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Contents

The Lost Oasis

The New York water front was in the grip of excitement. Expectant, curious crowds milled in the district, and more were arriving.

Nearly every pier end—these offered the best views of the harbor—held a cluster of staring individuals. There was much talk, and the watchers bought numerous newspapers.

Perfect strangers argued over the headlines as though they had been life-long acquaintances. These discussions always ended with both participants fixing intent stares upon the bay surface.

The absence of a moon made the early evening darkness rather murky. Many spectators secured binoculars and telescopes from hawkers who offered these articles for rent. Newsboys were yelling themselves hoarse. Peanuts, pretzels, hot dogs, and soft drinks were selling fast. But even the peddlers frequently took off long enough to scamper out on the piers and gaze at the bay.

Taxi after taxi crowded down to the water front, horns blaring, and unloaded passengers. Often as not, the drivers deserted their machines and hurried out on the wharves to watch.

Many of the taxi riders were newspaper reporters and cameramen, the latter burdened with equipment for taking flashlight pictures.

In the general hubbub, it was doubtful if any one noticed one cab which behaved differently than the others. For one thing, this machine did not head for the center of excitement, but made for a spot where warehouses cast deep shadows.

Once, in signaling a turn, the driver held out his hand. The hand was enormous. Indeed, it was such a huge hand that a motorist, an observant fellow, who chanced to be driving behind, blinked in amazement.

The cab pulled to a quiet, furtive stop in the gloom.

A traffic cop hurried up, calling: “Hey, fella, who d’you think you are? This is no-parking zone along here!”

The amazingly big hand of the driver swung out of the window, the massive thumb jerked expressively at the rear seat of the cab, which was in darkness.

The cop was puzzled, but he obeyed the invitation to inspect the taxi passenger. He tugged the door open, and used his flashlight. When he saw who occupied the cushions, his eyes flew wide. He stepped back and executed a smart salute.

“Begging your pardon, sir!” he exclaimed. “I didn’t know who it was! You can park anywhere, of course!”

The mysterious personage in the rear of the cab did not speak.

Shifting his flashlight from one hand to the other, the officer seemed to be striving to swallow an overpowering curiosity. But it got the best of him.

“I thought—that is, the newspapers have been saying you were out of town,” he stated uncertainly. “No one has been able to find you!”

“I returned to the city less than an hour ago.” The mysterious man in the cab had a remarkable voice. It was pleasant, yet it possessed a quality of vibrant power which was instantly impressive.

The cop saluted again. “If I can tell you anything about this strange business, I’ll be glad to do it!”

“Do you possess any information the newspapers have not published?”

“No, sir. The darn newspaper reporters know as much as we do, and they’ve smeared it all on the front pages. That’s why there’s such a crowd down here.”

“I have read the papers,” said the personage in the taxi.

The officer shifted uneasily, then finally mastered the determination to suggest, “The police are naturally curious about this affair, so we’d be mighty glad to know anything you can tell us.”

A pleasant laugh came from the man in the cab. “This is as much a mystery to me as to anybody, officer.”

The cop offered: “I thought perhaps your five associates——”

The driver—he of the enormous hands—interrupted in a voice so deep it almost sounded as if a lion had started roaring.

“We don’t know anything more than the newspapers!” he declared. “A radio message came from the steamer Yankee Beauty, in mid-ocean, seeking to get in touch with Doc Savage. It was signed simply, ‘Imperiled!’ We radioed back that Doc was out of town, and that nobody could locate him. The next thing we knew, this ‘Imperiled’ person had gotten in touch with the newspapers and offered the reward.”

The officer peered at the big-fisted driver. “You are Renny—Colonel John Renwick, the engineer, aren’t you? I should have recognized those fists.”

“That’s right,” said Renny.

Once more the policeman addressed a salute to the personage in the rear of the cab. “Anything you wish me to do, Mr. Savage?”

“Just don’t advertise the fact that I’m around here!”

“Very well, Mr. Savage!”

The cop drifted away.

There was some movement in the taxi. Then the remarkable passenger got out. From time to time, the headlights of distant cars splashed faint luminance over the vicinity. These sporadic glows disclosed the figure of Doc Savage.

A great man of bronze! His appearance was the more striking because, having shucked off a robe, he stood clad only in a bathing suit!

The muscular development of the bronze man was such as to command attention anywhere. Sinews wrapped his form like great cables. Their size, the way they seemed to flow like liquid bronze, denoted a strength little short of superhuman. Yet, because all the muscles in his giant figure were developed to an equal degree, Doc’s form possessed an unusual symmetry. There was none of the knotty, bull-necked look of the professional strong man about him.

Perhaps the most impressive thing about him were his eyes. They resembled pools of fine flake gold. And there was in them a quality of power and determination. They seemed to radiate limitless energy.

Doc took from the cab a bag which was fitted with a waterproof fastener.

Renny, still seated in the cab and with both big hands resting on the wheel, asked: “Want me to wait here?”

“That’s right,” Doc told him.

It was only a few seconds later that Renny glanced around, some question on his tongue. But he did not ask it. He blinked.

Doc Savage was gone—swallowed silently by the evening darkness. There was no sound, no stir, to show what direction he had taken. After the one blink of slight surprise, Renny settled back to wait. He was accustomed to the uncanny silence with which Doc Savage moved.

Long association with Doc had made Renny—and also the other four men who comprised Doc’s group of five aides—accustomed to the unusual things which the giant bronze man did. Feats which, if given publicity, would have been good for newspaper headlines, were taken without undue surprise by the five.

A man of mystery, the newspapers called Doc Savage. This was because it was next to impossible to interview Doc. To the reporters, he was one of those rarities—a man who really did not want to see himself splashed all over the front pages.

Rumors about Doc’s feats were plentiful, however, and from these some of the most inventive scribes had turned out yarns which, although a bit careless of the facts in spots, made interesting reading. They ascribed to Doc the ability to do almost anything. Since the bronze man was something of a phantom, about whom few facts were obtainable, the writers let their imaginations run riot.

Few knew it, but the laugh was on the reporters. This man of mystery, this strange giant of bronze, was a personage every bit as remarkable as they depicted. The truth would have surprised nobody more than the reporters.

Doc Savage was, had the facts been published, a man of wonders, as well as probably being the supreme adventurer of all time.

Renny, seated in the cab, was not thinking of these facts. He was straining his ears to understand the headlines the distant newsboys were shouting. The words were loud enough, but the newsies needed a few lessons on how to speak distinctly.

Renny at length ascertained what they were shouting.

“W-u-x-tra! P-o-i-per!” they bawled. “Advertisement offers one million dollars reward for information leading to location of Doc Savage!”

Renny had a sober, puritanical face which habitually bore the expression of a man who greatly disapproved of the world in general. But now a wide grin warped his features.

“A million reward!” he chuckled. “I don’t wonder that the crowd came down here to get a look at the party who would offer a reward like that!”

Renny was not exactly awed at the size of the sum—he was considerably more than a millionaire himself. However, the idea of a million-dollar reward was astounding. It was somewhat unbelievable. Privately, Renny thought there must be a joker somewhere.

His ears suddenly caught a new headline—one which the newsboys were not yelling very much.

“Ghost Zeppelin sighted in Maine!” was the cry.

Thoughtfully, Renny’s big knuckles tapped the steering wheel.

“A ghost airship!” he muttered. “That’s almost as fantastic as this million-dollar reward business! I wonder if the two can have any connection? Probably not! Anyway, somebody up in Maine must have seen a cigar-shaped cloud and let their imagination get the best of ’em!”

This explanation of the spectral Zeppelin seemed the most likely one. Indeed, several newspaper reporters standing on the end of a pier were echoing exactly the same idea.

“Forget the Zeppelin!” one scribe snapped at his companion.

The second news hawk was only a fledgling at the game, a cub newly out of journalism school.

“But the airship is a good story!” he objected. “Think of it! A mysterious Zeppelin! What could its mission be?”

“Maybe it’s comin’ down from the north pole to get a bunch of dumb cubs and take ’em on a visit to Santa Claus!” gritted the older head.

“But that Zeppelin——”

“Shut up!” roared the other. “When we get back to the city room I’m gonna drown you in a paste pot! Zeppelins! Zeppelins! Blazes with ’em! Here’s the hottest story of the year, in case you don’t know it! And it seems you don’t!”

“Publicity stunt!” jeered the cub. “Probably this Doc Savage offered the reward to himself, just to get his name in the paper!”

The older reporter made a gesture of tearing out his hair in rage. “Am I burned up! Am I a cinder! Your head will never make anything but a paperweight!”

The cub was not fazed. “It looks like a publicity stunt to me! The idea of anybody offering a million dollars to get hold of any man is ridiculous!”

“Did you ever interview Doc Savage?” the other asked fiercely.

“No.”

“Did you ever hear of anybody who had interviewed ’im?”

“No.”

“Then shut up! Doc Savage hasn’t been interviewed because he don’t go for publicity. That shows this is not a stunt!”

The cub scratched his head. He was obviously impressed.

“Just what kind of a bird is this Doc Savage?” he asked curiously.

“Didn’t you read my by-line story in the bulldog edition?” snorted the other.

“Yes. You told me to do that so I’d know how a good reporter writes, but I don’t mind telling you I thought it was lousy. Was what you put in the story all you know about Doc Savage?”

“Just about,” replied the older head, deciding to be patient with his understudy. “Savage don’t brag about himself; but people who have met him—people he’s helped—have told plenty. Some of it is hard to believe.

“For one thing, they claim this bronze guy is qualified as a specialist, not only in surgery and medicine, but in electricity, chemistry, geology, engineering—in about everything else! A specialist, mind you! Not a dabbler! They say none of the big shots in those lines are superior to Savage in learning. He can tell ’em all things about their own rackets.”

“I don’t believe it!” confided the cub.

“Well, that’s your privilege. They say furthermore that Samson was a piker alongside this guy Savage when it comes to physical strength. They say Savage can take a horseshoe and tie it in knots.”

“I don’t believe that, either!” said the cub.

The other glared. “D’you believe anything I tell you?”

“No,” grinned the cub. “They told me at the office that you were the biggest liar on the paper.”

The veteran gnashed his teeth, but his mock rage gave way to laughter.

The searchlight of a tub swept the bay at this moment, and both reporters staring at it, forgot their conversation.

A short distance from shore, a small steamer was visible. The vessel was primarily a freight carrier, but her superstructure held passenger accommodations. She was neatly painted. As the searchlight swept the craft, the lettering on the bows was momentarily readable:

“That’s the tub!” ejaculated the older reporter. “We’ve got to get aboard and interview the mysterious party who signed himself ‘Imperiled!’ and offered the reward. Imagine what a story must be behind that! I’d give a lot to scoop these other birds on the yarn!”

“Why isn’t the steamer tying up at the pier?” asked the cub.

“The company which owns her is small and has only one pier, which is occupied by another boat of the same line until midnight; then the boat sails. The Yankee Beauty will come alongside the dock when the midnight boat leaves and makes room.”

The veteran reporter cast a wily glance at other gentlemen of the press and their photographers, who were near by. Then he nudged the cub. “Let’s go!”

The cub exclaimed, “But what——”

“Sh-h-h-h!” The journalist dean guided his satellite away from the other scribes, taking care that their exodus attracted no attention. When well out of earshot, he made explanations.

“I’ve got an idea!” he whispered. “We’ll rent a launch and go out to the Yankee Beauty. We’ll interview whoever offered that reward, or know the reason why!”

“But the captain of the Yankee Beauty sent a radio message saying he would not let any reporters aboard! And when the ship reporters tried to go aboard down the bay, when the boat stopped at quarantine, they were prevented.”

“I know all that. The steamer captain was helping the person or persons, who offered the reward, to avoid publicity.”

“They’ll kick us off if we try to go aboard!” declared the cub.

“Not me!” boasted the other. “I’ve never seen the place yet that I couldn’t get into!”

The two newspapermen moved off in search of a small craft which they could rent. They kept in the shadows, so as not to be seen by other members of their profession.

They were passing a darkened warehouse when the cub gave a violent start. Leaning forward, he peered into the murk.

“Hey!” he ejaculated. “I just saw a naked man!”

“Where?” demanded the other.

“Over there!” He pointed—but there seemed to be little more than a heavy gloom. He explained: “I didn’t get much of a look——”

The older man snorted unbelievingly.

“First it was ghost Zeppelins, and now it’s ghost men!” he growled. “You didn’t see anything! Come on! We’ve got to find a small boat!”

The cub permitted himself to be led off. He was not positive he had actually seen a form.

The young fellow had forgotten to mention the most important detail—the unusual bronze color of the man he had seen. Had he spoken of that, his more experienced companion would have known instantly that the phantom figure was real—that it was Doc Savage!

When the two reporters had moved on, Doc Savage appeared from a recess into which he had stepped to avoid discovery. He approached the water, keeping to the shadows. His bathing suit was almost the color of his bronze skin, and both blended well with the night.

Halting where small waves sloshed gently against wharf piling, he opened the waterproof bag which he carried. Out of this came a luminous-dial compass fitted with a wristband. He donned it.

The next object to appear was the end of a flexible hose, equipped with a mouthpiece, and terminating in an artificial “lung”—the latter contained in the bag. There was also a small metal clamp for holding the nostrils closed.

Doc grasped the mouthpiece in his teeth, fitted the nose clamp, and adjusted the oxygen-feeding and breath-purifying mechanism in the bag. Then he closed the container, sealing it to make it waterproof. He slung it tightly to his back with straps provided for that purpose.

Hardly a splash sounded as the giant bronze man entered the water. He swam far beneath the surface, using an experienced, easy stroke. He glanced often at the luminous, watertight compass, so as to keep going in the direction he desired.

Doc Savage was headed for the little steamer, Yankee Beauty, to investigate the source of the fabulous reward. He was taking this unusual means of reaching the ship because he wanted to learn whether there was anything sinister about the fantastic offer. He desired to know what was back of it before he showed himself.

There might conceivably be men who would pay a million dollars to have Doc Savage killed.

In a way, it was part of Doc’s life work to make enemies. Many of those whom he antagonized were powerful. Doc played no favorites. Doc’s career, his purpose in life, was a strange one. He helped those who needed help, and punished those who deserved it. He traveled to the far corners of the earth in doing his work.

Naturally, his career was one calculated to make bitter foes of all evildoers. So Doc was taking no chances about this fantastic million-dollar reward business.

It was nothing unusual for a bad man, fearing Doc’s vengeance, to come seeking to murder the bronze man. This might be such a plot.

No ripple appeared on the bay surface to betray Doc’s presence, although searchlights frequently sprayed the water. He made great speed, a speed few professional swimmers could have equaled.

Doc was a wizard in the water, just as he was a wizard at many other things. His life work was one which called for the abilities of a superman, and Doc had been trained from the cradle, that he might have the strength to arise to any occasion. Each day, he went through an intensive exercise routine to develop his great brain and body. Two hours of intense practice!

There was no mystery about Doc’s powers. His terrific daily exercise accounted for them.

The necessity for a sanctum in which to study, that he might periodically increase his vast fund of knowledge, had led Doc to establish a mysterious retreat known as his “Fortress of Solitude.” None but Doc knew the whereabouts of this place, or what amazing scientific equipment it contained. No human could get in touch with Doc during the periods when he retired to his retreat for study. His strenuous mental labors brooked no interruption.

Doc had returned to-night from his Fortress of Solitude. Just how thoroughly a mystery his retreat was could be realized by the fact that not even an offer of a million-dollar reward had located him. Doc’s five men, those closest to him, could not find him!

Deciding he was near the Yankee Beauty, Doc stroked to the surface. He had calculated well. The ship lay only a few yards distant.

Doc sank once more, and when he came up, he was near the stern.

He removed the artificial “lung” and placed it in the bag. Out of the container, he took a coil of thin, stout silk fine. To one end of this was affixed a grapple hook of light alloy metals.

Doc flipped the grapple upward. It dropped over the rail and hooked securely.

The silken cord, because of its small diameter, would have presented quite a problem to an ordinary climber. But so toughened were the big sinews in Doc’s hands, that he gripped the line and climbed it with what looked like comparative ease.

He surmounted the rail, making no noise, and whipped behind a near-by capstan, which was nearly as large as a barrel. Lurking there, he wrung water out of the skirts of his bathing suit. His bronze hair, straight and lying tightly to his head, possessed the remarkable quality of seeming impervious to water—like the pelt of some water-dwelling animal. Scant moisture clung to his fine-textured bronze skin.

Doc was soon dry enough that he did not leave wet footprints on the deck. A great form which seemed to flow from shadow to shadow, he glided forward. The waterproof bag reposed under an arm.

Doc was hardly out of sight when a creeping figure appeared around the opposite corner of the deck house. A man! The fellow carried a large revolver, cocked for a quick shot.

He was tall, but with a body so wasted that it was composed of little else than bones. His skin was unnaturally white, as if it were a sheet stretched over his bony frame. His eyes were feverish, staring, sunken far in his head. He was not an old man—yet his hair was entirely white! A man physically broken!

It was apparent he had discerned some movement on the deck, but did not know what it meant. He crept slowly ahead.

A distant searchlight, its glow reflected by the white-deck house, lighted the deck faintly.

The skulking man discovered the damp spots where water had dripped from Doc’s bathing suit. The sight set him shaking as with the ague.

Whirling, he fled down the deck. His eyes roved incessantly, and he pointed his gun at every patch of darkness. His movements showed the grip of a consuming terror.

He made his way to a passenger cabin. He rapped twice on the door, then made a scratching noise with his finger nails. A signal!

“Who is there?” asked a shaking, scared voice from within the cabin.

“Eet ees me—Jules!” gulped the first man. “Let me een, M’sieu’ Red! Sacre! I have ze worst of news!”

The cabin door opened, framing a man who also held a revolver. This individual had a great, bristling thatch of fiery red hair. Once he had been stocky, powerful; but now he was hardly more than a gaunt frame of bones.

They were strangely alike, these two men, with their wasted bodies and their haunted, ridden faces. It was as if they belonged to the same brotherhood of terror. Both were broken men.

“What is your bad news, Jules?” asked the flame-haired one.

Jules shivered. His eyes rolled.

“Let us go to ze Lady Nelia,” he suggested. “Eet ees better that we three be together, oui.”

This seemed agreeable to “Red.” He and Jules moved down the passage a few yards, where they gave the knock-and-scratch signal upon a stateroom door.

The panel opened slightly, to disclose a gun muzzle.

“Oh—it’s you two!” said a musical feminine voice. “Come in.”

The young woman who admitted them, presented a striking figure. Her features were aristocratic, finely molded. She was as tall as either of the men, and an athletic grace marked her movements. Her hair and eyes were shades of brown; her lips were an inviting curve.

She was a queenly beauty—yet there was in her manner an air of restrained panic, a pervading terror.

“What is wrong?” she questioned tensely.

“Lady Nelia—M’sieu’ Red!” Jules gasped. “Some one ees come on ze ship secretly! I am on deck and I t’ink I see somet’ing zat move! Me, I go for ze look. Sacre! I fin’ on ze deck wet prints of ze human foot!”

Lady Nelia’s slender hand tightened visibly on her gun. “It must have been Sol Yuttal or Hadi-Mot! No one else would have reason to come aboard furtively!”

Red hefted his revolver grimly. “Yuttal and Hadi-Mot know we’re on the Yankee Beauty, I guess.”

“Of course they do!” Lady Nelia agreed emphatically. “The Yankee Beauty was the only boat sailing from Africa around the time we reached the coast in our flight. The fact that several times we heard the moan of engines overhead shows they were trying to find the boat. The only thing that saved us was the cloudy, foggy weather which the Yankee Beauty met during the first days of the voyage. They could not locate the boat.”

“You’re right,” Red assented. “It was the infernal Zeppelin we heard. If it hadn’t been for the fog, they’d have dropped bombs and blown us to pieces.”

“But ’ow could Yuttal and Hadi-Mot arrive at New York ahead of us?” Jules put in.

“In the airship!” Red pointed out. “The craft is easily capable of a non-stop ocean flight!”

“They will seek to murder us, of course!” Lady Nelia said in a strained tone. “Should we finally escape, it would mean the collapse of their whole hideous project!”

The young woman’s words had the effect of shattering Jules’s remnant of nerve. He emitted a tortured sob of a cry, covered his emaciated face with his hands and sank trembling into a chair.

“C’est trop fort!” he moaned. “Eet ees too bad! Eet ees more zan I can stand! I am defeat!”

“Jules!” Lady Nelia exclaimed sharply. “Brace up! You cannot lose your nerve after we have gone through so much and gotten this far!”

Jules rocked his face in his hands, whimpering, “Non, non! We ’ave no chance to escape! Yuttal and Hadi-Mot will trap us. They will turn upon us zat horrible death which they command! Zat death of ze darkness! Sacre! Eet will get us! Me, I cannot stand ze t’ing no longer! I will end eet!”

The broken, dread-stricken voice had lifted hysterically toward the last. Mad desperation suddenly seized him. He whipped up his gun and clamped the muzzle against his own temple!

“Jules!” Red snapped out the yell as he leaped. He knocked the weapon aside. The two men struggled a moment. Red finally got possession of the revolver.

Jules fell upon a berth and lay there shaking, sobbing from weakness and shame.

Lady Nelia and Red exchanged glances. There was no disgust in their eyes—only pity for the man on the berth. A man who had undergone an experience so frightful that it had reduced him to a frail, tremulous hull!

In their eyes was some of the dread and despair which racked Jules, even though they tried hard to mask it.

Lady Nelia moved to Jules’s side and dropped a sympathetic arm across his trembling shoulders.

“You must not take a coward’s way out, Jules,” she told him gently. “You must help us. We must fight this thing out together.”

“Non,” mumbled Jules. “Eet ees no use.”

Realizing sympathy was not going to bolster Jules’s nerve, Lady Nelia tried another method. She drew away from the frightened man. Scorn came upon her aristocratic features.

“Very well!” she said bitingly. “If you wish to think only of yourself, do so. Red and I will carry on. We’re going to save those hundreds of poor souls whom we left behind, if it is humanly possible!”

Jules flinched under her words as if they were lashing whips.

“Those others—those others,” he mumbled. “Sacre! I have almos’ forget zem!”

“So I thought!” Lady Nelia snapped witheringly. “You would leave them helpless, doomed to a ghastly living death! In us rests their only hope. And you haven’t the nerve to carry on for them, even if not for yourself.”

The scathing words obtained the effect desired. Jules straightened his shoulders. He even managed a strained twist of a smile.

“Non, non!” he said grimly. “Jules will see zis t’ing to ze end. He promise zat he will not try again to take ’is own life.”

Lady Nelia smiled and slapped his shoulder. “That’s the attitude, Jules! Things are not so hopeless! If we can manage to keep away from Yuttal and Hadi-Mot, we should eventually find Doc Savage. Then, if what I have heard of Doc Savage is true, our troubles will be in competent hands.”

Jules nodded. “Oui! Our offer of a million-dollars’ reward should find ze M’sieu’ Savage!”

“The million reward offer found plenty of other people,” Red interposed, forcing levity into his voice. “From the crowd on shore waiting to get a look at us, you’d think a circus was coming to town. This Doc Savage can’t very well help but hear we’re hunting him.”

“Maybe zis M’sieu’ Savage ees not want to aid us,” Jules muttered. “Maybe zat ees why he not answer our pleas.”

“I do not think so!” Lady Nelia said sharply. “Although I do not know Doc Savage, I have heard of him. Getting others out of trouble and punishing those who need punishing is his life’s work. He turns no one down.”

Jules brightened somewhat. “Bon! Maybe ze radio operator ’ave at las’ get a message from M’sieu’ Savage. Me, I go see.”

“Be careful,” Red warned him. “I’ll stay here and guard Lady Nelia.”

Opening the door, Jules cast a nervous glance up and down the passage, then stepped out. The door closed, and the lock clicked as Red secured it.

The radio cabin was a little box of a structure on top of the deck house. Jules climbed a companion and made his way through a forest of ventilators and skylights. He kept his revolver in hand.

In the wireless room, Jules met disappointment.

“Sorry, no message,” advised the single operator on duty.

Disheartened, feet dragging, Jules descended a companion to the sun deck. The darkness there was intense. Lifeboats, cradled along the rail, shut off whatever illumination that might have come from street lamps on the near-by shore.

A ghastly event occurred there in the sepia gloom. A listener might have heard Jules take a few steps. Then came a strange sound! A hideous sound! It was low, fluttering. It might have come from some foul cloth, gently shaken, for there was a slight loathsome odor.

Jules heard. He screeched—a ripping cry of terror which seared the membranes of his throat! His feet banged the deck as he ran wildly! His gun crashed again and again! Frenzied shots!

The gruesome fluttering became louder, more violent. It overtook Jules. A thud! The sound was not loud.

Jules shrieked—shrieked again and again! It was as though he were crying out his very life stream. His screeching became a spasmodic gurgling. The gurgling weakened, weakened until at last nothing at all could be heard.

A dreadful silence followed. It persisted for some seconds.

From far off in the darkness sounded a series of tiny, squeaky whistles.

As if this were some sort of a signal, the hideous fluttering sound arose where Jules had fallen. There was a wave of the faint, nauseating odor. The fluttering receded in the darkness until finally swallowed by distance.

Excited shouts rang from various parts of the Yankee Beauty. The human screams had been heard below decks. Indeed, they must have carried to the crowds of curious individuals on shore. Feet clattered as men ran about searching for the source of the cries.

A flashlight beam, long and thin as a white cord, appeared near where Jules had met misfortune. Roving, the light picked up Jules’s form.

The man lay on his back, limbs contorted in frightful fashion. His hand still gripped the revolver. His eyes protruded, his teeth were bared. His expression was that of a death mask of ghastly terror. A single horrible tear gaped in Jules’s throat. Through this, it was evident much of his blood had been sucked.

For ten seconds—perhaps fifteen, an ominous silence enwrapped the deck.

Then there came into being a weird sound. It was totally unlike the eerie fluttering which had preceded Jules’s death. This note was inspiring. It was musical, yet possessed no tune.

A strange, mellow, trilling note, it might have been the song of some exotic bird, or the sound of wind filtering through a jungled forest. Most uncanny of all was the way the sound seemed to come from no particular spot, but from everywhere, as if the very darkness were giving birth to it.

A moment later, the flashlight beam widened as some adjustment on the lens was turned. The deck planks, white from much scrubbing, reflected a glow which disclosed the man who held the flash—a statuesque giant of bronze.

Doc Savage had heard the uproar, and had lost no time in locating its source.

The strange trilling was Doc’s sound, omen of his presence. It was part of Doc, that mellow sound—a small, unconscious thing which he did in moments of utter concentration. Only when he was thinking furiously, or on the eve of some course of action, did the trilling come. And rarely did Doc realize he was making it.

Doc’s small bag opened silently under his bronze fingers. He removed a small container. This held a rather bilious-looking powder.

Doc sprinkled a thin film of the powder upon the deck, covering an area several feet in all directions from the body. The instant the powder came from the container, it glowed brilliantly. It became like liquid fire!

But after the stuff came to rest on the deck, it ceased to glow—except in spots.

The spots which still shone marked the ill-fated Jules’s footprints, as well as Doc’s own!

Doc Savage had many weird chemical mixtures at his command. Probably none were more unique than this powder. It had the quality of glowing only when jarred. The jarring caused the particles to break, exposing new surfaces to the air, and these shone momentarily because of a reaction between the compound and the air.

Why the footprints glowed was simply explained. Jules and Doc, stepping upon the deck planks, had depressed the wood to a microscopic degree with their weight. The wood fibers, still in the process of springing back into position, were jarring the unusual powder enough to cause it to expose new surfaces to the air, thus creating a phosphorescent reaction.

In Doc’s hand was a ruler. He glanced about, intending to measure the murderer’s footprints.

But there were no prints!

Doc’s golden eyes roved unbelievingly. But there was no question about it! The only footprints were his own and those of Jules. He measured the soles of Jules’s shoes, to make sure.

His flashlight roved up and down the deck, then skyward. Above, and perhaps twenty feet sternward, there was a rigging cable. On this glistened a wet, crimson stain.

If the stain was blood, it seemed incredible that any human murderer could have operated from the cable.

Doc glided down the deck. Leaping, he grasped the hawser and mounted. The wet stain was human blood, beyond question! Clinging to the cable with one hand, Doc played his light along it.

The Yankee Beauty was an oil burner, and the hawser bore a layer of sticky soot which had been deposited by the oil smoke. Had any one climbed the cable recently, the soot would have been rubbed off. But it was not disturbed!

