TOM SWIFT AND HIS UNDERSEA SEARCH

or

The Treasure on the Floor of the Atlantic

by

VICTOR APPLETON

CONTENTS

CHAPTER

 I UNTOLD MILLIONS II A STRANGE OFFER III THINKING IT OVER IV AGAINST HIS WILL V BUSY DAYS VI MARY'S ODD STORY VII THE TRIAL TRIP VIII THE MUD BANK IX READY TO START X STARTLING REVELATIONS XI BARTON KEITH'S STORY XII IN DEEP WATERS XIII THE SEA MONSTER XIV IN STRANGE PERIL XV TOM TO THE RESCUE XVI GASPING FOR AIR XVII WHERE IS IT? XVIII A SEPARATION XIX THE SERPENT WEED XX THE DEVIL FISH XXI A WAR REMINDER XXII STUDYING CURRENTS XXIII AN UNDERSEA COLLISION XXIV THE TREASURE SHIP XXV THE STEEL BOX

TOM SWIFT AND HIS UNDERSEA SEARCH

CHAPTER I

UNTOLD MILLIONS

"Tom, this is certainly wonderful reading! Over a hundred milliondollars' worth of silver at the bottom of the ocean! More than twohundred million dollars in gold! To say nothing of fifty millions incopper, ten millions in--"

"Say, hold on there, Ned! Hold on! Where do you get that stuff; as theboys say? Has something gone wrong with one of the adding machines, oris it just on account of the heat? What's the big idea, anyhow? Howmany millions did you say?" and Tom Swift, the talented young inventor, looked at Ned Newton, his financial manager, with a quizzical smile. 

"It's all right, Tom! It's all right!" declared Ned, and it needed buta glance to show that he was more serious than was his companion. "I'mnot suffering from the heat, though the thermometer is getting close toninety-five in the shade. And if you want to know where I get 'thatstuff' read this!"

He tossed over to his chum, employer, and friend--for Tom Swift assumedall three relations toward Ned Newton--part of a Sunday newspaper. Itwas turned to a page containing a big illustration of a diver attiredin the usual rubber suit and big helmet, moving about on the floor ofthe ocean and digging out boxes of what was supposed to be gold from asunken wreck. 

"Oh, that stuff!" exclaimed Tom, with a smile of disbelief as he sawthe source of Ned's information. "Seems to me I've read something likethat before, Ned!"

"Of course you have!" agreed the young financial manager of the newlyorganized Swift Construction Company. "It isn't anything new. Thiswealth of untold millions has been at the bottom of the sea for manyyears--always increasing with nobody ever spending a cent of it. Andsince the Great War this wealth has been enormously added to because ofthe sinking of so many ships by German submarines. "

"Well, what's that got to do with us, Ned?" asked Tom, as he lookedover some blue prints and other papers on his desk, for the talk wastaking place in his office. "You and I did our part in the war, but Idon't see what all this undersea wealth has to do with us. We've gotour work cut out for us if we take care of all the new contracts thatcame in this week. "

"Yes, I know, " admitted Ned. "But I couldn't help calling yourattention to this article, Tom. It's authentic!"

"Authentic? What do you mean

"Well, the man who wrote it went to the trouble of getting from theship insurance companies a list of all the wrecks and lost vesselscarrying gold and silver coin, bullion, and other valuables. He hasgone back a hundred years, and he brings it right down to just beforethe war. Hasn't had time to compile that list, the article says. Butwithout counting the vessels the Germans sank, there is, in variousplaces on the bottom of the ocean today, wrecks of ships that carried, when they went down, gold, silver, copper and other metals to the valueof at least ten billions of dollars!"

Tom Swift did not seem to be at all surprised by the explosive emphasiswith which Ned Newton conveyed this information. He gazed calmly at hisfriend and manager, and then handed the paper back. 

"I haven't time to look at it now, " said Tom. "But is there anythingnew in the story? I mean has any of the wealth been recoveredlately--or is it in a way to be?"

"Yes!" exclaimed Ned. "It is! A company has been formed in Japan forthe purpose of using a new kind of diving bell, invented by anAmerican, it seems. The inventor claims that in his machine he can godown deeper than ever man went before, and bring up a lot of this lostocean wealth. "

"Well, every so often an inventor, or some one who calls himself that, crops up with a new proposal for cleaning up the untold millions on thefloor of the Atlantic or the Pacific, " replied Tom. "Mind you, I'm notsaying it isn't there. Everybody knows that hundreds of ships carryinggold and silver have gone down in storms or been sunk in war. And someof the gold and silver has been recovered by divers--I admit that. Infact, if you recall, my father and I perfected a new style diving dressa few years ago that was successfully used in getting down to a wreckoff the Cuban coast. A treasure ship went down there, and I believethey recovered a large part of the gold bullion--or perhaps it wassilver. 

"But this diving bell stunt isn't new, and it hasn't been successful. Of course a man can go down to a greater depth in a thick iron divingbell than he can in a diving suit. That's common knowledge. But thetrouble with a diving bell is that it can't be moved about as a man canmove about in a diving suit. The man in the bell can't get inside thewreck, and it's there where the gold or silver is usually to be found. "

"Can't they blow the wreck apart with dynamite, and scatter the gold onthe bottom of the ocean?" asked Ned. 

"Yes, they could do that, but usually they scatter it so far, and theocean currents so cover it with sand, that it is impossible ever to getit again. I admit that if a wreck is blown apart a man in a diving bellcan perhaps get a small part of it. But the limitations of a divingbell are so well recognized that several inventors have tried adjustingmovable arms to the bell, to be operated by the man inside. "

"Did they work?" asked Ned. 

"After a fashion, yes. But I never heard of any case where the gold andsilver recovered paid for the expenses of making the bell and sendingmen down in it. For it takes the same sort of outfit to aid the man inthe diving bell as it does the diver in his usual rubber or steel suit. Air has to be pumped to him, and he has to be lowered and raised. "

"Well, isn't there any way of getting at this gold on the floor of theocean?" asked Ned, his enthusiasm a little cooled by the practical"cold water" Tom had thrown. 

"Oh, yes, of course there is, in a way, " was the answer of the younginventor. "Don't you remember how my father and I, with Mr. Damon andCaptain Weston, went in our submarine, the Advance, and discovered thewreck of the Boldero?"

"I do recall that, " admitted Ned. 

"Well, " resumed Tom, "there was a case of showing how much trouble wehad. An ordinary diving outfit never would have answered. We had tolocate the wreck, and a hard time we had doing it. Then, when we foundit, we had to ram the old ship and blow it apart before we could getinside. Even after that we just happened to discover the gold, as itwere. I'm only mentioning this to show you it isn't so easy to get atthe wealth under the sea as writers in Sunday newspaper supplementsthink it is. "

"I believe you, Tom. And yet it seems a shame to have all thosemillions going to waste, doesn't it?" And Ned spoke as a banker andfinancial man, who is not happy unless money is earning interest allthe while. 

"Well, a billion of dollars is a lot, " Tom admitted. "And when youthink of all that have been sunk, say even in the last hundred years, it amazes one. But still, all the gold and silver was hidden in theearth before it was dug out, and now it's only gone back where it camefrom, in a way. We got along before men dug it out and coined it intomoney, and I guess we'll get along when it's under water. No useworrying over the ocean treasures, as far as I'm concerned. "

"You're a hopeless proposition!" laughed Ned. "You'd never make abanker, or a Napoleon of finance. "

"That's why my father and I got you to look after our financialaffairs, " and Tom smiled. "You're just the one--with yourinterest-bearing mind--to keep us off the shoals of business trouble. "

"Yes, I suppose I can do that, while you and your father go oninventing giant cannons, great searchlights, submarines, and airships, "conceded Ned. "But this, to me, did look like an easy way of makingmoney. "

"How's that, Ned?" asked Tom, a new note coming into his voice. "Wereyou thinking of going to Japan and taking a hand in the underseasearch?"

