Around to the rear of the brick building, Doc glided. He found the back door. It was not locked inside — it was bolted. Heavy iron bars crisscrossed it.
   Doc leaped upward. The height of that tremendous spring would have astounded an onlooker. He clutched an extended ledge and worked his way to a window on a second-floor hallway, with hardly more sound than the noise of a prowling cat.
   The hall was dark. Doc drew things from his pockets. Some sticky gum, he affixed to the windowpane. Then a faint, gritty hiss sounded.
   Doc had cut the glass cut of the window! He kept it from falling inward by the gum he had stuck to it. He eased inside.
   Silence gripped the interior of the house. Doc prowled noiselessly. Only one room held a light. It was downstairs. The door was locked.
   Doc let Renny in. They went to the fastened door.
   "We might as well go in there all of a sudden!" Doc breathed.
   "0. K., Doc," murmured Renny.
   He lifted his gallon of iron-hard knuckles. He struck. With a rending crash, the door panel was driven inward by Renny's great fist.
   They sprang into the room. Renny held a gun. Doc's powerful bronze hands were empty.
   Horrified surprise halted them.
   Only two men were in the room. One was Victor Vail. The other, as denoted by the sanitary smock he wore, was obviously the dentist who had his place of business here.
   Both men hung suspended by ropes around their necks from a stout ceiling chandelier.

Chapter 7
THE MAP

   THE SUN was up. Doc's remarkable companions lounged in the skyscraper office. They had lost a night's sleep, but showed no effects of it.
   Ham was honing the blade of his sword cane to a razor edge, looking ominously at Monk each time he tested its sharpness. Monk sat in an easy chair, reading a pocket manual of how to raise hogs. He took pains to hold the book so Ham could see the title. Monk often maintained — always within earshot of Ham — that some day he was going to retire and raise pork for a certain finely dressed lawyer he knew. Johnny, the archaeologist, was penning a chapter in the book he was writing on the ancient Mayan civilization.
   Long Tom, looking pale as an invalid, was in the laboratory, humped over an apparatus which for intricacy would have given Steinmetz a headache.
   Truly an amazing crew, these men.
   Doc Savage entered. With him was Victor Vail. Renny walked in after them.
   The blind man's neck was swollen somewhat where the rope had nearly strangled him to death — Doc had arrived just in time to save him.
   The explanation of Vail's situation was quickly made.
   "The dentist don't know a thing about the gang that seized him," Doc concluded. "They called him to the door and cracked him over the head."
   "It was Ben O'Gard!" Victor Vail put in, his voice thick with emotion. "Oh, Mr. Savage, I was so mistaken about that man! I thought he was my friend. I had every confidence in the world in him. When he called me here
   "So it was Ben O'Gard who telephoned you!" Monk interposed.
   At the sound of Monk's mild voice, Victor Vail registered great remorse. Obviously, he was terribly sorry for that crack he had taken at Monk's head with the paper weight.
   "I do not know how I shall ever redeem myself for my horrible mistake," choked the blind man. "Ben O'Gard told me an awful story of how you men were holding me here to keep me from seeing him. I believed O'Gard. I know I was a fool to do that now, but at the time, I regarded O'Gard as a friend who had twice saved my life. He told me to escape and come to him. That is why I struck you."
   "Forget it!" chuckled Monk.
   Renny spoke up. "What baffles me is why Ben O'Gard took over the dentist's office."
   Doc's strong lips warped their faint smile.
   "Simple," he said. "Ben O'Gard wanted to use the dentist's X ray!"
* * *
   THIS STATMENT elicited surprised looks from every one present.
   "X ray!" Renny grunted. "Why'd they want the X ray?"
   "I'll show you the reason in a minute," Doc replied. "First, though, I want to find out what Ham learned about the liner Oceanic."
   Ham now divulged the information which several transatlantic telephone calls to England had gathered.
   "On the English records, the liner Oceanic is down as lost at sea-sunken without trace," Ham said. "There's no hint of this stuff about it being trapped in the polar ice pack."
   "I'm not surprised," Doc Savage said dryly.
   "I've got something that will surprise you," Ham smiled. "There was fifty million dollars in gold bullion and diamonds on the Oceanic!"
   An electric shock seemed to sweep the room.
   "Fifty million! Will you say that again!" Monk said mildly.
   "Fifty million in gold and sparklers," repeated Ham impressively.
   "That explains it!" Doc declared.
   "Explains what?" Renny wanted to know.
   "What's behind this whole mess," retorted Doc. "Come into the laboratory. I want to show you something, brothers."
   It was an excited crowd of adventurers which surged into the vast laboratory room.
   From a tray. Doc lifted several large photographic prints. These were X ray pictures which he had taken of Victor Vail in his course of examining the violinist to determine his eve affliction. Until now, Doc had not had time to as much as examine the prints.
   He held one up.
   "Holy cow!" barked Renny.
