"An' the sharks, Meester Madden," warned Deschaillon.

As Madden kicked off his clothes, he observed Caradoc stripping likewise. Then Farnol Greer came running down the deck with another buoy and a big clasp knife.

The American looked at these fellows. "Caradoc, you can't possibly hold out that distance; you're weak."

"I've done ten miles in--at home."

Greer said nothing, but rapidly undressed.

All three kept on their hats and undershirts as protection against sunburn. As Madden walked from the awning through the stinging sun rays, crimping up his naked feet from the blistering deck, Galton called to him.

"If we git a lot of grub, sir, couldn't it be hextra, and carn't we 'ave a spread to-night, sir?"

"Something like that," agreed Madden, tossing his buoy into the water.

The two other swimmers followed example, then all three dived off the twelve foot pontoon toward their floats. They came up shaking the water from ears and eyes. Madden was immersed in tepid water. His men were cheering stolidly. The schooner looked very, very far away now that he was at the surface of the water. Between him and his goal streaked mazes of sargassum. It suddenly struck the American that he might have trouble getting through those barriers.

However, the three swimmers were progressing boldly.

CHAPTER VI

THE CUL DE SAC

Madden thrust head and shoulders into his float, a round canvas-covered hoop of cork, and set off at an easy stroke. Now that he was flat on the water, he could no longer see the lanes of seaweed, and he would be forced to depend entirely upon signals from the dock.

Alongside Madden came Greer, and after them Caradoc. Like all Americans, Leonard gradually increased his energy, and forged ahead at a rate considerably faster than that required for long distance swimming. Once or twice Caradoc warned the swimmers to go more slowly, and at each monition Madden slowed up a trifle, but within a few minutes he would again speed up unconsciously.

The three swimmers could form little idea of the rate they were making in the lifeless sea. At the end of half an hour, when Leonard looked back at Hogan on the wall for signals, the dock still loomed above him, a vast glare of red in the dazzling sunshine. It seemed impossible to get away from it; the featureless red flare followed him as a mountain peak seems to follow a traveler.

The sun beat oppressively on his head and blistered his shoulders through his net undershirt. The warm water soaked the energy out of limbs and arms. He changed from breast to over-arm stroke, then he shifted to the crawl and trudgen stroke.

"Perhaps we'd better rest awhile, sir," suggested Greer, who came puffing close behind.

"Beastly hot, this sun," Leonard ducked head and shoulders under water for relief. His hat floated off and he grudged the slight effort to retrieve it.

"How far are we?"

"Dock looks as close as ever--where's Smith?"

Greer nodded toward a small head and shoulders bobbing behind a little white buoy.

At that moment, they heard the Englishman's voice calling, "To the right!"

The boys turned and struck out ahead once more. They regretted having to leave the straight line. As far as they could see there was no algae in sight, the water was one glassy blue. And the mysterious schooner, with its lights and shadows exaggerated in the tropical glare, seemed to the tired swimmers to be as remote as ever.

As Madden pressed on and on, changing strokes after the fashion of tiring swimmers, the constant beat of the sun made his eyeballs ache; the ocean felt like a Turkish bath; the muscles in his shoulders, back and legs grew numb, with an occasional cramping twinge. And what irritated him as much as anything else was the fact that he was swimming toward the right quarter of the schooner, throwing away his energy.

Just then Caradoc gave a distant call, "To the left."

With deep relief, Madden rounded back toward his goal. He had swung about some unseen cape of algae. He looked back toward the dock. Hogan, a very tiny figure, held his flag straight up; that meant "dead ahead."

In relief Madden turned over on his back, laid his hat across his face, then with hands resting on chest, he began sculling along with knees and feet.

He did not know how long he swam in this fashion. Queer ideas drifted through the lad's mind. He recalled standing on the bridge of the dock as it went out of the Thames and wondering what would happen. He had never anticipated anything like this. It seemed that he had been swimming for days and weeks. He reminded himself of those little kicking toys that never get anywhere. He felt as if he were a June bug buzzing helplessly at the end of a string. He kicked, kicked, kicked under the broiling sun, in the hot water. The sweaty smell of his hat band disgusted his nostrils. The crown of his hat seemed to coop the heat over his face, sweat seeped into his closed eyelids and stung his eyes.

He gave his head a little shake. The buoy slipped out and he bobbed under the tepid water head and ears.

This jerked him out of his dreamy state. He whirled over, struck to the surface, spat out brine, blinked his eyes. Somebody was shouting something in an urgent voice. The noise buzzed in his waterlogged ears.

"Hey, hello! What is it?" he cried, giving his head a shake and putting on his hat.

"School of sharks!" shouted Greer, coming toward his leader at a foamy speed.

"School of sharks!" echoed Madden with a sharp thrill. "Where? Which way?"

"Must be toward the dock, sir!" panted Greer driving up.

"Where's Caradoc?"

"Yonder." He pointed toward a distant twinkle in the water.

"We must get together--yell to him, warn him!"

The two lads began a strenuous chorus that further used up their exhausted strength. Caradoc responded by a wave of his hand. Then when he understood "sharks" he gathered speed in their direction.

By this time the dock seemed as far away as the schooner, and was in reality probably farther. On the wall of the dock, they could see Hogan's microscopic figure apparently having a fit, against the coppery sky. No doubt from his height he could make out the monsters. Perhaps Hogan could see the great fish shooting along with sinister, exertionless ease toward these clumsy adventurers--a school of trout striking at three awkward beetles.

"Hey, Caradoc! Caradoc!" screamed Madden. "Straight for the schooner!"

The American stared around with tense nerves for the little swishes on the surface that betray the attack of a shark.

From something near middle distance, the Englishman raised a hand toward his comrades and motioned them forward.

"Go on! Go on!" he gasped in a tired voice. "I'll catch you!"

Indeed, there was little to be gained from waiting. Caradoc moved toward his friends with a long overhand stroke that gave him the queer appearance of some huge water bug striding along. Madden and Greer propelled themselves slowly toward the schooner, waiting for their friend to close up. They could not keep their eyes off the Englishman.

Every moment they expected to see him jerked under, or they expected to see a huge shadowy form strike at themselves through the clear green water.

Once Madden looked at the dock. Hogan on the rim of the red flaring wall was flinging out all kinds of despairing gestures.

By this time Caradoc was in hailing distance.

"Did you say sharks?" he called out in a dull voice.

"Yes, sharks!"

"Where a way?"