The stain on the line was inexplicable—unless some gory, aërial thing had brushed against it!

Doc doused his light. Men were running down the deck. Stewards. They carried storm lanterns. They passed below Doc, never realizing he was clinging to the cable over their heads.

“Hey—look!” gulped one of the sailors, catching sight of the horribly contorted body.

It required only two or three minutes for a crowd to gather.

“What’s this stuff on deck?” demanded a man, indicating Doc’s strange powder. “It shines whenever you disturb it.”

“What killed this man?” pondered another.

“Pipe his throat! That’s what got ’im!”

“Yeah! Looks like the work of a vampire!”

“There ain’t no such thing.”

“Who is he?” asked a fellow in the oily garments of an engineer.

“Name is Jules Fourmalier,” replied a steward. “He had cabin No. 12. A passenger.”

Doc Savage had been awaiting information such as this. He ran, hand over hand, up the cable. He made no perceptible sound. The waterproof bag was swinging upon his back.

Reaching a mast, he located a rigging line which led to the opposite side of the ship. He descended swiftly. A very few minutes later, he was before the door of Stateroom No. 12.

The door was locked. Doc’s bag disgorged a tiny kit of locksmith’s tools. The cabin door soon opened under his practiced manipulation. He switched on the light.

The place was a wreck! The rug was torn up; the mattress on the berth was literally shredded. The washstand had been taken apart. A life preserver had been ripped open and the cork stuffing whittled to pieces. The search had missed nothing.

Doc hardly moved from where he stood just within the door. His gaze missed nothing, however.

Offhand, it might have seemed impossible to gain from the condition of the room the slightest inkling of what the searcher had sought. But to Doc’s sharp eyes, several things had a meaning.

The fact that the backs of three or four books had not been ripped off told him the hunt had not been for anything in the nature of a paper. Otherwise, the search would have extended to the book covers.

A bottle of colored shaving lotion had been emptied so that the container might be inspected. The quick-drying liquid was still quite wet. The search had been conducted only a few minutes ago!

Doc decided to try for the prowler’s footprints. He got his chemical from the bag, decided the nap of the corridor rug would be the most effective spot for its use, and stepped outside.

He noted casually that the lock on the door was a spring type. Whoever had ransacked the stateroom had no doubt merely slammed the door in departing.

The powder blazed resplendently as Doc scattered it. Then, after it had settled, the luster slowly faded, except for patches where feet had recently depressed the rug pile.

Ruler in hand, Doc bent to measure prints immediately before the door.

Down the corridor some distance, a hand appeared from around a cross passage. It held an automatic. The gun leveled at Doc. It crashed noisily!

The powder flash flushed redly on the corridor walls. The report thumped like thunder, piling echoes into the corridors, the lounge and deep into the steamer’s vitals! The bullet screamed down the passage and hit—nothing but wall paneling!

Doc had vanished as though by magic. Literally disappeared from before the bullet! As a matter of fact, Doc had whipped from sight into Jules’s cabin even before the shot was fired.

The bushwhacker down the corridor had slipped off the safety on his automatic a moment before shooting. This had made a faint click, a sound Doc had heard. A single glance had shown him his danger. His reaction was instantaneous.

Another shot thundered, proving the gunman to be somewhat excited!

In the stateroom, Doc was delving into his bag. He brought out an object about the size of a small condensed milk can. He twisted a key on this, then hurled it down the passage toward the marksman.

The object began spewing a dense black smoke. This swiftly filled the corridor.

More shots slammed. Doc counted them. When the automatic had emptied a clip, he flung into the corridor. He sped the opposite direction of the gunman. Once clear of the pall from the smoke bomb, he found a short passage and a door which gave out on deck.

Behind him, he heard a great hissing and splashing of water. Spray and an occasional splatter of water even reached to where he stood.

The bushwhacker had turned the fire hose down the passage to blot out his fiery footprints, so they could not be measured!

Doc stepped out on deck. There was nothing in his manner to show he had just engaged in a grim joust with death. It was not his first peril. Nor was it likely to be his last. Hazards were his heritage.

From forward, a chorus of excited yells was sounding! The shots had interrupted the palaver over the body of Jules. But not one of the sailors seemed willing to do more toward investigating than bellow encouragement at his fellows.

Doc glided along the deck. He found the cross passage from which the shot had been fired and dashed his flashlight in, knowing from long experience that he could duck back before an accurate bullet could be driven at him.

The passage was empty. Doc tossed his flash beam up and down the deck. No one was in sight. He sprinkled a quantity of his powder on deck. The fiery imprints which appeared were somewhat shapeless. Nevertheless, they told him the gunman had been hopping on one foot, around which he had wrapped a padding—probably cloth.

A few spots showed where the unmuffled foot had been employed as a prop. But there was certainly nothing which offered identifying measurements.

Doc bent closer to the deck, golden eyes searching intently. A moment later, his bronze hand descended. It lifted, with a yarn of gray wool gripped between thumb and forefinger. The yarn had been caught under a deck splinter, and it showed the cloth, muffling the man’s shoe, was coarse, gray.

Doc now evidenced a desire to go forward, glancing several times in that direction. But the sailors still dilly-dallied about investigating the shots. They were not inclined to risk becoming targets.

“Fire!” somebody howled suddenly. “All hands fall to! Fire! Fire!”

Doc evinced no alarm, knowing the cries meant the smoke bomb smudge had been discovered. But not so the seamen around Jules’s body. They charged, aft, filled with visions of the ship’s burning, with the consequent loss of their jobs.

Not a man remained to guard Jules’s lifeless form.

Doc Savage hurried forward. Twice, he stepped behind lifeboats to escape the notice of running men. Reaching the murdered man, he began a swift search of pockets, something there had been no time to do earlier. The proximity of death did not bother him—his training as a surgeon had inured him to such things.

The contents of the pockets were meager. There were a number of coins. Dashing the flashlight on them, Doc saw they were silver piastres, coins of various denomination, together with some United States money. He examined the Arabic characters on the piastres.

“Egypt!” he said softly, voicing the source of the coins.

An inside coat pocket held the most surprising find of all. This was a small bundle of magazine clippings, snapped around with a rubber band. Doc examined the clippings curiously.

Each item had to do with Zeppelin-type airships. Evidently they had been snipped from shipboard copies of general science magazines, since they covered the newer developments in lighter-than-air craft.

Doc played his light on the clippings, many of which bore pictures. Some of these held penciled notations, usually reproductions of the new developments depicted, as if the dead man had sought to familiarize himself with them.

Included in Doc’s almost universal knowledge was a nice fund of information on the history of airship construction. He riffled through the sheaf of clippings, putting his learning to use.

He made a discovery. The scientific attainments which had come in for the unfortunate Jules’s attention, as denoted by the penciled sketches, had all been made within the past dozen or so years. It was as if Jules had been unable to secure information on airship development for that period, and had been catching up.

In one place, the lifting capacity of a gas compartment was accurately calculated, showing Jules had been an expert on lighter-than-air craft, even though a little out of date.

On a picture portraying an entire Zeppelin, Doc made the most interesting discovery of all. Near the bows of the craft, as if absent-mindedly penciled there, were the identification letters ZX 03.

The dead man had placed the caption there, it might safely be believed. The title of a Zeppelin! It must have played a vital part in the fellow’s past or he would hardly have penciled its designation upon the picture.

Doc made a mental note to look up the airship ZX 03.

Recalling the ransacked condition of Jules’s stateroom, Doc continued his search. Some one had wanted something Jules had.

On the man’s legs, below the knees, he found several knotty protuberances. Five of them, to be exact. These proved to be objects the size of small walnuts held in place by crisscrossed strips of adhesive tape.

Doc removed and investigated them.

Each object was an uncut diamond of the first water. The stones were undoubtedly of enormous value.

Doc appropriated the gems. They might be useful in his investigation, and he could later deliver them to the heirs of the dead man. Or to whoever was the rightful owner!

He thought deeply. Diamonds—Egyptian money—a knowledge of air ships a dozen years behind the times! The clews did not lead to any sort of a direct explanation.

From the stern, shouts drifted. The sailors had evidently discovered the source of the supposed fire. Officers were bellowing questions and contradictory orders which only added to the confusion.

The murderer—be he human or some diabolic vampire thing—would have no trouble moving about unobserved in the turmoil.

Stowing the diamonds in his bag, and slinging the container on his back, Doc moved forward in the gloom. He was going to confer with the captain of the Yankee Beauty, as well as the radio operator, to learn who had offered the million-dollar reward.

There came an interruption. Toward the stern, a shrill feminine cry pealed out! It was a voice saturated in horror! A door slammed noisily. The scream continued, coupled with noises of a struggle!

A blurred flash of speed, Doc shot forward. He rounded the deck house. His flashlight beam licked down the deck.

The luminance disclosed a ghostly sight—a vision calculated to bring a cold sweat! It was a scene which, had Doc not schooled himself through the years until he was proof against all emotion, the bronze hair would have crawled on the nape of his neck.

A woman was writhing about on the deck before a closed door—evidently the door which had slammed. Her hands fought the air above her, striking mad blows! With each frenzied swing, the woman cried out in horror!

Yet, there was no visible assailant near her! She was fighting thin air, as far as could be seen.

She seemed to realize this as Doc’s flash lighted the spot brilliantly. Springing to her feet, she stared straight into the blinding eye of the flash.

She was a remarkable beauty, brown of eye and hair, features thin and aristocratic. She was very tall.

The fact that this was Lady Nelia, was something Doc had no way of knowing. Nor, blinded by the light, could she see him.

Unable to distinguish Doc, Lady Nelia whirled and fled. She reached a door which gave into the lounge, wrenched it open and sprang through.

Doc Savage slid forward in silent, swift pursuit. He was not certain what had provoked the woman’s spasmlike behavior upon the deck. She might have fled through the door from some unimaginable horror and slammed the panel upon it. So hideous, so frightsome must have been the attacking thing, that she had kept on fighting, not realizing in her hysteria that she had escaped.

But there was another angle more important. The unknown who had shot at Doc a few moments ago had muffled one shoe in a gray coat of coarse weave.

The fleeing woman was wearing a coat of such description.

Suddenly the door through which the woman had gone whipped open again. A man sprang out. He was gaunt as a skeleton. Red hair was like a blaze on his head. He held a revolver.

The young lady was at his back.

“There!” she gasped, and pointed at Doc’s brilliant flashlight beam.

The red-headed man flipped up his weapon, yelling, “Put up your hands, you!”

They had—these two who were seeking Doc Savage—mistaken the bronze man for their enemy.

Doc Savage did not feel the urge to surrender himself, not knowing what the intentions of the young woman and the brick-haired man might be.

His flashlight beam seemed to collapse in mid-air as he switched it off. A noiseless leap to the right put him in the shelter of a lifeboat.

An angry grunt came from the man with the carroty hair. He produced a flashlight of his own and spilled its brightness down the deck.

“He jumped behind the lifeboat, Red!” snapped the young woman.

“Get indoors, Lady Nelia!” Red directed her. “I’ll take care of this bird, whoever he is. Did you get a look at him?”

“No. His light blinded me.” Lady Nelia made no move to seek safety inside the deck house, as she had been commanded. “I do not know who he could be. But he was acting suspiciously.”

Red growled: “We’ll darn soon find out who he is!”

Raising his voice, he addressed the lifeboat. “You—back of there! C’mon out! C’mon, or I’ll uncork a few bullets!”

There was no reply from behind the lifeboat where Doc had taken shelter.

Red repeated his command and threat to shoot. Getting no results, he advanced gingerly. His flashlight beam did a spooky dance, so shaky was the hand which held it. The revolver muzzle wavered, Red’s finger twitching.

In his tottering, terror-haunted condition, Red was a most unreliable foe. He might at any moment begin shooting in an excess of nervous excitement.

“Come from behind that boat!” he rasped, still hoping mere threats would get results.

No response. Red sprang around the prow of the lifeboat. His flashlight fanned a glare; his revolver menaced. Then his jaw fell. There was no one behind the boat.

Very few seconds had elapsed since the moment of Red’s appearance on deck. He was a little stunned at the idea of his quarry escaping from behind the lifeboat in such short order. There had been no splash to denote a leap over the rail.

Red leaned far out and cast his light downward. The black steel plates of the hull were unbroken below and for many feet toward the bow and stern—unbroken except for portholes. And Red well knew the portholes were not large enough to admit a man.

“Where could he have gone?” Lady Nelia gasped.

“Search me,” Red muttered, striving to quell the nervous twitching of his muscles.

Low voices became audible. The sound of them seemed to drift along the hull of the steamer.

Red cast his flashlight beam in the direction of the voices. The funnel of luminance disclosed a small launch alongside the landing stage amidships.

Two men in the launch were arguing heatedly with a sailor of the Yankee Beauty crew.

The pair of wranglers in the small boat were the two newspaper reporters—the veteran scribe and his cub understudy—who had decided on this means of reaching the Yankee Beauty. They had heard the shots, the screams and the other excitement, and were wildly anxious to get aboard.

The sailor who barred their way held a boat hook. He was promising to belabor the first man who set foot on the landing stage.

Red addressed Lady Nelia in a low voice: “We’ve got to get off this boat. Sol Yuttal and Hadi-Mot are aboard. The death of poor Jules shows that.”

“And the attack on me.” Lady Nelia shuddered violently and covered her face with her hands, as if to shut out a frightful vision. “I got out on deck and got the door slammed before the thing reached me. The horror of it must have made me hysterical, because I imagined the thing was still after me, even after I had shut the door upon it!”

“It’s too dangerous to remain aboard,” Red muttered. “We are almost helpless against Yuttal and Hadi-Mot and their devilish way of doing murder!”

He pointed at the launch holding the two newspaper reporters. “Let’s grab that boat and get away from here.”

Lady Nelia nodded. “All right.”

The two moved away, Red glancing over his shoulder as if still trying to fathom how the mysterious figure with the flashlight could have vanished from behind the lifeboat.

“Keep a sharp lookout!” Red warned uneasily.

“Right-o,” agreed Lady Nelia. “And let us make no more noise than necessary.”

Sailors came galloping along the deck, intent on investigating the feminine screams.

Lady Nelia and Red hastily entered the lounge to escape notice. They made their way to Lady Nelia’s cabin.

Lady Nelia tugged the stateroom life belt out of its rack. Her slender fingers explored and made sure that certain small, hard objects were still embedded in the cork blocks, under the canvas covering.

“My share of the diamonds are in here,” she said grimly. “Have you yours, Red?”

Red pointed at his own ankles. “I fastened mine to my shins with adhesive tape, the same way Jules did.”

“Let’s go!” suggested Lady Nelia, donning the life belt so that her hands would be free.

The two descended the main staircase, passed the doors of the dining room, and gained the deck from which the upper platform of the landing stage could be reached.

The sailor and the two reporters still argued loudly at the foot of the stage.

Red ran down the stairlike stage, holding his revolver out of sight behind his back. Reaching the side of the sailor, he whipped the weapon into view.

“Get back!” he rapped. “You two mugs in the launch—come on up here with this sailor.”

The two reporters stared, popeyed, into the revolver muzzle. There was an electric light at the top of the landing stage and it showed the weapon to advantage.

“Get a move on!” growled Red.

The scribes clambered from the launch. For once, they were both speechless. Trailing the seaman they retreated up the landing stage, passing Lady Nelia.

Both journalists gave the young woman admiring glances, in spite of the menacing gun Red held. She impressed them both as about the most entrancing bit of femininity they had seen in some time.

“She’s a wow!” breathed the veteran scribbler.

Lady Nelia and Red entered the launch. They had the little craft to themselves, the newspapermen having done their own piloting.

When Red showed unfamiliarity with the operation of the launch, Lady Nelia took charge of the controls. The facility with which she started the engine showed she possessed no little knowledge of machinery.

Lifting his gun, Red smashed the electric bulb at the head of the landing stage with a single well-placed slug. Both reporters had stopped on the upper platform to stare. They dived from view, thinking they were being shot at.

In the darkness, and over the noise of the launch engine starting, Lady Nelia and Red failed to discover a bronze hand which appeared at the stern of the craft. The metallic fingers of this hand made a silken line fast to the base of the inevitable flagpole socket on the stern.

Like a thing disembodied, the hand retreated, paying out the line. There was no audible splash—hardly a stir in the water. The two in the boat had no inkling of the bronze presence near by. The silk line was of a color which blended with the darkness.

It was this same silk line, the grapple affixed to the end, which had lowered Doc Savage to the water from behind the lifeboat. Once he had entered the water noiselessly, Doc had but to flip the line, dislodging the grapple.

Sinking below the surface, he had stroked a few yards away from the hull. Thus simply was his mysterious disappearance explained.

The launch got into motion. Doc gave the line a turn in the strap harness which held the waterproof bag upon his back. The straps were stout enough to hold.

He was towed after the launch. Lying upon his back, arching his powerful body, he created a surf-board effect. The speed of the boat mounted, yet he felt little discomfort.

Doc’s position in the water was such that he could see the Yankee Beauty. A winking light under the bows of the steamer caught his attention. A small boat! The light glowed again. It disclosed the figure of a man clambering down the anchor chain!

The fellow seemed to have a great basket of an affair tied to his back. The thing was so huge it was giving him great difficulty in his descent.

The light went out, and the strange sight was blotted from view.

The rattle of the launch exhaust, the gurgling roar of water past Doc’s trailing form, made it impossible to hear the conversation of Lady Nelia and Red. Whether or not they had glimpsed the mysterious little drama under the bows of the Yankee Beauty, Doc could not tell.

The launch headed for shore, angling northward a bit so as to land at a point less infested by curious spectators. This also happened to be where Doc had left big-fisted Renny and the taxi.

Some fifty yards from shore, Doc jerked a slipknot in the silk cord. This left him floating free in the darkness. He dug his hands beneath the surface in powerful and silent strokes.

No one saw Doc pull himself out of the water, although not many feet distant, some half dozen men stood rubbering at the Yankee Beauty.

Doc’s ability to move silently was almost uncanny.

Renny gave a great start when Doc appeared alongside the cab.

“Two people are just getting out of a launch down the street,” Doc advised swiftly. “They’ll probably want a taxi. Pick them up. Let me know what you learn about them and where they go.”

“Sure,” said Renny.

“And watch out!” Doc continued. “I am not yet sure whether these two are friends or enemies. Keep your eyes peeled. You may be attacked or they may be attacked. In the latter case, I want you to guard them.”

“Sure,” said Renny, and meshed the taxi gears.

The machine negotiated a turn, then loafed down the gloomy thoroughfare. Sure enough, Red ran into the street. In the cab headlights, he looked like a skeleton in clothing.

Renny, feigning the part of a hack driver, stopped and opened the door.

Lady Nelia and Red entered the machine. Lady Nelia had removed her life belt and was carrying it under an arm. Renny drove them away.

The taxi had not progressed half a block when a boat slammed noisily into a near-by pier.

Doc made for the sound. He had been listening to this boat. It had come from the direction of the Yankee Beauty. He thought it was the mystery craft he had seen under the anchor chain.

He saw two men spring from the launch. The pair ran forward. One carried an enormous wicker basket, Doc saw as they dashed through the milky glow of a street light.

The illumination also gave Doc a good chance to see what they looked like.

One of them was by far the fattest man Doc had ever seen. The fellow was hardly more than five feet in height, and he seemed almost that thick. He was a great, lardy ball, with flapping sacks of fat for arms and legs.

The fat man’s head narrowly missed being a part of his round body. It was hardly more than a hump. His mouth was a gigantic curve; his nose was enormous; his eyes were very large.

Ample features usually lend a pleasant aspect to the human face. They did not do so to this fellow. His features were so evil as to be appalling.

The other man was slender, flashily clad. He by no means missed being a handsome fellow. His brown skin and the cast of his lineaments caused Doc to think of the Egyptian coins he had found in the pockets of Jules.

If the second man was not an Egyptian, he was of some closely allied race. He wore a coarse-woven gray topcoat. This was wrinkled. Here, Doc hazarded a guess, was the man who had shot at him.

It was this fellow who carried the great wicker basket. It was rigged with sort of a harness—a strap over the forehead for easier carrying. The wicker was finely woven. There was no chance of seeing what was inside.

The pair passed out of the lighted area.

“Qawam, bil’agal!” puffed the fat man. “Make haste! We must not let them escape us, oh Hadi-Mot!”

“Akhkh!” grunted Hadi-Mot. “I travel as fast as I can, Yuttal.”

The two had spoken partially in a foreign tongue, partially in English. Doc’s studies had embraced most known languages. He had no difficulty recognizing this one. Egyptian!

The few words had also given him the names of the two—Yuttal and Hadi-Mot.

Doc set out after the pair. In Egyptian, he reflected, the name Hadi-Mot meant something like quiet death. Probably it was a nickname.

“Yallah!” Hadi-Mot cried out suddenly. “Tayyib! Good! They are in yonder taxi! I caught a glimpse of Red’s hair as the machine passed under the street light.”

“Imshi, imshi!” rapped Yuttal. “Step on it! We have got to get hold of another cab!”

Although Yuttal spoke the tongue fluently, it was apparent he was white rather than native.

The two sprinted across the street, trailing Renny’s cab. Doc followed them, gliding silently in the darkness.

He promptly encountered bad luck. A car came along the street and splashed him brilliantly with light. The driver was evidently something of a wag, for he blew his horn upon sighting the incongruous figure of Doc running in a bathing suit.

Yuttal and Hadi-Mot looked around.

“Wallah!” gulped Hadi-Mot. He and Yuttal halted.

Doc also stopped.

The motorist rolled on past, leaving the street rather dark.

Doc had observed a narrow alleyway to the left. He ran toward it, bare feet making his progress silent. The place was black and smelled of stale fruit. He loitered there, waiting to see what Yuttal and Hadi-Mot would do. He found out in a most unpleasant fashion.

Out of the gloom before him came a hideous fluttering sound. A soft, repellent pulsation! It approached with a swiftness that was terrible. With it came a faint, obnoxious odor.

Doc whirled and ran. He possessed an iron nerve, but he also had good sense. The simplest method of avoiding this mysterious horror was to get somewhere else quickly.

The fluttering thing was overhauling him! Sprint as he would, he could not outdistance it! The brick walls of the alley were high, unbroken, except for heavily barred windows and ponderous doors, most of which were probably padlocked.

The doors seemed the best bet. Doc veered for them. His bare feet landed on an expanse of pebbled metal, to the accompaniment of a faint clank. A manhole.

Doc braked to a stop, wrenched up the iron lid, and eased into the space below. He lowered the cover. The manhole was the entrance to one of the numerous tunnels carrying telephone wires, which run under New York streets.

Over Doc’s head, a faint scraping rasped at the manhole lid. Something gritted on the iron—it sounded like needles digging at the metal. The redolence of the thing, whatever it was, penetrated the crack around the manhole, reaching Doc’s nostrils.

With both big bronze hands, Doc kept a grip on the underside of the lid. It would take tremendous strength to lift the cover against his pull.

A series of tiny, squeaky whistles penetrated the noises atop the manhole. The scrapings and raspings stopped. There was a soft fluttering. The odious creature of the night was departing—answering the signal!

Doc sat where he was and kept a grip on the manhole. He listened. His ears possessed a sensitivity attained by few other men, thanks to the part of his daily exercise routine which was calculated to develop the ear mechanism.

He had an apparatus which made sound waves of frequencies, so high and low, the ordinary human ear could not detect them. As a result of years of practice, Doc had perfected his ears until the sounds registered. He could detect noises beyond the ken of others.

He heard no sound of further attack, however. At length, he quitted his retreat and searched the neighborhood.

Nothing did he find. Yuttal and Hadi-Mot had left the vicinity, taking their fluttering horror of the night with them. Perhaps they had followed the taxi driven by Renny and carrying Lady Nelia and Red. It was impossible to tell.

Doc hailed a cruising cab. The driver of this machine was stricken speechless by the unique sight of a gigantic bronze man walking the city streets in a bathing suit.

Doc gave him the address of one of the tallest skyscrapers in New York. The driver recognized this address. He made a correct guess at who Doc might be.

“You’re Doc Savage!” he gulped. “Say, mister, there wouldn’t be a chance of me collectin’ that million-bucks reward, would there? The dough was supposed to be paid to the guy that found you!”

“It happens that I found you,” Doc pointed out sardonically. “Anyway, you’re a few hours too late.”

Doc Savage’s headquarters, in New York, occupied the eighty-sixth floor of a spike of brick and steel which towered nearly a hundred stories above the street.

Doc, paying off his taxi, strode into the building. He was an incongruous spectacle in his bathing suit, but the hour was late and no one chanced to be in the lobby but an elevator operator. The latter was too well trained to make a remark.

“Are my friends upstairs?” Doc asked.

“Yes, sir,” said the elevator attendant. “Johnny and Long Tom came in some time ago. Monk and Ham just arrived. But there has been no sign of Renny.”

“Renny is out on a job,” Doc smiled.

“Monk and Ham were hot at it when they came in,” chuckled the operator. “I thought they were going to murder each other on the way up.”

Doc showed no concern over this ominous news. It was a rare occasion when “Monk” and “Ham” were not on the verge of violence, according to appearances. Actually, they were pals. They would have been lost without each other.

This state of affairs dated back to the Great War, to the incident which had earned Ham his nickname. As a joke, Ham—then known only as Brigadier General Theodore Marley Brooks—had taught Monk some French words which were highly insulting, telling Monk they were the proper salutation for a French general. Monk had used the words innocently—and landed in the guard-house.

But within a week after Monk’s release, Ham was hailed upon a charge of stealing hams. Somebody had planted the evidence. Never able to prove Monk had framed him, Ham rankled to this day over the incident.

Doc could hear them quarreling as he stepped into the eighty-sixth floor corridor. Ham’s snapping, caustic voice—Monk’s gentle, mild tones!

It was deceptive, that voice of Monk’s. It did not match his appearance. The bellow of a bull ape would have been more fitting to Monk’s looks. He was a great, hairy gorilla of a man, with arms inches longer than his legs. He weighed near two hundred and sixty pounds. His strength was terrific.

Monk might resemble the missing link, but there was a keen brain back of his beetling brows. He was one of the greatest of living chemists.

Ham was the physical opposite of Monk. He had sharp, intelligent features. He wore the latest and most fashionable clothing obtainable. He was never seen without a straight, somber-looking cane. This was, in reality, a sword cane with a blade of finest steel.

Ham looked his station in life. He was one of the wisest lawyers Harvard had ever matriculated.

“You keep on riding me, you hairy accident,” Ham was promising Monk, “and one of these days I’m going to whittle you into the shape of a human being!”

Monk’s snort of mirth shook all of his gorillalike hulk. “Yeah? Ain’t that a nice way to talk? What’ve I done?”

Doc himself wondered what latest act of Monk’s had got under Ham’s skin. He soon saw what it was. Monk was wearing an outfit of clothing, from hat to spats, which exactly matched Ham’s garb. On Ham, the somewhat flashy attire was sartorial perfection. But the garb made the homely Monk look like he was rigged up for a carnival spieling job.

Ham was touchy about his garments. This had burned him up.

Both men sprang to their feet when Doc entered.

Doc lost no time getting down to business. “Where’s Johnny and Long Tom?”

These two men answered that question by appearing from an inner room. The room was a library, holding one of the most complete assortments of scientific books in existence.

Johnny—William Harper Littlejohn on his business stationery—was a tall man who seemed half starved. His coat hung on his bony shoulders as if on a hardwood cross stick. He was a geologist and archæologist, formerly of the natural science department of a famous university. There was little about the rocks and minerals composing the earth that Johnny did not know.

“Long Tom” seemed the weakling of the crowd. He was undersized and also had an unhealthy complexion. As Major Thomas J. Roberts, he had a world-wide reputation as an electrical wizard.

In their particular lines, the men were almost unexcelled.

The four of them, along with the absent Renny, made up Doc Savage’s group of five aides. Together, they comprised probably the strangest company of men to be found. They were together for one purpose—to go to the ends of the world looking for excitement and adventure, striving to help those in need of help, punishing those who deserved it. They might have been designated as the firm of Trouble Busters, Inc.

The four men waited for Doc Savage to speak.

“It looks like we have a little job ahead of us,” Doc told them grimly. “That’s why I summoned you fellows to meet here as soon as I got back and saw that fantastic million-dollar advertisement in the newspapers.”

He got extra clothing from a locker and began donning it. The men gathered close. They had not seen Doc for many days—had no idea where he had been, except that he had been away studying in his mysterious retreat of solitude. They were delighted that he was back.