   "Exactly," Doc agreed. "More than fifteen years ago, while Victor Vail was under the influence of an anaesthetic, some one tattooed a map on his back with a chemical, the presence of which could only be detected by use of a certain tensity of X ray."
   "You mean I have carried the map on my back these many years without knowing it?" Victor Vail questioned wonderingly.
   "You certainly have. You recall the man with the clicking teeth who seemed to haunt your trail through the years? Well, he was simply keeping track of you and the map."
   "But what is the map?"
   "It shows where the liner Oceanic is aground on a land far within the arctic regions," Doc announced.
* * *
   SOME MINUTES were expended examining the chart.
   "But I cannot understand why I carried the map around unmolested for so many years!" Victor Vail murmured.
   "Possibly I can reconstruct a story which explains that," Doc told him. "The fifty millions in treasure aboard the Oceanic led Ben O'Gard, Keelhaul de Rosa, and the other members of the crew to mutiny. They probably disposed of all who did not join them!"
   "The beasts!" Victor Vail covered his face with his hands. "My poor wife. My poor little daughter, Roxey! That devil, Ben O'Gard, murdered them! And I thought he was my friend!"
   "It's merely guesswork about the murder part!" Doc put in hastily. "I said that simply because the eagerness of Ben O'Gard and Keelhaul de Rosa to get this map shows they think the Oceanic is where they left it, even now. This indicates there were no survivors but themselves."
   Victor Vail recovered his control. '"When Keelhaul de Rosa tried to kidnap me from Ben O'Gard, he was really trying to steal the treasure map!"
   "Of course," Doc agreed. "That explains why the two factions split. No doubt they have been waging unremitting war with each other since that day, each faction trying to slay the other so they would be free to secure the chart off your back, and go get the fifty millions."
   "I'm surprised they left it behind in the first place!" Monk put in.
   "We barely escaped with our lives as it was," Victor Vail assured him. "To carry more than food over the ice pack was impossible."
   Ham made a quick gesture with his sword cane — and Monk ducked involuntarily.
   "Both Ben O'Gard and Keelhaul de Rosa now have copies of this map," Ham said thoughtfully.
   Doc Savage let his strange golden eyes rest on each of his friends in turn. The gilded orbs seemed to be asking a question — and receiving a highly satisfying answer.
   "Brothers," Doc said softly, "these birds who are after that treasure are fellows who have no right to any man's gold. What say we get it ahead of them? We can use the money to enlarge our secret institution in upstate New York to which we send criminals to be made into useful citizens. The place is becoming a little crowded."
   Pandemonium seized Doc's headquarters.
   Renny swung over to the door. His enormous fist struck. The panel flew out of the door as though hit by a cannonball. No door was safe around Renny when he was happy.
   Monk fled wildly about the place, each apelike leap barely taking him out of reach of the lusty whacks delivered by the pursuing Ham's sword cane.
   Long Tom and Johnny got into a mock fight and promptly upset a stand of apparatus. In the ensuing crash, several hundred dollars' worth of equipment was ruined.
   The horseplay was their way of saying they thought Doc's treasure-hunt scheme was the best idea they'd heard recently.
* * *
   BEFORE THAT day was done, Doc Savage had operated on Victor Vail's eyes.
   He performed the delicate bit of surgery in New York's finest hospital. Those who surrounded him as he worked were not ordinary nurses. They were some of the leading American eye specialists. One had flown from Boston to see the operation, another from Detroit, and two from Baltimore.
   They wanted to see this epochal piece of work, for Doc Savage was seeking to do something which every expert present had until this very day maintained was impossible.
   And what the assembled specialists saw the mighty bronze man do that day in the New York hospital operating room was something they would talk about for a long time to come. The mastery of it held them breathless long after big Doc Savage had taken his departure.
   Victor Vail would have his sight back!
* * *
   THE NEXT morning, as Ham entered Doc's office, Doc was taking his exercises.
   Ham sat down to wait. Doc took his exercises — a terrific two-hour routine each day of his life, and nothing interfered.
   Doc's ritual was similar to ordinary setting-up movements, but infinitely harder, more violent. He took them without the usual exercising apparatus. For instance, he would make certain muscles attempt to lift his arm, while other muscles strove to hold it down. That way he furthered not only muscular tissue, but control over individual muscles as well. Every ligament in his great, bronzed body he exercised in this fashion.
   From a case which held his special equipment, Doc took a pad and pencil. He wrote a number of several figures. Eyes shut, he extracted the square and cube root in his head, carrying the figures to many decimal places.
   Out of the case came a device which made sound waves of all tones, some of a wave length so short or so long as to be inaudible to the normal ear. Years of straining to detect these waves had enabled Doc to make his ears sensitive enough to hear many sounds inaudible to ordinary people.
   With his eyes closed, Doc rapidly catalogued by the sense of smell several score of different odors, all very vague, each contained in a small vial racked in the case.
