When the American pushed outside with his burden, a breeze swept the deck of the Vulcan with an unexpected coolness. The vibrations had almost ceased, but there was a slight hissing of water from somewhere, and a feeling of movement. The men were in a hubbub on the port side where the small boat lay tied.

Filled with the idea that the ship was about to founder, Madden stared about. To his vast astonishment, he discovered the tug was not sinking, but moving. The Vulcan was under way. The noise he heard was the swift displacement of water. For some unaccountable reason, the vessel glided southward at a speed of eight or ten knots.

In the uproar forward, Madden heard the cries: "Th' dinghy's swamped!" "We carn't reach 'er!" "Cut 'er loose and jump!" "We couldn't right 'er in th' water!" "Cut 'er and jump! Quick! 'Eaven knows w'ot's got us!"

"Steady! Steady, men!" bawled Madden, laying Caradoc down on the deck and hurrying across to his panicky crew. "What's moving us?"

"We don't know, sir! Th' sea sorpint! Grabbed our cable and made off!"

"Can you see it?"

"Just make it out, sir, ahead!"

"Cut th' cable!" cried another voice; "that'll get us loose!"

"Yes, get an axe—Quick!"

A dim figure came running aft past Madden for the axe. The American shouted at him: "Come back! Don't touch that towing line! Let things alone!"

"Yes, but this'll drag us to the bottom!" chattered one of the men forward.

"We'll get in the dinghy when the ship goes down!"

"We might row to the dock from here!"

The men stood in a string along the rail, below them in the hissing water the dinghy tossing topsy turvy.

"What's towing us? I don't see it?" cried Madden.

Several arms pointed forward. Leonard peered through the gloom. The crescent moon and the stars filtered down a tinsel light. The faint shine merely made the darkness more evident Madden seemed to catch a glimmer of a bulk at the end of the anchor line some hundred yards distant. He listened but heard only the gurgle of the Vulcan's wake and the creak of her plates.

When the sheer panic of surprise had worn away somewhat, the weirdness of the uncanny voyage came upon the crew with tenfold force. They stood gripping the rail, staring ahead with the feeling of condemned prisoners on their way to the gallows.

"We're 'eaded for the 'ole in th' sea!" muttered Mulcher.

"We'll go down tug an' hall," mumbled Galton unsteadily. "Fish bait, that's w'ot we are!"

"I've heard sea serpents can sting a man and numb him so he won't live or die," shivered Hogan, "like a spider stings a fly."

They spoke in half whispers under the influence of the unknown terror.

"If anything happens, I shall keel myself," declared Deschaillon, with nervous intensity, "but I shall see it first."

"That's w'ot went with the other two crews—killed theirselves," chattered Mulcher.

Another silence fell. The cool breeze came as a sort of mockery of their unknown peril. For the first time since the storm every man was thoroughly comfortable physically.

"Boys," planned Hogan, "whin th' thing comes aboard, we'll put up th' best foight we can!"

"It don't come aboard—it bites a 'ole in th' 'ull."

"Aye, like th' Minnie B."

Just then a figure approached the men unsteadily, and Madden saw that Caradoc had recovered consciousness and was able to walk. As the tall, gaunt figure approached, the crew eyed him as if he were some new danger, then he asked.

"What is this? Are we moving?"

"Yes we're off," replied Madden.

"Under our own power?" he inquired, turning around and staring at the smokeless funnel.

"No, we're being towed."

"Towed! Towed!" exclaimed Smith in a weak voice. "What's towing us?"

"We don't know, sor," replied a cockney.

There was a silence in which Caradoc stood tall and cadaverous as a ghost. "Am I dreaming this, Madden?" he muttered finally. "Did you say we were being towed?"

"That's right."

"What's towing us—not—not the dry dock—don't say the dry dock's towing us!"

"We don't know, sor," repeated the cockney.

"Where are we going?"

"To be killed, sor."

Caradoc moved slowly over to the rail and sat against it near Madden.

"A cool breeze," he murmured gratefully.