Speaking swiftly, Doc told them what had happened.

He drew the diamonds from his waterproof bag and placed them upon a costly inlaid table with which the outer office was furnished.

“Johnny,” he said, “here’s a job that you, as a geologist, will find right up your alley. I want you to take these diamonds and examine them. Stones from various parts of the world possess different characteristics. See if you can find where these came from.”

Johnny picked up the diamonds. He removed his eyeglasses. The left lens of these spectacles was in reality a powerful magnifying glass. Johnny’s left eye had been rendered useless in the World War, and he wore the magnifier there for convenience.

He inspected the gems briefly, then said: “They’re from Africa.”

“I reached the same conclusion,” Doc told him. “But what part of Africa?”

“That will take some research,” said Johnny.

He entered Doc’s library, knowing he would find in the tomes there, all the data he needed.

Doc now addressed Long Tom, the electrical wizard. “We must perfect a means of fighting that fluttering death of the darkness, whatever it is. Suppose you rig up a projector of infrarays which are invisible to the naked eye. Then equip us with fluoroscopic spectacles sensitive to the rays.”

“I get you.” Long Tom grinned. “You want us fixed up so we can see in the dark, without using an ordinary flashlight or searchlight.”

“Exactly!”

Long Tom passed into the library, then into a chemical and electrical laboratory beyond. This laboratory was fitted completely with modern devices, as well as many of Doc’s own inventions, which were entirely unique.

“What about me?” Monk questioned, anxious to use his chemical skill.

“Suppose you concoct powerful, quick-spreading gas for battling the infernal things,” Doc suggested. “Make a vapor which will produce instant unconsciousness, yet which will not prove fatal. And you can look over our collection of gas masks to make sure they’re serviceable.”

Monk lumbered for the laboratory.

Doc now spread upon the table the clippings from science magazines which he had found in ill-fated Jules’s pockets. He addressed Ham.

“See that designation ZX 03, penciled on one of the airship pictures,” he indicated. “I want you to get on a battery of long-distance telephones and find out what airship, either present or past, bore that identification number.”

Ham fingered through the clippings. Ferreting information was something for which his training as a lawyer eminently fitted him. More than once, Ham had coaxed startling testimony from reluctant witnesses in courtroom cross-examinations.

“I wonder if there is some connection between this ZX 03 Zeppelin and the mystery craft the newspapers say was sighted over Maine?” Ham pondered.

“That possibility occurred to me,” Doc admitted. “When you make your phone calls, ask each person if they are acquainted with the names of Lady Nelia, the red-headed fellow, Yuttal, or Hadi-Mot. Also ask about the dead man, Jules Fourmalier.”

Ham nodded thoughtfully, saying nothing.

“Jules showed a knowledge of airships from the figuring he did on the clippings,” Doc explained. “He may be known to the lighter-than-aircraft profession.”

“You want me to try Europe also?” Ham questioned.

“It might be advisable to do that the first thing.”

Nodding, Ham busied himself at the telephone. The names of those to be called were supplied by a business directory of the aircraft profession, which Doc brought from the library.

The first call Ham made was to England. While the radio-land-line connection was being put through, he requested lines to certain American builders of Zeppelin-type ships.

Doc entered the library. He possessed a great file of newspaper clippings, kept up to date for him by a firm engaged in such work. He glanced under the subhead of “English Royalty.”

He was hunting something on Lady Nelia. And he found it almost at once!

There was a picture of the tall, aristocratic young lady. She was in flying togs, and stood beside a small monoplane. The headlines below the picture read:

There was more. It merely recited information about Lady Nelia’s career. She was a brilliant young lady, as well as a famous beauty. She had been lost some four months ago.

Ham called while Doc was still reading, saying, “Here’s Renny on the phone!”

Doc ran to the instrument. Renny was a caldron of news.

“Lady Nelia, Red, and the dead man, Jules, are the ones who offered that fantastic reward to get hold of you,” he explained. “I overheard them talking in the cab.”

“Where are you now?” Doc queried.

“In the lobby of the Hotel Rex. Lady Nelia and Red are registered here. Lady Nelia is on the sixteenth floor and Red on the seventeenth.”

Doc swiftly described Yuttal and Hadi-Mot.

“Have you seen any sign of two birds answering that description?” he asked.

“Why, sure,” Renny said innocently. “They just registered for a room. They were carrying a big wicker basket between ’em. They wouldn’t let a bell hop touch it!”

“Get hold of Lady Nelia and Red—quick!” Doc rapped. “Tell them Yuttal and Hadi-Mot are in the hotel. Get them out of the place—no, don’t try that. Have them lock their doors and windows and wait for me!”

Banging the receiver down, Doc hurtled for the door. He was through it and into an elevator before the men he left behind could get organized.

Doc was gone when his four aides ran into the corridor. They were disgusted. Doc’s slam-bang departure showed there was action ahead. They hated the thought of missing it. Excitement was the thing they enjoyed most. It was the nectar which they drew from their association with Doc.

But they had lost out this time; they did not know where Doc was bound.

The Hotel Rex was a new hostelry. It contained more than two thousand rooms, which placed it among the larger hotels of the city. The location was only three blocks from the skyscraper which harbored Doc’s office.

Doc did not trouble to get a taxi. He took the center of the street, where the going was less hampered, and ran.

More than one pedestrian gaped in surprise at sight of the flashing bronze form.

A policeman drew his gun and started after Doc. He had recognized the bronze man and thought he might be of some help. He knew Doc held a high honorary commission on the New York police force.

Doc came into view of the Hotel Rex. Confusion was rampant in front of the hostelry. One of the uniformed taxi starters lay prone on the sidewalk, crimson spilling slowly from a gash in his head.

Frightened employees were dashing in and out of the lobby.

Doc did not need to ask questions. A dozen excited yells told him what had happened.

“Two men ran out, dragging a woman!” a man shouted. “They crowned the taxi starter when he tried to interfere. He ain’t hurt bad.”

“Did’ya get a good look at ’em?” demanded some one.

“Sure. One was fat, the other slim and dark.”

“Them’s the two that just registered for a room,” vouchsafed a bell boy. “They had a strange-looking basket when they came in.”

“They had the basket when they went out, too. The thin guy was carryin’ it, while the fat one handled the woman.”

Doc dived into the lobby. Renny, it seemed, had gotten on the job a little too late.

A glance at the register cards showed Doc the numbers of the rooms taken by Lady Nelia and Red. He glanced about and located the elevator starter—the fellow who was stationed at a signal board in the lobby to keep the cages running at regular intervals.

“Just a little before the excitement started, a big fellow with huge hands probably dashed into one of the elevators,” Doc explained. “Did you see what cage he entered?”

The elevator starter pointed. “That one.”

Doc collared the operator of the indicated lift. “What floor did you let the big-fisted fellow off upon?”

“Sixteen.”

That meant Renny had gone to Lady Nelia first. Doc rode upward, alighting at the sixteenth.

The door of Lady Nelia’s room gaped open, lock torn out. Inside, the rug was wadded in a corner and coverings were off the bed. Bureau drawers lay on the floor. The rapid search had even been extended to the cover on the telephone-bell box, which was ripped off.

Doc, thinking of the diamonds Jules had carried, guessed accurately that more such stones had been the object of this hunt.

He sped to the stairs, mounted one flight and made for Red’s room. There, also, the door was ajar.

On the floor, twisted grotesquely, lay Red’s gaunt body. The features were set in death. They held an expression of horror that was hair-raising.

A hole was torn in the man’s neck. There was no question but that he had been a victim of the same weird, fluttering death-dealer who had slain Jules.

The man’s trousers legs were drawn above his knees. Certain marks showed where several small objects, fastened there with adhesive tape, had been plucked away.

Doc’s golden eyes roved. There was no sign of Renny. The window was locked on the inside.

Hurrying down to the lobby, Doc made inquiries. Yuttal and Hadi-Mot had taken Lady Nelia away in a taxi, but no one had thought to get the taxi license number in the excitement. So small a chance there was of following it, the machine might as well have vanished in thin air.

Most disquieting of all, Doc discovered Renny had not come back downstairs. No one had seen him reappear in the lobby. The big-fisted fellow must be somewhere in the upper regions of the great hotel!

Doc went up to give Lady Nelia’s room a more thorough inspection, and to search for Renny. On his first visit, one fact about the ransacked chamber had come to Doc’s attention.

The bed pillows had been missing. There was no blanket, either. And hotel beds were usually supplied with an extra blanket.

As Doc surveyed the place, he observed the window was unlocked and open widely. He glanced out of it.

A four-story building adjoined the hotel. The roof of this lay directly below the window. The flashing of a neon sign on the hotel jerked light over the roof at twenty-second intervals.

A form was spread-eagled on the roof!

Doc’s golden eyes acquired hot little lights as he studied the figure. For he could make out the suit Renny had been wearing! And Renny’s hat lay near by.

The form reposed about where a man would land, were he to be shoved from this window.

Leaving the figure below, Doc’s gaze traveled up and down the sheer brick walls. A dozen stories to the rooftop where the sprawled object lay. Twice that many above. Overhead, however, the walls stepped inward at ten-story intervals, pyramid fashion.

The abrupt expanse was rather scantily ornamented. Above the window from which Doc leaned, a narrow ledge passed. It was hardly two inches wide. But a man, by standing on tiptoes on the window sill, could reach it and swing over to the next aperture.

“Renny!” Doc called.

The adjacent window opened. Renny’s head appeared. He gave Doc a wryly sheepish grin.

“Reckon you think I’ve lost my nerve!” he rumbled. “But I didn’t have a gun!”

Doc shook his head slowly. “There’s an old saying that he who retreats wisely may live to fight other battles, or something like that. I did some fast moving to get away from the thing, myself. What happened?”

“I charged up here after calling you,” Renny explained. “The young woman wasn’t in her room. I started up to find Red, but met Yuttal and Hadi-Mot. I retreated into Lady Nelia’s room when they started fumbling with their infernal basket.

“The lights went out. They opened the power switch on this floor, I guess. I could hear them preparing to smash open the door. So I made up a dummy with my clothes and threw it out of the window. Then I shinned along the ledge to this place. It evidently worked, making them think I had tried to get away and had fallen.”

Renny left the window. A moment later, he appeared in the hallway. He was wrapped, toga fashion, in a sheet.

“The main part of my clothes are on the dummy down below,” he explained.

Discovering the plundered condition of the room, he emitted a grunt of surprise. “They must have pulled this search after I gave ’em the slip! Yeah—sure they did! I could hear ’em scuffing around, but didn’t know what they were up to.”

“Didn’t you get a look at the thing in the basket—the thing of death?”

“Nope. I never waited. I figured that if I saw the thing, it might be too late.” Renny wiped perspiration off his forehead. “I tell you, Doc, that thing, whatever it is, must be frightful. Lady Nelia and Red were scared to death, riding up here in the taxi.”

“I wish we could have had a talk with them,” Doc said thoughtfully.

Renny looked disgusted with himself. “I didn’t dream trouble would come so quickly. Blast it! I wish I’d have had a gun!”

“If you were not armed, your retreat was a wise move,” Doc assured him. “Did you overhear Lady Nelia and Red say anything other than that they had inserted the reward advertisement?”

“A little.” Renny wrinkled his brow. “It didn’t make much sense. They spoke of other persons who had been left behind somewhere. They talked like these other poor devils must be existing in a ghastly sort of slavery. It seemed Lady Nelia, Red and Jules had escaped from the same fate, and were anxious to help those they had left behind.”

Finishing, Renny rubbed his square jaw and looked his soberest self.

“A very strange state of affairs,” Doc meditated aloud.

He lifted bed coverings and moved the rug aside, foraging for anything of interest. He came upon a late newspaper. A portion was missing from the front page. It lay near by, partly folded.

Lady Nelia had apparently been in the act of removing the item when interrupted by Yuttal and Hadi-Mot.

“They bought the newspaper en route up here,” Renny offered.

Doc examined the torn segment, expecting to see the story of the fabulous reward. Lady Nelia would naturally be interested in that. But he got a surprise.

The item concerned the sighting of a phantom Zeppelin over a remote section of Maine.

“It would seem that the airship fits into this puzzle,” he said grimly.

Doc placed a telephone call to his four friends in the skyscraper office, advising them where he was. He suggested they come over as soon as they had completed their allotted tasks.

Johnny, the gaunt geologist, was first to arrive. He came in wiping his glasses, which had the magnifying lens on the left side.

“I learned something a bit mystifying about those diamonds,” he reported. “They come from Africa, all right—but from no known field! The stones, for their size, are remarkably perfect.”

Johnny paused to adjust his glasses on his bony nose. “Now, here is the mystifying part. Other gems, with characteristics akin to these, have been appearing on the world markets, a few at a time, for the past several years. The stones naturally attracted attention. Persons connected with the diamond trade sought to learn where they came from. But they had no luck. Whoever has been selling the diamonds has taken great pains to cover his tracks.”

Doc nodded. The completeness of Johnny’s information was not surprising. Records are kept of large gems, just as the serial numbers of large bills are preserved. Doc’s wonderfully complete library held such data.

Long Tom and Monk put in an appearance. Long Tom was burdened with a device which might have been a complex magic lantern. This was a projector for light rays below the visible spectrum. He also carried six oversized goggle affairs. These could best be described as fluoroscopic glasses which converted the infra-rays into beams visible to the human eye.

There was a set of the goggles for Doc, and for each of his five aides.

“Are you a magician?” Renny grinned, marveling at the swiftness with which Long Tom had materialized the apparatus.

“I’ve had this stuff on hand for an emergency,” Long Tom told him. “All I had to do was check it over to make sure it was in working order.”

Monk hefted an egg-shaped blob of metal, one of many which he carried in a canvas sack.

“Each one of these hold enough gas to lay out a herd of elephants,” he said, a fierceness in his mild voice. “Doc had these metal eggs on hand. All I had to do was mix the yolk for them.”

“You’re sure they won’t kill?” Doc asked sharply.

“Positive!” declared Monk.

“That is well,” Doc replied. “We don’t want any killing—except when necessary in defense of human life.”

Swinging over to the window, Doc stood looking down at the night traffic in the street. His back was to his men. His towering size, his enormous physical build, was very evident in contrast to the proportions of the window.

Doc’s low, mellow, trilling sound abruptly became audible to those in the hotel room.

The men exchanged glances. They had heard this weird, melodious, untuned note many times. They knew the varied occasions upon which it sounded. Often it came when Doc was thinking.

They decided he must be thinking now, seeking some means of aiding Lady Nelia and of punishing Yuttal and Hadi-Mot. Probably, also, searching for a salvation for those others, those mysterious enslaved beings, the existence of whom Renny had overheard.

The men maintained silence. They had faith in this strange bronze man. They knew the things of which he was capable—or rather, knew he was equal to any occasion, for Doc’s bag of tricks seemed bottomless.

They waited, believing Doc’s mellow, unearthly sound meant he was devising ways and means of rescue.

They were wrong. In the street, nearly two blocks distant, Doc had noted a peculiar incident. A taxi had entered a parking lot and backed into position with an array of other cars. There were no other taxis in the lot, and the parking fee was fifty cents. This was unusual. Cab drivers do not usually pay such a sum to park, since regular stands are allotted them.

A few moments later a man left the cab, getting out at the rear. From that distance, and due to the gloom, even Doc’s sharp gaze could tell little except that he was a very fat man.

Yuttal was of such pudgy build.

In the hotel corridor an elevator door opened. Ham appeared, dapper and swinging his sword cane briskly. He swung into the room.

“I dug up some hot stuff!” he announced.

Doc, without taking his eyes from the distant cab in the parking lot, said, “Let’s have it!”

“Ever hear of the airship Aëromunde?” Ham countered.

“Probably there are few living people who have not heard of it,” Doc replied. “That is the Zeppelin which vanished more than a dozen years ago while on a flight over the Mediterranean. The body of the commander was found floating in the sea. But no trace of the ship itself was discovered. What happened to the Aëromunde is one of the world’s great mysteries.”

“The Aëromunde was the ZX 03, in European military files!” Ham said dramatically. “And Jules Fourmalier was a member of the crew of the lost airship! There was also a red-headed man in the crew—a fellow who answers the description of the dead chap upstairs.”

Doc said nothing. He was watching.

The fat man had walked out of the distant parking lot and lost himself on the darkened streets.

Moving with decision, Doc turned out the lights.

“Come over here,” he directed Long Tom and Renny. Then he indicated the cab in the parking lot. “See that machine?”

“The hack?” said Long Tom; and Renny echoed, “Yeah!”

“We may want to trail it,” Doc told them meaningly. “You know what to do?”

“You bet,” Long Tom grinned. He hastily quitted the room, Renny at his heels. They were in a great hurry.

Long Tom had been gone perhaps five minutes when the night manager of the hotel strode into the room. He nodded and rubbed his hands briskly when he caught sight of Doc.

“A party is asking for you on the telephone,” he explained. “This person said it was very important, and that you might be found on this floor or the one above. This phone was out of order, so——”

But Doc was already in the corridor, making for the desk of the floor clerk. The room phone had been wrecked in the search. He used the instrument on the floor clerk’s desk, and asked to be connected with the caller.

For the first time, he discovered the floor clerk, a slick-haired young man, unconscious behind his desk. He was breathing noisily, seemingly not greatly damaged. Yuttal or Hadi-Mot must have given him a rap over the head during their raid.

“Is this Mr. Savage?” questioned a low, snarling voice over the phone line.

It was Yuttal.

“This is Savage,” Doc told him.

“We will not waste time!” Yuttal growled. “I want the diamonds.”

“You mean the five which Jules Fourmalier carried?” Doc asked quietly.

“I mean the others—the ones Lady Nelia Sealing had. I have come to the conclusion that you have them. Lady Nelia must have gotten them into your hands in some fashion. I want them! As for the gems Jules Fourmalier had—pouf! You may keep those as a reward for promptly returning the others.”

Doc’s voice was dryly expressionless. “I presume there is some good reason why I should do this?”

“You bet there is! You won’t live long unless you do!”

Hot lights danced in Doc’s golden eyes. “I may flatter myself, but I believe you’re taking in a lot of territory, my friend.”

“You heard me!”

Doc spoke hastily, his tone still easy: “What about Lady Nelia Sealing?”

“You ain’t interested.”

Yuttal, Doc decided from the man’s fluent use of slang, was the product of some American city slum, even if he had spoken Egyptian to Hadi-Mot.

“I might,” Doc suggested, “swap the diamonds for Lady Nelia.”

“Nix.”

“You had better give that proposition some thought before you decline it, Yuttal!”

“Listen, you ain’t got anything you can swap for the dame. You’ll never have anything valuable enough to swap for her! Do you know why?”

“I can guess,” Doc said grimly. “The information she could give me would mean your finish. Is that it?”

“You don’t know the half of it,” Yuttal sneered. “But that’s enough. I want them diamonds. You take ’em and get on the next train bound for Washington. Stand on the back platform, and when you see a light flash three times——”

“Never mind the details,” Doc interrupted. “You’re wasting your breath.”

“You won’t return ’em?”

“No!”

“You’d better think——”

“No!” Doc repeated. “That is final.”

A curse crackled in the receiver. Then the wire went dead. Yuttal had hung up.

Doc returned to the room where his three men waited. Night air drifted in damply through the open window. With it came a low sound, a cross between a hiss and a whine. This noise was so vague that only a sharp ear could detect it. It seemed to come from the sky overhead.

“That’s Renny,” grinned the dapper Ham. “He’s flyin’ low, too!”

Doc did not lean from the window to peer into the night heavens. He knew what was up there.

Manhattan is a narrow strip of land surrounded by water. A fast car can reach the water front in a few moments from any part of the isle. In a boathouse on the Hudson River side of the island, Doc Savage kept two amphibian planes. One was a monster high-speed trimotored craft. The other was an autogyro, also of rather large size. Both craft had silenced motors.

The autogyro was hovering overhead now. The hissing was the note of its muffled engine. Renny was at the controls.

Doc and his men watched the taxi in the distant parking lot.

“Did Long Tom get to the machine?” Doc asked.

“I don’t know,” muttered gorillalike Monk. “If he did, he pulled a slick job. We never saw him.”

The men continued to scrutinize the cab.

Long Tom walked into the hotel room. He was grinning broadly.

“I fixed it!” he declared. “I also got a look at the inside of the taxi. It was empty. If Yuttal drove there in the machine, he must have left Hadi-Mot and Lady Nelia somewhere else.”

An instant later, the fat man appeared in the far-off parking lot. He made for the hack. It was undoubtedly Yuttal.

Monk knotted his hairy hands. “If we were just down there, we could nab that guy!”

“That’s about your style,” Ham offered bitingly. “It would wipe out our chances of finding Lady Nelia, but you never thought of that.”

Monk bent a bilious eye upon the sartorially perfect Ham. He screwed his homely face into the most frightful of grimaces. From his lips came a perfect imitation of a pig squealing.

Ham’s neck reddened. His hands clenched on his sword cane. He looked as if he could have slain Monk.

Any reference that Monk made to pigs, caused Ham to remember the ancient ham-stealing charge. It got his goat.

Monk knew this. How well he knew it! He had practiced for many hours to perfect a repertoire of piggy gruntings and squealings for just such occasions as this.

The lights of the cab in the lot came on. To the unaided eye, they presented nothing unusual.

But Long Tom had attached to the rear of the cab a small, lanternlike device which gave off infra-rays—rays which became very distinctive when seen through fluoroscopic eyepieces.

Renny, lurking overhead in the autogyro, possessed such an eyepiece. He should have no difficulty trailing the cab, thanks to Long Tom’s device. The infra-light was unlike anything else in the city!

The taxi pulled out of the lot. It was soon lost to view from the hotel window.

Doc listened to the hissing from the night-mantled sky. The sound receded. Renny was on the trail.

As they moved toward an elevator, Doc told his four friends of Yuttal’s call, and of the threat.

“We couldn’t give him the diamonds if we wanted to,” Monk snorted. “We haven’t got ’em!”

To this Doc replied nothing. But he stopped the elevator on the fifth floor of the hotel. The floor clerk let him into a room, the window of which gave upon the roof of the adjacent building.

On this roof lay the dummy composed of Renny’s outer clothing, and pillows, and blankets.

Monk snorted softly. “Renny made a swell-lookin’ sheik in that sheet! I’ll bet he stirred up a panic when he left the hotel.”

“It’s lucky it wasn’t you!” Ham retorted bitingly. “Every guest would have been scared out of the hotel!”

While Monk groped for a suitable insult in return, Doc eased out of the window. A narrow ventilator shaft separated the two buildings. He sprang across easily—he could jump many times that distance if necessity required.

He got Renny’s clothing. Then he slapped his bronze hands over the pillows. Finding nothing, he shook out the blankets.

A life belt, marked with the name of the Yankee Beauty, dropped from the woolens. Ten seconds later, Doc had located hard objects inside the belt.

He ripped off the canvas cover. A clicking wealth poured out in his hands. The gems were uncut, but all were flawless diamonds.

He carried them back into the hotel room, examined them under the lights, then handed them—more than a double fistful—to Johnny.

“Brothers,” he said quietly, “I doubt if you have ever seen a finer group of stones. Cut and polished, I believe they would be a perfectly matched collection. I’d be willing to bid a good round million for the lot.”

The gaunt geologist employed the magnifier in the left side of his glasses for an inspection. He knew diamonds, knew almost as much about them as Doc knew.

“I believe I’d raise your bid, Doc,” he declared.

Doc Savage and his men now repaired to the skyscraper headquarters. They lost no time doing so. In the laboratory, Doc clicked a short-wave radio transmitter and receiver into operation. Twirling the dials, he soon had Renny’s voice roaring from a loud-speaker.

Renny had an efficient two-way radio in the autogyro.

“The taxi bearing Yuttal went uptown,” Renny reported. “It stopped in a side street for a while. It was too dark to tell what happened, but I think Yuttal must have picked up Hadi-Mot and Lady Nelia. The car is headed north now. It looks like they’re leaving town.”

“Yuttal seems to be nobody’s fool,” Doc replied, speaking into a microphone. “He evidently called me in the faint hope of scaring me into giving up the diamonds. The death threat was a bluff. He’s not going to try to carry it out.”

“Have you got the diamonds?” Renny boomed in surprise.

“They were in the blankets you used to make the dummy.”

“Holy cow!” Renny exploded. “Say, I wish I had my clothes. I feel like an angel up here in my underwear, with this sheet flapping around my shanks!”

“Tell him he’d better enjoy the sensation while he can,” put in the sharp-tongued Ham. “It’s probably as near to being an angel as he’ll ever get.”

The microphone was sensitive. Renny heard the crack.

“Sic Monk on that shyster lawyer,” he requested.

Ham hastily subsided.

Doc addressed the four men in the laboratory. “Get your usual outfits together. We’re going after this gang, and no telling what we’ll tie into before we’re through.”

“And bring my clothes!” Renny chimed in plaintively from somewhere in the sky, several miles distant.

Doc’s aides busied themselves. This was old stuff to them. They knew exactly what they needed, and had the equipment where they could lay hands on it.

Doc locked the diamonds in a safe.

Long Tom garnered wire, tubes and coils from which, should the need arise, he could concoct a surprising variety of electrical devices.

Monk secured a case which contained a compact, abbreviated chemical laboratory. He also packed his assortment of gas bombs.

Johnny, the geologist, and Ham, the lawyer, since most of their equipment was in their heads, busied themselves packing a supply of ammunition and Doc’s special machine guns.

These rapid-firers were marvels in themselves. Little larger than ordinary automatics, they were fitted with curled magazine and fired at tremendous speed. In operation, the weapons made a roar like the note of a gigantic bull fiddle.

Renny’s voice suddenly boomed out of the loud-speaker. “Say! Yuttal and Hadi-Mot just threw a body out of that taxi!”

A body! The words jangled like breaking ice.

“There’s no doubt about it!” Renny roared. “I can see the form in the lights of an automobile.”

A ghastly silence seized Doc and his men. Gone was their bantering air. They were men inured to peril, to horror, to violent death. Monk and Ham rarely surrendered their good-natured quarrel. Doc himself seldom showed the slightest emotion.

But they were cold and grim now. All their thoughts were the same. Could that body be the lifeless form of Lady Nelia?

Doc’s powerful voice, frozen as his men had seldom heard it, crashed out: “Drop down, Renny, and take a look!”

“Yes, sir,” came Renny’s dull rumble from the loud-speaker.

Doc and his fellows now left the eighty-sixth floor quarters. That in itself gave a hint of the grim efficiency with which they operated. Momentous news impended. But they went ahead at their self-appointed task.

That task was the smashing of Yuttal and Hadi-Mot, and whatever sinister organization they stood for. This work would go on. If beautiful, stately Lady Nelia Sealing had been slain, it would but serve to harden their determination, to speed a little the justice they intended to inflict.

In a garage, constructed to his specifications in the skyscraper basement, Doc kept his cars. The machines could be lifted speedily to the street. Few individuals not connected with the great building knew of the garage or the unusual vehicles it held.

It had cost a great sum, that garage. The automobiles in it were expensive. But Doc Savage had vast wealth at his disposal—a fabulous trove of gold which lay, lost to the rest of the world, in a remote valley in Central America. A clan of Mayans, self-exiled from the rest of civilization, kept Doc supplied with funds, thereby paying a debt of gratitude they owed the strange bronze giant.

Doc chose a large sedan of inconspicuous color.

The men piled in, stowing their equipment and Renny’s clothes.

As the machine was lifted to the street, Doc switched on the powerful radio transmitter and receiver with which the car was equipped. In a moment, he was again in touch with Renny.

“There’s a pasture alongside the highway,” Renny reported. “I’m preparing to land in that.”

Shortly afterward, several jarring noises came from the speaker. Renny had evidently left the autogyro transmitter in operation, and it had broadcast the shock of landing.

Silence ensued. Hissing of the muffled plane engine poured from the radio.

Doc’s car swerved silently into the street. It spun northward.

Doc rolled the windows shut to close off outside sounds. On the front of the car, a big red light began to glow. Alongside this gory eye, a siren started moaning softly. Scarlet light and whimpering siren insured a clear way through traffic. The siren was not loud enough to interfere appreciably with the radio.

“Holy cow!” Renny’s voice reached them suddenly. “Am I relieved!”

“Who was the person thrown out of the taxi?” Doc demanded.