   There were other exercises, far more intricate. Ham shook his head wonderingly. He knew that five minutes at the clip Doc was doing the routine would be more than he, himself, could stand. And Ham was husky enough to give most professional boxers a drubbing.
   From the cradle, Doc had done these exercises each day. They accounted for his astounding physique, his ability to concentrate, and his superkeen senses.
   "What's on your mind?" Doc asked suddenly. His routine was over!
   Ham plucked a newspaper out of a pocket.
   "What do you think of this?" He handed Doc the paper, indicating an item, It read:
   WANT TO BUY A POLAR
   SUBMARINE EXPEDITION?
   There is one for sale. Captain Chauncey McCluskey
   announced this morning that he is hunting a purchaser for a
   share of the projected trip of the submarine Helldiver under
   the polar ice.
   Captain McCluskey has the submarine, fully equipped and
   ready to go. But it seems he has run out of money.
   There was more of it, written up in typical tabloid style. But it told nothing more of importance — except that the submarine Helldiver was tied up at a local pier, and Captain Chauncey McCluskey could be found aboard.
   "Who is Captain McCluskey?" Ham inquired.
   Doc shook his head slowly. "Search me! I never heard of the man before. Nor have I heard of any other projected submarine trip under the pole."
   "This sub may be just what we need," Ham declared. "But there's one point which has me guessing. It's darn queer the thing should pop up at just the time we're interested."
   Doc smiled slightly. "It won't hurt to look into it, anyway."
   The regular elevator — not the super-speed one — lowered them to the street level.
   They took the first taxi which rolled up.
   Doc gave their driver the address of the pier to which was moored the polar submarine, Helldiver.
   Office workers were going to their daily tasks. The walks were crowded. Each subway kiosk vomited humanity like an opened anthill. The cab rolled down into a cheaper district, where merchants were setting a part of their wares out on the walks.
   Ham toyed with his sword cane, and wondered what kind of a tub the Helldiver would be.
   Suddenly he snapped rigid as an icicle.
   In to the cab had permeated the low, mellow sound which was part of Doc. Weird, exotic, the note trilled up and down the musical scale. Looking directly at Doc's strong lips, Ham could not tell the sound was coming from them, such a quality of ventriloquism did the trilling note have. Indeed, Doc himself probably did not quite realize he was making it..
   The sound could have but one meaning now.
   Danger!
   "What is it?" Ham demanded.
   "Listen!" Doc told him abruptly.
   Silence lasted about a minute. Then Ham's high, intelligent forehead acquired a dubious pucker.
   "I hear a clicking noise at intervals, I think," he said. "Sounds like somebody shaking a couple of dice!"
   "Remember the clicking noise Victor Vail mentioned having heard often during the past years?"
   Ham never got to say whether he recollected or not.
   Their driver suddenly flicked several small objects back into the tonneau. He was careful to keep his face from being seen.
   The objects he flung were the grape-like balls of anesthetic Doc had used to overpower Ben O'Gard's hired gangsters. No doubt these had come from the scene of that affair, since Doc had neglected to retrieve such of them as had not been broken.
   The globules shattered.
   Doc and Ham were caught. With hardly a quiver, they tumbled over unconscious on the cushions.
   They had not glimpsed the countenance of their driver.

Chapter 8
STEEL WALLS OF DEATH

   HAM sat up. He groaned loudly.
   "If you're complaining about the darkness," came Doc's steady, capable voice, "that's why you can't see anything. And as for where we are — we seem to be inside a steel vault."
   "What a dream I had waking up!" Ham muttered.
   "The anesthetic sometimes has that effect. I judge we've been unconscious nearly two hours. One shot of the anesthetic lays a man out for about that long."
   Ham suddenly clutched at various parts of his person. His hands made loud slaps on his bare hide.
   "Hey!" he yelled. "I've only my underclothes!"
   "So have I," Doc told him. "They took our clothing. They even combed our hair, from the way mine feels. And they swept the interior of the vault clean. There are no shelves, or anything else — except a candle and three matches which they kindly left us."
   "Light the candle," Ham suggested. "This place is blacker than the inside of an African savage!"
   "No, Ham," Doc replied. "They left the candle, hoping we'd light it."
   "Huh?" Ham was puzzled.
   "A flame will exhaust the oxygen in this place very quickly, and hasten our death by suffocation."
   ''You mean the vault is airtight? "
   "Yes. And soundproof, too."
   Ham now listened. He realized he could not hear a sound but the booming of his own heart. It was so quiet he could almost hear the blood gurgle through his arteries. He shivered. A heavy lead weight seemed to climb on his chest.
   "The air in here must be pretty foul already," be muttered.
   "Very," Doc agreed. "I have been thinking, Ham. You recall that some months ago a large chain of New York banks went out of business. Probably we are in the vault of one of those banks."
   "Ugh!" Ham shuddered. "Can't you think of something cheerful?"
   Doc Savage's low laugh vibrated through the awful steel cubicle. He rarely laughed.
