mounted to the forward deck and Sam was caught as in the breakers of the ocean. He was clinging to a low guard, unaware that the thing was partly rotted away. Without warning came a cracking and before he realized it he was over the side.

Down and down, and still down went poor Sam, until he felt that he must be going straight to the bottom of the lake. He was so bewildered that for several seconds he scarcely knew what to do. He turned over and over and clutched out wildly, reaching nothing but the water, which, at this distance below the surface, was as calm as ever.

At last the youth struck out for the surface. He wanted to breathe but knew that if he opened his mouth and took in the water it might prove fatal to him. His head began to grow dizzy and a strange pain shot across his chest. Then he came up, opened his eyes and gave a gasp.

“I went overboard,” was his thought. “Where can the sloop be?”

He tried to call out, but his puny effort was drowned completely by the wind, which whistled as fiercely as ever. On every side of him the water boiled and foamed as before and he was thrown around like a cork, often turning over and going beneath the surface.

The next few minutes were to the boy little short of an age. He strained his eyes for some sign of the sloop but could see absolutely nothing of the vessel. He was alone on the broad bosom of Lake Maracaibo!

Alone! It was an awful thought and as it flashed over his mind he felt his heart sink like a lump of lead in his bosom. Alone! Would they come back for him, or would he be left there to drown?

“They ought to come back,” he muttered. “They must come back! Oh, God spare me!” And the prayer was repeated over and over again. It gave him strength, and he struck out as best he could, determined to keep afloat as long as possible.

All told the squall did not last over twenty minutes, but to poor Sam it seemed an age. He made scant progress through the milklike foam, but this did not matter, since he knew not in what direction he was heading.

“I may be going away from the sloop and away from land too,” he thought dismally. “But I’ve got to do something,” and he continued to swim.

His strength was nearly gone when he bumped into something hard. Laying hold of the object he found it was a spar, which, from its general appearance, had been in the water for many months. He clasped the spar tightly and this sustained him without further aid.

The gusts of wind had been followed by a heavy downpour of rain and this continued for all of half an hour. It was still dark and Sam could not make out in what direction he was drifting. At last, however, he saw a dim outline of land ahead and did his best to shove the spar in that direction. His feet touched bottom, and more dead than alive he dragged himself out of the lake and flung himself headlong in some rank grass under a clump of wild plantains.

When Sam sat up he found the storm going down and the setting sun trying to break through the clouds. The rain had ceased and the bosom of the lake, while still covered with whitecaps, was gradually resuming its normal condition.

“What an experience!” he murmured, as he looked out upon the water. “Wonder if the sloop weathered it or went to the bottom? Oh, if only all the rest are safe!”

He arose to his feet but found himself so weak that he was glad enough to rest again. He was on a bit of an island for behind him was a wide ditch which separated the patch from the mainland. In the distance was a hill backed up by a lofty mountain. Not a human being nor a habitation of any sort was in sight.

“I’m alone and no mistake,” he mused. “I wonder how I had best strike out? Let me see, by the way the sun lies I must be on the eastern shore of the lake and if that’s so I’m opposite to the strait where the town is situated. I’m sure I can’t see how I’m going to get back to Maracaibo.”

Before Sam could make up his mind how to move darkness was upon him—the darkness of the tropics, which descends without warning. At this he sprang up in added alarm.

“I can’t remain here all night,” he thought. “At least I don’t want to. The place may be full of snakes and those uncanny land crabs. I must get up on higher ground if nothing else.”

He set out for the hill he had noticed, but before he had gone a hundred yards, found himself in the mire surrounding the ditch.

“This won’t do,” he muttered and started to go back, but only ended by getting in deeper until he was up to his knees. He was now thoroughly alarmed and came to a standstill almost in despair.

Had it been light Sam might have seen that not far away was a firm stretch of ground leading up to the hill. But he could not see this and so deemed it best to get back to where he had first landed.

Retracing his steps was not easy and once he fell, covering his arms and breast with mud. When he did get back to the wild plantains he was a sight to behold and it took him some time to regain his wind.

“I’m a prisoner on this bit of marshland—that’s all there is to it,” he mused, as he flung himself down near the edge of the lake. “I suppose I’ve got to make the best of it until morning. But how am I going to pass the night?”

At the risk of stirring up some of the dreaded crabs, he waded into the lake and washed himself of the mud. Then he wrung out his jacket and hung it up to dry. Fortunately it was a hot night, so there was no danger of catching cold.

The squall had driven away a good many of the mosquitoes, which infest Lake Maracaibo almost as numerously as they do Staten Island, but now the little pests began to return and presently Sam found himself kept busy by them and also by a species of gnats which are equally annoying. To save himself from their bites he tied his wet handkerchief over his head and neck.

In planning for the trip Mark had mentioned how handy it would be for each to take along a waterproof match-safe and Sam had provided himself with one of these. Satisfied that he would have to remain where he was for some hours at the least, he hunted around for some dry grass and plantain leaves and proceeded to build himself a smudge fire. This burnt slowly because of the dampness and the thick smoke soon put the most of the gnats and mosquitoes to flight.

The fire, dim as it was, gave an air of cheerfulness to the spot, and Sam felt much better as he watched it glow up and then droop. He did not let it go out, but kept piling on the grass, which he tore up in clods with ease. This grass is of the wire variety, very strong, and is much used by the natives in making baskets and various household articles.

“I heard something, what was it?”

It must have been close to midnight when Sam fell into a doze, being so worn out he could scarcely hold up his head. He had piled the fire as high as possible and his only danger was that the smoke might veer around and choke him to death.

How long he dozed he could not tell exactly, afterward, nor could he tell what awoke him. But he opened his eyes with a start and was on his feet almost before he was aware.

“I heard something,” he told himself. “What was it?”

He listened but only a faint breeze blowing through the grass and wild plantains reached his ears. He strained his eyes, yet only the total darkness met his gaze.

Much alarmed Sam continued to stand on guard. He had cut himself the stalk of a young plantain with his jack-knife and he held this in his hands, at the same time keeping as close to the fire as possible, knowing that all wild beasts dread anything burning.