"No. But stock in this company is being sold, and shareholders stand towin big returns--if the wrecks are come upon. "

"That's just it!" exclaimed Tom. "If they find the wrecks! And let metell you, Ned, that there's a mighty big 'if' in it all. Do yourealize how hard it is to find anything on the ocean, to say nothing ofsomething under it?"

"I hadn't thought of it. "

"Well, you'd better think of it. You know on the ocean sailors have tolocate a certain imaginary position by calculation, using the sun andstars as guides. Of course, they have navigation down pretty fine, anda good pilot can get to a place on the surface of the ocean and meetanother craft there almost as well as you and I can make an appointmentto meet at Main and Broad streets at a certain hour. 

"But lots of times there are errors in calculations or a storm comes uphiding the sun and stars, and, instead of a captain getting to where hewants to, he's anywhere from one to a hundred miles out. Now thelocation of Broad and Main Streets doesn't change even in a storm. 

"And I'm not saying that a location on an ocean changes. I'm onlysaying that the least disturbance or error in calculation makes italmost impossible to find the exact spot. And if it's that hard on thesurface, where you can see what you're doing, how much harder is it inregard to something on the bottom of the sea? So don't take any stockin these ocean treasure recovering companies. They may not be fakes, but they're mighty uncertain. "

"Oh, I don't know that I was really going to buy any stock in thisJapanese concern, Tom. I only thought it would be interesting to thinkabout. And perhaps you might sell them a submarine or some of yourdiving apparatus. "

"Nothing doing, Ned. We've got other plans, my father and I. There'sthat new tractor for use in the big wheat-growing belt, to say nothingof--"

Tom's remarks were interrupted by voices outside his office door. Onevoice, in particular, rose above the others. It said:

"No can go in! The Master he am busily! No can go in!"

"Nonsense, Koku!" exclaimed a man, and at the sound of his voice Tomand Ned smiled. "Nonsense! Of course I can go in! Why, bless my watchfob, I must go in! I've got the greatest proposition to lay before TomSwift that he ever heard of! There's at least a million in it! Let mepass, Koku!"

"Mr. Damon!" murmured Tom Swift. "I wonder what he has on his mind now?"

As he spoke the door opened rather violently and a short, stout man, evidently much excited, fairly burst into the room, followed, moresedately, by a stranger. 

CHAPTER II

A STRANGE OFFER

"Hello, Tom Swift! Hello, Ned! Glad to see you both! Busy, as usual, I'll wager. Bless my check book! I never saw you when you weren't busyat some scheme or other, Tom, my boy. But I won't take up much of yourtime. Tom Swift, let me introduce my friend, Mr. Dixwell Hardley. Mr. Hardley, shake hands with Tom Swift, one of the youngest, and yet oneof the greatest, inventors in the world! I've told you a little abouthim, but it would take me all day to tell you what he really has doneand--"

"Hold on, Mr. Damon!" laughed Tom, as he shook hands with the man whomMr. Damon had named Dixwell Hardley. "Hold on, if you please. There's alimit to it, you know, and already you've said enough about me to--"

"Bless my ink bottle, Tom, I haven't said half enough!" interrupted thelittle, eccentric man. "Wait until you hear what he has done, Mr. Hardley. Then, if you don't say he's the very chap for your wonderfulscheme, I'm mighty much mistaken! And shake hands with Ned Newton, too. He's Tom's financial manager, and of course he'll have something tosay. Though when he hears how you are going to turn over a couple ofmillion dollars or more, why, I know he'll be on our side. "

Ned's eyes sparkled at the mention of the money. In truth he dealt indollars and cents for the benefit of Tom Swift. Ned shook hands withMr. Hardley and Tom motioned Mr. Damon and his friend to chairs. 

"Now, Tom, " went on the strange little man, "I know you're busy. Blessmy adding machine, I never saw you when--"

At that moment there arose in the corridor outside Tom's private officea discord of voices, in which one could be heard exclaiming:

"Now yo' clear out oh heah! Massa Tom done tole me to sweep dish yeahplace, an' ef yo' doan let me alone, why--why--"

"Huh! Radicate him big stiff--dat's what! Big stiff! Too stiff forsweep Master's floor. Koku sweep one hand!"

"Oh, yo' t'ink 'case yo' is sich a big giant, yo' kin git de best obole black Rad! But I'll show yo' dat--"

"Excuse me a moment, " said Tom, with a smile to his guests as he arose. "Eradicate and Koku are at it again, I'm sorry to say. I'll have to goout and arbitrate the strike, " and he left the room. 

While he is settling the differences between his faithful old blackservant and Koku, the giant, I will take the opportunity of telling mynew readers something about Tom Swift. 

Those who are familiar with the previous books of this series may skipthis part. But it will give my new audience a better insight into thisstory if they will bear with me a moment and peruse these few lines. 

As related in the first book, "Tom Swift and His Motor Cycle, " the heroseemed born an inventive genius. It was this inventive faculty whichenabled him to take the motor cycle that tried to climb a tree with Mr. Wakefield Damon on it and make the wreck into a serviceable bit ofmechanism. Thus Tom became acquainted with Mr. Damon, who among othereccentricities, was always "blessing" something personal. 

Tom Swift lived in the city of Shopton with his father and theirfaithful housekeeper, Mrs. Baggert. It was so named because the Swiftshops were an important industry there. Tom's father, as well as Tomhimself, was an inventor of note, and employed many men in buildingmachines of various kinds. During the Great War the services of Tom andhis father had been dedicated to the government. 

There are a number of books dealing with Tom's activities, the list oftitles of which may be found at the beginning of this volume. 

Sufficient to say here, that Tom invented and operated motor boats, airships, and submarines. In addition he traveled on many expeditionswith Mr. Damon, Ned, and others. He went among the diamond makers andit was when he escaped from captivity that he managed to bring awayKoku, the giant, with him. Since then Koku and Eradicate Sampson, thefaithful colored man, had periodic quarrels as to who should serve theyoung inventor. 

Besides inventing and using many machines of motive power, Tom Swiftengaged in other industries. He helped dig a big tunnel, he constructeda photo-telephone, a great searchlight and a monster cannon. Occasionally he had searched for treasure, once under the sea, withconsiderable success. 

Of late his and his father's industries had become so important that anumber of new buildings had been constructed and the plant greatlyenlarged. Ned Newton, who had once worked in a Shopton bank, becamefinancial manager for Tom and his father, and plenty of work he foundwith which to occupy himself. 

Just prior to the opening of this story Tom had perfected a noiselessaeroplane--or one so nearly silent as to justify the name. The detailsof it will be found in the book called "Tom Swift and His Air Scout. "In this mechanism of the air Tom had had some wonderful experiences, and they had not been at home more than a few weeks when New Newtonbroached the subject of undersea wealth. 

The talk of Tom and his financial manager was interrupted by thearrival of Mr. Damon and the stranger he had introduced as Mr. Hardley. 

Eradicate, or "Rad, " and Koku, have been mentioned. Rad was an ancientcolored man who once owned a mule named Boomerang. Sampson was thecolored servant's last name, and he declared he had chosen the one"Eradicate" because in his younger days he was a great cleaner andwhitewasher, "eradicating" the dirt, so to speak. 

Boomerang had, some time since, gone where all good mules go, thoughEradicate declared he would get another and call him Boomerang II. But, so far, he had not done so. 

Rad, though too old to do heavy work, still believed he wasindispensable to the welfare of Tom and his father; and as the giantKoku, who was physically an immense man, held the same view, itfollowed there were frequent clashes between the two, as on theoccasion just mentioned. 

"What was the matter, Tom?" asked Ned, when the young inventor cameback into the room. 

"Oh, the same old story, " replied Tom. "Rad wanted to sweep the hall, and Koku insisted he was to do it. "

"What'd you do, Tom?" asked Mr. Damon. 