   "How's this for something cheerful?" he inquired. "As a matter of fact, I've only been waiting for you to regain consciousness before walking out of this place."
* * *
   HAM EMITTED a howl of delight that was almost a sob. He sprang erect. They were two semi-naked men inclosed in thick walls of hard steel. Their voices could not penetrate outside, just as no sounds could get in. The situation seemed hopeless.
   But Doc Savage had a way! He never joked about matters as serious as this.
   "How do we do it?" Ham demanded.
   "Our captors probably looked in our mouths," Doc explained. "But they forgot to count my teeth. They didn't notice that in my upper jaw there is an extra wisdom tooth on each side. They're false, and they hold two chemical compounds of my own concoction. When combined, these form one of the most powerful explosives."
   Doc now went to work on the vault door. He operated in darkness, guided only by his sensitive finger tips.
   "Kind of them to leave us the candle," Doc said.
   He used the candle wax to chink his explosive in the joint of the vault door, near the lock.
   "Get in a corner!" he directed Ham.
   "How you gonna explode it'?" Ham questioned.
   "It explodes itself, due to chemical reactions, about four minutes after the two compounds are mingled."
   They huddled in the corner farthest from the vault door. Doc employed his mighty bronze form to shield Ham — although Ham did not realize it at the time, so great was his nervous tension.
   "It's about time for the blast!" Doc breathed swiftly. "Open your mouth wide to equalize the pressure on either side of your eardrums, so there'll be less likelihood of them being ruptured."
   Ham barely had time to comply.
   Wh-a-a-m! Compressing air smashed them against the solid steel with stunning force. It crowded their eyeballs inward. It seemed to tear the flesh from their bones.
   So terrific was the explosion that Ham was reduced to senselessness.
   Doc Savage, huge and bronze and apparently affected not at all by the concussion, flashed to the heavy steel door. It was still shut. But the hard metal was ruptured about the lock. He shoved.
   The door opened about a foot and stuck. But that was enough. Doc carried the unconscious Ham outside, thence through two vacant chambers.
   Ham revived after several minutes in a large, bare room — the lobby of a former bank.
   Pedestrians moved on the street outside the unwashed plate-glass windows. One of these chanced to look in. He was a portly man with spats and a cane, smoking a cigar. No doubt he had heard the blast.
   Doc Savage rushed Ham to a side door. It was locked. The lock came out of the hard wood like an ear of corn out of its shuck, when Doc exerted a little of his tremendous strength.
   A taxi driver at a stand in the street heard the lock tear out. He glanced around. He was just in time to see the two men climbing into his hack.
   The driver bellowed for a cop.
   The cop came. He did not know Doc Savage by sight. He pinched both Doc and Ham. Doc did not put up an argument. This was the quickest way of getting clothes. The cop was tough, and swore a lot.
   At the police station, the captain in charge insisted on stripping to his underwear so that Doc would be properly clad.
   And the cursing cop got a lecture from his superior that would make him remember the giant bronze man the rest of his life. He would also have gotten suspended a month without pay if Doc hadn't interceded.
   "Anyway, begorra, yez had better learn to know some of the big men in this town by sight!" the captain warned his cop.
* * *
   TWENTY MINUTES later, Doc Savage stood on the wharf, appraising Captain Chauncey McClusky's under-the-polar-ice submarine.
   The thing looked like a razor-backed cigar of steel. The hull was fitted with lengthwise runners resembling railway rails. As a matter of fact, these actually were such rails, converted to the purpose of ice runners. They were supposed to enable the underseas craft to slide along beneath the arctic ice pack.
   A wireless aerial, collapsible, was set up for action. There was a steel rod of a bowsprit ramming out in front, the size of a telegraph pole. The rudder and propellers were protected by a steel cage intended to keep out ice cakes.
   Doc liked the looks of this latest of polar-exploring vehicles. He stepped aboard.
   A man shoved his head out of the main hatch amidships. All this man needed to make him a walrus was a pair of two-foot tusks. Doc had always believed Monk the homeliest human creation. It was a toss-up between Monk and this man.
   The man squeezed out of the hatch. He would tip a pair of scales at three hundred pounds, if he'd budge them at an ounce.
   "What the blazes do you want aboard here, matey?" the man demanded.
   His voice was a roar that frightened roosting gulls off floatsam in the middle of the bay.
   "I'm hunting Captain Chauncey McCluskey," Doc announced.
   "You've found him!" roared the walrus. "An' if yer a dinged landlubber just wantin' a look at this bloody hooker, you can take shore leave right now! I been pestered to death by cranks since that piece come out in the papers this mornin'!"
   Doc didn't bat an eye. He rather liked to deal with a man who got down to business and said what he thought.
   "Let's look your vessel over," he suggested.
   The walrus blew noisily through his mustache. "Mean to say you're interested in buyin' a share in this expedition?"
   "Exactly — if your craft meets my needs."