“The taxi driver!” Renny explained from the distant autogyro. “Yuttal and Hadi-Mot evidently whacked him over the head and took his hack. He wasn’t in the machine when it was parked in the lot near the hotel, so he must have been a prisoner with Lady Nelia. They threw him out to get rid of him.”

“Is he badly hurt?”

Renny’s chuckle mingled with the louder hissing of the autogyro motors as he took off. “The guy was awake and cussing a blue streak when I left him. He just got hit on the head.”

“Did you question him?”

Doc’s limousine rolled past an electric power plant at this point, with the result that Renny’s reply was lost in a cackling bedlam of local interference.

Doc waited until they were well beyond the plant, then spoke into the microphone, asking Renny to repeat.

“I questioned him,” Renny asserted. “It seems Yuttal and Hadi-Mot engaged his cab down at the water front. They must have done that shortly after they encountered you, Doc. Anyway, they told the taxi driver they were detectives, and had him follow my machine to the Hotel Rex.”

Renny interrupted himself briefly. Probably he was scanning the highway below through his fluoroscopic glasses in an effort to locate the gleam of infra-rays on the rear of Yuttal’s fleeing cab.

“The driver said he overhead none of Yuttal and Hadi-Mot’s conversation,” Renny continued. “When they came dashing out of the hotel dragging Lady Nelia, and kayoed the cab starter, the driver also tried to interfere. He got knocked cold for his pains. And that was everything he knew.”

Doc Savage wheeled the sedan across a bridge over the Harlem River, the northern water boundary of Manhattan Island.

“Where are you now?” he asked Renny.

“Following the Hutchinson River Parkway,” replied the voice from the autogyro.

“Have you got Yuttal’s taxi located?”

“I’ll say! That machine is sure making time!”

Doc now settled himself to the grim task of overhauling their quarry. As they entered the fringes of the city, streets turned into wide boulevards, gently curved. They were built for motoring speed, these thoroughfares, with underpasses and overpasses instead of crossroads. Fast driving was the rule, with slowpokes frowned upon. But it was doubtful if the turnpikes had seen a faster pace than Doc was setting.

The sedan was heavy, yet at such a clip were they traveling that slight rises in the pavement often flung them entirely into the air. Asphalt-chinked joints in the concrete passed under the big tires in a stuttering procession. Air whistled past the tightly-closed windows.

Long Tom rode in front with Doc, nursing his packet of electrical equipment lest the jarring should smash some of the delicate apparatus.

Johnny, so gangling and bony that he seemed to rattle with each bump, sat in the rear between Monk and Ham.

From time to time, Ham favored Monk with a scowl. He was still piqued at the garish imitation of his own natty attire which Monk wore.

Monk’s unlovely features bore a blissful look. He was never happier than when annoying Ham.

“Yuttal has turned into farming country!” Renny reported suddenly from the far-off autogyro.

Speaking swiftly, he gave Doc the location of the side road which their quarry had taken.

Doc eventually turned off upon this thoroughfare. It proved to be incredibly rough and crooked. The sedan bucked like a cow-country bronc. Several times, it nearly left the road.

Slowing the machine, Doc turned into a clearing.

“Can you come back and pick us up without losing the taxi?” he asked Renny.

“I believe so,” Renny replied. “That infra-light shows plainly.”

Doc and his aides unloaded from the sedan.

A few minutes later, with a swishing as of a strong wind, the autogyro spun down into the clearing, guided by flashlights waved by Doc’s men.

The machine was a cabin craft, easily capable of accommodating six passengers. The men inserted themselves in the wicker seats. Renny lost no time taking off again.

Every one at once donned the somewhat bulky fluoroscopic eyeglasses. These were near the size of shoe boxes, for their functions were intricate. They were not very heavy, however. In addition to being padded to fit the face, they were held in position by straps.

The earth was discernible as effectively as with the naked eye, the apparatus being sensitive also to normal light rays. But the gloominess of the night made it difficult to see much.

They soon located Yuttal’s taxi. An eerie, fleeting glow marked its position. A luminance like no other!

Leaning from the autogyro window, Long Tom focused his infra-ray projector on the terrain beneath. To the naked eye, these rays were invisible. The fluoroscopelike spectacles converted them, by an intricate process, into a colorful luminance which reacted on the eye in the fashion of a prosaic searchlight.

But the autogyro was too high to permit the infra-light to be effective.

“Blast it!” Long Tom grumbled. “This lantern is not powerful enough. The first chance I get, I’m going to equip all our planes with strong infra-ray searchlights. But that don’t help us now.”

“We will have no trouble keeping track of the cab, anyway,” Doc declared.

“Yeah, but it’d be swell if we could watch the machine as if it were running along in broad daylight,” Long Tom muttered.

Minutes dragged past. It was impossible to tell much about the country below, due to the smudging darkness. But the cab seemed to be traversing a very crooked road over wooded hills. The course bore steadily northward.

Monk peered up gloomily at the cloud-swathed heavens. “If the moon was just shining,” he wished. “But in that case, we’d have to fly a lot higher to keep from being discovered.”

The autogyro overhauled the taxi. At an altitude of some thousands of feet, it whirled steadily forward.

“Get well ahead of the machine,” Doc told Renny. “We’ll drop a few fistfuls of Monk’s gas bombs in the path of the cab. When the car runs into the vapor, those aboard will be made unconscious. Pick a spot where the road is crooked—where the taxi will be traveling slowly. We don’t want any one hurt.”

Drawing ahead of its quarry, the plane began settling earthward.

“What are we gonna do with Yuttal and Hadi-Mot?” Monk pondered. “They’re murderers.”

“You know very well we have a place for them,” Doc said dryly.

Monk’s question had been somewhat unnecessary. He knew quite well what would happen to Yuttal and Hadi-Mot, once they were in Doc’s hands. But it still seemed a bit incongruous to Monk that all wrongdoers, from master killer to petty crook, received the same treatment from Doc.

Treatment it indeed was! Doc maintained an elaborate institution in up-State New York—a strange place, unknown to the general public. Here great brain surgeons, trained by Doc’s skill, operated on such criminals as Doc sent to them. The operations took from the crooks all knowledge of their past. Then the fellows received intensive training in the ways of an upright citizen, including a trade with which to make an honest living.

No former criminal, once having undergone treatment, had ever returned to shady ways. From murderer to cheap racketeer, they underwent the same metamorphosis.

“We shall induce Yuttal and Hadi-Mot to talk, of course, before we send them to our institution,” Doc said.

Monk nodded. “You mean to learn where the diamonds came from?”

“Something a good deal more important than that is troubling me!” Doc told him grimly. “Those mysterious slaves of whom we heard!”

“Slaves!” Monk grunted. “Do you really think——”

“We’re going to probe very deeply indeed into that mystery,” Doc assured him.

The earth was now close enough for Long Tom’s portable infra-ray projector to be effective. Accordingly, he leaned over the side and adjusted the various switches and knobs on the device.

The others studied what was disclosed. A strangely unreal panorama, it was.

“There’s an excellent spot!” Doc declared.

Below them, there lay a stretch where the road was more narrow and crooked than before. It also wended up a steep grade. It was a route a car could not travel at excessive speed.

Best of all, a pasture a few hundred feet distant offered a landing place.

Doc glanced back, searching for the taxi. There was no sign of the machine. The compact infra-ray lantern, being secured to the rear of the vehicle, was naturally obscured from view by the body.

The autogyro landed. The men piled out, carrying Monk’s gas grenades and donning gas masks. Fortunately, these masks consisted merely of mouthpieces and nose clips and fitted under the boxlike fluoroscopic spectacles.

Doc, huge and swift, his complexion retaining its bronze hue even in the infra-light, led the way toward the road. They were a weird group, like warriors from another sphere, sprinting through the uncanny light with their features rendered fantastic by the apparatus.

To the unaided eye, they were in intense darkness. But Long Tom’s projector of infra-light illuminated their way clearly.

They laid a barrage of gas in the road. The vapor would hang there, since practically no wind was blowing. The gas cloud could easily be replenished.

They listened. A bit uneasily, their eyes sought Doc. They knew the keen quality of his hearing.

Presence of the gas made it inadvisable to remove the masks to talk. So Monk asked a question—using the deaf-and-dumb sign language. Each of Doc’s men could finger out sentences with fair proficiency. Doc himself was quite adept at it They had more than once found this knowledge of the sign language a useful asset.

“Do you hear the taxi?” Monk queried with his furry fingers.

“No,” Doc spelled back.

They waited. A subtle change came into Doc’s metallic eyes. The others shifted uneasily. The taxi should have reached them. But they could not even hear it!

The machine was not coming. They became sure of that. Then they received a most unpleasant shock.

Back along the road, not more than two miles distant, an airplane engine suddenly began to drone.

Doc and his men knew what it meant. They spun and raced for their autogyro.

Long before they reached it, however, the far-off plane lifted noisily into the night sky. It hooted away at great speed, losing its sound swiftly in the darkness.

Wrenching off his mask—they were now clear of the gas cloud they had spread so uselessly upon the road—Monk groaned, “We’ll never be able to follow that plane through this black cat of a night! It sounded like a fast ship.”

Monk’s statement was the truth.

Doc used strong binoculars on the packed soot of the heavens. He detected no flame lipping from exhaust stacks. That dispelled their last hope of trailing the departing plane.

Taking the controls, Doc lifted the autogyro into the air. He climbed rapidly to a considerable height, then shut off the motor and glided forward.

“Use your infra-light,” he advised Long Tom. “Let’s see if we can learn where they had that plane cached.”

It had hardly been a cache, they soon discovered. At the edge of a weed-grown field stood two ramshackle hangars. Evidently this was some rural flying field built a few years ago, when aviation was experiencing a boom.

The taxi was parked near one of the frowzy sheds.

“Look!” Doc said sharply. “There are men down there—three or more of them! But they’re not our quarry!”

Grabbing binoculars, the others discerned what Doc’s somewhat uncanny vision had revealed.

Two men stood before a hangar. At least one more was partially in the shadow of the structure—Long Tom’s infra-light cast a shadow very much as did ordinary light, except that it was a good deal blacker.

All three men were staring upward—straight at the spot where the autogyro hovered.

“Holy cow!” Renny gulped his pet ejaculation. “D’you suppose they can see this infra-light?”

“No!” Long Tom snapped. It irked him to have any one cast doubt on his ingenious devices. “I put filters on the thing which stop all visible wave lengths of light!”

Doc cast a gaze upward at the heavens. The clouds were quite thick. It was hardly likely the autogyro had been glimpsed against the sky.

He rocked the stick, trod the rudder—sent the craft sliding away from the tumble-down landing field. The ship sank rapidly—the engine was still dead. They would have to land soon, or start the motor, which meant they would probably be heard. The plane had yet to be built which did not make noise.

They were in luck. A patch of level ground materialized below. It was a find, for the rest of the terrain was matted with timber.

Doc made a deadstick landing, which was something for an airman to dream about. There was hardly a jar. A few rods distant, it could not have been heard. If anything, Doc’s skill as a flyer exceeded some of his other abilities.

The loudest noise—it was only a dull thump—was made by Monk, who tripped inexplicably getting out of the gyro, and fell on his head.

“You little shyster!” Monk addressed Ham fiercely. “You stuck that sword cane between my feet!”

“Listen,” Ham sneered, “when I get ready to stick you, I’ll pick a spot right in the middle of your gizzard!”

“And I,” big-fisted Renny put in grimly, “am gonna pound both of you guys into the ground so deep they’ll need a shovel to dig you up! Pipe down, will you!”

Doc moved toward the ancient flying field. It was nearly a mile distant. He held no apprehension that Monk and Ham’s encounter had been heard. Ham had known there was no danger of that before he tripped Monk.

They moved forward in purposeful silence, lighting their way with Long Tom’s device. Whenever they could, they ran.

Once Renny slid a chill whisper between his teeth. “I’m glad we have this light, what I mean! If they turn their infernal fluttering death loose on us, we can at least see what it is!”

“The fellows at the flying field may know nothing of the grisly thing,” Johnny suggested. “Yuttal and Hadi-Mot may merely have chartered a plane from them.”

“But you don’t really think that is the truth,” Renny said pointedly.

“No-o-o,” Johnny admitted. “An honest bunch of flyers would hardly be on the job at this time of night. That airport is certainly not fixed up for night flying. Anyway, if they were on the up-and-up, they wouldn’t stand by and see Lady Nelia hauled away forcibly in a plane.”

Johnny fell silent. An ugly thought had gripped him. Was it possible Lady Nelia Sealing had been slain and flung from the taxi somewhere en route? Such a hideous event might have escaped their notice from the autogyro.

Half a mile from the antiquated airport, Doc signaled a halt. So that quiet might be preserved, he addressed his companions in sign language.

“I am going to leave you fellows in the dark,” he explained with his digits. “I will take our lantern and size up the situation.”

Possibly the others did not think much of the idea. It meant they might miss some action. But there was no argument. They were well aware that Doc could go with ease where the most careful of them would be discovered.

Carrying the lantern, Doc continued onward. He made speed considerably greater than when they all had been together. He evaded twigs which might crackle or leaves which might rustle. The dry bed of a gully led him part of the distance.

He worked through a fringe of brush. The old airport lay before him. He turned the infra-light boldly upon the hangars, knowing it could not be seen. It smacked of the supernatural, this casting of a brilliant luminance upon men without their being aware of it.

The three men still stood near the hangar. This building, Doc now ascertained, was empty. A somewhat decrepit brown monoplane reposed in the other shed.

Doc moved forward, keeping near bushes where a chance appearance of moonlight would not betray him. But he did not assume needless chances of discovery. He stopped some yards from the men.

They were a vicious-looking trio, although their faces were intelligent in a sharp, foxlike way. They betrayed uneasiness, as if they were waiting for something to happen.

Much of the time, they stared steadily at the sky and seemed to be straining their ears.

This behavior relieved Doc of some anxiety, showing as it did that their strangely intensive gazing upward, when he had first sighted them, did not mean they had discovered the autogyro.

A fourth man suddenly appeared. He came running up in the darkness.

The waiting three promptly drew guns, demanding, “Who is it?”

“It’s me!” puffed the newcomer, who had apparently sprinted some distance. “Say, they’re here!”

The words carried to Doc’s ears with a fair degree of distinctness.

“Who’s here?” demanded one of the others.

“The Savage guy and his crowd, I guess,” wheezed the runner. “An autogyro landed in that clearing I was watching. A gang of men got out and started for this place!”

Doc’s bronze features did not show the disappointment he felt. His arrival had apparently not been as secretive as he wished.

“Blast the luck!” gritted one of the flyers. “They may be closin’ in on us right now!”

“They ain’t quite had time to get here!” retorted the messenger. “They’ll come slow so as not to make any noise.”

“How many of ’em?”

“I dunno.” The runner wiped off perspiration. “It was too dark to tell. How they found that clearing without showing a light beats me. They come like ghosts. There wasn’t nothing but the whistle of air past the wings. And that wasn’t loud! And the way they walked off! Just like they could see in the dark!”

The fellow was closer to the truth than he thought. But the others were skeptical.

“Don’t go talkin’ through your hat! One of ’em must know this neck of the woods, from the way they found these clearin’s. I was posted at the one up the road when they landed. The way they come down there was spooky, too. But we located ’em, didn’t we?”

This was illuminating information. The gang had taken thorough precautions. They evidently had a lookout at each spot in the neighborhood where a plane could be landed. No doubt they had the road watched, too. They were guarding well against a surprise.

“Quit gassin’!” snapped a man who seemed to be in charge. He addressed the panting messenger. “There’s a bomb in the hangar—a radio bomb. You know how it works. It’s got a midget receiving set and a relay in it. When we send a certain signal from the transmitter in our plane, the bomb will explode. Take the thing and hide it in Savage’s autogyro!”

“Sure, I can do that. But——”

“Don’t waste time! Do it! Then come back here. If you can get back without gettin’ caught—fine! If you can’t, take to the timber!”

“This may not work——”

“It’ll work if you hide the bomb. We’ll take off in the mornin’ to join Yuttal, and Savage will follow us. All we gotta do is draw him thirty or forty miles away from here, so it won’t look suspicious, and transmit the radio signal that’ll explode the bomb.”

“But what if that man grabs you tonight——”

“He won’t! We’re gonna play innocent around here. Not let Savage think we know he’s within miles. He’ll come prowlin’ around here, and we’ll let loose a few remarks about us takin’ off in the mornin’ to join Yuttal. Savage will wait and follow us.”

“This is a risky business!”

“The dickens it is! Even if Savage grabs us, we can spring a story about Yuttal and Hadi-Mot seizing a plane by force to take the girl away. There ain’t nothin’ wrong with that story.”

Doc Savage, standing near by and viewing the men as though they stood in broad daylight, suddenly experienced vast pleasure. So Lady Nelia Sealing was still alive!

“Get goin’!” snapped the leader. “They’ll be showin’ up around here pretty soon, even if they do go slow on account of the dark.”

The messenger got his bomb—a package of fair size—and skulked away.

The other three settled back to wait, blissfully unaware that Doc had been enabled, by the infra-light lantern, to reach the airport much sooner than they had thought possible.

The trio nested their guns in accessible pockets. One went to the brown monoplane and got a submachine gun. He placed this near at hand and covered it with a coat.

“No need of takin’ chances,” he muttered in a voice so low that Doc, acute though his hearing was, barely caught it. “This is a far-fetched scheme, if you ask me. I’ve heard of this Savage. He’s bad stuff. They say that if he wanted to, he could tear a man to pieces with his bare hands. I’ve heard the guy ain’t human, at all!”

His chief snorted. “I don’t believe them fairy tales. What does get me, though, is how he traced Yuttal up here.”

The third man strode over to the taxi, using a flashlight, and got an object off the ground.

“If we could figure out what this thing is, I’ll bet we’d know how Savage trailed the taxi,” he declared.

He was right. The mechanism he had picked up was the infra-light lantern which Long Tom had secured to the rear of the cab. One of the gang had found it. But their scientific learning was not extensive enough to tell them what it was.

“Throw it down before it blows up on you!” snorted one of the trio only half joking.

“Yeah—do that! We want you along when we join Yuttal in the momin’!”

The latter statement was made in loud tones. It was obvious the words were intended for unseen listeners.

The men dropped their voices.

Doc moved closer. It did not matter greatly if they heard him. Employing a knowledge of lip reading, he added to what he could hear, and managed to understand most of the low talk.

“I don’t like this, I tell you,” a man mumbled. “We’re givin’ ourselves away with that talk. If Savage does grab us, we can’t tell ’im Yuttal took our other plane by force——”

“Oh, dry up! If he gets us, we’ll think up another pack of lies. We’re good at that!”

There followed a few sentences which Doc, strive as he would, did not catch.

“What kind of a job d’you reckon this Yuttal is givin’ us?” came audible words.

“It’ll beat diamond smugglin’!” snorted another. “Whatever it is, I’ll bet it’s connected with the diamond business, too! Yuttal knows the guy in Europe that we been runnin’ stones in for. That’s how he got in touch with us.”

Doc made mental note of this. It told him these fellows were recent recruits to Yuttal’s evil cause, whatever it was. Their former following had been that of jewel smuggling. That accounted for their using this out-of-the-way airport.

“We’ll find out what the job is when we join Yuttal in the mornin’!” This was spoken in the loud tone, intended to be overheard.

Doc concluded not to disappoint them. He purposefully stepped on a near-by dry weed. It cracked loudly.

The three men showed extreme nervousness. But they maintained their acting.

“Yeah,” one of them quavered. “We’ll fly to Yuttal’s hang-out with the crack of dawn.”

Doc Savage, gliding silently away in apparent darkness, but actually in a brilliant infra-light glow of his own making, reflected that they no doubt really intended to join Yuttal and Hadi-Mot. Their talk hinted at this.

Doc hurried to rejoin his five aides. He had a plan. It was a very good plan. But it would require some fast work to put it in operation.

No human eye could have discerned his passing, for he moved in a blackness that was not black. And the silence of his going was as though no living thing had stirred.

Possibly an hour before dawn, strange things began happening in the night sky near where Doc Savage had lost the trail of Yuttal and Hadi-Mot and their prisoner—Lady Nelia Sealing.

The clouds, which had obscured moon and stars for most of the night, were gradually dissolving. But a few banks of vapor still mantled the heavens. Far below one of these, only a few thousand feet above the earth, a very small wad of gray suddenly appeared.

This wad seemed to stretch like a gigantic woolly worm crawling out of an invisible hole in the sky. It raced on for thousands of yards, then turned sharply and strung a gray column alongside the first.

A close observer might have noted a fleeing dark speck at the head of the gray worm, seeming to pull it along.

This speck was a monster trimotored plane, the engines silenced as perfectly as modern knowledge allowed. It was laying a smoke screen.

Back and forth, it swept. Back and forth! The smoke spread slowly, merging into a vast cloud. Since nature was dispersing her clouds, the aviator was making one of his own.

He even flew off to the sides and loosened a few puffs of gray smoke so the larger cloud would not be suspiciously lonesome.

A red flush suffused the sky. The sun was arriving.

The plane banked abruptly and vanished into the cloud of its own making. There was a breeze at that altitude. But the aviator knew just how fast it was blowing. He had released a number of test smoke puffs and, by watching their movement, obtained the information he desired.

The big cloud was moving along at such a pace that it would be almost above the ramshackle airport when the sun appeared.

Once inside his own cloud, the aviator remained hidden.

At the ancient airport, four very relieved flyers greeted the sun. The fourth man had returned some time ago, with word that he had hidden the radio-equipped bomb in the autogyro.

“Savage will never find that pineapple!” he leered, very brave now that daylight was upon them. “I stuck it in the back of the fuselage, but close enough to the cabin to blow ’em all to blazes!”

The four rolled their brown monoplane out of the old hangar. They glanced about nervously, then got in, after one had turned the propeller over until the engine started.

“D’you reckon Savage was really around here last night?” one pondered, as they waited for the cylinders to warm.

“Sure! Didn’t you hear that stick crack?”

In due time, they took off. They pointed the noisy snout of their plane into the north.

“There’s the autogyro!” one shrieked over the engine howl.

“Pretend you didn’t see it!” the man at the controls was warned.

They watched, breath bated. They saw six men enter the autogyro. One of these six seemed to be suffering from an injury, since two of his fellows all but carried him into the plane.

The autogyro eventually took off. It climbed swiftly, as if those aboard were anxious to conceal themselves in the big, gray cloud overhead. The craft chewed its way into the cloud.

For a goodly number of minutes, it lurked there. Those in the brown monoplane, which had been speeding away all this time, became a bit worried.

All four heaved a sigh of relief when the autogyro appeared—following them.

They let the windmill plane trail along for perhaps twenty-five miles, all the while dropping back slowly until their brown ship was leading by no more than two miles.

“Now!” yelled one fiercely.

Another man bent over the radio transmitter and laboriously made a certain combination of dashes and dots.

They watched the autogyro—as long as it was there to watch. For, as the combination was finished, a hideous jinni of smoke and flame seemed to pop out of nowhere and gobble up the gyro. An instant later, the smoke jinni spat out the smoldering bones of the craft. These fell earthward.

There was no audible explosion—the engine of the old brown monoplane had a deafening howl. But the four schemers could see the bomb had done good work. They flew on.

“This oughta put us in solid with Yuttal!” one hazarded, screaming to make himself heard.

The brown monoplane receded to a fly speck in the distance. Even the speck vanished. However, a good pair of binoculars could make it visible.

Good binoculars were trained upon it, too. Not one pair, but six. Those who stared were aboard the giant monoplane which had finally come out of the cloud of its own spawning.

Ham was flying the air monster. At Doc’s suggestion, Ham had sped to New York for the plane, which was Doc’s private craft. Ham, in addition to being a brilliant lawyer, could fly with the best and weave a mean smoke screen.

He had taken Doc and the others off the autogyro, which had then been allowed to fly away, controlled by an ordinary robot pilot, in the wake of the brown monoplane. As for the illusion of six men boarding the gyro in the clearing—the sixth man had been a scarecrow of sticks and various garments. The bomb had finished him.

Ham was proud of his cloud. He looked back at it. “Pretty neat, eh?”

Monk surveyed the mass of vapor critically. “Yeah, it’s swell! It’s just the kind of a cloud you’d make. It’s got the shape of a——”

Monk broke off to squawl as if he were a tomcat accidentally stepped on in the dark. He had intended to say the cloud had the shape of a pig, which was not far from the truth. But Ham had given him a crack with the cane.

“If you weren’t flyin’ this tin bird, I’d sure throw you out!” Monk growled.

Doc suggested mildly: “A little more steam, please. Those fellows are far enough ahead that we can start after them.”

Levity—it was merely a way of celebrating the tricking of their enemies—vanished. The trail became grim. They hoped that the brown monoplane would lead them to Yuttal.

To more than Yuttal! To Lady Nelia Sealing! And to those beings who were existing in mysterious slavery.

The pursuit extended into hours. Doc kept far back. Only twice could he discern the brown monoplane with his unaided eye. The others did not see it at all, except through their binoculars.

They passed over Connecticut, going slightly to the west of the State capital. Massachusetts dropped behind. The sun beat warmly on the wings of the great speed plane. The cabin, literally a huge vacuum bottle, was noiseless and comfortable. The men took turns flying and watching, those off duty catching up on their sleep.

In a remote corner of the cabin, Doc took his exercises. They were remarkable, those exercises. They ran two full hours, and Doc had been taking them from his cradle days. They accounted for his terrific strength, the keenness of his senses.

He made his muscles tug and strain against each other; he juggled complex mathematical problems in his head to sharpen his concentration. He had an apparatus which made sound waves of remote frequencies; he had an assortment of scores of different odors which he identified swiftly. A page or two of Braille printing—the writing of the blind—developed his touch.

He had many other things in his routine. Two hours of terrific work!

It made the other five men perspire to watch him. After seeing Doc’s grueling daily work-out, it was no mystery why he had become one of the most remarkable of living men.

The southeast corner of New Hampshire unrolled like a green carpet beneath the plane. Then came Maine. Mile after mile of it. The pursuit seemed to have no end.

Doc’s men swapped looks. Monk voiced their thoughts.

“The ghost Zeppelin! It was sighted up here!”

“Does any one want to bet that Zeppelin is any more of a ghost than I am?” Johnny invited hopefully.

“You always want a sure thing!” Monk snorted.

Deep in the Maine woods country, the chase ended. The finish was, as they rather more than expected—the Zeppelin!

Doc was first to sight the craft, to catch the glint of sun on the great, cigar-shaped envelope with its coating of aluminum paint to minimize the absorption of heat.

It lay in a cup of a hollow among the hills, in the center of a natural clearing of considerable extent. The bow was moored to a large tree; the stern was drag-anchored to a weight, probably of logs, which permitted the airship to swing with the breeze.

Doc, who was flying the plane at the moment, banked slowly around, careful not to cant the ship enough in the heavens that it would reflect a betraying sun flash.

He could see the brown monoplane spinning slowly down into the clearing where the sky monster lay.

“Imagine that!” Ham exploded. “Where did that thing come from? What’s it doing here?”

“It might have come from a long way off,” Doc told him. “Those things can make tremendous flights without refueling.”

Ham scratched his head. “Do you think it is the vanished Aëromunde?”

“We are not near enough to be certain, of course. There is neither name nor identification numerals on the craft, you’ll notice. But her construction—she is a bit out of date, as shown by her streamlining—is that of the Aëromunde. We’ll have to get closer before we can be sure.”

“Going to fly over?”

“No. We’ll land and go forward on foot. It’ll mean a tough afternoon of walking. But it is our best bet.”

“If the airship just don’t pull out while we’re tramping through that wilderness!” Ham groaned, peering alternately at the brier patches below, then at his own immaculate garments.

Doc picked a handy lake—the great speed ship was capable of a landing on land or water—and dropped upon the surface. The beach was rocky, so they anchored the craft securely, some distance offshore, and paddled to land in a collapsible rubber boat.

Fashioning back packs out of their supplies—chemicals, electrical equipment, weapons—they trooped into the timber.

The going was tough—very tough. It began to look as if the trek to the valley where the air mammoth lay, would be an all-afternoon affair.

“I think I’ll run on ahead of you birds,” Doc decided. “When you get on the scene, don’t go too near the ship. Hang around due south of the valley. There may be guards posted. I’d better say, there are sure to be guards posted. They think we’re dead now, and we don’t want to destroy the illusion. Stay to the south, and I’ll find you.”

Doc swung on ahead, traveling easily, although he bore the heaviest pack of the group by a good many pounds.