"I settled it by having Rad sweep this hall and sending Koku to doanother--a bigger one I told him. He likes hard work, so he waspleased. Now we'll have it quiet for a little while. Did I understandyou to say, Mr. Damon, that--er--Mr. Hardley I believe the name is--hada proposition to make to me?"

"That's exactly it, my dear Mr. Swift!" broke in the man in question. "I have a wonderful offer to make you, and I'm sure you will admit thatit will be well worth your while to consider and accept it. There willbe at least a million in it--"

"Bless my check book, I thought you said several millions!" exclaimedMr. Damon. 

"So I did, " was the rather nettled answer. "I was about to say, Mr. Damon, that there will be at least a million in it for Mr. Swift, andanother million for myself. There may be more, but I want to beconservative. "

"Talking in millions, and calling himself conservative, " mused NedNewton. "Somehow or other I don't just cotton to this fellow!"

"When our mutual friend, Mr. Damon, told me about you, my dear Mr. Swift, " went on Mr. Hardley, "I at once came to the conclusion that youwere the very man I wanted to do business with. I'm sure it will be toour mutual advantage. "

Tom Swift said nothing. He was willing to let the other talk, while hewaited to see how far he would go. And, as Tom said afterward, he, ashad Ned, took an instinctive dislike to Mr. Hardley. He could not saydefinitely what it was, but that was his feeling. That he might bemistaken, he admitted frankly. Time alone could tell. 

"Have you a half hour to give me while it explain matters?" asked Mr. Hardley. "I may go farther and say I need considerable time to go intoall the details. May I speak now?"

To tell the truth Tom Swift had many important matters to consider, and, in addition, Ned Newton was prepared to go over some financialends of the business with Tom. But the young inventor felt that, injustice to his friend Mr. Damon, who had brought Mr. Hardley, he coulddo no less than give the stranger a hearing. But only the introductionby Mr. Damon brought this about. 

"I shall be glad to hear what you have to say, Mr. Hardley, " said Tom, as courteously as he could. "I will not go so far as to say that mytime is unlimited, but I will listen to you now if you care to go intodetails. "

"That's good!" exclaimed the visitor. "I'm sure that when you havelistened you will agree with me. "

"He's a little bit too sure!" mused Ned. 

"Bless my pocketbook, Tom, but there are millions in it!" exclaimed Mr. Damon. "Literally millions, Tom!"

Mr. Hardley settled himself comfortably in his chair and looked fromTom to Ned. 

"May I speak freely here?" he asked, with obvious intent. 

"You may, " the young inventor answered. "Mr. Newton is my financialmanager, and I do nothing of importance without consulting him. You mayregard him as a member of the firm, in fact, as he does own some stock. My father is practically retired, and I do not trouble him withunimportant details. So Mr. Newton and I are prepared to listen to you. "

"Very well, Mr. Swift, I'm going to ask you a question. Have you allthe money you want?"

Tom laughed. 

"I suppose any man would answer that question in the negative, " hereplied. "Frankly, I could use more money, though I am not poor. "

"So I have heard. Well, would a million dollars clear profit appeal toyou?"

"It certainly would, " was the answer. 

"Then I am prepared to offer you that sum, " went on Mr. Hardley. "Butthere are certain conditions, and I may say that this vast wealth isnot easy to come at. However, with your inventive genius, I am sure youwill be able to solve the mystery of the sea. Now then as to details. There lies, on the floor of the ocean--"

"Hark!" exclaimed Tom, raising a hand to enjoin silence. "I think Ihear some one coming. " At that moment there was a knock at the door. 

CHAPTER III

THINKING IT OVER

"Father, is that you?" asked Tom. "Father hasn't been feeling well, oflate, " he said to the assembled company, "and I told him to go to liedown. But he's hard to manage, and he won't rest more than ten minutesat a time. My father, I might explain, Mr. Hardley, " Tom went on, "isactively associated with me in business. "

"So I have understood, " said the man who had been introduced by Mr. Damon. 

"Dis Koku!" came the guttural voice of the giant from the other side ofthe door. "Koku want more work. Hall, him all clean. Maybe I help datno-good Rad now. "

"No you don't, Koku!" exclaimed the young inventor, with a laugh. "Youkeep away from Rad. You'll get to disputing again and interrupt me, andI have business on hand. Here, wait a minute. I'll find something foryou to do, " he went on, opening the door to disclose the immense manstanding outside, a broom in his hand seeming like a toy. 

"Excuse me one moment, " went on Tom to his friends. Taking up his desktelephone he called one of the shops, asking: "Have you any heavy workon hand this morning; lifting big castings, or anything like that? Youhave? Good! I'll send Koku right over. "

Turning to the giant who apparently had not paid much attention to thetalk over the wire, Tom said:

"Koku, go over to shop number ten, ask for the foreman, and he'll keepyou busy. There are some five-hundred-pound castings that needassembling, and you can help him. "

"Good!" exclaimed the giant, with a cheerful grin. "Koku like bigwork--no like sweep. Good for women and Rad, but not for Koku!"

"He spoke the truth there, " remarked Ned Newton, as the giant stalkeddown the hall. "I never saw such a strong man. I'm afraid to shakehands with him, for fear I'll be minus a couple of fingers in theoperation. "

"Well, he's disposed of, " remarked Tom, as he closed the door. "Andnow, Mr. Hardley, I'm at your service, as far as listening to yourproposition is concerned. "

"Thank you. I shall endeavor to be brief, " remarked the visitor. "Am Icorrect in assuming that you have had some experience in submarinework? I believe Mr. Damon mentioned something of that sort. "

"Submarine work? Bless my hydrometer, I should say so!" exclaimed theeccentric man. "And not only in submarine, but in aeroplane! but youdon't need any aeroplanes, my dear Mr. Hardley. It's the submarine endof it that you are interested in, as far as Tom Swift is concerned. Nowgo ahead and tell him what you told me, and how many millions there arein it. "

"Very well, " assented the visitor. "Have you ever had any experience inrecovering treasure from sunken wrecks?" he asked Tom. 

"Yes, " was the answer. "And it is curious that you should ask me that, for my friend here, Ned Newton, and I were just talking about that verymatter. Here's what brought it up, " and Tom showed the page from theSunday paper. 

"Hum! Yes!" musingly remarked Mr. Hardley. "That's all very well. Partof it is true; but I imagine most of it is the work of imagination ofsome enterprising reporter. Of course there is no question but thatthere are untold millions on the bottom of the ocean. The only trouble, as I think you will agree with me, Mr. Swift, is in coming at themoney. "

"Exactly, " said Tom. 

"And will you bear me out when I say that if the wreck of a treasureship could be exactly located in water that is not too deep, half thetrouble would be solved?" asked Mr. Hardley. 

"A good share of it would, " answered Tom. "That is usually the chiefdifficulty--locating the wreck. Nearly always they are anywhere fromone to five miles from where the persons seeking them think they are. And five miles, or even half a mile, is a good distance on the bottomof the ocean. "

"Exactly, " echoed Mr. Hardley. "Then if I could give you the exactlocation of a sunken treasure ship, and prove to you that the ownershad given up the search for it, leaving it open to salvage on the partof whoever wished to try--would that be any inducement to you to makean attempt, Mr. Swift?"

"I should want to hear more about it before I gave an answer, " repliedTom. "As perhaps Mr. Damon has told you, I once went on a hunt fortreasure in my submarine. We found it, but only after considerabletrouble, and then I declared I'd never again engage in such a search. There wasn't enough net profit in it. "

"But there are millions in this, Tom! Bless my gold tooth, but thereare millions!" cried the excitable Mr. Damon. "Hurry up and tell him!"he urged his friend. 

"I will, " assented Mr. Hardley. "I can readily believe, " he went on, "that the cost of hunting for undersea treasure is great. I have takenthat into consideration. Now, in brief, my plan is this. I will joinforces with you, and bear half the expense if I am allowed to sharehalf the proceeds. That's fair, isn't it?" he asked Tom. 

"So far, yes, " replied the young inventor. 