The American was lost amid the wildest speculations as to the mysterious agent that had the Vulcan in tow. He was trying to think logically, but found it hard in that atmosphere of terror. The utter weirdness of the whole affair defied analysis. The towing of the Vulcan by an unknown power was the very climax of the fantastic. No hypothesis he could form even remotely approached an explanation.

It could not be some sea monster surging steadily at the tow line of the Vulcan. That theory was untenable. A monster might attack; it would never tow.

But any other, attempt to account for the strange predicament fell equally as flat. What human agency would operate so mysteriously in this hot, stagnant sea? Why should any group of men entrap the helpless crew of the Vulcan with such a display of mystery and power? It was useless. It was ridiculous. It was shooting a mosquito with a field gun.

All his thoughts ended in utter absurdity. He felt that he had run up against some vast power. The schooner Minnie B, the tug Vulcan, were but trifling units in the enigma of this deserted, weed-clogged sea. It must be some power whose operations were ocean-wide.

Why such a spot should be chosen?—Why a power that sank one ship out of hand and towed another mile after mile?—Why it operated only at night?—What lay at the heart of this brooding fabric of terror—he could not form the slightest conception. Outlawry, piracy, smugglery, were all goals too small for such operations.

His thoughts seemed to be physical things trying to clamber up the smooth polished side of an enormous steel plate. They made not the slightest progress. The more he thought, the more unaccountable all phases of the question became.

In absolute perplexity, he turned to the Englishman at his side. He could just make out the blur of Caradoc's face.

"Have you a theory about this, Smith?" he asked in a low voice.

The Englishman nodded in silence.

"What is it?"

"I—I got my head hurt awhile ago. I believe I'm delirious—dreaming."

Leonard thought this over without any feeling of amusement. "That doesn't explain why I see it too," he objected gravely. "Nothing wrong with my head—that I know of." He tried the time honored experiment of pinching himself.

"I shall assume that I am awake," he decided after he had felt his pinch. "I may not be, but I'm going to act as if I were."

Madden had an impression that Caradoc was smiling in the darkness. Just then Gaskin began laughing shrilly in a queer metallic voice.

"Quit that!" snapped half a dozen thick voices at once, as if his laughter had violently shocked their tense nerves.

Gaskin pointed a stumpy arm off the starboard bow, "Look! Look!" he gasped. "It's that rotten whiskey! Whiskey done it! Whiskey made me see that! Look w'ot whiskey done!"

Leonard had no idea that anything could be added to the nightmarish quality of the adventure, but there off the starboard arose a great bulk, blotting out the stars. It was not a ship; it was not a barge; there was not a light on it, but it seemed somehow dimly illuminated. It was as shapeless as death.

"The Flyin' Dutchman!" shuddered Galton.

"It burns a blue light!" corrected Hogan with chattering teeth.

"Th' ship o' the dead!" shivered Mulcher.

A sudden explanation flashed into Madden's head. "You fools are afraid of our own dry dock," he whispered briefly. "We've traveled in a circle and reached the dock again."

"Oh, no, sor, it ain't that! Tain't th' dry-dock, sor!" aspirated several fear-struck voices.

The crew held their breaths as if the apparition might vanish as suddenly as it appeared.

By this time the moon lay flat on the sea, throwing a faint shining streak across the dark Sargasso. This vague light was enough to show Madden, when he took a close look, that it was not the dock.

The thing he saw was an enormous mass without the severe angular shape of the great dock. Its outline rose crude and shapeless, as well as he could trace it among the canopy of stars, and gave not the slightest intimation as to what use it could be.

As they stared, the speed of the Vulcan slackened sensibly. The faint rippling of water under the prow ceased. The breeze fell away into a dead blanket of heat. It was as if a sweatbox had been cooped over the crew.

"The thing's cut loose from us," said a weary voice.

Hogan laughed shortly: "Everybody out—fifteen minutes for refrishmints."

"Yonder goes that thing!" cried Galton. "Hi can see it!"

Indeed, by peering carefully, Madden could follow the slender outline of the mysterious craft that had towed the Vulcan to this uncanny spot. It had now left the tug and was gliding away to the great misshapen fabric that sprawled on the sea.