   "Come below, matey," rumbled Captain McCluskey. "I'll show ye her innards."
   They looked at her innards for an hour and a half. They came back on deck.
   Doc was satisfied.
   "It will take approximately two hundred and fifty thousand dollars to see you through," he said. "I will put up the sum — on one condition."
   Captain McCluskey blew through his walrus mustache and eyed Doc as if wondering whether the bronze man had that much money.
   The walrus would have been surprised if he had known the true extent of Doc's wealth. For Doc had at his command one of the most fabulous treasure troves in existence — a vast cavern stored with the wealth of the ancient Mayan nation. This was located in a lost canyon, the Valley of the Vanished, in the remote recesses of Central America. Survivors of the ancient Mayan civilization, living isolated from the rest of the world, kept Doc supplied with mule trains of gold whenever he needed it.
   "What's the one condition?" McCluskey rumbled.
   "The expedition must be entirely in my hands the first two months," Doc explained. "Within that length of time, I shall visit a certain remote spot in the arctic regions, and secure the thing I am going after."
* * *
   CAPTAIN MCCLUSKEY was surprised. "The thing you're goin' after — what d'you mean, matey?"
   "I'm afraid you'll have to swallow your curiosity on that point, captain. The object of our quest will be disclosed when we arrive, and not before. I can assure you, though, that it does not involve breaking the law in any way."
   The walrus considered deeply. "All right, matey. I'll sail two months under your sealed orders. But, strike me pink, if yer breakin' the law, I'll throw ye into the brig the minute I finds ye out."
   "Fair enough."
   "Cap'n McCluskey is as honest a swab as ever sailed the ocean," the walrus continued his roaring. "I've saved me money many a long year to bank enough to build the Helldiver. The good lads in me crew have done the same. We want to do somethin' to leave our mark in the world, so we'll be remembered after we're in Davy Jones's locker.
   "This explorin' v'yage under the pole is our bid for fame, matey. It means a lot to us. We ain't gonna be throwed off our course this late in the game. Maybe ye don't understand our feelin's, but that's the way it is."
   "Naturally, my project will not interfere with your goal of sailing under the north pole," Doc replied. "And you may rest assured we shall make no effort to share in the glory of your accomplishment. I shall not permit my name to be mentioned, either as partial backer, or as having accompanied you."
   The walrus man seemed deeply moved.
   "Yer a generous man, matey," he mumbled. "But one other point, we'd better clar up."
   "What's that?"
   "The hearty lads in me crew," chuckled Captain McCluskey. "Them swabs ain't sissies, matey. They're good men. They've sailed in naval submarines aplenty in their time. But they're hard as iron an' a little rough in their ways. You said you'd bring five of your own mates along. That's all right. But if they ain't got hair on their chests, my crew is liable to haze 'em around some."
   Doc smiled faintly. "I don't know about the hair, but I think my lads can hold their own."
   "Blow me down!" grinned the walrus. "Then we'll get along like frogs on a log!"
   "I wish to make a number of changes in this craft," Doc declared. "I shall pay for them. naturally."
   The walrus frowned. "What kinda changes?"
   "A special radio. Electrical apparatus for sounding and locating icebergs. A collapsible seaplane. Better diving suits than you have. And other things of that nature."
   "Strike me pink." chuckled McCluskey. "Yer a swab that knows his his business, I can see that. How long'lI it take?"
   "Two weeks."

Chapter 9
TOUGH CARGO

   THE TWO weeks had passed.
   "Helldiver is right!" Monk grumbled. "The name sure fits!" The under-the-polar-ice submarine was off the Maine coast, sailing northward. The craft had run into a stiff blow. And nothing is quite as disturbing as the movement of a U-boat in heavy going.
   As each gigantic sea approached the sharp bows of the sub, the steel cigar of a craft did a sort of devil dance of anticipation. It shimmied from side to side. It squirmed. It groaned like a thing in agony. Then it would sink in the wave as though going to its death.
   They had to keep the hatches closed. To breathe the air inside was something like being shut up in a can of axle grease.
   "It's an old-fashioned hell ship, if you ask me," Long Tom muttered.
   Doc Savage glanced sharply at the frail, unhealthy-looking electrical wizard. This was Long Tom's way of telling important news.
   "What do you mean by that, Long Tom?" Doc asked.
   "Last night, I had a dream," Long Tom began.
   "So did I," groaned Monk, who was slightly seasick. "I dreamed I was Jonah, and the whale had swallowed me."
   "Shut up!" snapped Long Tom. "In my dream, I saw somebody bending over me as I slept. I heard a clicking noise, as though a pair of dice were being rattled in somebody's hand."
   Strange lights flickered in Doc's golden eyes. "You're not trying to be funny, are you, Long Tom?"
   "I never felt less funny. 1 grabbed at the man bending over me in the dream. I got this." Long Tom drew an object from his pocket. It was a black-haired wig.