"Now then, to business!" exclaimed the visitor. "Will you join with mein searching for some of the wealth-laden wrecks that are rotting atthe bottom of the sea, Mr. Swift?"

"Do you mean make an indiscriminate search for any one of a number ofwrecks?" Tom wanted to know. 

"I should want the understanding broad enough to include all wrecks wemight discover, " was the answer, "but I have in mind one in particularnow. It is the wreck of the steamer Pandora which was sunk off thecoast of one of the West Indian Islands about a year ago. "

Ned Newton quickly caught up the page of the Sunday supplement andscanned the list of wrecks given there. 

"No mention of the Pandora here, " he said. 

"No, " agreed Mr. Hardley, "the story of this wreck is not generallyknown, and the story of the treasure she carried is hardly known atall. As a matter of fact, this money, mostly in gold, was to finance aSouth American revolution, and such matters are generally kept quiet. That is why nothing much appeared in the papers about the Pandora. ButI happen to know that she carried over two million dollars in gold, andI know--"

"Think of that, Tom! Think of that!" cried Mr. Damon. "Two milliondollars in gold! Why bless my--bless my--"

But the eccentric man could think of nothing adequate to bless underthe circumstances, and he subsided with a murmur. 

"Excuse me for interrupting you, " he said to his new friend. "But Ijust couldn't help it. "

"That's all right, " Mr. Hardley remarked, with a smile that showed tworows of very even, white teeth. "I don't blame you for getting excited. Does that interest you?" he asked Tom. "Two million dollars in gold, besides a quantity of silver--just how much I don't know. "

"It certainly sounds interesting, " replied Tom, with a smile. "But areyou sure of your facts?"

"Absolutely, " was the answer. "I was a passenger on the Pandora whenshe was wrecked in a storm. I saw the gold put on board. It was nottaken off, and is on her now as she lies at the bottom of the sea. "

"And the location?" queried Tom. 

"I know that, too!" said Mr. Hardley eagerly. "I was with the captainjust before we had to abandon ship, and I heard the exact nauticallocation given him by an officer who made the calculation. I have itwritten down to the second--latitude and longitude. That will be a helpin locating the wreck, won't it?"

"Why, yes, " Tom had to agree, "it will be, but if you know it, then thecaptain and others must know it. And what is to prevent them frommaking a search for the Pandora if they have not already done so?"

"The best reason in the world, " was the answer. "The boat containingthe captain and the officer who gave him the ship's position was sunk, and all on board lost. The boat I was in was the only one picked up, and I believe I am the only one who knows exactly where the Pandoralies. 

"Now, here is my offer, Mr. Swift, " went on the seeker after theocean's hidden wealth. "I will bear half the expense of fitting out asubmarine, or for any other kind of expedition to go in search of thewreck of the Pandora. I will furnish you with the exact nauticallocation, as I have it. And when the wealth is found and brought to thesurface, I will give you half--in other words at least a milliondollars! Does that appeal to you?"

"I must say it is a fair, though perhaps strange, offer, " conceded Tom. "And a million dollars is not made every day nor every year. But whatabout the title to this money? After we have recovered it--provided weare successful--will not some person or some government lay claim toit?"

"None can successfully, " declared Mr. Hardley. "As I told you, themoney was to finance a revolution. It was raised for an unlawfulpurpose, so to speak, and no one has a valid claim to it under thecircumstances, so lawyers whom I have consulted have told me. But ifthat is not enough, I have papers to prove that those who might becalled the owners have given up the search for it. More than a year haselapsed, and though I don't know just how long it takes to outlaw anunder-ocean claim, I feel sure that we would have a legal and moralright to take this gold if we could find it. "

"I should want to be satisfied on that point before I undertook thesearch, " said Tom. 

"Then you will undertake it?" eagerly exclaimed Mr. Hardley. 

"I will think it over, " Tom answered quietly--so quietly that distinctdisappointment showed on the face of the visitor. 

CHAPTER IV

AGAINST HIS WILL

For a moment it seemed that Mr. Damon, as well as Mr. Hardley, feltdisappointment at Tom's answer, for the eccentric man exclaimed:

"Bless my leather belt, Tom, but you aren't very keen on making amillion dollars!"

"Oh, yes, I like to make money, " the young inventor answered. "I guessyou know that, as well as any one, for you've been with me on severaltrips. And I don't mind hard work, nor danger. "

"I'll say you don't!" added Ned, as he thought of some of Tom'sperilous voyages, among the diamond makers and in the caves of ice. 

"Well, if you are anxious to make money, as I admit I am, " said Mr. Hardley, "why can't you give me an answer now?"

"Because, " answered Tom, "there are many things to be considered. Hunting for a treasure on the floor of the Atlantic isn't like going tosome location on land, however wild or inaccessible it might be. Do yourealize, Mr. Hardley, what a large difference in miles a small error innautical calculations makes? We might go to the exact spot where youthought the wreck of the Pandora lies, only to find that we would haveto hunt around a long time. 

"I must think of that, and also think of my other business affairs. Then, too, there is my father. He is getting old, and while he is stillactive in the affairs of the company, particularly when it comes totaking up new lines of work, I do not like to think of leaving him, asI should have to, in case I went on this trip. "

"Take him along!" exclaimed Mr. Damon. "He's gone with us before, Tom. "

"He's too old now, " said the young inventor a bit sadly. "Father willnever make another extended trip. But I will let you have my answer assoon as I can, Mr. Hardley, and I will give the matter considerablethought. "

"I'm sure I hope you will, and also that you will consent to go, " wasthe answer. "A million is not easily to be come at in these days afterthe Great War. "

"I realize that, " agreed Tom with a smile. "And you shall have myanswer as soon as possible. "

With this the visitor was forced to be content, and a little later hewithdrew with Mr. Damon, the latter telling Tom that he would see himagain soon. 

"Well, that was queer, wasn't it?" remarked Ned, when he and Tom werealone again. 

"What was?" asked Tom, as though his mind was far away, as indeed itwas. 

"That this man should come in with his project to search for a sunkentreasure wreck just as we were talking about how many millions were onthe bottom of the ocean. "

"Yes, it was quite a coincidence, " Tom admitted. 

"What do you think of it--and him?" asked Ned. 

"Well, to tell you the truth, I didn't take a great fancy to Mr. Hardley, " Tom said. "I think he's altogether too cocksure, and takestoo much for granted. Still I may misjudge him. Certainly he doesn'thave a chance at a million dollars every day. "

"Do you think you could get the treasure out of this wreck, Tom, if youcould locate her?"

"Why, it's possible; yes. We proved that with the Boldero. "

"Would you use the same submarine?"

"No, I think I'd have to rebuild it, or make an altogether new one. Possibly I might get one of Uncle Sam's and add some improvements of myown. "

"Yes, you could do that, " agreed Ned. "You've done so much for thegovernment that it couldn't refuse you something reasonable, now thatthe war is over. Then do you think you'll go?"

"Really, Ned, I can't make up my mind yet. Now let's forget the Pandoraand all the millions and get down to business. This Criterion companyseems to me to want altogether too much, We'll have to trim theirrequest down a bit. They owe the money and ought to pay it. "

"Yes, I'll get after them, " said Ned, and then he and his chum, as wellas employer, plunged into a mass of business details. 

It was the next afternoon, when Tom, following a strenuous morning ofwork, leaned back in his chair at his desk, that Mr. Damon wasannounced. 

"Tell him to come in, " ordered Tom, always glad to see his friend. "Wait a minute, though!" he called to the messenger. "Is any one withhim?"

"No, sir; he is alone. "

"Good! Then show him right in. I was afraid, " said Tom to Ned, who wasalso in the office, "that he had Hardley with him. I'm not quite readyto see him yet. "

"Then you haven't made up your mind about going for the treasure?"