If it occurred to his men that south of the valley took in considerable territory for a meeting place, they did not remark on it. They were cognizant of Doc’s somewhat astonishing fund of wilderness lore. He would have little difficulty locating them.

Mounting toward a ridge, the way lay through evergreen trees and small brush. Doc settled into a distance-cutting run. Miles lay ahead, but he gave no thought to fatigue. Not for nothing had he schooled his muscles from childhood.

After crossing several ridges and intervening valleys, he came to a region of swampy ground—not mire, but damp earth covered with big, thickly packed trees. The ground was a mat of brambles and thorny vines.

Doc stopped under a drooping-branch, sank to his haunches, then leaped and caught the branch. A flip put him atop it. He ran along the swaying limb as if performing on a tight rope. A plunge through space to clutch another bough on the next tree—he made a good deal more speed than on the brush-cankered ground.

It was no job for average muscles, that swinging along the aërial lanes. Nor for an uncertain eye or hand. Often he was a score of feet above the earth, sometimes more.

He covered half a mile before lowering to the ground where the timber was open, with many glades where he could sprint. Doc was traversing in an hour the distance which his men would expend two hours or more in conquering.

And Doc’s friends were far from being inexperienced woodsmen. Their physical trim was of the best. They simply fell a good deal short of Doc’s abilities.

Anxiety to solve this whole puzzling business was behind Doc’s hurry. He wanted to get Lady Nelia Sealing out of danger. He wanted to find and destroy that hideous thing of fluttering death, whatever it was.

He wanted—and this last was steadily growing in his thoughts—to probe the mystery of the slaves. What was this horrible existence to which they were enthralled? Who were they? Where were they?

Lady Nelia was one being in trouble. Those others were many. That was why their predicament was growing in import.

Well along in the afternoon, Doc came to the cup of a valley in which the dirigible lay.

Encircling the depression, and at a distance of perhaps a mile, guards were stationed. They were not many rods apart. This meant a considerable force of men were present.

Doc studied the guards with no little interest. They were natives—of Africa, he concluded—for the most part. Great, strapping fellows! Nearly all bore scars. Fighting men! And cruel men, judging from their features.

They were armed with the latest automatic rifles, and handled the weapons as if they knew very well how to use them.

There was a regular sentry system, with a roundsman visiting each man at short intervals.

“Opaf! Dur!” the watchmen challenged each sound. “Imshi! Yallah!”

The words were Egyptian for the military commands of halt, and move forward. These fellows apparently knew no English.

Doc crept past them. With an aboriginal stealth, he glided forward. Rarely was he visible amid the brush. And seldom did a leaf flutter because of his passing.

His progress was almost magical in its quiet. Doc had devoted study to this business of stalking; he had observed the great predatory creatures of the jungle, masters of the hunt.

He was soon ensconced in a cluster of evergreen seedlings, looking out upon the glade where the airship was moored.

The craft was the Aëromunde, the vanishing of which had become one of the aërial mysteries of all time. The name and identification numbers had been daubed over with aluminum paint, but from close range, they could be discerned still.

ZX 03! The Aëromunde!

Lady Nelia Sealing could be seen in the control cabin. She was seated, evidently, at a chart table. But she arose from time to time and paced nervously. Doc perceived she was chained to a girder. The chain was light, and fastened about her neck—slave fashion!

Yuttal and Hadi-Mot appeared. They rambled about, giving orders, always together. It was apparent, however, that Yuttal possessed the greater authority.

There was no sign of the sinister wicker basket.

A few hours later, Yuttal and Hadi-Mot consulted with a strapping, sepia-skinned native near the clearing edge. When the native departed, the pair lingered, conversing.

Neither were aware of a man, a great bronze man like a tawny animal, who was harbored by near-by shrubs.

“Oh, that woman!” Hadi-Mot complained in Egyptian. “Akhkh! I think it best that we use a singa upon her pretty throat, opening it from ear to ear!”

“La!” snapped Yuttal. “Bi-ziadah! No! That is enough! I do not want to hear any more about it! We take her back, alive and unharmed! Fahemt? Do you understand?”

Hadi-Mot shrugged. “She has already caused trouble. She may do so again. Wallah! Why do you want such a woman?”

“You’ll see!” Yuttal leered. “When we get her back, and she realizes there is no hope of escape, her spirit will break.”

Hadi-Mot shook with laughter. “Na’am? Yes? We shall see!”

“And you keep the men from harming her!” Yuttal scowled. “Her spirit will break, all right. It took a big crack when she found out that Savage bird was dead.”

The two moved off, Hadi-Mot saying: “We shall depart with night.”

Soon afterward, a great, tawny figure moved from the concealing bushes. Noiseless as a shadow, the bronze form quitted the vicinity.

Doc was no little relieved. Lady Nelia Sealing seemed to be safe for the time being, due to a rather grotesque idea of chivalry on Yuttal’s part.

Once clear of the sentries, Doc put on speed. He had formulated a plan—a daring plan! One that risked infinite peril. But he had five men to whom just that sort of thing was the spice of existence. They would give it a try.

Doc Savage encountered his five friends some three miles from the valley. Angling back and forth, he first found their trail, then came upon the group, perspiring and tired, creeping through a thicket of conifers.

“Whew!” Renny grinned, sagging on a log. “What a life! I’ll bet Daniel Boone never went through a wilderness the equal of this!”

“That,” Ham assured him, “explains why this country is unsettled. Why, I’ve heard that deer in these woods live out their whole lives in the same clearing in which they are born. The brush is so thick they can’t get out.”

“I ain’t in no mood for that stuff you call humor!” Monk grumbled. Then, to Doc: “I hope you ain’t gonna tell us we gotta turn around and go back?”

“You will probably wish you had done that before we’re through with this mess,” Doc replied. “But we’re not. We’re going to stow away on that dirigible.”

“What?”

“From what I was able to learn, the craft has finished its mission here,” Doc explained. “That means it must have come for the sole purpose of intercepting Lady Nelia and the two men with her.”

Doc repeated the conversation he had heard—so remarkable was his memory that he could give the exact words.

“Lady Nelia is safe enough for the time being,” he went on. “Much safer than she would be with us, if Yuttal and Hadi-Mot were still at liberty.”

Renny picked brier thorns out of his big fists. “We have gas! By taking this gang by surprise, we could make a swell stab at overcoming them.”

“Sure we could!” Monk echoed.

They had no conception of the proper odds for a fight, these two. They would, and more than once had, cast themselves against an Overwhelming force. Miraculously enough, they usually got out without being greatly damaged.

But Doc thumbed down the suggestion.

“There is hardly a breeze to-day,” he pointed out. “We could not lay a gas cloud and let the wind carry it over. Moreover, these fellows bear complete military equipment. And that, my brothers, includes gas masks!”

Johnny pulled at his jaw with a bony hand. Of the five, Johnny was the freshest. His qualities of endurance were astounding. He never tired. Ham claimed this was because there was nothing on Johnny’s bones to get tired—Johnny being only a few degrees more plump than a skeleton.

“Military equipment!” he ejaculated. “Does that mean they’re the soldiers of some nation?”

“No,” Doc replied. “They’re not that, I’m sure. They look like the scrapings of African gutters. Some are Europeans. Yuttal is an American. He’s the only Yank, I believe. But I have the whole gang catalogued as criminals.”

“And we’re going to stow away on the airships!”

Doc nodded soberly. “Exactly! We’re going to look into the mystery of those slaves!”

The group moved into a cluster of shrubs, that they might be less susceptible to discovery. They could do little until after the sun went down. In the meantime, plans must be made.

The sun sank, a majestic, exaggerated scarlet salad on the green garnish of the wooded horizon. A fan of engilded light made a beacon of the west for a time, gradually retreating. A few clouds hung like crimson puddles in the sky. Dusk came slinking in like a black fog. The sky was cloudy.

About the time night reached the great aluminum cigar of a dirigible, Doc and his men also arrived. They closed in warily, keeping together.

Doc had drawn from a fund of knowledge concerning airships and their characteristics. He knew that the cool air of night would cause a contraction of lifting gas in the envelopes, with a consequent loss of buoyancy. If he and his men could but get aboard now, their added weight would be attributed by Yuttal to shrinkage of the lifting gas. At this hour, the craft naturally became heavier. Yuttal would not—if things went right—suspect he had acquired stowaways.

A cable, swinging down from the tail of the ship, was fastened to a drag of logs.

A swarthy fellow kept watch over this drag for the sake of safety. He carried a stubby automatic rifle.

This watchman, Doc had noted during the afternoon, frequently retreated a few rods to smoke. The fact that he backed away a safe distance before lighting his tobacco showed the dirigible was charged with explosive hydrogen lifting gas.

Shortly after dark, the man moved off once more. Preparations for departure were under way. He wanted a last smoke.

Doc Savage glided to the cable. It was of wire, and offered, to his sinewed strength, simple climbing. He ran up it with his hands, making no noise.

The gloom—darkness had come quickly in the cup of a valley—concealed his presence.

The cable terminated, as he had expected, in a small windlass room. From this, a precarious catwalk led forward toward the motor gondolas and control car. Another catwalk, even narrower, trailed back toward the rudder and elevator structure.

The place was dark, although wired with electric lights. Doc did his exploring by the sense of touch.

Sliding back down the cable, he joined his five men.

“Shin up!” he breathed. He did not tell them to be quiet—they knew the necessity for that.

Renny went first. Upon his back was a sizable pack. This held five arms, a few pills of concentrated ration, and a collapsible flask filled with water from a brook in the neighborhood.

Johnny was the second to ascend. He also bore a pack, as did the others.

Doc circled a few yards from the group, watching alertly. Forward toward the control cabin, electric lanterns were blazing. Men were loading food aboard, and adding gas to the ballonets. A great pile of five-gallon gasoline tins attested to fuel already in the tanks.

These supplies had, Doc decided, been brought in by plane during the last few days. They had certainly not been transported through the wilderness.

Long Tom and Ham clambered up the cable.

A red, glowing spot, perhaps a hundred yards distant, marked the cigarette of the guard.

Monk mounted the line, swinging with a simian ease by his long arms.

The red eye of the guard’s cigarette flew in an arc and burst in a shower of jeweled sparks. Footsteps sounded. The man was coming back to his post!

Grasping the hawser, Doc left the ground. He stopped thirty or so feet up. It would not do to crowd Monk. That might mean noise.

Doc heard the guard arrive below, heard the thud of the man’s gun butt on the drag logs. The cable vibrated slightly. It was, due to the added weight in the rear of the dirigible, slightly slack.

Suddenly a gasp swished below! A surprised grunt! The guard had chanced to rest a hand on the cable—had discovered the jarring.

“Min henak?” he rasped. “Who is there?”

Over Doc’s head a faint growl of disgust sounded. That would be Monk, no little irked to think they had so nearly gotten aboard without being discovered.

“Ma taharraksh!” grated the guard below. “Do not move!”

Doc spoke to the man in his native tongue. The facility with which the words were handled was high tribute to the retentive quality of Doc’s trained brain.

“Oskut!” he growled in a hoarse, low tone. “Shut up! Thou fool! I am but adjusting the cable!”

“Ya! Samih ni!” muttered the watchman, evidently mistaking Doc for a hard-boiled officer. “Oh, excuse me. I thought perhaps it might be an enemy.”

Doc now climbed. The man below would probably never realize he had been tricked.

But things were not to come off so nicely. From above came a low whistle. Doc stared upward.

The windlass room was now lighted. The hatch was a reddish panel. Over the hatch rim, a hairy paw appeared. Monk’s hand! It gestured, beckoning upward.

But Monk’s fingers twisted rapidly, assuming different positions. The deaf-mute language! He was spelling out words:

“We’re caught!”

Doc hardly paused in his climbing, so quickly did he reach a decision. Some one must have come along the catwalks and trapped his friends!

The guess was correct. The instant Doc’s bronze head topped the hatch, he found himself facing the muzzle of two automatic rifles. Fierce, cruel, dark faces glared over the gun sights.

“Idkhol, hush!” hissed one of the pair. “Come in!”

Doc complied with the command. Nothing had altered about his bronze features. Things might have been going smoothly, for all the expression he showed.

“They crept along the catwalk from either direction,” Renny said in a low, tense voice. “We heard them, but a fight would have spread an alarm. We figured——”

“Oskut!” came the grated order. “Shut up!”

Doc’s golden eyes roved over his men. His glance dropped meaningly to his own chest. Then he drew air into his lungs and held it. The others followed his example. In a moment, they were all holding their breath.

The swarthy pair with the rifles found this behavior puzzling. They blinked and scowled and slapped their weapons meaningly.

“’Oa!” one hissed. “Take care!”

Then he drew air into his own lungs, apparently for the purpose of voicing an alarm. His lips parted. The beginning of the shout convulsed his throat.

He and his companion sagged forward silently upon their faces! The manner in which this happened was uncanny. One moment they were alert, deadly. The next, they were asleep on their feet!

Doc and his men did not relax. They were still holding their breath. Twenty seconds they retained it! Forty! Long Tom’s pale face began to get mottled and purple with the effort.

Long Tom knew better than to inhale, however, for the air was impregnated with a powerful anæsthetic vapor. The stuff had been in a pocket of Doc’s coat, contained in glass globes. With a casual pressure, unnoticed by the two captors, Doc had broken the globes.

A minute elapsed. Doc released his breath. The others promptly did likewise.

After the anæsthetic had mingled with the air for a minute, it became ineffective.

The men eyed the two swarthy sleepers.

Doc bent over them, a small hypodermic needle in his hand. He applied the tip to the forearm of each slumbering fellow.

This needle held a drug which would keep the men in a strange stupefied state until they were administered an antidote. It paralyzed certain portions of their brains, making it impossible for them to speak or think for themselves. They would be able to eat, to walk about—but only when told to do so.

“El khabar eyh?” called the guard at the foot of the cable. He sounded suspicious. No doubt he had noted that Doc, climbing into the lighted windlass cubicle, did not resemble one of the gang. “What is the matter?”

“We’re in a pickle!” Monk muttered. “That guy is gonna give an alarm in a minute. Even if he don’t, these two birds are gonna be missed!”

The electric bulb, illuminating the windlass compartment, was inclosed in a stout wire protector.

Inserting a pair of fingers between the mesh of the guard, Doc unscrewed the bulb. There was no time to hunt for the current switch.

Darkness gushed into the small cubicle. Out of Doc’s pockets came more of the glass globes containing the unusual anæsthetic gas. He pegged four of them downward, aiming at the voice of the uneasy sentry. The man himself was, of course, invisible in the murk.

“El khabar——” The sentry’s call ended suddenly. Silence followed.

“That got him!” grunted Monk. “Now—what’ll we do with the three of ’em?”

Not answering, Doc bent over the two guards. They wore stout cartridge belts. He fastened them together with these belts, tying their ankles in a secure bunch. Then, slinging them head-downward over his giant, corded shoulder, he eased through the hatch. He slid down the cable to the ground.

Up toward the control cabin, the excitement of preparing to depart had caused the encounter to go unnoticed. But it would hardly escape discovery for long.

Doc restored the belts, with which he had tied the two men, to their proper positions. He found the sentry slumped on his face, snoring softly. With the hypo needle, Doc gave the fellow a treatment of the peculiar brain-paralyzing drug. Then he arranged the three in a close group.

The woods walled in the glade at a distance of some rods. Doc ran for the nearest brush. He knew what he wanted. They were plentiful at this season of the year. Berries!

He found a patch, broke off several well-laden twigs, and carried them back. He smeared some of the purple-tinted juice on the fingers of the senseless men. He stained their lips in the same fashion.

Into numerous of the berries which remained, Doc probed the point of his hypo needle, depositing a small quantity of the drug.

A shout pealed from the control cabin.

“Cast off the stern mooring cable!”

Doc hastily clambered up to the windlass room. The next few minutes would see the success or failure of his trick.

The stowaways did not linger in the windlass compartment, not wishing to invite discovery. They moved forward, treading the narrow grid of a catwalk which gave underfoot like banjo strings.

On either side flared alloy metal girders—beams perforated and hollowed out to attain the greatest possible lightness. Taut brace wires sang softly whenever they were jarred. The fabric envelope was stretched over the whole. It was thin, that covering. A misstep meant they would plunge through. The fall to the ground, even though the craft was moored, was great enough to cause death or serious injury.

Above the catwalk, pressing down upon it, were the netting bags which retained the gas ballonets of goldbeater skin and linen.

They went slowly, for the catwalk sloped downward steeply, following the flare of the plump craft. And the way was cramped, especially for Doc, Renny and Monk, who were men of greater than ordinary size.

The framework of the dirigible was constructed of several so-called ring-girder assemblies, joined together by other longitudinal beams, and the whole braced by wire. Inside these ring-girders were ladderlike catwalks.

Coming to one of the rings, Doc led his procession to the right. Their route curved upward. Soon they were climbing vertically. They reached a celluloid-windowed observation port.

By pressing close to the port, Doc could see what was happening back at the tail anchor.

The three stupefied men had been found. Over their forms, an excited conversation was in progress. A dozen or so electric lanterns cast ample radiance.

“What in blazes has happened to these guys?” yelled Yuttal, speaking English.

“Ma arafsh!” wailed slender Hadi-Mot. “I do not know! What are those stains upon their hands and lips?”

“They’ve been eating berries!” Yuttal snorted. “But berries like that are not poison!”

It began to seem that Doc’s deception was not going to prove effective.

Only through the stupidity and greed of one of the gang, did it eventually succeed. This fellow had seized upon the berries when he first arrived, and had downed several, never a thought entering his thick head that they might be unpalatable. No doubt he had eaten other berries just like them during his stay in this remote valley.

A bilious look now overspread his unlovely features. He emitted a howl of fright. The drug, taken through the digestive tract, worked somewhat slowly. He staggered about wildly, and becoming listless, fell prone.

“Wallah!” shouted Hadi-Mot. “It was the berries which poisoned them!”

Yuttal scratched his fat knob of a head. “Yeah, I reckon. But danged if I ever knew them kind of berries to be poison before!”

Doc and his men continued their climb upward, knowing their presence was undetected.

A gentle chuckle purred in Monk’s barrel of a chest.

“They’ll take them guys aboard and doctor ’em, of course,” he said softly. “I’ll bet they find they’ve got the strangest case of poisonin’ on their hands that they ever met up with.”

The others, thinking how the drug acted—it literally made living dummies out of its victims—stifled laughter. They were in a mood for mirth. Their plans were working out perfectly.

Only Doc was unmoved. He rarely laughed, unless for the purpose of putting some one at ease, or in playing a part—which did not necessarily mean he was perpetually gloomy. He merely did not show delight, just as he rarely betrayed horror, disgust or other emotion.

Too, he was thinking of other things—of the weird death of the darkness! Of the young woman prisoner aboard! Of their unknown destination! And of the enslaved souls, the existence of whom had led him to attempt this perilous business of stowing away!

Reaching the ridge catwalk, the men sought a suitable spot for concealment.

“We’ll stay near the stern,” Doc decided. “In a pinch, we may find it necessary to seize the controls. They can be operated by hand from a compartment near the rudders, I believe.”

They took up their positions in an inspection tunnel which, being remote from catwalks and motor gondolas, was not likely to be used.

Water ballast, spilling with a roar somewhere below, denoted the air giant was being lightened for the take-off. Soon the tail lifted, swinging lazily.

With a heave that was plainly perceptible, the dirigible left the earth. The motors started—five of them. Noise of the unmuffled exhaust joined in a moaning symphony of power.

Speed gave the huge ship additional lift, plane-fashion. It sloped up into the night. A thousand feet! Another!

The stowaways could sense the tightening of the gas bags as pressure of the surrounding air lessened.

Doc pricked a hole in the outer envelope and took a star bearing through a rift in the clouds.

“Southwest,” he announced.

“Does anybody want to bet we’re not headed for Africa?” questioned Johnny, who never offered to wager unless he had a sure thing.

Hours later, the dirigible left the clouds behind and swam in a platinum haze of moonlight. Below lay what looked like a great table top of blue-black, scratched here and there with thin creamy chalk.

It was the sea, with the moonlight upon wind-blown spindrift. A dark and somber sea, sullen and threatful, it impressed the stowaways.

The airship droned on. The six men slept, but with one always on watch.

Trouble was ahead. Doc and his men sensed its coming. It could not be more than an hour or two distant. There was nothing they could do but wait. They did that, grimly.

Two days had gone. A third was well under way. The dirigible had met favorable air currents for most of the route across the Atlantic. No storms. Engines had been run at an economical speed, yet progress had been excellent, due to tail winds.

It sailed the sky lanes like a modern ship, did this craft which had been lost to the ken of mankind for many years. The Aëromunde had been the queen of her day; she was still far from outdated.

They had entered Africa somewhere beyond the Canaries, flying fairly high to avoid attention. They were now far in the interior. For hours, desert had been swinging below. The heat and the glaring sun made the earth like a platter of molten copper.

The Aëromunde had lost much of her buoyancy—the flight had been a very long one. Much water ballast had been expended. Practically all of it was gone from the tail water sacks. But the ship was still tail-heavy.

Yuttal, Hadi-Mot and their crew of villains were becoming suspicious. Several times, men had ventured aft to search for the trouble. They seemed to think there was a leak in one of the aft gas ballonets.

Ham, who had been up scouting the ridge catwalk, clambered down to report. He still carried his sword cane.

“Several men are making another inspection,” he advised. “They are going over every ballonet thoroughly as they can. There is not a chance of them missing us.”

Renny knobbed his big hands into fists and inspected them. “Well, it was too good to last. And I can stand a fight. In fact, I’d be glad to see one.”

“Yeah,” Monk grunted. “About three days we’ve been in here. I never put in three longer ones, what I mean! I could do with some water, too!”

The last of their water had trickled down their throats some hours ago. They still had concentrated rations, although these were not what could be called delicious eating. They tasted like wood.

Long Tom juggled one of the marvelously compact little machine guns, then placed it aside, a thoughtful expression on his somewhat unhealthy-looking features.

“We dare not do any shooting in these catwalks and inspection tunnels!” he declared. “They’re loaded with leaking hydrogen gas. A spark would blow the works!”

Doc put in dryly, “Don’t get worried. I think we can hold them off. The narrowness of these catwalks will prevent them rushing us. And they won’t dare use firearms, any more than we will.”

Taking several of Monk’s gas bombs, Doc worked up to the ridge catwalk. He donned a mask—his five friends had started putting on theirs as he left.

One of the ring tunnels gaped ahead. Down the one to the right, he saw a man working. He unkeyed one of the grenades and tossed it near the fellow.

The man whirled at the mushy smack of the grenade—they opened mechanically, by a spring effect, and made no flame and little sound. A knife and a pistol decorated his belt. He ignored the gun, showing he realized the fatal consequence of a shot, and clawed his knife from its sheath. The blade was long and curved. He sprang for Doc.

As he came down after the first leap, the fellow’s legs became limber as strings. He sank, weaving from side to side, and tumbled backward a few yards down the steeply-curving ring tunnel, to become wedged in brace wires. It worked swiftly, that gas.

From forward on the ridge catwalk, an excited yell pealed.

“Wallah! Ta’ala hena! Come here! Quickly! The bronze devil has come back from the dead!”

Doc flung a grenade at the shouting man. Almost instantly, the fellow caved down.

More swarthy figures leaped out of girder tunnels and catwalks as the trouble-shooting party answered the alarm cry. But the gas accounted for them in swift succession.

Monk popped into view—a milky light penetrated the doped cloth skin of the great gas bag lighting the catwalks faintly. He signaled deaf-mute talk with his hairy fingers.

“The jamboree has started!”

The other four men trailed Monk. They all wore gas masks.

Doc produced a flat case from his coat, opened it and distributed the contents. These were metal thimbles which fitted tightly on the finger tips. And each held a needle so sharp that it could penetrate a man’s skin without causing noticeable pain.

The needles were hollow; through them Doc’s remarkable brain-paralyzing drug was forced.

Doc’s men donned them, and their mere touch became capable of producing instant unconsciousness.

Ham bared his sword cane, flourished it and the fine steel twanged like a guitar string. Since the gas made use of firearms unfeasible, Ham’s sword was the best weapon in the group.

Doc placed an ear against a girder, gesturing the others to do the same. The vibration of the five motors was a throbbing moan. But over that came erratic thuds and patterings. Feet! Men climbing to the attack!

Two husky brown knifemen came mincing down the catwalk from the direction of the bows. They gripped singas with razor-sharp blades half as long as their arms. Both wore gas masks.

Fierce grins wreathed their toast-colored features as Doc advanced to meet them—bronze hands empty. They knew how to use those singas, did these two. Many a desert Arab and bush country trader had been spitted on the blades.

They were so confident that they elbowed each other on the narrow catwalk to be first to slide steel into the bronze man.

They never did find out exactly what happened next. One got Doc’s neck within easy reach; he stabbed viciously, aiming for the jugular. He missed, his arm passing over Doc’s shoulder.

Bars of steel seemed to trap the fellow’s arm and wrist. The arm disjointed. The singa flipped up and stuck in the dirigible skin. But the man did not suffer long—Doc wrenched off his mask.

The second knifeman never even struck the first blow. A flashing movement, and he found himself without his gas mask. Surprise caused him to inhale the vapor. He collapsed, falling atop his gassed companion.

Doc removed boots and belts from his victims. He tied the boots into a tight bundle with the belts.

The ring tunnels and a few vertical shafts extending from keel to ridge spewed attackers. They closed in slowly, watching each step, for the cramped ridge catwalk had never been intended as a battleground. Too, few of them had gas masks. They were wary.

Behind Doc, Ham’s sword cane suddenly engaged a knife, to the tune of a high-pitched clicking and rasping.

A scream! The knife wielder plunged in flight, wrist tendon slashed.

Some one threw a knife at Doc. He twisted aside, but instead of letting the blade go by, caught it in the bundle he had made of the shoes. He did not want the steel to pass him and perhaps find lodging in one of his five friends.

Another blade came like an arrow. He caught it in the same fashion.

“Wallah!” shrieked the swart men, and began squawling their personal opinions of Doc, his five aides, and their assorted ancestors. They used many expressive camel-driver words, expletives which would have made a Yankee mule skinner blush. But they were in no hurry to charge. There was no gas where they stood.

In the background, far way along the dimly illuminated catwalk, Doc caught sight of fat Yuttal. The man evidently thought he was out of danger.

“Hugum!” he brayed angrily at his reluctant followers. “Charge! Charge!”

Two more razor-sharp singas came hissing along the cramped, girder-and-wire-walled corridor.

Doc caught them in his bundle of boots—so close together that the sound of steel biting leather was a blended thud.

“By the life of my father!” howled one who had flung his blade. “The man is in truth a ghost! No son of a woman could move so swiftly! He is a ruh! A spirit!”

“Hugum!” shrieked Yuttal. “Charge! Are you offspring of scared dogs, that you are afraid of a little magic?”

Doc had been waiting for the gas to reach the gang, but now he decided it was not going to penetrate that far. There was a fairly strong draft along the catwalk tunnel, due to the forward motion of the airship. This had evidently swept the vapor back.

His great right arm turned into a bronze blur as he flung one of the long-bladed singas.

The brown men saw it coming. They ducked as though pulled by a single string.

Yuttal suddenly found himself to be plainly exposed—which was what Doc had calculated upon. Yuttal was too fat to dodge quickly.

Chink! The steel glanced off Yuttal’s shoulder—Doc had intended to maim rather than kill—and passed completely through the envelope fabric. Yuttal wore, under his blouse, some sort of a jacket of chain mail.

Like an overgrown desert rat, Yuttal popped from view.

Behind Doc, Ham’s sword cane was singing and clicking again.

Monk emitted a great roaring and bellowing, the sounds he always made when in a fight! His fists smacked! Men howled and groaned! The taut metal of the catwalk jarred to the stamp of fighting feet.

The attack from the rear suddenly ceased. Doc’s men were victorious.

The gang in front of Doc got up nerve enough to charge.

He flung a gas grenade.

The men who did not have masks, promptly fled. Those with masks wavered.

Doc flung two knives. Both blades lodged in leg muscles.

That settled it for the time being. The cinnamon-skinned crew retreated, dragging the pair who had steel in their legs.

They encountered Yuttal, perspiring and somewhat pale, in a vertical shaft. This shaft was a yard in width and extended perpendicularly from the ridge to the keel, terminating in a hatch which admitted to the control cabin.

“Wallah!” gritted Yuttal, addressing them in their native tongue. “You are rabbits!”

“La!” was the muttered reply. “No! By your father’s beard, we are wise men who know well when to retreat!”