   "Did you get a look at his face?" Doc rapped.
   "It was too dark. And he was gone before I could follow."
   Doc considered in silence for perhaps a minute.
   "This is serious, brothers," he said at length. "That killer of Ben O'Gard's is aboard this sub. And we don't know him by sight."
   "It oughta be easy to find him now," snorted Monk, eying the black wig. "Just find the guy whose hair changed color during the night."
   It was astounding, the way Monk's seasickness had vanished, now that danger threatened.
   '"No good," said Long Tom. "I looked everybody over this morning. And no hair had changed color. That means the man was wearing the wig as a disguise while he did his dirty work."
   "What dirty work?" Doc inquired.
   "I forgot to mention the fellow had a knife," Long Tom said dryly.
* * *
   THE UNHEALTHY-LOOKING electrical wizard went below. Long Tom's looks were deceptive. Although the weakling of Doc's crowd, he was man enough to thrash a good nine out of ten of the men you pass on the street.
   Long Tom was serving as radio operator. He had installed a radio set so powerful he could keep in touch with the remotest corners of the earth, even while resting on the bottom of the sea.
   He had also equipped the Helldiver with the most sensitive devices for measuring underwater distances with sound waves. Simply by watching dials, Long Tom could tell how far below the sea bottom was, how far they were from the nearest iceberg, and how big the berg was. An alarm bell would even ring the instant they came within dangerous distance of any floating object big enough to harm the sub.
   Monk left Doc considering the new danger which threatened them. Monk had confidence Doc would find a way to trap their enemy with the clicking teeth.
   Monk retired to the cubicle where he kept his chemicals. Monk's contributions to the expedition were numerous. The most remarkable of these was a chemical concoction which, when released in quantities from the sub, would dissolve any ice which happened to be above it.
   This removed any danger of the Helldiver being trapped under the ice!
   Special apparatus for supplying oxygen within the sub, concentrated foods which were composed simply of the necessary chemical elements for nourishment in a form easily assimilated — these and other things were products of Monk's genius.
   Renny was doing work which his experience as an engineer eminently fitted him. He was the navigator. At this, Renny had few equals. Moreover, he was making maps. The voyage of the Helldiver would lead through unexplored arctic regions, and Renny's maps would be of great value to future generations.
   The archaeologist and geologist, Johnny, possessed a fund of knowledge about the polar ice cap and ocean currents which would be invaluable. There were very few things about this old ball of mud we call the earth which Johnny did not know.
   As for Ham, he had taken care of the legal angles, such as securing the necessary permission to put in at Greenland seaports. The Danes run Greenland as a monopoly, and a hatful of permits are necessary before a foreign vessel can touch there.
   Ham also furnished everybody aboard the Helldiver an example of what the well-dressed voyager under the polar ice should wear. His oilskins were impeccable. The fact that he always carried an innocent-looking black cane afforded Captain McCluskey's crew some chuckles. They didn't know this was a sword cane. If Ham ever drowned, he would still have that sword cane in one hand.
   About noon, Ham searched Doc Savage out. Doc was on deck. It seemed a miracle that each terrific wave did not sweep him overboard. But the seas had no more effect upon Doc than upon a statue of tough bronze metal. There was a strange quality about Doc's bronze skin — it seemed to shed water like the proverbial duck's back, without becoming wet.
   Ham was excited.
   "Good news!" he yelled. "Radio message from New York, Long Tom just copied it!"
   "What is it?" Doc asked.
   "Victor Vail left the hospital this morning," Ham replied. "He is no longer blind. He can see as well as anybody!"
* * *
   THE SMASHING waves soon drove the immaculate Ham into the greasy vitals of the submarine.
   "I've inhaled so much oil already, it's oozing out of my hide," he told Monk.
   But Monk was making a chemical concoction capable of giving off warmth for several hours at a stretch — something that would be very handy to tuck in a man's shoes and gloves when he took a. stroll on the ice in the vicinity of the north pole. He didn't want to be bothered.
   "G'wan off an' chew a bacon rind!" he sneered.
   Ham bloated indignantly. Monk had been goading him for several days about pigs and pork, and Ham hadn't been able to devise a single way to get back at Monk. Ham wished mightily he dared take a swing at Monk, but he knew better. A grizzly bear with any sense would think twice before tackling Monk.
   Muttering to himself, Ham ambled forward. He heard a sound which might have been an angry bull in a china shop. Ham quickened his pace. It sounded like a fight. He ducked gingerly through a slit of a door in a steel bulkhead.
   One of the Helldiver's crew sprawled on the grilled floor of the engine room. The man was an oiler. He was big — fully as big as Monk. He looked tough. Privately, Ham had considered getting this oiler and Monk embroiled in a fight, just for his own amusement.
   But the fighting oiler now sprawled on his back. He whimpered. His lips had been smashed into a crimson pulp. One of his eyes was closed.
   Over him towered walrus-like Captain McCluskey.