"Not exactly. I shall, perhaps, this week. "

"Bless my matchbox, Tom, but I'm glad to see you!" cried Mr. Damon, ashe hastened forward with outstretched hand. "I was afraid you might beout. Now look here! What about my friend Hardley? He's very anxious toknow your decision about going for that treasure, and I said I'd comeover and sound you. I don't mind saying, Tom, that if you go I'm goingtoo; if you'll take me, of course. "

"Well, Mr. Damon, you know you'll always be welcome, as far as I amconcerned, " said the young inventor; "but, as a matter of fact, I don'tbelieve I'm going. "

"What? Not going to pick up a million dollars off the floor of theocean, Tom? Bless my bank balance! but that's foolish, it seems to me. "

"Perhaps it is, but I can't help it. "

"What's your principal objection?" asked the eccentric man. "It isn'tthat you don't want the money, is it?"

"Not exactly. "

"Then it must be that you object to Mr. Hardley personally. " went onMr. Damon. "I began to suspect that, Tom, and I want to say that youare wrong. Mr. Hardley is a friend of mine--a good friend. I have notknown him long, but he strikes me as being all right. He had some goodletters of introduction, and I believe he has money. "

"Where'd he get it?" asked Tom. 

"I don't know, exactly. Seems to me I heard him mention silver mines, or it may have been gold. Anyhow, it had something to do with gettingwealth out of the ground. Now, Tom, I don't mind saying that I stand tomake a little money in case this thing goes through. "

"How's that, Mr. Damon?" asked the young scientist in surprise. 

"Why, I agreed to bear part of the expense, " was the answer. "I thoughtthis was a pretty good scheme, and when Mr. Hardley came to me and toldme of the possibilities I agreed to help him finance the expenses. Thatis, I have taken shares in the company he formed to raise his half ofthe expense money. 

"Of course I thought of you at once when he spoke of having to searchout a sunken wreck, and I proposed your name. He'd heard of you, hesaid, but didn't know you. So I brought you together and now--bless myapple pie, Tom! I hope you aren't going to turn down a chance to make amillion and, incidentally, help an old friend. "

"Well, " remarked Tom, slowly, "I must admit, Mr. Damon, that I didn'tthink you'd go into a thing like this. Not that it is more risky thanother schemes, but I thought you didn't care for speculation. "

"Well, this sort of appealed to me Tom. You know--sunken wreck underthe ocean, down in a diving bell perhaps, and all that! There'sromance to it. "

"Yes, there is romance, " agreed Tom. "And hard work, too. If Iundertook this it would mean an extra lot of work getting ready. Isuppose I could use my own submarine. I could get her in commission, and make improvements more quickly than on any other. "

"Then you'll go?" quickly cried the eccentric man. 

"Well, since you tell me you are interested financially, I believe Iwill, " assented Tom, but he spoke reluctantly. "As a matter of fact, Iam going against my better judgment. Not that I fear we shall be indanger, " he hastened to add; "but I think it will prove a failure. However, as Mr. Hardley will bear half the expense, and as by using myown submarine that will not be much, I'll go!"

"Then I'll tell him!" exclaimed Mr. Damon. "Hurray! This is great! Ihaven't had an exciting trip for a long while! Don't tell my wife aboutit, " he begged Tom and Ned. "At least not until just before we start. Then she can't object in time. I'll have a wonderful experience, Iknow. This will be good news to Dixwell Hardley!"

And as Mr. Damon hastened away to acquaint his new friend with Tom'sdecision, the young inventor remarked to Ned:

"I'll go; but, somehow, I have a feeling that something will happen. "

"Something bad?" asked the financial manager. "No, I wouldn't go so faras to say that. But I believe we'll have trouble. I'll start on thesearch for the sunken millions, but rather against my better judgment. However, maybe Mr. Damon's luck and good nature will pull us through!"

CHAPTER V

BUSY DAYS

Once Tom Swift had made up his mind to do a thing he did it--eventhough it was against his better judgment. His word, passed, was hisbond. 

In conformity then with his decision to take Mr. Damon and the latter'sfriend, Mr. Hardley, on an undersea search for treasure, Tom at onceproceeded to make his preparations. Ned, too, had his work to do, sincethe decision to make what might be a long trip would necessitate achange in Tom's plans. But, as in everything he did, he threw himselfinto this whole-heartedly and with enthusiasm. 

Not once did Tom Swift admit to himself that he was going into thisscheme because he thought well of it. It was all for Mr. Damon, afterTom had learned that his friend had invested considerable money in acompany Mr. Hardley had formed to pay half the expenses of the trip. 

Tom even tried to buy Mr. Damon off, by offering the latter back allthe money the eccentric man had invested with his new friend. But Mr. Damon exclaimed:

"Bless my gasolene tank, Tom! I'm in this thing as much for the love ofadventure, as I am for the money. Now let's go on with it. You willlike Hardley better when you know him better. "

"Perhaps, " said Tom dryly, but he did not think so. 

The young inventor insisted, before making any preparations for thetrip, that all the cards be laid on the table. That is, he wanted to besure there had been such a ship as the Pandora, that she was laden withgold, and that she had sunk where Mr. Hardley said she had. The latterwas perfectly willing to supply all needful proofs, even though somewere difficult, because of the nature of the voyage of the treasurecraft. As a filibuster she was not trading openly. 

"Here are all the records, " said Mr. Hardley to Tom one day, when theyoung inventor, Ned, and Mr. Damon were gathered in Tom's office. "Youmay satisfy yourself. "

And, with Ned's help, Tom did. 

There was no question but what the Pandora had sailed from a certainport on a certain date. The official reports proved that. And that shedid carry a considerable treasure in gold was also established to thesatisfaction of Tom Swift. Because the gold was to be used forfurthering ends against one of the South American governments, the goldshipment was not insured and, in consequence, no recovery could be made. 

"Then you are satisfied, are you, Mr. Swift, that the ship, set outwith over two millions in gold on board?" asked Mr. Hardley. "Yes, that seems to be proved, " Tom admitted, and Ned nodded. "The next thing to prove is that she foundered in a storm aboutthe position I am going to tell you, " went on Mr. Damon's friend. 

"He doesn't tell you the exact location now, Tom, " explained Mr. Damon, "because it might leak out. He'll disclose it to us as soon as we areout of sight of land in the submarine. "

"I'm willing to agree to that proposition, " Tom said. "But I want to besure she really did sink. "

This was proved to him by official records. There was no question butthat the Pandora had gone down in a big storm. And Mr. Hardley was onboard. He proved that, too, a not very difficult task, since theofficial passenger list was open to inspection. 

Mr. Hardley repeated his story about having overheard the exactlocation of the ship a few minutes before she sank, and he also told ofthe captain and several members of the ship's company having beendrowned. This, too, was confirmed. 

"Then, " went on Mr. Hardley, "all that remains for me to do is todeposit at some bank my half of the expenses and await your word to goaboard the submarine. "

"I believe that is all, " returned Tom. "But, on my part, it will takesome little time to fit the submarine out as I want to have her. Thereare some special appliances I want to take along which will aid us inthe search for the gold, if we find the place where the Pandora issunk. "

"Oh, we'll find that all right, " declared Mr. Hardley, "if you willonly follow my directions. "

Tom looked slightly incredulous, but said nothing. 

Then followed busy days. The submarine Advance, which had made severalsuccessful trips, as related in the book bearing the title, "Tom Swiftand His Submarine Boat, " was hauled into dry dock and the work ofoverhauling her begun. Tom put his best men to work, and, after aconsultation with his father, decided on some radical changes in thecraft. 

"Tom, my boy, " said the aged Mr. Swift, "I wish you weren't going onthis trip. "

"Why, Dad?" asked the young inventor. 