Fuming, Yuttal descended to the control cabin. He traversed the ladder with an agility that was somewhat surprising, considering his figure was nearly as round as a ball.

His men followed. The only casualty of the fray then occurred. One fellow lost his balance and fell upon the gas ballonets. Unfortunately, he was holding his knife in one hand and it cut through the netting retaining the bag, as well as through the linen fabric and goldbeater skin of the ballonet. He fell in the bag and the hydrogen gas suffocated him before he could be hauled out.

Yuttal sent a volley of profanity, much of it English, up the shaft when he heard of the big leak in the ballonet. The fate of the man did not seem to bother him as much as the hole in the bag. They were already shy on buoyancy—thanks partly to the added weight of strapping Doc Savage and his five men.

Slender, handsome Hadi-Mot was in the control cabin, where he had been handling the big dirigible.

“I gather that you were unsuccessful,” he chided Yuttal.

Yuttal glowered, then scowled at Lady Nelia Sealing.

The pretty young woman, bright-cheeked and extremely attractive, sat at the chart table. The only incongruous note was the light chain which ran from her slender neck to an alloy girder.

She looked happy, and she was. Her delight was not because of her own lot, however, but came from the recently acquired knowledge that Doc Savage was far from being as dead as Yuttal and Hadi-Mot had claimed.

“You lied to me!” she told them, almost triumphantly. “You told me Savage had been killed by a bomb in his plane, but you knew all the time he was alive!”

Yuttal’s scowl became darker. “Nobody was more surprised than me to learn the guy was still kickin’!” he disclaimed.

The four aviators who had set the bomb trap for Doc in far-away New York State now put in a sheepish appearance. They took a bitter tongue flaying from Yuttal and Hadi-Mot.

“We thought we got him!” was all they could mutter in defense.

“Bass!” Hadi-Mot finally interrupted the wordy exchange. “That’s enough! While we talk, we get very near our destination. We must think of a way to dispose of this bronze man. Wallah! He has caused us much trouble!”

“And he will cause you more!” Lady Nelia cut in sharply. “He will smash this whole devilish business you are conducting! He will free those poor slaves!”

“You have great confidence in this Savage!” sneered Hadi-Mot, speaking fair English. “Yet you have never seen him.”

Lady Nelia nipped her upper lip with white teeth. It was true she had not yet seen Doc Savage. Her one encounter with the bronze man had been when she was blinded by a flashlight on the Yankee Beauty in New York harbor. Moreover, on that occasion, she had mistaken him for an enemy.

“I have heard enough of him to know what he can do!” she retorted. “He once did a great favor for an acquaintance of mine in England, and the man who was helped, told me, should I ever be in terrible trouble, to get hold of Savage. At the time, little did I think that the advice would ever come in handy!”

“But it did,” Hadi-Mot said absently.

“It did,” the young woman said pointedly. “And I have succeeded in getting him to work against you and your infernal plans. You’ve noticed he’s around, haven’t you?”

The last was nothing if not a nasty dig.

Hadi-Mot and Yuttal glared at her.

Suddenly a pleased leer overspread Yuttal’s oversize, hideous features. He scratched his tremendous nose, pulled at his huge, thick lip.

“I’ve got it!” he gloated. “We’ll use our little pet in the wicker basket. It ain’t so light in them catwalks but that the thing will go to work!”

The words caused Lady Nelia to become very pale. She sank back in the chair beside the chart table, the chain about her neck clanking on the table as she did so. She blinked in dull horror. Then, unexpectedly, she flung back her head. A piercing scream tore from her throat.

“Savage—watch out for——”

Yuttal’s puffy hand over her mouth choked off the cry. She struggled desperately, but the fat man held her and managed to insert an effective gag between her even white teeth. This eliminated her last chance of shrieking a warning, in hopes her voice would carry to Doc Savage and his friends in the distant stern of the gigantic gas bag.

Orders were now issued and relayed to the farthest reaches of the dirigible. Obeying the commands, men came weaving along the delicate catwalks.

Most of them went to a long compartment in the keel, which was fitted with bunks and served them as quarters. Entering, they closed the doors, which were of light veneer wood. They took great pains to see that the panels were securely fastened.

Other men clambered into the motor gondolas and shut the hatches, securing them tightly.

It was as if they were barring themselves from some horror which was to be loosened on the air monster. Some deadly terror of which, knowing well what it was, they were in great fear!

Yuttal, Hadi-Mot, the four villainous American aviators and three other men remained in the control room. They drew their guns and inspected them thoroughly. This showed that, so frightsome was the thing about to be released, they were willing to risk firing shots which might ignite the inflammable hydrogen, if only they could defend themselves against it. They drew their knives.

Lady Nelia sat, white as paper, trembling from head to foot and fighting the gag. There was little possibility of her getting it out of her teeth, for Yuttal had also tied her hands behind her.

Yuttal now went to a storeroom. He returned with the bulky wicker basket.

He pressed the lid of the basket to the perpendicular inspection shaft which led straight upward to the ridge. Then he turned an uneasy face to Hadi-Mot.

“You get over here,” he said thickly. “The thing will come back to your call. You’re the only one who can control it!”

“Very well,” agreed Hadi-Mot.

Taking his position, he jammed the basket to the shaft mouth. A single jerk would free the lid, letting the thing in the wicker container go free to make its way up the shaft.

“Hurry up!” Yuttal mumbled. He was plainly scared of the caged horror.

Doc Savage and his friends were having it so easy they felt a bit suspicious.

“Something is up,” Johnny muttered. “I feel it in my bones!”

“You couldn’t very well feel it anywhere else!” said the sharp-tongued Ham, eying Johnny’s thin frame.

Monk scowled at Ham, then at the others. “I wonder if we could get along without this shyster?” he pondered. “If I thought so, I’d pitch him out. I sure get tired of him trying to be funny!”

“Funny!” Ham sneered. “This gang don’t need any jokes to make ’em laugh! All we have to do is take a look at that homely fizz of yours and start chuckling!”

Monk only grinned amiably. If Ham could not think of a better comeback than that, he must be slipping.

“It’s strange!” Long Tom echoed the general feeling of uneasiness. “Every one of our enemies seems to have disappeared!”

“Did you fellows hear the start of a woman’s scream a moment ago?” Doc Savage asked unexpectedly.

The others looked at him in surprise. They had heard nothing; only Doc’s hearing had been keen enough to catch the distant shriek. The scream with which Lady Nelia had tried to warn them of the horror about to be unleashed!

Doc stood erect on the catwalk. Leaning slightly to one side, he drove a big, metallic fist against the skin fabric of the dirigible. The doped cloth burst with a loud report before the terrific blow. Tearing, Doc opened the hole to a greater size.

Without a word, he swung outside.

A terrific blast of air hit him. The titan of fabric and alloy upon which he stood was traveling at a fast clip. The air was very warm. Heat beat up from the aluminum-treated back of the Aëromunde. The African sun was reflected in a blinding glare.

Off to either side, heat-scored desert flung away to the horizon. It was an ominous waste of shifting sand dunes, as trackless as all eternity.

Ahead, low mountains reared. They were chopped masses, as if a titanic meat cleaver had hewn and beaten at the expanse of stone. Bald and hideous; repellent to the eye. Not even a bush.

Doc’s golden eyes were thoughtful as he surveyed the rugged fastness of rock. He had a good idea as to the dirigible’s position. And maps did not show these mountains.

That was understandable, however. This portion of Africa was uninhabited—a desert which offered no livelihood, even to the hardy Arabs. A few aviators flying across Africa were probably the only civilized men who had ever seen much of it.

The dirigible was heading straight for the low, bare mountains.

Doc moved toward the bows, bending against the tearing rush of wind. Footing was treacherous. A misstep meant he might easily skid off the top of the airship into space.

He was wasting no time. His scrutiny of the earth below had been brief, and now he was running easily.

The unnatural lack of life, the ominous tension which had seized upon the craft, had conveyed warning. Some plot was unfolding. Too, Doc had heard the portion of a cry Lady Nelia had uttered!

The Aëromunde had originally been constructed as a ship of war. Stationed along the ridge were four machine-gun emplacements.

Doc, reaching the first of these, noted the rapid-firers were still in place, swathed in canvas weather jackets.

Access to this machine-gun nest was through one of the perpendicular keel-to-ridge shafts—the one which terminated in the control cabin.

Doc lifted the hatch. His gaze sank through the vertical flue.

At the shaft mouth, plainly visible, he saw the wicker basket. The lid was jammed tightly to the opening. A brown, supple hand fumbled at the lid and, as Doc watched, the lid was yanked back.

A hideous black shape lifted upward in the shaft.

The deadly, fluttering creature mounted with amazing speed. It was like a trembling, lividly black cloth pulled on a string. The thing shut off what illumination came from the bottom of the shaft. The resulting murk concealed the exact nature of the horror.

Doc Savage carried no guns; he subscribed to the theory that the man who carries a firearm will come to put too much dependence upon it and will, as a consequence, be virtually helpless when without the gun.

No doubt cartridges were in the ammo drums cased beside the machine guns in the ridge emplacement. But it would take time to rip off the rapid-firer covers, detach them and turn the muzzles down the shaft.

Time! There were only splits of seconds.

Not even Doc could get the machine gun into action. Anyway, copious quantities of hydrogen gas were pouring from the shaft maw, coming from the rent where the unfortunate brown man had fallen into a ballonet and suffocated. A powder flash would ignite the vapor.

Doc’s bronze hand dived into his clothing and came out with several of his anæsthetic-containing glass globes. These, although they produced an effect similar to Monk’s gas, were not as potent. Moreover, the anæsthetic became ineffective after approximately a minute, whereas Monk’s gas retained its power until dispersed by a breeze.

Doc had a supply of Monk’s grenades. Yet, for reasons of his own, he used the glass balls. He pegged them into the shaft, causing them to break on the girders and brace wires.

The revolting creature in the shaft lifted with convulsive floppings. It entered the cloud of anæsthetic vapor. Onward, it came! The gas seemed to have no effect!

But no! The gloomy mass wavered! It hung poised! It contorted in grisly fashion! Then it plummeted back down the shaft!

Doc Savage, peering into the gloomy well of metal and fabric, found it impossible to ascertain the exact nature of the creature.

The thing crashed back into the open cage, still being held against the shaft.

The shock knocked the man who held the cage to his knees.

Terrified yells drifted upward! The men thought their monster had turned upon them. They did not know Doc had overcome it. The wicker basket with its grisly contents was dragged away from beneath the shaft.

Deliberately, Doc dropped more glass spheres down the vertical passage. These, for the most part, fell entirely to the bottom and burst, their contents flooding the control room.

The shouting abruptly subsided.

Doc waited a full minute, ears timed to penetrate the drone of the engines. The motors were not nearly as loud as usual; they had apparently been throttled down. A minute gone! The gas had dissolved.

Traveling so rapidly that he might have been sliding on a cable, Doc descended. He soon stood in the control cabin.

Lady Nelia Sealing slumped at the chart table, sleeping from the effects of the gaseous anæsthetic.

Men—Yuttal, Hadi-Mot, the four aviators—sprawled in various positions.

The wicker basket could not be seen. But the control-car door was unlatched.

Doc stepped to a window and glanced downward.

Below and to the rear, a tiny splotch could be discerned upon the hot desert sand. Doc seized binoculars which dangled from a hook over the array of controls at the front of the compartment. He focused the lenses upon the spot.

The wicker cage! The men had flung the thing overboard in their fright, wishing to be rid of their hideous creature. The basket and its contents, a pulpy mass, had been buried in the sand by the fall. It was impossible to tell what the horror had been.

The Aëromunde moaned through the hot sunlight like a vehicle of the living dead. No one stirred. There was no sound over the cadence of the motors, except for an occasional noisy snore.

The crew were still barricaded in their quarters, either unaware the wicker basket had been hurled overboard or fearing the creature of fluttering death had not been in the container.

Doc’s gaze ranged the controls, centering particularly upon the gauges showing the amount of fuel remaining, the quantity of ballast still unexpended, and the status of the gas supply.

Fuel was almost gone; little ballast reposed aboard; the ballonets were slack, the one above virtually empty. These things told Doc that the dirigible could remain in the air but two hours or so longer.

He had hoped he and his friends might seize the craft and sail it to civilization. No chance of that! They would never get out of the desert!

The chain securing Lady Nelia was padlocked securely at her neck and a girder. Doc worked over the padlock with one of the young woman’s hair pins. He got it open.

Carrying her slender form easily, he mounted the shaft.

He left Yuttal, Hadi-Mot, and the others behind—unharmed. He had an excellent reason for doing this. The men would revive in time to direct the landing of the airship.

The goal of the flight—the lair of these men—must be near, and Doc wished the leviathan of the air to reach its destination. He was curious to fathom whatever the secret the spot held.

It was characteristic of the big bronze man, this permitting himself and his aides to be carried into the rookery of his enemies. Reckless, overconfident, his move might have seemed to the uninitiated. It was none of these. He was merely unafraid, and prepared for any jeopardy.

Doc’s five friends welcomed his return with astounded glances at the limp form of Lady Nelia. They rattled questions, to which Doc gave terse, descriptive replies.

While Doc administered restoratives to hasten Lady Nelia’s return to consciousness, the others clambered out on the ridge of the sky giant to get first glimpses of the strange, bleak country ahead.

They beheld an awesome sight The Aëromunde was over the low, rugged mountains. The array of rocky peaks lay in the shape of a ring, miles across.

In the center of the stony ring lay an oasis. A lost oasis! For certainly no hint of its presence would have reached a traveler on the desert.

A vast platter of green! The utter denseness of the vegetation caused the men to turn binoculars upon it. They saw such a jungle as they had seldom beheld.

Tropical trees were matted in such profusion that they seemed to grow one out of the other. Lianas and aërial creepers tied the whole into an impenetrable mat. Orchids and other rare and brilliantly colored blooms could be seen.

Luxuriant though the jungle was, and contrasting as it did with the blazing desert, the oasis, nevertheless, possessed a sinister and unwholesome air. It was like something green and hideous lying there in an infinity of furnace-hot, wind-tortured sand.

Black, living specks sailed in the air above the strange oasis.

Johnny, after studying the dark birds with his binoculars, said: “Pharaoh’s hens!”

“Huh?” gulped Monk.

“Vultures!” Johnny then elaborated. “They call this species Pharaoh’s hens.”

The others shivered. Scavengers! Birds of death! They hung over the repellent green of the oasis as if it were a carrion thing.

“Say, the buzzards behave strangely,” Ham ejaculated after a time. “Watch ’em! They circle and circle, but they don’t go near the jungle. It almost looks as if the birds were afraid of the vegetation.”

“The thing that impresses me,” Renny muttered, “is that there are no other birds. Only vultures!”

“Hey—the birds are not afraid to go down!” Monk ejaculated. “There goes one black cuss now! See ’im!”

The men watched. They witnessed a weird, horrible occurrence.

The black scavenger bird settled swiftly into the vegetation. Apparently, it grasped some titbit of food.

The vulture sought to lift into the air again. Its hideous black wings flailed madly. But it did not get off! The plant, the sickly-hued shrub upon which it had landed, seemed to have grasped the bird.

Slowly, the shrub closed its tentacle-like shoots. It enveloped the vulture!

“Holy cow!” Renny croaked.

Of the five men, Johnny seemed the least surprised. He possessed a knowledge of strange earthly plants second only to Doc’s learning.

“Carnivorous plants!” he ejaculated. “They grow in boggy regions, and trap insects and small animals which come in contact with them! That’s the way they get food.”

“That vulture wasn’t so small!” Monk muttered.

“No-o-o!” Johnny admitted. “The carnivorous qualities must be developed to a more than ordinary degree!”

Ham now pointed with his sword cane. “There seems to be our destination!”

The spot Ham indicated was a patch of rocky ground, higher than the surrounding jungle. This stony prominence was split with a deep crack.

The airship was swinging over the rent. Steep, overhanging, the rocky walls were three or four hundred feet in height.

“Hey!” Monk yelled. “D’you see what I do?”

“A sort of natural dirigible hangar!” one of the others grunted.

The overhang of the cliff on one side of the deep rut in the rock formed a ready-made shed. In this, stout fore-and-aft mooring masts of timber had been erected.

Men appeared on the ground, dozens of them. They were assembling in a compact group in the center of the cut.

A landing crew to handle the Aëromunde!

It was Renny who called attention to one of the most disquieting discoveries of all.

A rectangular stockade! It was constructed of tall posts, set so closely together that nowhere was there space for a man to squeeze through. At one point was a stout gate. The tops of the posts were sharpened to ugly points.

Within the stockade were human figures—dejected, wasted beings! Many were little more than living hulls.

They were chained, neck to neck, in groups of ten.

The forlorn sight was blotted from view as the dirigible swept over. The craft turned slowly and began nosing down into the rent. A slight breeze sweeping steadily between the precipitous walls simplified the landing, eliminating the menace of a cross wind.

It was while the giant aluminum cigar was over the north end of the crack that Doc’s men made an additional find—a deep pit, not unlike a monster well.

Treacherous paths led down into the void. Chained figures shuffled along these paths. And, when the Aëromunde was in a favorable position, they could observe many more shackled beings slaving in the bottom.

Around the mouth of the digging, bluish piles of waste were heaped. The stuff seemed to be clay—blue clay, with a faintly greenish tinge.

“This clears up the mystery of the slaves!” Ham declared grimly. “The slaves are poor devils being forced to work these diggings.”

“Yeah—being made to mine diamonds!” Monk muttered, forgetting himself so much as to agree with Ham.

“The blue ground means diamonds, of course! This must be the source of the stones Lady Nelia carried!”

The latter statement reminded them of something.

“Lady Nelia!” Renny grunted. “We’d better see if Doc has got her conscious yet.”

“And we’d better get us some plans, too!” Monk asserted. “We’re getting into a mighty tight spot!”

The men clambered back inside the airship body.

Lady Nelia Sealing was conscious. She gave them a faint, but entirely brave smile.

Doc Savage, in spite of their deadly peril—they were only six men against scores of heavily armed opponents—went through a formal routine of introductions.

The fact that they took the situation so calmly obviously strengthened Lady Nelia’s already fine courage. She acknowledged the presentations, saying to Renny: “It is unfortunate we did not know we were allies when I rode from the New York water front to the Hotel Rex in the taxi you were driving.”

Renny’s usually solemn face wreathed in the widest of grins. He liked this young woman. She possessed a nerve that was surprising for one of the feminine sex.

“We’ll have to postpone Lady Nelia’s story a bit,” Doc said.

He clambered out on top of the dirigible to reconnoiter. The airship was barely moving. Landing was a ticklish business, for care had to be taken that the gigantic craft did not rub against the rocky cliffs and tear her sides out.

Somebody took a shot at Doc with a rifle.

Yuttal or Hadi-Mot—both were certainly conscious by now—must have dropped a note, divulging the situation to those below.

The bullet missed Doc by a few feet, tearing a small hole in the Aëromunde. It had been fired from a spot near the stockade which held the chained slaves.

The big bronze man dropped back inside the hull before a second slug could be discharged. He had seen enough.

“Here is our plan of action!” he declared, calling his aides together.

He spoke rapidly, each clipped sentence conveying an abundance of meaning. When he finished, no questions were asked, so clearly had he outlined their immediate work.

Long Tom leaped to his bundle of electrical apparatus, opened it and began to assemble the device which Doc had requested.

The other four spread out along the ridge catwalk, taking up widely separated posts. In their hands, they held stout pocketknives.

“You had better stick close to me,” Doc told Lady Nelia.

The young woman nodded quietly, not taking her eyes off Doc. She had, as a matter of fact, been watching Doc almost steadily, averting her gaze only when she thought the bronze giant might notice.

She seemed fascinated by Doc’s strapping physique, his quietly gentle manner in the face of danger, and—not by any means the least point—his undeniably good looks.

Men seldom noted that Doc’s features were extremely handsome, being drawn more by his nearly superhuman muscular build and his mental attainments. But women noticed—and could not help but be fascinated.

Long Tom straightened from his task. “I’ve got it!”

He had assembled a powerful induction coil. The input terminals of this he had connected to the electric light circuit which extended to a searchlight mounted in one of the machine-gun emplacements. One of the output wires, he grounded to the metal frame of the dirigible.

To the other output terminal, Long Tom connected a long, heavily-insulated wire, to the free end of which was a metal weight—he had dismounted one of the machine guns and was using a part of it for the weight.

The men waited. Of the six, Doc and Johnny understood the language of their enemies. Renny had once handled an engineering job on the Nile, and possessed a smattering of the tongue.

They were alert for a certain command from below. The dirigible was now very near the ground—the landing lines should soon be seized by the handling crew.

At last, the shouted words came:

“Shidd! Shidd! Ishtaghal ya walad!”

“Pull! Pull! Work, oh boy!”

The wire cable landing lines had been grasped. The groundsmen were being ordered to haul the air monster down.

“All right!” Doc told Long Tom.

The electrical wizard dropped the weighted end of his wire to the earth. Current from his induction coil would now make a circuit through the wire, the earth, the dirigible frame, the metal landing lines and the bodies of the men handling the lines.

The airship frame was bonded, a protection against static and lightning, so there was no great chance of a spark igniting the hydrogen. Long Tom had calculated the strength of his current, too, so as to lessen the chances of a spark which might prove disastrous.

He threw a switch. A whine came from the induction coil interruptor. Invisible current spurted into the circuit—not a killing current, but one which would deliver a robust shock.

A salvo of yells arose from the men holding the landing lines! Taken by surprise, they wrenched their convulsing hands from the metal cables.

The Aëromunde, free of restraint, was swept slowly and ponderously down the chasm.

Long Tom shut off his coil.

The shouts had been the signal for Doc’s other helpers. They went to work with their knives on the gas ballonets. Slashing madly, they opened great rips in the linen and goldbeater-skin cells. They wore gas masks, that the escaping hydrogen might not suffocate them.

The dirigible began to sink, her buoyancy dissipating through the rents. In the control cabin, ballast levers were wrenched furiously. But there was not enough ballast aboard to lighten the airship sufficiently.

Down—the ship settled. She touched the sandy floor with a loud scraping noise. She keeled!

Doc’s bronze arm kept Lady Nelia from being flung into a tangle of girders and brace wires.

She rewarded him with a ravishing smile for the service.

The Aëromunde finally scraped to a stop and lay as if mortally wounded. The airship was not greatly damaged—the rips in the gas ballonets could be quickly repaired. And no doubt there was a large supply of hydrogen on hand in this weird, lost oasis.

Doc Savage’s silken line, with the grapple on the end, came into use. Rapidly, his friends slid down it, over the bulging flanks of the dirigible, to the ground. They carried the packs which held their equipment.

Doc was last to go down. Doubting that Lady Nelia could navigate the line without injury to her slender hands, Doc had her cling across his shoulder.

Reaching the ground, he found his men industriously pegging gas bombs at the crew of the airship. Nobody dared begin shooting, because of the leaking hydrogen.

“Let’s get away from here!” Doc’s powerful voice rapped.

They retreated, taking a direction such that the keeling hulk of the Aëromunde would shelter them from the landing crew who had not yet caught up with the wind-borne ship. These latter men were out of the hydrogen gas area, and could shoot without danger of causing a fire.

“We’d better lay a few eggs as we go!” Doc declared.

Suiting action to the statement, he lobbed one of Monk’s gas grenades far behind them.

“Set the time fuses for three or four minutes!” he warned.

The grenades were fitted with a tiny clockwork fuse, whereby detonation could be delayed for as much as several minutes. Their pursuers would be over the bombs, or ahead of them, before they released. Thus the breeze would not sweep the vapor harmlessly away.

The ground crew rounded the extremities of the giant airship. Some encountered the first gas barrage which Doc’s men had lain down, and collapsed. Others ran on, and clear of the hydrogen, turned loose with automatic rifles.

Bullets ripped lines through the sand, made shiny smears on the cliffs or snapped past the running group with piping, sudden whistles.

Doc steered the retreat to the right. He did not offer to return the fire, nor did his men. They were fighting men; they knew when the odds were too great.

Large boulders, masses of stone toppled from the cliffs above down through the ages, offered them shelter. They worked ahead, and left the crack.

“Do not try the jungle!” Lady Nelia warned. “Escape by that route is impossible!”

“We’re not trying to escape,” chuckled the homely Monk. “The idea is to get set some place where we can fight off an attack!”

They swung around and mounted the rocky hill which the crack bisected. The going was easy, their pace correspondingly rapid. They crossed a comparatively smooth stretch and came to a cluster of wind-carved rocks. These stood clear of the surroundings, comprising a natural fort of sorts.

“We’ll camp here a while,” Doc said dryly. “Long Tom, let’s have a coil of fine insulated wire.”

Long Tom extracted the wire from his pack.

Moving as swiftly as possible, Doc strung the wire around the rock pile at a distance of perhaps three hundred feet, carrying the two ends into their shelter.

Pursuit seemed to have come to a sudden stop—the work, doubtless, of the timed gas grenades they had strewn along their back trail.

To the ends of the wire, at Doc’s direction, Long Tom attached a device of vacuum tubes working on the principle of the early-day radio sets which squealed when a hand was brought close to them. Only in this case, should any one come near the wire, a squeal would sound from a small loud-speaker.

“May come in handy after dark,” Doc explained. “It’ll tell us if any one tries to sneak in close enough to throw a bomb.”

Two or three glances went skyward. The sun was nearing the horizon, although still blinding in its superheated glory.

They worked in silence, piling small stones in breastworks which would stop bullets. It was very hot—so hot they did not perspire a great deal. Or perhaps the lack of perspiration was due to the fact that they had been without water nearly the whole day. Nor was any water to be had at this spot.

Ten minutes saw a fair defense.

A few bullets drifted past shrilly, or spanged on the rocks. The belated pursuit had arrived.

Doc’s men did not return lead. The sharpshooters did not try a charge, showing they had become wary.

“We might as well have your story now,” Doc told Lady Nelia.

That Lady Nelia Sealing was a young lady with a nerve as unusual as her beauty, was becoming more and more evident. She ensconced herself in the lee of a boulder and began speaking as calmly as though she were in a London drawing-room. The qualities which had made her one of England’s outstanding aviatrixes were evident.

“Yuttal and Hadi-Mot have been partners for many years,” she said. “Some fifteen years ago, they were engaged in the ivory and slave trade in this part of Africa. The slave trade was outlawed, of course, and both men got into trouble with the law. There was a price on their heads—charges against them which would have meant long prison terms.”

She paused to glance up at a procession of shiny freckles which had appeared magically on a spire of rock—splattered bullets from an automatic.

“I am giving you their history as I learned it while a prisoner,” she explained. “The fact that Yuttal and Hadi-Mot were outlaws drove them to remote districts. In their evil moving about, trafficking in ivory and slaves, they came upon this oasis.

“The jungle surrounding this spot is impenetrable, due to the presence of carnivorous plants of huge size as well as poisonous thorn trees and creepers. Nothing lives in the growth.” She glanced upward and shuddered. “Nothing—except the vultures—and many venomous snakes, upon the carcasses of which the vultures feed.

“While exploring the edge of the oasis, Yuttal and his partner saw the vultures fly out of the place bearing shiny objects in their beaks. These shiny things proved to be diamonds. The birds—crowlike—were evidently attracted by the glitter.”

At this point, a shrill squeal came from the wire warning device. One or more of the besiegers were creeping in!

Doc borrowed Renny’s compact little machine gun and began a careful watch. He soon located a leg projecting from behind a rock.

The gun roared—firing so swiftly that it set the air throbbing as if a Gargantuan bull fiddle had come to life!

Shrieking, the skulker dragged himself back! His leg was mangled.

The piping wail ceased to come from the alarm, showing the man had advanced alone.

Lady Nelia continued, seeking to speak as though nothing had happened, but not quite managing to do so.

“For a year or two, Yuttal and Hadi-Mot haunted the outskirts of the oasis, shooting vultures every time they saw one which looked like it might be carrying one of the gems. They gathered a fair fortune in stones.

“But they were greedy. They wanted to get at the lode from which the stones came. They got a plane and flew over the oasis, discovering the deposit of blue ground which held the stones. They knew it was fabulously rich. They could see gems glittering on top of the ground.

“There was no landing for a plane. There is now, of course, because they have cleaned out the rubble in the crack. But the bottom of the gash was originally too rough for a landing field.

“The upshot of it was that they took the money from the diamonds they had already found, and hired a gang of thugs. These men got aboard the Aëromunde and seized the ship. They tied weights to the officers and threw them into the Mediterranean. You will recall that the body of the commander was found years ago. It must have broken away from the weight.”