Every eye strained to see the outcome of this strange maneuver, when suddenly from the gliding vessel there shot a dazzling light that spread over the bulky mass. Under the beating illumination every detail of the huge vessel stood out garishly. She was immense, with a broad flat prow like a railway ferryboat. She stood high in the water and seemed to have three promenade decks around her.

There was no mast, no rigging, no outside gearing. One squat funnel amidship told that she used steam for some purpose, and out of this funnel black masses of smoke rose slowly in the motionless air. She resembled no craft Madden had ever seen.

Notwithstanding her enormous size, everything about the vessel impressed Madden that she was built for secrecy. She was squat, considering her length and breadth. It was as if her designer were trying to make a craft invisible at sea. As near as Madden could determine in the strange light, she was painted a pale sky-blue. During the day, no doubt, she melted into the sky like a chameleon.

As the smaller craft approached its huge mate, its circle of light contracted until it finally concentrated into a dazzling white spot centered on the prow of the monster. This spot diminished to an intense point, like an electric arc between carbons. A sharp reflection of this point streaked the water between the tug and the mysterious vessels.

Then, under the unbelieving eyes of the crew, the little vessel ran completely into the larger one and was gone. The light vanished instantly. Utter blackness fell over the dazzled eyes of the watchers.

There were gasps, explosive curses of bewilderment, amazement. The little boat had disappeared into the larger. Impossible! Gaskin began his shrill laughter again. Then he gurgled in the darkness as if somebody's fingers had clamped his windpipe.

Madden's mind attacked more violently than ever the incomprehensible motives behind this inscrutable mystery. What was the key to this incredible affair? In the midst of his mental struggle, he felt a hand on his arm, Caradoc said in his ear,

"What do you say we get in the small boat and pay them a visit?"

"It's a big risk. I daresay we'll get our heads blown off."

"I had thought of that," agreed Caradoc.

"Come on," said the American, and the two moved across the deck to see if they could still use the dinghy, which had been trailing along all this time.

Nearly an hour later, the two boys in the dinghy approached the puzzling craft with muffled oars. As Madden and Caradoc drew near, the vast size of the strange ship grew more striking. The faint impression of light which they had first received grew stronger and Madden saw that the decks were illuminated by long bands of diffused light, although he could not guess its origin.

On the lowest deck, the American made out the small figure of a man marching back and forth with a gun.

At this sight, both boys stopped rowing, lifted the oars from tholes and began paddling noiselessly, canoe-fashion.

"That must be the accommodation ladder," whispered Madden, "where the guard is."

"Who are they afraid will board them?" queried Caradoc. "Mermaids?"

"It is a strange precaution to take in the Sargasso," agreed the American. "It is going to make our entrance difficult."

They ceased paddling now and drifted silently toward the monster.

"I wonder if they aren't smugglers," hazarded Caradoc,

"Must be up-to-date, to use submarines—a submarine would defy detection, wouldn't it?"

"And rich—nobody but millionaire smugglers could get together all this paraphernalia."

"I'll venture insurance is at the bottom of this fraud, Caradoc," hazarded Madden. "These swindlers insure a cargo, bring it to this place, reship it, sink the vessel, or repaint and rebuild it, then collect the insurance money—do you remember the log of the Minnie B?"

"No, I didn't read it."

"It stated her cargo had been reshipped—reshipped from the Sargasso. The entry may have been for the benefit of Davy Jones. Anyway, they are methodical scoundrels."

The lads fell silent as the hugeness of this nefarious business gradually dawned on them. For insurance swindlers and smugglers to work on such a large scale, very probably the organization branched over the whole civilized world. This vast shapeless vessel was a spider at the center of a great network of criminality.

"Say, the Camorras are mere infants in crime compared to these men," shuddered Leonard. "I suppose they murder the crews—drown 'em."

"They would have to get 'em out of the way somehow."

"Then Malone and all the tug's crew are..."

There was an expressive silence.

After a while Caradoc whispered, "Well, shall we try to get aboard?"