"Because I fear something will happen. We don't really need this money, and suppose--suppose--"

"Oh, I'm not worrying, Dad, " was the answer. "I've taken worse risksthan this, many a time. I'm really doing it as a favor to Mr. Damon. He's got too much money invested to let him lose it. And we can use amillion dollars ourselves. It will enable me to put in operation a planto pension our workmen. I've long had that in mind, but I've never hadenough capital to carry it out. "

"Well, of course, Tom, that's a worthy object, and I won't make anyfurther objections. But take my advice, and strengthen the submarine. "

"Why, Dad?" asked Tom in some surprise. "Because you'll find the waterthere of a greater depth than you think, " was the answer. "I know youhave the official hydrographic charts, but there's a mistake, I'm sure. I once made a study of that part of the ocean, and there are currentsthere at certain seasons of the year that no one suspects, and deepcaverns that aren't charted. If the Pandora lies in one of theseyou'll need a great strength of walls to your submarine to withstandthe pressure of deep water. "

The craft Tom Swift proposed to use in searching for the treasure shipPandora was of the regular cigar-shape, but inside it had many specialfeatures. It was more comfortable than the usual submarine, not beingintended for fighting, though it did carry guns and a torpedo tube. Tomintended renaming the craft, which had been called Advance, and oneday, when there had been some discussion as to what the undersea craftought to be called, Ned explained:

"Why don't you name it after her?"

"After whom?" inquired Tom, in some surprise, looking up from a letterhe was writing. 

"Your friend and future wife, Mary Nestor, " answered Ned. "I'm sureshe'd appreciate it. "

"That isn't such a bad idea, " conceded Tom musingly. "The only thingabout it is that I don't want Mary's name bandied about that way. "

"Use her initials, then, " suggested Ned. 

"How do you mean

"Why not call it the M. N. 1. ? Isn't that a good name?"

"The M. N. 1. " mused Tom. "Not so bad. If the N. C. 4 flew over theocean the M. N. 1 ought to be able to navigate under it. I think I'lldo that, Ned. "

So the Advance, rebuilt and refitted in many ways, was christened theM. N. 1, and a wonderful craft she proved to be. Mary Nestor was quitepleased when Tom told her what he had done. She appreciated thedelicate compliment he had paid her. 

Busy and more busy were the days that passed. As the M. N. 1 had to berefitted some miles from Tom's home, where it was feasible to launchher for the trip, he had to make the journey between the drydock andhis shop either by automobile or aeroplane. Often he choose the latter, since he had a number of small, speedy craft in his hangars. SometimesNed or Mr. Damon went with him, but Mr. Hardley could never be inducedto ride in an airship. 

"I'll travel on the ocean or under it, " he said, "but I'm not going totake a chance in the air. I'm too afraid of falling. "

"Tom, what's this?" asked Ned one day, when he and Tom had come to seehow the work of remodeling the submarine was getting along. "It lookslike something you used when you dug your big tunnel. "

"That's a new kind of diving bell, " Tom answered. "You know it isn'teasy to get treasure out of a sunken ship. It isn't like picking it offthe bottom of the ocean. We've got to get it out from inside--perhapsfrom inside a strong box or a safe. This bell may come in useful. "

"Can't you use the special diving suits that you always used to carry?"the financial manager wanted to know. 

"We might, if the water isn't too deep, " replied Tom. "But you knowthere is a limit to how far down a man in even my kind of diving dresscan go. With this diving bell a much greater depth can be reached. Andthis diving bell is not like any you have ever seen or read about. Myfather gave me the idea for it. I'll demonstrate it to you some day. "

A diving bell is shaped like its name. A common glass tumbler thrustdown into a pail of water, with the open side down, will show exactlythe principle on which a diving bell works. It illustrates the factthat two things cannot occupy the same place at the same time. 

Pushing the tumbler, open end down, into the pail of water, leaves aspace in the upper end of the tumbler which the water cannot fill, because it is already occupied with air. Imagine a big tumbler, made ofthick steel, lowered into the water. Air pumped into the upper part notonly keeps the water from entering, but also enables a man inside tobreathe and to move about inside the bell which may be lowered to thefloor of the ocean. But, as Tom told Ned, his diving bell was a bigimprovement over those commonly used. 

The two young men inspected the progress made in refitting thesubmarine, and Tom expressed himself as satisfied. 

"How soon do you think you can start?" asked Ned. 

"In about two weeks, " was the answer. "I'll want to get to the WestIndies before the fall storms start. Not only will it be impossible tomake a search then, but the very location of the sunken wreck may bechanged. "

"How so?" asked Ned. 

"Because of undersea currents. They are strong enough, not only tosweep a wreck away from the place where it may have settled, but theymay cover it with sand, and then it is hopeless to try to dig it out. So We've got to go soon, if we go at all. "

"Well, I'm with you!" exclaimed Ned. "Hello! here's some one lookingfor you, I guess, " he added, as a boy came hurrying down to the dockfrom the temporary office Tom had set up there. 

"You're wanted on the telephone, Mr. Swift, " said the messenger. "It'simportant, too. "

"All right. I'll come at once, " was the answer. "Hope it isn't badnews, " mused Ned, as his chum hurried on in advance. "Maybe Hardley hasfound out he hasn't a right to search for that sunken gold after all. That would be too bad for Mr. Damon!"

CHAPTER VI

MARY'S ODD STORY

"Hello! Hello! Yes, this is Tom Swift. What's that? You've had anaccident? Great Scott, Mary! I hope you aren't hurt. "

Ned overheard these words as he stood outside the temporary office, from inside which Tom Swift was telephoning. 

"There's been an accident!" thought the financial manager. "I wonder ifI can help?"

He was about to hurry in to offer his services when he heard Tom laugh, and then he knew it was all right. He heard his chum say:

"I'll be right over and get you. Just where are you?"

Then followed a period of listening on the part of Tom, to be broken bythe words:

"All right, I'll be right with you. Lucky I have my Air Scout with me. You aren't afraid to ride in that, are you? No, that's good! I'll beright over. Ned is here with me, and I'll have him telephone to yourfather and mother. "

With that Tom hung up the receiver and joined his chum. 

"Mary had a slight automobile accident about five miles from here, " Tomtold his chum. "Some green driver ran into her and dished one of herwheels. No one hurt, but she hasn't a spare wheel and can't navigate. She called me up at the house, not wishing to alarm her father, andMrs. Baggert told her you and I had come down to the dock, so shereached me here. I'll go in the small aeroplane and get her. Luckily Ileft it here the last time I made a trip. Will you call up Mary's homeand let them know she's all right and that I'll soon be home with her?They might hear an exaggerated account of the accident. "

Ned promised to do this, and at once put in a call for the home of hischum's fiancee, while Tom had one of his men run out the Air Scout. This was an aeroplane recently perfected by the young inventor whichslipped through space with scarcely a sound. So silent was it that thecraft had been dubbed "Silent Sam, " and it stood Tom in good stead asthose of you know who have read the volume just before the presentbook. This sky glider Tom would now use in going to the rescue of MaryNestor was not, however, the same large craft that figured in theprevious story. That airship had been given to the United Statesgovernment for war purposes. But Tom had built himself a smaller onefor his own use. It had the advantage of enabling him to carry on aconversation with his passenger when he took one aloft. 

About a week before Tom and Ned had flown from Shopton to the dry dockwhere the submarine was being reconstructed in this small airship. Engine trouble had developed after they had landed, and they had goneback by automobile, leaving the Air Scout to be repaired. This had beendone, and now Tom intended to use it in going to Mary's rescue. 

Now, when the Air Scout had been run out of the hangar, Tom climbedinto it. 

"Sorry I can't take you along, " he called to Ned, who had finishedtelephoning to Mary's home, "but, under the circumstances--"

"Two's company and three's a crowd!" laughed Ned. "I know!"

"No, I didn't mean that, " Tom said. "You know Mary likes you, but thiswill carry only two. "

"I know!" answered his chum. "On your way!"

And with an almost noiseless throb of her engine and a whirr of herpropeller, the aeroplane rolled swiftly over the level starting groundand took the air like a swan leaving its lake. 