   "I kin lick any swab aboard this iron fish!" the captain bellowed. "Rust my anchor, but I'll wring the neck of the next scut I find shirkin' his work. Get up on yer feet, you! An' see that them engines is kept better oiled!"
   Captain McCluskey evidently ran his craft like an old-time clipper master.
   Ham mentally kissed the oiler good-by as a prospective opponent for Monk. He addressed Captain McCluskey.
   "I like your discipline methods," he said flatteringly.
   "They'll do, pretty boy." bellowed the walrus.
   Ham writhed under the appellation of pretty boy. But he kept the oily smile of admiration on his face.
   "I'm afraid you're going to have trouble with one man aboard this vessel," he said in the air of imparting a warning to his hero.
   "Who?" roared the giant captain.
   "The hairy baboon they call Monk," said Ham blandly.
   "I'll watch 'im!" boomed the walrus ominously. "If he bats an eye at me, I'll hit the swab so hard his fur will fall off!"
   Ham had a foxy look in his eye as he ambled back to Monk's steel cubicle. He looked in at Monk.
   Monk gave him an elaborate, pig-like grunt.
   Ham ignored the insult.
   "The captain says the next time you bat an eye at him, he's gonna hit you so hard you'll shed all that red fuzz," Ham advised.
   "Yeah?" Monk heaved to his feet. "Yeah? Well, I'll just go tell 'im I don't like guys talkin' behind my back like that."
   He waddled out. He was so big he barely got through the door of his cubicle.
   Ham trailed along. He wouldn't have missed what was going to happen for a thousand dollars.
* * *
   MONK FOUND walrus-like Captain McCluskey in the officers' quarters. The two giants promptly glowered at each other. Monk's little eyes sparkled with the prospect of a fight. The walrus blew noisily through his mustache, each hair of which was like a crooked black peg.
   "Listen, guy!" Monk began in a sugary voice. I don't like — "
   The walrus hit Monk. It sounded like a gun going off.
   Monk hadn't expected it so soon. He was caught off guard. The blow drove him backward as though he had accidentally stood in front of a twelve-inch coast-defense gun.
   His bulk collided with Ham, who was standing behind him. That kept Monk from falling.
   But Ham was tumbled end over end. His head cracked a valve wheel. He was promptly knocked senseless.
   From Ham's point of view, nothing worse could have happened. He slept through the whole fight. He was cheated of enjoying the fruit of his devilment. it was the biggest disappointment Ham had suffered in years. For days afterward, he was wont to get off in a corner and swear to himself about it.
   Monk emitted a series of deep bawling noises. He jumped up and down like an ape. This cleared his head. He rushed the walrus.
   The walrus kicked him in the stomach.
   Monk folded down to the floor. The walrus leaped high into the air, and came down — and his face collided forcibly with Monk's driving feet.
   Captain McCluskey turned over completely in the air. He spat out three teeth. He got up, roaring. Monk knocked him down, loosening two more teeth in the process.
   The walrus tried to bite off Monk's left ear with what teeth he had left.
   Monk stopped this by grasping great folds of his opponent's ample stomach in monster fists and striving to tear the man open.
   They stood toe to toe and traded haymakers. They swapped indiscriminate kicks.
   It was a battle of the giants. A fray primeval! A thing of pristine savagery! It would have drawn a million-dollar gate in the prize ring — except that the women's clubs would have stopped it.
   And poor Ham, sleeping through it all, would have cut off an arm rather than miss it.
   Captain McCluskey lunged unexpectedly. Monk was carried backward. His bullet of a head crashed against a hard steel bulkhead.
   Monk fell senseless.
   The walrus drew back a foot to kick him.
   At this point, Renny dashed forward. He grasped McCluskey's huge arm.
   "You whipped him!" Renny rumbled. "No need of crippling him!"
   Renny only wanted to keep Monk from serious damage. He was a peacemaker. He got what peacemakers usually get.
   The walrus knocked Renny flat on his back.
* * *
   THE FIGHT now started all over. Renny was nearly as heavy as Monk. He was also a fine boxer. And for years he had been smacking panels out of doors with his fists.
   Renny got up from the floor and hung a left jab on McCluskey's nose.
   The walrus emitted a sound that was a combination of Vesuvius and Niagara. By a marvelous feat of acrobatics, he managed to jump on Renny's midriff with both feet.
   Air came from Renny's mouth so fast it almost blew out his teeth. He collapsed — largely to keep his middle from being jumped on again.
   Captain McCluskey rushed in to the kill.
   Renny hooked a fist. It hit McCluskey's ear. It smashed the ear fiat as a well-ironed handkerchief.
   A strange thing now happened.
   McCluskey got to his feet as calmly as though he were arising from the mess table. He ambled toward the slit of a door. He was unsteady on his feet, it was true, and nearly walked a circle. But he seemed to have forgotten there was such a thing as a fight.
   McCluskey was extremely punch drunk.