The sun seemed to be sinking much faster as it neared the evening horizon, a peculiarity of tropical regions.

“The crew of the Aëromunde were enslaved and made to work the diamond mine,” Lady Nelia went on, with a slight shudder. “Other men have been seized and brought here. Yuttal has an organized ring in Cairo which keeps him supplied with victims. You see, the death rate among the slaves is high. This is a horrible climate for a laborer.

“The whole thing has been kept secret, because Yuttal and Hadi-Mot are wanted criminals! They have a gigantic plant here, when you consider its secretive nature. Supplies are brought over the uninhabited desert and into the oasis in the airship. The original crew of the dirigible have been kept alive and forced to maintain the ship in repair, as well as teach Yuttal’s men how it is operated.”

“Where do you come in?” Doc interposed.

“I was making a London-to-Cape-Town flight, and my plane developed engine trouble,” the pretty aviatrix explained. “I landed here. They took me prisoner.

“They didn’t harm me.” She shuddered violently. “Ugh! That was because Yuttal has some insane idea that I’ll marry him willingly in the course of time.”

She gave a grim little laugh. “Instead, I enlisted the aid of Red and Jules Fourmalier. We got to the supply of linen and goldbeater skin kept to repair the airship, and made a balloon, filling it with hydrogen—a large quantity of which is also kept here. We got away—the wind carried us clear of the oasis.”

Bullets were screaming among the rocks with increasing frequency.

Doc interrupted the story while they did a little fighting back, shooting always at arms or legs. They were all accomplished marksmen. They soon discouraged the attack.

“We three managed to cross the desert,” Lady Nelia resumed. “But Yuttal and Hadi-Mot followed us.”

“You had some of their diamonds?” Doc queried.

“Not theirs! Those gems were stones Red and Jules and I had mined ourselves, and smuggled into hiding. The reason we were followed was to kill us—to silence us!

“We got to the coast and took the first steamer, which happened to be the Yankee Beauty, bound for New York. Our pursuers learned we were on the boat. They tried to overtake us in the airship, but fortunately the weather was too foggy for them to find the boat.”

Darkness came—very suddenly, it seemed to the men enrapt in the strange tale the young woman was telling.

“We knew Yuttal and Hadi-Mot would stop at nothing to end our lives!” Lady Nelia said in the murk. “We decided against appealing to the law for help. Even had our story been believed, the authorities could not have protected us from devils as clever as Yuttal and Hadi-Mot. Too, justice might never have reached the pair. This part of Africa is so remote it is almost like another world.”

“You decided to get hold of me?” Doc said quietly.

“Yes. I had heard of you. We radioed—and you know the rest. You were not to be found. We each contributed part of our diamonds to my pool to offer that tremendous reward. You see, the diamonds meant little to us. If we didn’t find you, we would be killed, and money from the sale of the gems would be of no use. If we did find you—there are plenty more diamonds in this oasis.”

Her voice lifted, became emphatic. “Diamonds! Yuttal and Hadi-Mot have untold wealth in the stones! Bushels of them, almost! They have been selling them, a few at a time, down through the years. But only a few in each sale—so as not to glut the diamond market and bring prices down.”

“Holy cow!” Renny muttered, overcome by the magnitude of the thing in which they were involved. “When I first heard of that million-dollar reward, I thought it was about the most fabulous thing I had ever heard of. Now it turns out that that was just a starter!”

“Well, I hope it don’t get too big for us to handle,” Monk grinned.

Squirming about, Monk projected his gorillalike head and shoulders above the bulwark. It was dark; he had no fear of being selected as a target.

Standing furtively erect, Ham swiped his sword cane above Monk’s head, causing the blade to make a bullet whistle of a sound.

Monk ducked wildly, then discovered the hoax and emitted a roar!

Ham promptly scuttled away, with Monk prowling in pursuit.

Lady Nelia managed a strained laugh. “They do not seem greatly worried.”

“They haven’t got sense enough to worry!” Renny chuckled.

This was punishing the truth somewhat, since Ham and Monk were leading lights in the fields of law and chemistry, respectively.

Johnny was tying his glasses on with a string around the back of his bony head, a precaution against losing them in a fight in the darkness.

“Things are a little too quiet!” he grumbled. “I wonder if Long Tom’s whistler could be out of whack——”

The words froze on his lips. A faint, grisly shuffling sound had reached their ears. It came out of the sky—came from a dozen different directions! From every side!

Lady Nelia screamed hysterically.

Against the stars—the moon was not yet up—weird, hideous creatures appeared. They seemed like bundles of dirty cloth folding and unfolding in the air. They swooped for the rock pile which sheltered Doc and his friends.

Near by, Monk and Ham howled simultaneously: “Watch out! They’ve turned their infernal night killers loose on us!”

There was no time to don gas masks so that the grenades could be employed.

Doc whipped to Long Tom’s pack of electrical apparatus. He drew out the infra-light lantern and the sack which held the fluoroscopic glasses. One of his bronze hands was switching on the lantern as the other clamped the spectacles in place.

“Get these goggles on!” he rapped.

The invisible light gushed out not a moment too soon. It disclosed one of the flying creatures not more than a dozen feet above. The weird aspect of the light added to the frightful appearance of the thing.

Doc’s compact machine gun moaned deafeningly. Every third bullet was a tracer—he had put in a tracer-charged drum before darkness. The slugs ran upward so swiftly they resembled a thin red string.

Shooting from the hip, Doc cut the flying horror almost in halves with the scarlet thread of bullets.

Another came swooping. He got that one also.

Then his men got the strange goggles on and went into action. The moaning of the rapid-firers made a sort of colossal music.

But more of the hideous things came. Hundreds! Fighting them off began to seem a hopeless task.

With one hand, Doc clipped his gas mask in place. Then, realizing there was no spare mask for Lady Nelia, he removed it and prepared to offer it to the young woman.

He halted when he observed Monk and Ham, scowling with mock fierceness at each other, matching a coin to see who should surrender his mask—at the same time doing some excellent shooting.

Ham lost, dooming himself to an hour or so of enforced slumber.

Doc replaced his own mask. He had work to do in the course of the fight—work which he did not wish interfered with.

When every one but Ham was masked, they began tossing gas grenades. Monk, adding insult to injury, purposely dropped one metal egg directly in front of Ham. Picking it up, Ham managed to fetch Monk a nasty crack before he keeled over.

The attacking creatures began to collapse, dropping with mushy thuds to the rock. For the next few minutes, it fairly rained the things.

Then quiet came.

Monk, picking up one of the deadly flyers, inspected it curiously. His snort of surprise blew the mouthpiece of his mask from between his teeth. A strangely vacant look upon his homely features, he lay down slackly, almost beside Ham.

Renny kicked the creature Monk had been inspecting, then made deaf-mute talk on his fingers.

“Vampire bats!” He began dispatching the things with his gun.

Fifteen minutes later, when the breeze had carried the gas cloud away, Lady Nelia Sealing imparted some additional information.

“Ugh!” she shuddered. “They’re just ordinary vampire bats, except that they are poisonous, and very large. Hadi-Mot takes care of them. He has trained the things to come when he makes a tiny squeaking noise. He always makes that sound for a time before he feeds them.”

Doc had been inspecting the hideous snouts of the things. Now he straightened.

“I thought perhaps the fangs were artificially poisoned,” he said. “But that is not the case. They seem to be venomous by nature. Did you ever hear where they came from?”

“From some savage native tribe far in the interior of Africa, I think,” the young woman replied. “The tribal witch doctors had developed the things, spending generations at the task. They used them to murder savages upon whom they had cast a spell. At least, that is what Hadi-Mot boasted. He and Yuttal lived with that tribe when they were trading.”

“That probably explains it,” Doc decided. “The things are bloodthirsty by nature, and when famished, will go for any living form. The venomous quality might be developed through a process of feeding or breeding.”

Artificial restoratives revived Monk and Ham, giving Ham a chance for the last laugh. Monk listened to it in grumpy silence.

“The poisonous bats are kept to be turned loose when any of the poor slaves manage to escape,” Lady Nelia said in a somewhat unsteady tone. “If the infernal jungle does not stop them, the bats will.”

She shivered, and sought Doc in the darkness. Ostensibly, this move was to obtain the encouragement offered by the nearness of the big bronze man. Actually, Lady Nelia could not get Doc’s handsome features out of her thoughts.

She made, however, a slight mistake. She encountered the sour-featured Renny and seated herself very close to him, which made Renny feel very warm and comfortable. He did wonder, though, why the attractive young woman departed shortly after he spoke to her.

The night dragged on. No one slept. They could hear occasional distant shouts. Commands! Their enemies were not idle, but there was nothing to do but wait.

The waiting came to an end some two hours later, when a low wail from the wire alarm broke the tense spell.

“I wonder what they’ll pull now,” Long Tom muttered. He turned on his infra-light and swept the beam about.

The eerie luminance came to rest upon a strange-looking contraption. This consisted of a crude, but very solid cart, upon which were lashed several large steel cylinders of the type used to contain hydrogen.

Men, sheltered by a plate of steel, were laboriously shoving this forward. So heavy was the device that they seemed to be using light girders, no doubt from the airship spare parts supply, as levers.

Renny boomed: “What is that th——”

He found out the next instant. He observed wires being jerked. These opened valves on the tapering snouts of the hydrogen cylinders. With a roar, gas rushed out. From behind the bulletproof shield, a blazing brand sailed forward to ignite the vapor.

Flame spurted a space of many yards. It flung a wave of heat which reached Doc and his friends with a near-cooking temperature.

The men behind the steel plate urged their cart forward more rapidly.

Johnny yelled: “They’ll roast us out!”

Doc’s men opened with their machine guns. The scarlet tracer threads converged on the metal plate, showering sparks, making the whole shield red with phosphorus.

Stopping the fiery carriage with bullets was impossible, they speedily saw.

The thing came ahead remorselessly! The brown men pushing it howled gleefully in their native tongue.

From all sides, automatic rifles spat cackling volleys. Torrents of slugs drove Doc and his aides to prone positions among the boulders.

Heat rolled in stifling waves. Their skin began to redden. Perspiration oozed.

Lying flat, Doc Savage fumbled in his pack. He brought out grenades. These did not contain gas. They were blue-black, efficient looking.

Chancing the leaden storm, he hurled one.

Crack! The report was sharp, sharper even than a pistol report. And it rendered them deaf for some seconds, it was so loud! A blinding white flash accompanied the detonation.

The burning hydrogen was extinguished.

The general relief was so great that for several moments no one spoke.

“What was that stuff?” Monk muttered at last.

“Did you ever hear of snuffing out an oil-well fire with explosive?” Doc questioned.

“Sure. They blow out gas-well fires that way, too.”

“There was a very powerful explosive in that bomb,” Doc told him. “It was strong enough to put out the flame.”

They now turned their infra-light on the remains of the fire carriage. The thing was a wreck.

They were just in time to witness the disappearance of the last of the gang who had been pushing the unusual vehicle. Not one had been killed, although three could hardly crawl! They had been knocked backward many feet by the steel bullet shield, which had broken the force of the blast.

The rest of the night gave promise of being moderately quiet, for the crackling of automatic rifles soon ceased.

Long Tom kept his peculiar light going steadily, since the encircling wire had been broken and battered by the explosion, rendering the alarm inoperative.

“The batteries in this light won’t hold out for another night,” Long Tom offered uneasily. “The thing draws a lot of juice, and the batteries are very small.”

“Turn it off for a few minutes,” Doc suggested. “No need of using it steadily.”

Long Tom complied. Some five minutes afterward, he switched the device on again.

A stifled shriek came from Lady Nelia.

“Oh! Mr. Savage is gone!”

It took the men some time to soothe the young woman’s anxiety by explaining that Doc had this disconcerting habit of vanishing silently when he wished to depart on some mission of his own.

“I guess he does it that way so he won’t have to listen to us argue reasons why we should go with him,” Monk said cheerfully. “Don’t you worry, miss. Doc could climb in the devil’s vest pocket, and the old boy with the horns and tail would never know it!”

But Lady Nelia could not repress her uneasiness.

Her frame of mind would have been even less settled had she been able to observe Doc at the moment. He was standing hardly more than a double-arm length from four of his enemies.

“Wallah!” one of the quartet muttered. “With the coming of the day, we shall find means of getting rid of those sons of camels.”

“Na’am!” agreed another. “Yes! But by the life of my father, it pleases me that we shall see no more fighting to-night!”

Doc moved on, a bronze wraith lost in the murk of the African night. It was well to know his companions would not be attacked in his absence.

He descended to the entrance of the gash which slashed through the rocky hill, and entered. His going was slow, careful, and he paused often to listen, his ears hearing all noises.

The darkness was more intense within the defile. But he had retained a mental picture of the place, including distances within it. He made for the slave stockade.

As he came nearer, he was guided by piteous sounds—low groans and strange, unreal nightmare cries of the men confined within the inclosure.

A match flared as a watchman lighted a cigarette, and the fitful gleam disclosed a peculiar spectacle. The sentry was incased in a cage made of light, stout rattan. The wicker affair had no bottom. The fellow carried it about him, looking not unlike an oversize, toast-colored canary in a cage.

Doc needed only the one glimpse to tell him what the cage was—a defense against the venomous bats.

Why the guards should be wearing the cages continuously became apparent a few minutes later. Drawing closer to the stockade of the slaves, Doc’s sensitive nostrils detected a faint, nauseating odor. The stench of the bats!

A faint shuffling ahead!

Doc waited. But the bat did not come nearer. For some time, Doc listened. He heard other faint fluttering sounds—sounds which told him the hideous vampires were picketed around the stockade like so many watch dogs!

An electric lantern blazed brilliantly on the other side of the stockade, casting a faint grill of light through the upright, sharp-pointed posts of the inclosure. The figures of the slaves could be distinguished—some asleep, some too tortured for slumber, and nearly all of them occupying the grotesque positions of men in a state of physical exhaustion.

The sentry with the light was making a round to see that all the picketed vampires were in position.

Doc had entertained the idea of gassing the creatures. Now he dismissed the thought. Such an act was certain to be discovered. Instead, he reconnoitered a bit.

Near the cliff, he soon found a long, thatched shed. Within this were scores of spare cages of the type used by the sentries. Doc appropriated one. Once inside it, he walked through the line of picketed bats.

Two of the things fluttered against the wicker cage, making considerable noise. But it was evident the vampires often struggled against the small chains holding them to pegs driven in the ground, because the flurry attracted no unwelcome attention.

Doc found an aperture between the stockade posts through which he could thrust a great bronze arm. He made no sound, and none of the slaves seemed aware of his presence.

In the sand inside the stockade, Doc scooped a hole. He drew a rather bulky packet from a pocket and buried it, smoothing the sand over carefully, that the cache might not be discovered. Then he retreated.

He got away without being observed, and made for the great shape of the disabled Aëromunde. Although the gigantic cigar of fabric and metal was canted over on its side, the motor gondolas were accessible. They had escaped damage.

In fact, the whole airship was not seriously mutilated. It could be repaired in a short time and sent into the sky.

Doc clambered into the motor gondolas, his command of stealth enabling him to escape the notice of two watchmen posted near by. In one gondola, he located a wrench. Using this, he removed essential parts from each motor.

The purloined mechanism he buried in the sand, marking the spots by nearby boulders so that he might find them again. The dirigible, he was now confident, could not be used to drop bombs upon their defense.

The parts he had removed were articles which seldom wore out or broke. It was highly improbable that spares were kept on hand in the oasis.

Doc was entirely human, so he mentally congratulated himself upon his good work. And like many a self-satisfied individual who has encountered an unexpected setback, trouble pounced upon Doc when he felt the most like pluming himself.

One of the watchmen flung a casual beam from an electric lantern. The glitter impinged upon Doc’s form.

“Wallah!” shrieked the sentinel. “Look! It is the devil himself!”

Shots rang out! But Doc Savage had covered many yards, and was traveling like a desert wind. The bullets snicked harmlessly through the night.

Doc veered slightly to one side and seized the cage which gave protection from the vampires. Chances were excellent that he might need it.

A light spotted him. Lead pattered like vicious hailstones.

Dodging into a rocky hollow, he lost the light, then went on, the somewhat unwieldly cage held above his head.

“Hazir ol!” The shouts spread with telegraphic speed. “Alert!”

At scattered points, electric lanterns spat glaring white funnels. Then, at three widely separated spots, brown men propped hydrogen cylinders up so they pointed at the night sky, opened petcocks and ignited the escaping gas.

The terrain became entirely too bright for safety. Doc’s figure was sighted. He became the focus of volley after volley from the automatic rifles.

His means of return to his friends was securely cut off.

Shooting with uncanny accuracy, Doc doused a few electric lanterns. But that did not help much. The flaming gas gave the greater illumination.

Doc found himself driven to retreat toward the encircling jungle. It speedily became evident that his only escape was into the deadly vegetation.

Once this was apparent, Doc wasted no time in useless debate. Dropping the rattan cage over his form, he entered the unlovely growth. The contraption had been built for a man of much smaller stature. Doc was forced to crouch as he walked.

For some yards, the lights on the rocky hill brightened his way. And for some yards, nothing untoward happened. He might have been penetrating an ordinary tropical maze of plants. Then the horror of the place began to make itself apparent.

There came a slight tug at one side of the cage. Doc used a small flashlight which he drew from a pocket—and came as near shuddering as he ever did.

The tentacles of a huge carnivorous plant had grasped the wickerwork of the cage. Bilious and unwholesome in hue, the prehensile shoots closed slowly. They might have been embodied with a sluggish life!

Doc wrenched free. The plant arms were far from being strong. Indeed, most small animals could have struggled clear. The growths reacted rather slowly, judged by human standards, making them dangerous only to the unwary.

As Doc progressed, however, the very numbers of the carnivorous verdure became a menace. Clutches upon the cage came in increasing succession, until at last there was almost a continuous drag.

Doc kept his flash on. Some of these plants were poisonous, Lady Nelia had warned. Using his knife, Doc sliced through such of the tentacles as projected through the cage bars, doing so with quick slashes. Uncanny as the behavior of the grisly shrubs might be, they closed only upon such objects as touched them.

Furthermore, they did not seem to have the ability to distinguish between animal and plant tissue—between Doc and his cage, for instance, and other herbage of their own species. At times the plants were shoved in contact and attacked each other with a slow ferocity, cannibal fashion.

There came a low hiss. Through the thin bars of the cage projected a blunt, green-dappled serpent head. A venomous snake, the color of which blended closely with the surrounding hideous jungle!

Doc used his knife before the reptile could wriggle in far enough to reach him. A single quick stroke severed the repellent head.

After that, Doc kept a sharper watch, the incandescent eye of his flashlight blazing unwinkingly.

The light furnished a faint glow visible to Yuttal’s men. They drove bullets at the spot. Most of the slugs were stopped by the jungle, but a few glanced unpleasantly close.

It had already been noted by Doc that passage through the strange jungle was an impossibility, even for his vast strength, unless many hours were spent with a long-bladed machete, hacking down the carnivorous plants and the entangling creepers. He had, however, no wish to get out of the oasis.

The shooting at his light suggested a plan. Working carefully, he plucked numerous slender, harmless vines and wove them into the mesh of his cage. Soon he had the lower half of his refuge closed tight enough to keep out snakes.

He planted his flashlight, still glowing, in the spongy earth, so that the beam played upon the jungle in a fashion to attract Yuttal’s marksmen.

Slowly, Doc pushed along at right angles to his former course. Behind him, the flash drew flurries of automatic rifle slugs.

Progress was slow, laborious, dangerous. To avoid noise, he had to slash through such of the tentacles as seized his cage. He struck matches often, cupping the tiny flames carefully so that they might not be discovered.

Once something grated underfoot. Stooping and using a shielded match, he saw he had come upon a yellowed human skeleton. The bones were still enmeshed in a mass of the carnivorous plants.

This, Doc realized, must be the remnant of some unfortunate slave who had sought to escape through the jungle.

It took him the balance of the night to get out of the fearsome vegetation. He left the jungle at a point some distance from where his enemies still sniped at the flashlight. The glow of the light had faded a great deal, due probably to the battery nearing exhaustion.

Carrying the useful cage, Doc rejoined his friends. He had little difficulty working through the ring of besiegers.

The embattled group greeted him with exclamations of relief.

“The young lady, here, just about had us persuaded that we should launch a hunt for you,” Monk chuckled.

“I thought you might be trapped—they’ve been shooting all night!” Lady Nelia explained, trying to keep her voice from showing just how relieved she was.

Doc imparted the information that the bullets had been aimed, for most of the night, at his flashlight.

“They evidently think I’m sitting out there waiting for daylight,” he finished.

“What did you accomplish before they discovered you?” Renny wanted to know.

“I’ll be badly disappointed if they can use their airship to bomb us,” Doc advised, and elaborated about the hiding of essential motor parts.

Dawn came shortly, and with it—heat. The lack of water had been no more than unpleasant during the night. Now it assumed the proportions of torture.

Johnny, looking somewhat more bony than usual, studied their rocky surroundings. His glasses were still in place, tied around the back of his head with the string.

“This stone is of a very imporous nature,” he said thoughtfully. “I notice it is pocked in spots with potholes. There’s just a chance we may find some rain water near. I think I’ll look around.”

“Keep your head down,” Monk warned.

Johnny scuttled off, flattening as close to the terrain as he could, lizard fashion. He experienced little difficulty. No bullets stung the boulders near him, although at one point he thought certainly he had exposed himself by accident.

On the far side of their rock-pile fortress, he found a rain-carved groove down which he could crawl without great danger. He proceeded to do so.

In a circular pit in the groove bottom, he found water!

The pool was clear, somewhat too clear! There was none of the usual moss on the bottom. Had Johnny looked closely, he would have observed that there were no encircling rings stained on the pool sides to show that the level of the liquid had receded through the past weeks.

All of these things might well have indicated that the water had been poured into the rock pit the previous night.

Johnny, however, was too dry to be suspicious. He was suffering more from thirst than the others, despite his remarkable qualities of endurance. It was a peculiarity of Johnny’s gaunt physique that he needed more drinking water than the average man.

The bottom of this little gully was where one might logically expect water. So Johnny drank. He only downed several swallows, however, knowing better than to overdo it.

Scooping up a quantity of the liquid in his hat, Johnny retraced his steps.

He slipped two or three times as he neared the others.

“Must be the heat!” he muttered. He felt a little dizzy.

The dizziness became more pronounced. Then came a dull sensation in his stomach.

He suddenly understood what had happened. A wild look on his features, he plunged recklessly forward. He staggered. A deadly paralysis seemed to be seizing him. He collapsed, entirely, a moment after he came in sight of his friends.

“Poison!” he gulped. “I’ve been poisoned!”

No medico in an emergency hospital ever worked with greater speed than Doc had in the next few minutes. His small medicine case held all the restoratives necessary.

The others stood around anxiously.

“What about it, Doc?” Monk muttered. “Is he too far gone?”

Doc worked in silence, making no reply. Bottles tinkled together as he concocted necessary potions.

An hour later, Johnny awakened. He sought to sit up, could not quite manage it, and wrapped both hands over his middle, grimacing painfully.

“You’ll be all right,” Doc assured him, and offered a collapsible flask filled with a clear liquid. “Here, drink this!”

Johnny cocked an eye at the flask contents. “What is that stuff?”

“Water,” Doc told him.

Johnny groaned. “I don’t want any more water!”

“This won’t hurt you.”

“Where’d you get it?”

“From the same pool you drank out of!”

Johnny’s big jaw fell. “Say—you wouldn’t be trying to finish me off, would you?”

Monk snorted mirthfully at Johnny’s surprise, then explained: “Doc analyzed the water and found out what kind of poison was in the stuff. Then he added chemicals which neutralized the poison, making the water drinkable.”

“You mean,” Johnny gulped, “that Yuttal’s gang planted that poisoned water, hoping to do us in—and Doc made it harmless?”

“That’s the idea,” Monk grinned. “It turned out that they kindly furnished us with a supply of water.”

“And are their faces red.” Ham laughed.

As the hour dragged on, there was sporadic shooting. The firing seemed but an attempt to convince the besieged they were far from being clear of their difficulties. None of the bullets inflicted damage or even more than mild uneasiness.

Lady Nelia, after a bit of casual maneuvering, engaged Doc in conversation. As a matter of fact, Doc had maneuvered a little himself in an unsuccessful effort to avoid just that.

Lady Nelia was an extremely attractive young woman—Doc had seen few of the feminine sex more entrancing. She was educated, polished and finely mannered. But Doc could read the signs. The young lady was in the way of falling for him.

Doc had had this sort of thing happen before. It embarrassed him no little. There was no provision for love-making in his scheme of things. The ladies, however, never saw his viewpoint. As a result, they risked broken hearts by letting themselves become enamored to the big bronze man. All of which, Doc sought to avoid.

Noon came with its vertical, blazing sun rays. They crowded under what shade they could find and suffered.

“This,” Monk said emphatically, “is beyond a question the hottest spot on earth! I’m as roasted as a turkey!”

To which Ham sneered: “No—you’re not! You can still gobble.”

More bullets were impinging upon the boulders. Whereas the shooting through the morning had been erratic, there was a machine quality about the firing now.

Doc Savage detected this fact at once.

“The sniping is a bit too organized,” he declared. “It has all the earmarks of being part of a plan!”

He moved about carefully, returning a few shots when he could place the bullets without killing. None of the brown men had died at his hand thus far, although there was ample justification for slaying them. Nor would Doc kill—although his enemies had a way of meeting fate in death traps of their own concocting.

“They’re trying to get our nerves on edge,” he decided aloud. “But I am unable to learn the reason.”

The answer came like an echo to his words.

From half a dozen different points, compact groups of men appeared. They advanced, moving with a slow, scuffling tread—a tread of men going to their death. Some of them shrieked wildly and sought to break away from the groups! But chains held them back.

These men were the slaves. They were being used by Yuttal and his gang as living shields.

“Holy cow!” Renny groaned. “Now they’ve got us! Our gas is no good! Yuttal’s thugs are masked!”

Doc and the others held their fire. They could not, of course, shoot down these defenseless, shackled men—although most of the slaves seemed to think that might happen. It was a study in human emotions to watch them advancing. Some had steeled themselves to a sort of exaggerated unconcern. Others trembled until they could hardly walk. Many strode mechanically, like men already dead. A few had collapsed and were being dragged.

It was no time, though, for delving into psychology and human behavior.

Doc’s powerful voice crashed through the rattle of automatic rifles! So mighty was his tone, such sharp command did it carry, that the shooting halted.

“Auz eyh?” a yell pealed. “What do you want?”

Doc replied in the native jargon, wishing all the attackers to hear.

“As you have learned by now, your airship is useless because of missing parts!” he informed them. “I alone know the whereabouts of those parts. And if one of my group is slain, you’ll never learn the hiding place!”

“Wallah!” barked a man—it was Hadi-Mot himself. “We can find the motor parts!”

“I do not think you can,” Doc replied. “And without them, you fellows are doomed. You cannot escape from this place. Your supply of food will be exhausted eventually.”

This was stretching possibilities a bit—the gang might easily inflate the airship and free-balloon it into the desert, from which a trek to civilization could be made.

There was a good deal of talk among their enemies. Finally, an angry shout gave the result.

“Surrender and tell us where the motor parts are, and your lives will be spared!”

“We’ll surrender!” Doc called back, without hesitation.

“Hey—Doc—they won’t keep their part of the bargain!” Monk wailed.

“Of course not,” Doc told him. “But they’ll keep us alive until they find out where the engine parts are cached. And believe you me, brothers, it’ll be a long old day before they get the information!”

Howling delightedly, the brown men ran forward to disarm and seize Doc and his friends.

The rocky hill seethed with jubilation as the prisoners were led downward and into the sheer-walled gash. More than one villainous fellow fingered his singa edge hopefully and cast questioning glances at Yuttal and Hadi-Mot.

“La!” growled Yuttal. “No! We have yet to find the missing machinery. You—Savage—will take us to it at once!”

“I’m not quite that simple,” Doc assured him in English. “Turning us loose was part of the bargain.”

“Nothing was said about turning you loose!” Yuttal snapped.

“That’s right—there wasn’t. Well, we’ll add that clause to the articles of contract.”

“Nix,” grated Yuttal, also reverting to slangy English.

“Suit yourself!”

Doc’s unconcern got under Yuttal’s plump hide. He squirmed, growling profanely in assorted Egyptian and English.