Tom did not rise to a great height, as he would need only a few minutesto reach the place where Mary was stalled by the accident to hermachine. Soon he was hovering over a level field, one of several thatlined the country highways in that section. A small crowd on theturnpike gathered about an evidently disabled automobile gave Tom theclew he needed, and presently he made a landing. Instantly the throngof country people who had gathered to look at the automobile crashdeserted that for a view of something more sensational--an airship. 

Cautioning the boys who gathered about not to "monkey" with any of themechanism, Tom hastened over to where Mary was standing near her car. 

"Are you sure you aren't hurt?" he asked her anxiously. 

"Oh, yes, very sure, " she replied, smiling at him. "It isn't much of anaccident--only one wheel smashed. We were both going slowly. "

"But it was all my fault!" insisted a young fellow who had been drivingthe car that crashed into Mary's. "I'm all kinds of sorry, and ofcourse I'll pay all damages. I wanted this young lady to let me driveher home and then send a garage man to tow her car, but she said shehad other plans. I don't blame her for not wanting to ride in my jitneybus when I see what kind of car you have, " and he looked over towardTom's aeroplane. 

"Thank you, just the same, " murmured Mary. "I'm not quite sure that itwas all your fault. But if you will be so good as to send a man aftermy machine I'll go back with Mr. Swift. Wait until I get my bag, " sheadded, and she extracted it from the seat in her automobile. "There'llbe room for this, won't there?" she asked. "I've been shopping. "

"You must have made some large purchases, " laughed Tom, lookingcritically at the small bag. "Yes, there'll be room for that, allright. "

He made a brief examination of Mary's machine, ascertaining that thedished wheel was the main damage, and then, having given the young manwho caused the accident directions for the garage attendant, Tom ledhis pretty companion across the field to the waiting airship. 

Of course a crowd gathered to see them start off, and this was not longdelayed, as Tom was not fond of curiosity seekers. In a few minutes heand Mary were soaring aloft. 

"Well, how are you?" he asked Mary, when they were alone well above theearth. 

"Fine and dandy, " she answered, smiling at him, for they were ridingside by side and could converse with little difficulty owing to thesilent running of Tom's latest invention. "I'm sorry to have called youaway from your work, " she added, "but when Mrs. Baggert told me youwere at the submarine dock I thought perhaps you could run out and getme in your machine. I didn't expect you to fly to me. "

"I'm always ready to do that!" exclaimed Tom, as he shot upward toavoid a bank of low-lying clouds. "Were you frightened at the crash inthe machine?"

"Not greatly. I saw it coming, and knew it was unavoidable. That chaphasn't been running autos very long, I imagine, and he lost his head inthe emergency. But I had my brakes on and he just coasted into me. Iwas lucky in that it wasn't worse. "

"I should say so! Do you want to get right home?"

"I think I'd better. Mother and father may be a little worried aboutme. And they've had trouble enough of late. "

"Trouble!" exclaimed Tom, in a questioning voice. "Anything serious?"

"No, just family financial matters. Not ours, " she hastened to add, asshe saw Tom look quickly at her. "A relative. I shouldn't havementioned it, but father and mother are a little worried, and I don'twant to add to it. "

"Of course not, " agreed Tom. "If there's anything I can do?"

"Oh, I expected you to say that!" laughed Mary. "Thanks. If there iswe'll call on you. But it may all be straightened out. Father wasexpecting a message from Uncle Barton today. So, though I'd like totake a cloud-ride with you, I think I'd better get home. "

"All right, " agreed Tom. "I told Ned to telephone that you were allright, so they won't worry. And now try to enjoy yourself. "

"I'll try, " promised Mary, but it was obvious, even from the quickglances Tom gave her, that she was worried about something. Mary wasnot her usual, spontaneous, jolly self, and Tom realized it. 

"Well, here we are!" he announced a little later, as they soared abovea level field not far from her home. "Sorry I can't let you down righton your roof, but it isn't flat enough nor big enough. "

"Oh, I don't mind a little walk, especially as I didn't have to hike itall the way in from Bailey Corners, " she said, referring to the placeof the automobile accident. "I suppose the time will come wheneverybody who now has an auto will have an airship and a landing place, or a starting place, for it at his own door, " she added. 

"Either that, or else we'll have airships so compact that they can setoff and land in as small a space as an auto now requires, " said Tom. "The latter would be the best solution, as one great disadvantage ofairships now is the manner of starting and stopping. It's too big. "

Tom left his Air Scout in a field owned by Mr. Nestor, where he hadoften landed before, and walked up to the house with Mary. 

"Oh, I'm glad you're back!" exclaimed Mrs. Nestor, when she saw the twocoming up the steps. 

"You weren't worried, were you, after Ned telephoned?" asked Tom. 

"Not exactly worried, but I thought perhaps he was making light of it. Do tell me what happened, Mary!"

Thereupon the girl related all the circumstances of the smash, and Tomadded his share of the story. 

"Did father hear anything from Uncle Barton?" asked Mary, after hermother's curiosity had been satisfied. 

"Yes, " was the answer, in rather despondent tones, "he did, but thenews was not encouraging. The papers cannot be found. "

"It's mother's brother we're talking about, " Mary explained to Tom. "Barton Keith in his name. Perhaps you remember him?"

"I've heard you speak of him, " Tom admitted. 

"Well, " resumed Mary, "Uncle Barton is in a. Peck of trouble. He wasonce very rich, and he invested heavily in oil lands, in Oklahoma, Ibelieve. "

"No, in Texas, " corrected Mrs. Nestor. 

"Yes, it was Texas, " agreed Mary. "Well he bought, or got, somehow, shares in some valuable oil lands in Texas, and expected to double hisfortune. Now, instead, he's probably lost it all. "

"That's too bad!" exclaimed Tom. "How did it happen?"

"In rather an odd way, " went on Mary. "He really owns the lands, or atleast half of them, but he cannot prove his title because the papers heneeds were taken from him, and, he thinks, by a man he trusted. He'sbeen trying to get the documents back, and every day we've beenexpecting to hear that he has them, but mother says there has been noresult. "

"No, " said Mrs. Nestor. "My brother thought sure he had a trace of theman he believes has the papers, or who had them, but he lost track ofhim. If we could only find him--"

At that moment a maid came into the room to announce that Tom Swift waswanted at the telephone. 

CHAPTER VII

THE TRIAL TRIP

"This is my busy day!" announced the young inventor as he went into theNestor sitting room, where the telephone was installed. 

"Perhaps it is some one else who wants you to come to their rescue, "suggested Mary. 

But it was not, as Tom related a little later when he had finished histalk over the wire. 

"Just a business matter, " he announced to Mary and her mother, when herejoined them. "A gentleman with whom I expect to make a submarine tripis at the house, and wants to consult with me about details. He isgetting anxious to start. Mr. Damon is there, too. "

"Blessing every thing he lays eyes on, I suppose, " remarked Mrs. Nestor, with a smile. 

"Yes, and some things he doesn't see, " agreed Tom. "He is going with uson this submarine trip. "

"Oh, Tom, are you going to undertake another of those dangerousvoyages?" asked Mary, in some alarm. 

"Well, I don't know that they are particularly dangerous, " replied Tom, with a smile. "But we expect to make a search for a sunken treasureship in a submarine. That's the vessel I'm working on now, " he added. "We're rebuilding the Advance, you know, making her more up-to-date, and adding some new features, including her name--M. N. 1. "

"I suppose Mr. Damon's friend is getting anxious to make a start, particularly as he has already invested several thousand dollars in theproject, " went on the young inventor. "He formed a company to pay halfthe expenses of the search, and they will share in the treasure--if wefind it, " Tom said. "I wish Mr. Damon, who holds most of the shares thepromoter let out of his own hands, had not gone into it, but, since hehas, I'm going to do the best I can for him. "

"Then aren't you friendly with the other man?" asked Mary. 

"I don't especially care for him, " the young inventor admitted. "Heisn't just my style--too fond of himself, and all that. Still I may bemisjudging him. However, I'm in the game now, and I'm going to stick. I'll have to be traveling on, " he said. "Mr. Damon and his friend areat my house, and they've been telephoning all over to find me. I guessthis was one of the first places they tried, " he said with a smile, referring to the fact that he spent considerable time at Mary's home. 