   He sobered before he got out of the room, though. Whirling, he emitted a bellow and sprang upon Renny.
   Renny roundhoused two good swings. The first folded McCluskey like a barlow knife. The second ruined the walrus's other ear and spun him like a top.
   McCluskey staggered backward and fell into a bunk. An instant later, however, he came out of it.
   He was a lot of man, that walrus.
   The two bartered punches. Renny blocked one with his jaw. For an instant, he was dazed. That instant was his undoing. Another swing landed on top of the first.
   Renny dropped, kayoed for one of the few times in his career.
   Mountainous Captain McCluskey took two weaving steps for the narrow bulkhead door. Then he sighed loudly, and, turning around twice like a dog finding a place to lay down, slumped prone on the floor.
   Afterward, Ham awakened. The combatants had been attended to, and Ham was so disappointed that he crawled out on deck and actually mingled salty tears with the sea.
* * *
   DOC SAVAGE now inaugurated a campaign of his own. He began to fraternize with the crew in a most diligent manner. It was only another evidence of his immense knowledge that he found something of interest to discuss with each man.
   Doc was hunting for the fellow whose teeth clicked.
   A strange thing became evident. None of the crew was willing to open up and talk frankly with him. Instead, half a dozen of them sought, none too adroitly, to worm from Doc his reasons for coming along on the under-the-polar-ice expedition.
   The big oiler whom Captain McCluskey had chastised for neglecting the engines was most outspoken. His name was, not without reason, "Dynamite" Smith.
   "Just where is this boodle yer goin' after, sir?" asked Dynamite Smith.
   "What boodle?" queried Doc innocently.
   Dynamite Smith shifted uneasily.
   "Well, me an' my mates kinda got the idea yer was goin' after somethin' up in the bloody arctic," he said. "Have yer got a map that shows where it is?"
   "What put all this into your head?"
   "Nothin'," muttered Dynamite Smith. Then, unable to stand the searching gaze of Doc's strangely potent golden eyes, the big oiler turned away.
   It was obvious the man knew more than he had divulged. It was also evident that some sinister devilment was breeding among the crew.
   Doc didn't like it.
   "I'll bet that bird with the clicking teeth is stirring up the crew," Doc decided.
   An idea hit him. He went to make sure he still had the treasure map he had taken off the back of blind Victor Vail by X ray.
   The map was gone! Somebody had stolen it!
* * *
   SEVERAL DAYS passed. Nothing happened. The Helldiver now sailed off a barren section of northern Greenland. Great blue icebergs cocked nasty snouts out of the sea all about them. The sub sloughed through mile after mile of thin pan ice.
   Occasionally, where the pan ice had joined with fields of growlers, or small bergs, to make a solid barrier, they submerged and passed under.
   The submarine was behaving beautifully. Long Tom's wonderful apparatus kept them out of danger, with the double safeguard of Monk's special chemicals, should something go amiss.
   Monk, Renny, and the walruslike Captain McCluskey had resumed relations. Indeed, they got along handsomely. They had a hearty respect for each other's fighting qualities.
   Doc hadn't found the man with the clicking teeth. He was mystified He couldn't imagine who had his treasure map, but he did not worry greatly about it His retentive brain held all details of the chart. He could sit down and reproduce it perfectly from memory.
   The only discovery of note he had made was that Dynamite Smith, the big oiler, used narcotics almost steadily. Doc consulted Captain McCluskey about this.
   "Sure, I knowed the swab was a dope head," the walrus assured him. "Rust my anchor, but it don't seem to hurt him. He's been usin' the stuff for years. Let'm alone, matey. The stuff just keeps 'im harmless."
   Doc was not so sure about that. But there was nothing to be gained by starting trouble.
   Long Tom radioed their position daily to Victor Vail. The violinist showed a great interest in their progress, as well as the exact course they intended to follow.
   Sometimes Doc wondered about Victor Vail's avid desire to know their whereabouts to the fraction of a mile.
   They were in a zone of continuous daylight now. The sun shone the full clock around. It was never night.
   "Confound such a region!" Ham complained. He had just found out that for the last three days, Monk had awakened him at midnight, and made him believe it was noon the next day. Consequently, Ham had been losing a lot of sleep, and couldn't understand what was making him feel so groggy.
   A strange, sinister tension was growing aboard the Helldiver.
   The crew congregated in groups, whispering. They dispersed, or fell to speaking loudly of commonplaces when Captain McCluskey, Doc, or any of his five men came near.
   "Rust my anchor, but I smells trouble!" Captain McCluskey confided to Doc.
   Day after day, the submarine bored into the polar regions. Twice it traveled under the ice more than a score of hours. It made many shorter jaunts under the pack.
   On one occasion, they would surely have been trapped under a vast field of ice more than thirty feet deep, had it not been for Monk's chemicals. Released from compartments in the skin of the underseas boat, the stuff let the craft reach the surface through a great self-made blow hole.