"Wouldn't do any good."

"It won't do any good to stay here."

"No, we can't hide on the tug always, and we can't run her engines. You don't know anything about marine engines, do you, Caradoc?"

"Very little. I couldn't run one."

For several minutes, the two adventurers sat in silence, watching the small erect figure of the guard pace and repace his short path. Presently Madden said:

"I've thought of one chance, Caradoc, to escape being starved or murdered."

"Yes, what's that?"

"It—it's almost too wild to propose, but it's all I can think of. As far as I know it's absolutely our last chance."

"Go on, go on," urged the Englishman impatiently. "I don't know of any way out whatever."

"If we could slip aboard there and—and—well, kidnap somebody who knows how to run our engines, bring him back to the tug, fire up and make a race to South America—but there's no sense to a scheme like that. Captain Kidd himself wouldn't be up to it."

A long silence followed this ultimatum, then Caradoc said, "Oh, it's possible, I suppose. The mathematical formula of possibility would work out about ten million chances to one that we lose."

"Yes, I know it's risky."

"And how do you hope to get in past that guard?"

"We'll have to climb up the ladder right under him, hang there until he is on his up-deck walk, then swing inside and when he turns around we could be simply strolling up the deck toward him. There must be a lot of fellows on such a big ship. Maybe he doesn't know them all."

"Why do you want to stroll toward him?"

"Because if he saw us walking off in the other direction, he would know we had not passed him, and so we must have come up the ladder."

Caradoc shook his head in the darkness. "I'm going to try to jump on that guard when he turns his back, and down him."

"He'd give an alarm sure. We mustn't disturb him till we get ready to leave, then let him yell."

"What you are planning, Madden, is simply impossible. I like to be as conservative as possible."

"We can turn around and row back to the Vulcan—and starve."

"Go ahead to the accommodation ladder. However, it's impossible."

As the two moved silently nearer a murmur of machinery in the vast fabric came to them. As their tiny boat swung in beside the high hull, they could hear this noise quite plainly, and they trusted to this rumble to screen their operations somewhat. They ceased paddling and allowed the dinghy to drift against the iron side of the vessel. They could no longer see the deck and the guard, owing to the swell in the high metal wall. But presently they came to the rope ladder which they anticipated hung below the guard's station.

Madden caught this and tied the dinghy to it with the crawly feeling of a man who expects to have a gun fired at him the next moment.

Caradoc came up and the two adventurers stood in the boat's prow, both holding to the ladder.

"I'll bet that scoundrel shoots down," whispered Leonard, "before we get halfway up."

"Don't talk so loud—are you ready to try it?"

"What are you going to do—jump on him?" breathed Leonard.

"No, your plan. If you see he is going to shoot you before you get inside, jump backwards and dive."

"And remember to go far enough out not to hit the dinghy."

"Good."

Madden stared up into the mysterious vessel, caught the ladder and swung himself silently onto the rungs. Caradoc mounted close behind him. They had mounted only two or three steps, when a sudden terrific report thundered above their heads.

It was so unexpected, so violent, that the two boys almost tumbled into the sea. The next instant they found themselves wrapped in an atmosphere of hot, stifling steam. They clung to the rungs in a veritable steam-bath that roared and plunged around them. When Madden collected his senses, he realized that it was merely a safety discharge from the boilers. The main steam pressure did not strike them, but they swung in the hot wet fringe of the exhaust. Had they been ten feet farther aft, they would surely have been boiled to death. As it was they were immersed in uncomfortably hot vapor.

They clung, rather unnerved by the uproar, enduring the heat for four or five minutes, when suddenly an idea occurred to Madden. He leaned down to Caradoc and shouted in his ear.

"How about going up now? Couldn't see us in this steam."

For reply, Caradoc shoved his friend upward, and so they scrambled aloft like two monkeys.

Fortunately for them, the night was windless and the white steam drifted straight up and as it rose, it spread out in an impenetrable fog. Cloaked in this vapor, the two adventurers scrambled up some thirty-five feet to the first deck. The steam was thick inside the rail. Covered by the noisy shriek of the exhaust, they jumped inside the promenade without being heard or seen, and a moment later, they dropped arm in arm, like two casual strollers, and moved up deck.