“All right,” he said finally, a wily look in his unpleasantly big eyes. “I give you my word. Show us the machinery, then we will release you.”

Monk snorted loudly. “His word! Did you hear that, Doc?”

“He was joking, of course,” Doc told Monk in mock seriousness. “He knows that we are aware his word is not worth anything!”

Yuttal’s big-featured face purpled with rage. He could not stand the hard-boiled calmness with which these men were taking their predicament.

Even Lady Nelia seemed not too greatly concerned. This last irked Yuttal most of all. He had hoped to see the pretty young woman reduced to such a state of dull hopelessness that she would accept his advances.

“What do you think I’m going to do?” he snarled. “Let you go and expect you to mail me a letter telling where the motor parts are?”

“We’ll figure out some way in the course of time,” Doc told him.

“And I,” Yuttal sneered, “am gonna give you a few reasons for workin’ fast!”

Just what Yuttal intended to do to make their servitude most unpleasant was soon evident.

Lady Nelia Sealing was taken to a small thatched hut and secured ignominiously to a post by a chain around her pretty neck. She was not, however, subjected to any worse abuse than this, except a copious number of threats.

Doc and the others were herded into a large shack and forced to denude themselves of clothing. The garments were burned in a bonfire.

Doc’s finger nails were pared very close, as were those of his men. This was to make sure no weird chemical was concealed there. Their teeth were examined.

From the rear of Doc’s jaws, an extra pair of molars were removed. These teeth were hollow shells containing two chemicals which, when mixed, produced a powerful explosive.

One of the brown devils, in investigating these contents, chanced to mingle the ingredients. As a result, there was a blast in which he almost lost his life, and did lose a hand.

It looked for a moment or so as though Doc and his friends would be dispatched forthwith, so great was the rage of Yuttal’s men over the mishap to their fellow.

Yuttal’s profane use of their mother tongue prevailed, however, and there were no casualties.

Water and rank soap were produced, together with swabs made of rags tied on the ends of poles. Doc and his men received a washing. The captors were taking no chances of anything being concealed upon their bodies which might aid in an escape.

A bearded fellow manipulating a swab gave Monk an unnecessarily hard whack, which nearly precipitated a riot.

Doc himself interfered.

“You’d better not push ’em too far,” he warned. “They might get excited enough to think they can get along without us.”

“A wise decision, indeed!” sneered the sleek Hadi-Mot, who had overheard.

Fragments of none-too-clean cloth were thrown Doc and his companions to serve them as garments. These comprised little more than breechcloths.

Yuttal now ordered that they be taken to the diamond mine.

“You are going to do a little useful work!” he leered at Doc.

The big bronze man replied nothing, meekly allowing himself to be nudged out of the hut by the muzzle of an automatic rifle.

En route to the diamond pit, his eyes roved alertly, adding to his fund of knowledge about the place. The outlook was none too pleasant. Every one of their captors was heavily armed. Moreover, none of the fellows were ever far distant from one of the rattan cages used as a defense against the vampire bats.

“You have some of the bats left?” Doc asked curiously.

“Plenty of ’em!” Yuttal laughed harshly.

Doc had hoped the flock of the bats he and his men had disposed of the night before had comprised the entire supply.

The venomous vampires, he learned upon reaching the gem mine, were kept in a cave dug into the side of the diamond-bearing blue ground. The cave was deep, and its entrance so small that it had previously escaped his notice.

Inside were cages, the doors electrically operated from a distance by pressing buttons on an elaborate alarm system. Pressure on the buttons, which were situated at strategic points, also rang bells. These signals warned the guards to seek shelter in their rattan baskets.

The whole device might have seemed a bit comical, had it not possessed such deadly possibilities.

Any concerted uprising on the part of the unfortunate slaves would be disastrous, for the unarmed, chained men were helpless to fight off the darting, bloodthirsty attacks of the poisonous bats.

Doc and his men were handed picks and shovels and put to work in the murderous heat of the afternoon sun. Their task was that of loading blue ground into buckets and hauling it to the top of the pit, where other slaves added it to the vast quantity already lying there. It had been exposed to the sun for some weeks, until it was disintegrated. To hasten this disintegration, slaves were forced to sprinkle frequently the diamond-bearing earth with water, there being little rain in this arid region.

Other of the wasted, chained workers were sieving the weathered or “rotted” blue ground, then running it into revolving washing pans. The “concentrates” from these pans were then passed over pulsators with greased plates. The grease on the plates did the final trapping of the brilliants.

Altogether, it was a rather up-to-date plant.

Doc and his friends found themselves the object of every conceivable indignity. They were cursed fluently. When they asked for water, the liquid was brought—and poured on the ground in front of their eyes.

A blacksmith came with iron collars and chains. Great pains were taken to make the collars fit too tightly.

“You’ll soon sweat off enough to make ’em loose!” Yuttal leered.

They were ordered back to the labor, and the abuse continued. They were forced to confine themselves to the sunny, hot side of the pit. The heat was sickening; the sun like a gas flame.

Doc’s bronze skin was showing little burn, but the others were turning red.

Doc and his gang did not take things with entire meekness, however. They did as little work as was humanly possible. Their deportment was an education in laziness.

More than once, when no one was observing, a guard would suddenly drop, knocked senseless by an accurately heaved clod of the blue ground. Their boyish enthusiasm for this form of exercise became so troublesome that the guards finally retreated a safe distance. This caused a let-up in the indignities.

They had been ordered not to speak to the other slaves. They disobeyed this order in fervent fashion.

Few of the chained unfortunates dared answer their questions.

“They beat and starve us!” one trembling wreck of a man whimpered. “But, worst of all, they do not give us water unless we obey.”

“Then we’re probably in for a long drought,” Monk muttered.

In two or three chained groups men were entirely unconscious, prostrated by the terrific heat. Sometimes they were taken from the toiling human linkage, but more often, they were left to be dragged about.

Whips were plentiful and in free use. The lashes were ghastly things of knotted wires, bringing crimson with their every stroke. Their use called forth screams and moans—piteous, blood-freezing cries.

Twice in the course of the first hour, slaves were beaten into unconsciousness for no greater offense than being unable to keep working.

“I vote a strike!” Ham said grimly.

Picking up handfuls of hard clods, Doc and his men rambled calmly, chains clinking, to the shade. They sat down, heedless of wrathful bellows from the guards. When the latter came near with their whips, they were met by a barrage of clods.

Yuttal and Hadi-Mot arrived and added their curses to the general benediction Doc and his gang were receiving. A few shots were fired for the sake of intimidation. But Doc’s crew could not be intimidated.

Nor did they do another lick of work.

“We can’t keep this up indefinitely, of course,” Doc said as night approached and signs of knocking off for the day became evident.

Monk, for some time, had been industriously pegging rocks at the mouth of the cave which held the venomous bats. For lack of anything else to do, he was trying to wreck the electrical system whereby the hideous creatures were released.

In this he was not successful. Guards, braving a fusillade of clods, rushed in with whips flying. For the next few minutes, a fine free-for-all fight held sway.

Doc’s outfit, handicapped by being chained together, was driven to the opposite side of the pit, out of throwing distance of the bat cave.

Shortly after this, darkness stopped work in the mine pit.

Reaching the top, the mutineers engaged in fresh rowdyism. The day’s take of diamonds was in trays near the pulsators. Making a lumbering rush, Doc and his gang seized the gems, and after looking them over, threw some of them at guards and the rest back into the pit, where they would have to be mined again.

For this outrage they were all but shot. Only sweating efforts on the part of Yuttal and Hadi-Mot saved them.

“Sons of donkeys!” Hadi-Mot berated his men. “These prisoners are our only hope of finding the missing engine parts!”

At the points of fixed bayonets, Doc’s gang was urged toward the stockade.

They saw hunting for the absent machinery had been in progress. Here and there, the sandy ground had been dug up. They had not, Doc noted, excavated anywhere near the right spot.

Work was also going forward on the Aëromunde. A rigging crew had done considerable toward repairing the ripped gas ballonets.

The stockade floor was decorated with numbers of short posts, equipped with rings. To one of these, the human chain comprising Doc and his men was linked. Doc was given honor position next the post, without sufficient slack to sit or lie down.

“You’ll hang yourself if you try to sleep there!” Renny muttered uneasily.

“I haven’t the slightest intention of sleeping,” Doc assured him.

They were not given water. As a cruel gesture at food, several packages of very salty soda crackers were tossed at their feet. They knew better than to eat these thirst-increasers.

“These birds are old heads at the torture business,” Monk declared sourly.

Other slaves in the stockade, those who still had enough life left to show interest in anything, cast sympathetic glances at Doc’s outfit.

“Do you ever try to make a break?” Doc asked one of them.

“Many times,” the man said listlessly. “It is no use. If you get free, there is the jungle—and the bats!”

“Lady Nelia and the two men with her got away.”

“Yes. And Lady Nelia is back—and the other two dead!” the speaker mumbled. “Anyway, they had an advantage. Lady Nelia had the run of the place, and she was able to get the stuff to make a balloon. That won’t happen again. They’re keeping her chained.”

Doc said nothing more. It would be a waste of breath. These men were hopeless, resigned to their fate—for which they could not be blamed. This frightful servitude was enough to break the spirit of the strongest.

“How many of the original crew of the Aëromunde are alive?” Ham asked a neighboring vassal.

“Six or seven,” was the mumbled reply. “I don’t know for sure. We—we lose track of identities here.”

As a final gesture before the night began in earnest, a sentry brought Doc and his friends a large, clean jar filled with sparkling, delicious-looking water.

The water was saltier than any ocean brine. Absolutely undrinkable!

The night was extremely dark, due to the height of the frowning walls of the crack and the absence of a moon.

Two hours after dusk Doc’s outfit thrust hands into their ragged breechclouts and each produced two or three diamonds. Not for nothing had they rushed the gem trays at the pulsators. Their act had not been rowdyism, but had been deliberately planned, so as to get their hands on these stones.

They had selected brilliants with sharp edges. They set to work on the chain links. The task was not difficult. Few substances are better cutters than diamonds.

Doc Savage was the first to free himself. He stood erect. He had cut through the link which hooked the connecting chain to his iron collar. The collar was still about his neck, so tight it was half buried in his hard bronze flesh.

“You birds know what you are to do?” he breathed.

“I’ll tell a man,” Monk chuckled, dryness of tongue making his whisper sandy.

Each move they were making was part of an elaborate plan they had formulated during the afternoon of striking in the diamond mine.

“We’ve got to move fast!” Doc warned. “Some of these guards may come in at any time to take a look at us!”

After the admonition, he glided away in the murk, stepping over sleeping slaves, after first carefully feeling out where they lay.

Doc was making for the side of the stockade where he had, on his nocturnal foray of the night before, buried the package. He had the location accurately in mind.

An electric lantern blazed outside the stockade as a watchman made his rounds, inspecting the tethers of the blood-hungry vampires.

Abruptly, the man came and popped his light through the compound piles. No doubt, he wanted to gloat a little over the bronze giant who had caused so much trouble.

Doc thought the jig was up.

But the alertness of his five men saved the night. They had the foresight to be standing in a compact group about the mooring post, thus masking the fact that Doc was not among them.

The sentry finished his circuit.

Doc continued to advance. It was no mean foresight on his own part that he had thought to bury the package inside the stockade. He had done so on the bare chance that need for it might arise. And it certainly had!

The packet contained articles which he believed would enable them to make their escape. Certainly, they stood scant chance of getting away without the bundle contents.

Doc found the burial spot. His tendon-wrapped bronze hands dug in. The ground was soft, showing he was at the right place. He scraped more swiftly. His fingers encountered hard earth. The bottom of the hole!

The package was gone!

During a period of perhaps a minute, Doc Savage crouched there in the hot African night, thinking as he had seldom thought before.

The very fact that the hole had been filled in by whoever had taken the packet, caused him to reach his decision. The finder was none of Yuttal’s men. Those fellows would not have bothered to refill the hole.

It must have been one of the slaves! Probably one which had seen the burial.

Doc glided swiftly to the nearest human chain. He awakened one of the linked men, managing to prevent the chap from emitting a noise.

“Were you fellows staked to this post last night?” he breathed.

“No,” was the reply. “We don’t have any regular stations.”

“Do you know what group was here last night?”

The man—puzzled—considered. “Why—I think it was the gang who are nearest the gate to-night.”

“Thanks!” Doc whispered. “And you might as well stay awake. You’re going to see some excitement before long.”

Making his precarious way to the ten captives chained closest to the stockade entrance, Doc began awakening them. It was no mean task to do this and at the same time maintain silence. But he finally accomplished it.

“Did any of you fellows dig up a package near the wall last night?” he asked them.

The end man on the chain had the big news. “I did. I thought it was somebody trying to slip us something. I couldn’t see who was burying it!”

“Where did you put the bundle?”

“I buried it again—right beside the post we were anchored to,” the man replied. “I looked in it, but there wasn’t anything but some bottles of stuff.”

“I hope you didn’t break the bottles, or empty them?”

“Oh—no!”

Five minutes later, Doc Savage had his packet.

The sharp-pointed poles of the stockade were designed to offer an insurmountable obstacle to any man of ordinary agility. But Doc was far from falling in that category.

A crouch, a silent spring upward, and he had grasped the top, calculating neatly enough to avoid the needled tip. An acrobatic swing put him over, still without noise.

He dropped and cushioned his landing with great leg muscles, the power of which had been lessened hardly at all by the hardships encountered during recent hours.

Creeping forward, his keen nostrils soon advised him of the location of a fetid-smelling vampire. Now came a ticklish job. He had ordinary chloroform in one of the bottles. With this, it was necessary to stupefy the bat long enough to get past it, yet not cause the thing to pass out entirely, as that would attract notice from the next guard who made a round of inspection.

Doc solved the problem by dousing chloroform on a rag torn from his breechcloth. He did the tearing with care. The instant the cloth was soaked, he tossed it at the vampire.

There was a snapping sound as the creature grabbed at the fabric, under the impression that it was something alive.

Doc waited a few moments, then took a chance and glided forward. He found the hideous bat too stupefied to attack.

Recovering the cloth for future use, Doc went ahead. He headed for the long, thatched shed which held the supply of wicker cages. Once there, he entered and worked rapidly.

With a swab already contained in one of the bottles which had been in the buried package, Doc daubed chemical on each of the cages.

He worked swiftly, but the number of the rattan baskets made the job tedious.

When he had finished, he worked toward the more pretentious hut where Yuttal and Hadi-Mot had their quarters. Outside the door, Doc found two rattan cages. He painted a bit of his chemical on each.

He operated with greater speed now, prowling about in the gloom, working upon each basket he located. He even succeeded in getting to the cages which the stockade guards kept close at hand. Finally, he made for Lady Nelia’s prison.

The young woman was awake when Doc entered. Her chain rattled. Not being able to see him, she gave a gasp of fright.

“Sh-h-h!” he warned. She had been working on her chain padlock.

“Oh!” She had recognized him. “I’ve been trying to pick this lock with a hairpin, as you did. But I can’t make a go of it.”

“There’s a trick to it,” Doc said softly, making no effort to keep admiration of her courage out of his voice.

He took the hairpin and opened this padlock as easily as he had the one in the dirigible, at the time of the first rescue.

“You’re lucky,” he whispered. “They did not padlock the chains to our necks—they riveted them! We used diamonds to cut the links.”

She managed a low, somewhat shaky sound of attempted mirth. “You fellows must have cut up terribly this afternoon. I heard Yuttal and Hadi-Mot talking. They’re afraid you will spread your mutinous attitude to the other slaves.”

“We’ll spread more than that, if we have decent luck!” Doc assured her grimly. “Come on!”

They stepped to the door together—and halted.

A light was bobbing toward them. One of their enemies approaching!

“A guard comes here every half hour or so to see that I am safe,” Lady Nelia breathed. “That must be him!”

Doc Savage urged the young woman back, directing: “Arrange the chain as if you were still fastened!”

He did not wait to see if the command would be complied with—he knew it would be, for Lady Nelia was certainly not going to become hysterical under this minor stress.

Doc glided around the corner of the hut and lurked there.

The sentry approached, swinging his electric lantern and making a low humming sound under his breath. He was entirely unsuspicious. He cast his light into the hut.

“Ya inta!” he called loudly. “Oh, you!”

His purpose seemed to be to destroy whatever chance Lady Nelia might have had of slumbering. He was still grinning cruelly over his little joke when a mighty hand of metal clasped his throat. Air, which he tried to expel in a shriek of terror, only pumped up and down in his lungs.

The fellow sought to fire his rifle.

Doc delivered a snapping blow with the edge of one bronze hand. The thud as it landed was not loud, but the victim collapsed instantly. Doc had struck for the temple nerve center.

Doc now did a somewhat inexplicable thing. He placed the unconscious sentry on the floor and covered him carefully with a sleeping mat which had been provided for Lady Nelia.

“Why take all that trouble?” the young woman whispered.

“I’d rather not see an unconscious man die with no chance to aid himself,” Doc replied.

The bronze giant did not elaborate his explanation. Grasping one of Lady Nelia’s hands—something the young woman did not mind at all—he led her toward the stockade.

A few score of feet from the inclosure, just outside the area paced by the sentries and guarded by the vampires, Doc left his pretty companion. But first, he found her ear in the murky night.

“Stay right here!” he warned. “I’ll be back soon. And be ready for action!”

A watchman came tramping around the compound, dangling a light beam over the bats.

Even as the man passed, Doc was soaking his fragment of rag with chloroform. He tossed the cloth—a vampire snapped at it. The bats possessed eyes more adapted to the darkness and could see the fabric. Doc let this bat go into a permanent sleep from the anæsthetic effects.

Whipping forward, Doc plucked softly at the gate fastenings. These consisted of a heavy sliding bar and a peg to hold it in place. Doc extracted the peg.

“Anybody there?” he asked softly.

“Me!” came Renny’s harsh whisper. “We’re all set in here! Got the chains holding every single group of slaves cut through at the anchor posts. It was a dickens of a job, though. But everybody is ready for the break!”

“Here we go, then,” Doc told him. “Tell them to run straight out from the gate. The vampire immediately in front is out of commission.”

The gate could not be opened without noise—Doc had noticed this when they were put in the compound at sundown. So he made no effort at silence. Slamming back the bar, he wrenched the great portal open. Crude hinges squeaked loudly!

“Eysh huwa!” bellowed a sentry. “What is this?”

Out of the gaping gate plunged Renny and the others. Behind them surged the slaves, still chained in groups of ten.

Doc and his men scattered, each charging a shouting sentry.

“Make for the airship!” Doc barked at Lady Nelia.

The slaves had also been instructed to race to the Aëromunde. They did so, not understanding what good that would do, since the dirigible was not yet airworthy. But the leadership of this giant bronze man and his hard-boiled, devil-may-care companions offered the only real chance of escape which had come their way. They were glad to take orders.

“Eysh huwa?” howled the guards. “What is this? What is happening here?”

About the gate, all was chain-clinking confusion. Some of the linked men were sobbing in their excitement. Not a few forms, slaves ill almost to death, were being carried.

The guards approached, using their electric lanterns.

Doc and his men had been foresighted enough to circle a bit, coming upon the sentinels from the sides.

A bearded fellow dropped under the mallet of Doc’s big fist without ever knowing what had occurred.

An automatic rifle chattered. Another!

A man squawled as Renny’s big hands found his neck.

Ham’s sword cane spitted one of the riflemen through the shoulder, dropping the man in a writhing pile of agony.

With a ghostlike clanking of many chains, the slave groups retreated through the darkness toward the Aëromunde.

Over toward the sleeping quarters, men were piling out of bunks to seize their arms.

Light brightened the doorway of Yuttal and Hadi-Mot’s hut. Then both leaders bounded outside, waving flashlights.

Bayoneted rifle thrust out, a sentry charged Doc.

Nimbly, Doc evaded the ugly blade. Lunging in, he seized the man and flung him against another, who was clipping fresh ammunition into his rapid-firer. Both went over in a kicking, swearing pile.

Doc pounced upon them, fists driving expertly.

A watchman, who had been stationed around at the rear of the stockade, arrived on the scene. Glimpsing Doc, he flung up his rifle. The muzzle of the weapon, glinting nastily in the gleam of the man’s electric lantern, was beaded upon Doc’s back.

Lady Nelia Sealing then paid whatever debt of gratitude she might have owed Doc. She had not retreated to the Aëromunde—for once disobeying Doc’s orders. She had gathered up a pair of rocks and waited, hoping she might be of some aid.

She flung one of her rocks—and missed. Her second heave, however, was a bull’s-eye. Hitting the watchman in the center of his whiskered features, the stone bowled him over!

The fellow’s rifle cracked, and so narrow was the margin of escape that the slug blew cold air on Doc’s features!

“You’re sure handy to have around,” Doc chuckled, reaching the young woman’s side and carrying her along toward the dirigible.

Over his shoulder, Doc roared: “C’mon, gang!”

The brief, furious fight waged by Doc and his crew had given the slow-moving, chained strings of slaves time to reach the Aëromunde. With an eagerness that bordered on frenzy, they were clambering into the control cabin, thence on into the cubicles occupied by officers and crew when the leviathan of the skies was cruising.

Rifle slugs clanked viciously upon the metalwork of the airship. But the electric lanterns furnished poor illumination for shooting. None of the bullets were accurately placed.

The whole thing had happened a bit too quickly for Yuttal and his followers to comprehend what was going on. They were confused.

Yuttal’s men were of a strain addicted to much yelling when in combat. This added to the uproar. Moreover, it prevented any general organization, because orders could not be heard above the din.

Doc gained the Aëromunde, swung Lady Nelia inside, and bent his strength to aiding some of the weaker strings of slaves.

“Hurry!” he warned them. “We have very little time!”

“Sacre!” whined a man, apparently a native of France. “What good zis do? We ’ave no gun wit’ which to fight zem! Zey weel——”

Doc gave him a boost which sent him flying into the control car.

Only one string of ten captives now remained outside. As Doc’s outfit lent their aid to these men, a loud jangling of bells suddenly sounded!

From fully twenty assorted points in the night, the bells clamored out. None of them were especially loud, but the effect of all ringing in unison was uncanny.

“The alarm bells attached to the electrical circuit that releases the vampires!” Ham shouted; then, to the chained individuals whom he was helping: “Get a move on! I know you guys are about dead, but get a move on!”

Doc and the rest did their best to redouble the efforts of getting every one inside the airship.

The bell ringing had stopped every bit of the shooting—stopped it as though the jangling clamor was the voice of magic.

“That means Yuttal and the rest are getting into the rattan cages for protection against the vampires!” Ham yelled, hoping the ominous information would spur on the already frenzied slave chain.

At last they got the final man inside. They bounded through the door themselves. Doc slammed the panel and latched it.

Fumbling, he located a switch and clicked it. The lights came on.

A bullet snapped through the metal-and-veneer control room wall below the windows!

Doc promptly turned the lights out.

“Account for everybody!” he rapped. “Make sure all hatches are battened. Crowd as many as you can into the crew quarters and fasten them in! You’ll have to do the job in the dark!”

His five men plunged to follow the suggestions, making much noise.

Doc turned to peer through the cabin windows. Lady Nelia Sealing materialized at his side—the first he knew of her presence being the touch of her hand upon his arm.

“I still do not know what will get us out of this,” she said, excitement and recent exertion making her words spasmodic. “You seem to be working to a definite plan. What is it?”

Doc was rather slow replying. Then, grasping Lady Nelia’s elbow, he guided her through the darkness to a door which gave entrance to the officers’ quarters.

“The plan is about to see its climax,” he told her shortly. “That climax will not be pleasant. You won’t want to see it.”

He left her with that, and returned to the control-car windows.

Many electric lantern beams danced about in the hands of Yuttal, Hadi-Mot and their confederates. Frequently, their lights rested upon each other, permitting Doc to obtain a fair idea of what was going on.

Yuttal and the rest were not acting like men confidently awaiting the elimination of their enemies. They were struggling madly with their cagelike contraptions of rattan.

The cages were coming to pieces at their touch!

Shouts of fright arose! Wild questions were shrieked, showing they had no idea what was wrong with the cages! Soon, though, terror, swiftly coming into their voices, indicated they realized the fate ahead.

The bronze, regular features of Doc Savage for once were showing expression. They were grim, a bit sorrowful, as if he regretted this thing he had found it necessary to cause to happen.

For Doc had taken the only course which offered security to the unfortunate individuals he was aiding.

He had daubed an acid upon the lashings which held the rattan cages together. The powerful chemical had rendered the lashings so weak that they were breaking as the cages were put into use.

A stray electric beam came to rest upon Yuttal and Hadi-Mot themselves. Standing close together, they were striving frantically to get their cages to stick together. They were like evil little devils whose toys had broken.

Time after time, they grasped toppling staves of the baskets and shoved them back in place. Their actions seemed ludicrous, more than a bit horrible, for death was very close upon them.

Out of the night, that death came! A black, fluttering object appeared in the light. Then several others. The deadly vampires!

The creatures swarmed upon their masters!

Yuttal and Hadi-Mot sought to run, just as other men around them were striving to flee to safety. But their flight was hopeless. The huts were too far distant.

Both Yuttal and Hadi-Mot went down together, stricken by the venomous fangs of the vampires.

The bats, lusting for blood, covered their prone bodies like a black living blanket.

Then, as if to mercifully blot out the frightsome vision, the electric lantern was kicked over or flung aside and buried its glare in the sand.

Doc clicked on the switch which brightened the lights in the Aëromunde control cabin. There would be no more bullets flying this way now. The men out there were doomed, except perhaps for a few who might bury themselves in the sand, or reach the huts, or otherwise escape.

Victims of their own odious murder trap were Yuttal and Hadi-Mot, and the rest. They probably did not know it, but they were not the first of their kind to depart the world in that fashion, while seeking the lives of Doc Savage and those he had chosen to aid.

Here in the dirigible was safety, providing no hatches chanced to be open. Doc made the rounds, turning on lights, ascertaining that the hatches were secure.

With the coming of dawn, it was merely a matter of patience and a keen eye to pick off the vampires, using rifles and machine guns from the Aëromunde armament. Before noon, the task was done.

A scant handful of brown, bearded men had found shelter from the vampire attack. They came out of hiding, trembling and fearful and even anxious to surrender.

Repair work on the dirigible at once got under way. There was not much to do. But Doc Savage directed that the task proceed slowly, that the enslaved men, freed of their shackles, might have time to regain their strength.

More than one trip to civilization would be necessary in order to transport every one, it was found.

The diamonds were gathered together and cased. They represented a fabulous sum.

“What’re we gonna do with these things?” Monk pondered, hefting a collection of walnut-sized sparklers.

“Divide them,” Doc said, giving voice to a decision he had reached. “Lady Nelia will get a share. The rest will go into our working fund—to be expended in construction of a few hospitals and so on.”

Lady Nelia stared at Doc wonderingly, surprised that he showed no particular elation over the wealth at hand. She did not know that this treasure, great as it was, hardly compared to the gold trove which was Doc Savage’s mysterious source of funds.

Four days had passed since the death of Yuttal, Hadi-Mot, and their men, and the interment of the bodies.

In that period, a truth had dawned upon the attractive young Englishwoman. She saw that Doc was not for her. He was no woman’s man. She had accepted the situation, and masked her inner feelings with determination.

“We will, of course, have to sell these stones over a period of years,” Johnny pointed out. “Dumping such a quantity of the finest gems all at once would knock the bottom out of the market.”

“I will not accept a share,” Lady Nelia said abruptly. “Perhaps I have not mentioned it, but I am independently wealthy. I do not need money.”

Doc showed no amazement—he had a fine enough opinion of Lady Nelia Sealing to expect just this.

“In that case,” he said, with one of his rare smiles, “we will use your share to create a fund in England—for any sort of hospital construction or charity you may wish.”

“Thank you,” smiled the young woman.

On the morning of the fifth day, the Aëromunde took off on her first trip to civilization. The departure was without mishap; the ship handled perfectly, with Doc and his five aides at the more important controls.

“Want me to set the course for Cairo?” asked Renny, who was navigating.

“That’s right,” Doc agreed.

Long Tom, a hand under his eyes to shade them from the glare off the desert sands, peered into the shimmering heat haze ahead.

“Cairo—on the banks of the lazy River Nile!” he chuckled. “That sounds peaceful enough.”

Mis-spelled words and printer errors have been fixed.

Inconsistency in hyphenation has been retained.

[The end of The Lost Oasis by Kenneth Robeson [Lester Bernard Dent]]