Two minutes later, when the roaring exhaust had ceased and the vapor had cleared away, the guard with the gun could never have guessed that the two men he saw slowly promenading the deck had drifted over the rail, out of the night, with the clouds of the noisy exhaust.

Neither of the lads so much as glanced at the sentinel as they strolled past him. Caradoc was saying in the low tones men use when conversing in the darkness:

"Do you suppose that fellow knows anything about engines?"

And Madden replied just as confidentially, as he sized the gun man up out of the tail of his eye, "No, I'm sure he doesn't. An engineer never has to stand guard."

"How are we ever going to spot an engineer?"

For the first time since starting, a little thrill of the joy of adventure crept into Madden's heart. He felt like a ferret venturing into a rat's den.

"Why you can tell an engineer easily," he murmured. "You've seen 'em, oily fellows, with black smudges."

"That describes a fireman, too."

"No, a fireman's not so oily and is more cindery—then we'll know one by his cap."

"Certainly," breathed Smith. "I hadn't thought of that."

Notwithstanding his danger, Madden could not help smiling as he moved along after the fashion of a careless stroller, when he was really keenly alert for a man with an engineer's cap.

The two youths were walking up a long deck, dimly lighted by small incandescent bulbs placed on the inner surface of the outside stanchions about thirty feet apart. Each bulb was carefully blinded from the ocean by a sheath, which confined its glowworm radiance exclusively to the promenade. On the inboard side were a long series of port holes, likewise hooded from observation. Some were aglow, others dark.

The deck, rails, cabin walls, ports, hoods, joists of the top-deck were newly washed and scrupulously clean. Fifty yards up-deck, where perspective and the sheer of the ship gave the promenade the appearance of a long, up-curved tunnel, the boys caught sight of a gang of men scrubbing down deck. A little beyond the scrubbing gang, some garments fluttered on a line drying in the night air.

As they drew nearer, Madden perceived they were muscular men, with faces bronzed by tropic sunshine. Some of their necks and cheeks were peeling, as if from sunburn. On the whole they had a healthy, hearty appearance that fitted in badly with Madden's theory of murderers and thieves. Instead of a piratical aspect, the promenade bore a strong resemblance to a deck scene on some crack transatlantic liner, except for the blinded lights and ports and the armed guard.

The wanderers passed the scrub gang without trouble and came to the drying laundry. The number of these shirts and trousers and under clothing suggested the hulk must contain a large number of men. If these men were smugglers and insurance swindlers, they had systematized their life after rigid military discipline.

They moved through the laundry with fading hopes of kidnapping an engineer from such a formidable institution, when they were startled by a human laugh. It sounded in their ears and was as unexpected as a shriek in church. For an instant they thought they were apprehended. Then they understood the sound came from one of the lighted ports.

They moved softly among the shirts and trousers until they reached the suspected port. Inside they heard a very trivial conversation in English.

"I'm after that jack of yours, Captain Cleghorne," declared a thick voice with a laugh.

"I played low, remember that,"

A silence, then a burst of laughter.

"He ran that jick over your king!"

Leonard stood beside the port blind making a tantalizing effort to recall something. Where had he heard the name "Cleghorne?" He repeated it mentally several times.

"Cleghorne, Cleghorne——" of a sudden it came to him. He had never heard it, but had seen it framed in the license that hung in the chart room of the schooner, Minnie B.

With a heart thumping against his ribs at this strange and amazing coincidence, the American ducked his head carefully under the port hood and looked in.

For a moment his eyes were blinded by electric lights. Then he observed a group of men sitting around a table playing cards. They were in obviously comfortable spirits, nothing criminal or warlike. One was a long cadaverous figure that suggested to Madden, Cleghorne, the Yankee commander of the Minnie B.

When his eyes strayed across the table to Cleghorne's partner, Leonard's knees almost crumpled in surprise. He was looking at the old commander of the floating dock, Mate Malone.