"Well, I'm glad they found you, but I'm sorry you have to go, " Marysaid with a smile. 

A little later Tom Swift, with Ned, for whom he called, was on his wayback home in his Air Scout, having said goodbye to Mary and her motherand expressing the hope that Mr. Keith would soon be over his businesstroubles. 

"Oil wells are queer, anyhow, " mused Tom. 

Then Tom got to thinking about Dixwell Hardley: "I don't like the man, and the more I see of him the less I like him. But I'm in for it now, and I'll stick to the finish. I only wish I could locate the treasureship, give him his share, and get back to my work. I'm going to try toturn out an airship that a man can use as handily as he does a flivvernow. "

Musing on the possibilities in this field, Tom, having left Ned at thelatter's home, soared down from aloft, and a little later, having toldKoku to look after the Air Scout, much to the delight of the giant andthe discomfiture of Rad, the young inventor was closeted with Mr. Damonand Dixwell Hardley. 

"Bless my straw hat, Tom!" exclaimed the eccentric man, "but we justcouldn't wait any longer. How are you coming on, and when can we starton this treasure-hunting trip? I declare it makes me feel young againto think about it!"

"Well, it won't be long now, " was the answer. "The men are working hardto get the submarine in shape, and I should say that in another week, or two weeks at the most, we could set off!"

"Good!" exclaimed Mr. Hardley. "I have received additionalinformation, " he went on, "to the effect that the amount of gold onboard the Pandora was even greater than we at first thought. "

"That sounds encouraging, " replied Tom. "It only remains to find thesunken ship now. But what interests me greatly is whether, after wehave gotten this gold, supposing we are successful, we shall be allowedto keep it. "

"Bless my bank book! why not?" asked Mr. Damon. "Isn't it wealthabandoned at the bottom of the sea, and isn't finding keeping?"

"Not always, " answered Tom. "There are certain rules and laws abouttreasure, and it might happen that after we got this--if we do--itcould be taken away from us. "

"I think there will be no difficulty on this score, " said Mr. Hardley. "In the first place, two attempts were made to get this wealth, andwere unsuccessful. Then it was practically abandoned, and I believeunder the law the persons who now find it will be entitled to keep it. Besides the persons who gathered it together did so for an unlawfulpurpose--that of starting a revolution in a friendly country--and theywould not dare claim it for fear of giving their secret away. "

"Well, perhaps you are right, " assented Tom. "We'll make a try for it, anyhow. "

"You say the submarine is nearly ready?" asked Mr. Hardley. 

"She will be ready for a trial trip at the end of this week, " said Tom, "and be fitted up for the voyage within another seven days, I hope. Then for the great adventure!" and he laughed, though, truth to tell, he had no real liking for his task. The more he saw of Mr. Hardley theless he liked him. 

"I shall begin getting my affairs in shape, " said the latter, as hegathered up some papers he had brought to attempt to prove to Tom thatthe wealth of the Pandora was greater than had been supposed. "I havemany large interests, " he went on, rather pompously, "and they needlooking after; especially if I undertake anything so extra hazardous asa submarine trip. "

"Yes, there always is some danger, " admitted Tom. "But then there isdanger walking along the street. "

"Oh, there's no danger with Tom Swift!" exclaimed Mr. Damon. "I'vebeen under the sea and above the clouds with him, and, bless myrainbow! he always brought us safe home. "

"And I'll try to do the same this time, " said the young inventor. 

Busy days followed for Tom Swift and his friends. The force at work onthe submarine turned night into day to rush her completion, and in dueseason she was set afloat in the dry dock basin and formallyrechristened the M. N. 1. 

Mary blushed as she gave the boat her new name, and there was a littlecheer from the group of workmen gathered at the dock. There was nolaunching in the real sense of the word, since as the Advance thatceremony had been gone through with for the undersea craft. 

She had been greatly changed interiorly and outwardly. Her skin, orplates, having been doubled and strengthened. For Tom proposed to go toa much greater depth than ever before. 

In addition to using the submarine herself in a search for the gold onthe Pandora, Tom had installed on board some new kinds of divingapparatus and also a diving bell. If one would not serve, the othermight, he reasoned. 

"Well, Tom, " remarked his aged father the night before they were tostart on the trial trip, "I understand you have practically rebuilt theAdvance. "

"Yes; and I think she's a much better craft, too, Father. "

"Glad to hear that, Tom. Of course you kept the gyroscope rudderfeature?"

"No, I didn't, " replied Tom. "If I had left that installed it wouldhave meant carrying a smaller diving bell, and I think that last willbe more useful than the gyroscope. I put in a set of double-actingdepth rudders instead. "

Mr. Swift shook his head. 

"I'm sorry for that, Tom, " he remarked. "There's nothing like thegyroscope rudder in a tight pinch--say when there's a storm. And forholding the boat steady, if you have to make a sudden turn under water, to avoid an obstruction you come upon unexpectedly, a gyroscope can'tbe improved on. It holds you steady and prevents your turning turtle. "

"I've put side fin-keels to correct that, " Tom explained. 

But still his father was not satisfied. 

"I'd rather you had kept the gyroscope, " he said, and the time was tocome when Tom Swift wished that himself. 

But it was too late to make the change now, and so, with more thanusual confidence in his own designing abilities, the next day the younginventor and his friends went aboard the M. N. 1 for the trial trip. 

"You don't easily get seasick, do you?" Tom asked Mr. Hardley, as theydescended the hatchway into the interior of the craft. 

"No, I'm considered a good sailor. "

"Well, you'll need to be, " went on Tom, with a smile. "Not that we arelikely to strike any rough water now, though the reports say a stiffbreeze is blowing in the bay. But when we once start for the WestIndies you are likely to experience a new sensation. I've knownsailors who never had any qualms, even in terrible storms, to get illin a submarine when she went through only a small blow. The motion isdifferent from that on a surface boat. "

"I can imagine so, " returned Mr. Hardley. "But I'll be thinking of themillions in gold on the Pandora, and that will keep my mind off beingseasick. "

"Let us hope so, " murmured Tom. 

He gave the word, they all descended, the hatch covers were closeddown, and the M. N. 1 was ready to start on a trial trip. 

CHAPTER VIII

THE MUD BANK

"What's that noise?" asked Mr. Hardley. 

Mr. Hardley, Tom Swift, Mr. Damon, Ned Newton, Koku, and one or twonavigating officers of the craft, were gathered in the operating cabinof the M. N. 1. 

"That's water being pumped into the tanks, " explained Tom. "We are nowgoing down. If you'll watch the depth gauge you can note our progress. "

"Going down, are we?" remarked Mr. Hardley. "Well, it's interesting tosay the least, " and he observed the gauge, which showed them to betwenty feet under the surface. 

"Bless my hydrometer, but he's got nerve for a first trip in asubmarine! He's all right, isn't he?" whispered Mr. Damon to Tom. 

"Well, I'm glad to see he isn't nervous, " remarked Tom, honest enoughto give his visitor credit for what was due him. And indeed many aperson is nervous going down in a submarine for the first time. "Stillwe can't go more than thirty feet down in this water, " went on Tom. "Abetter test will be when we get about five hundred feet below thesurface. That's a real test, though as far as knowing it is concerned, a person can't tell ten feet from ten hundred in a submarine underwater, unless he watches the gauge. "

"Well, I think you'll find Mr. Hardley all right, " said Mr. Damon, whoseemed to have taken a strong liking to his new friend. 

Certainly the latter showed no signs of nervousness as the craft slowlysettled to the proper depth. He asked numberless questions, showing hisinterest in the operation of the M. N. 1, but he showed not the leastsign of fear. However, as Tom said, that might come later. 

"We are going down now, " Tom explained, as he pointed out to Mr. Hardley the various controlling wheels and levers, "by filling ourballast tanks with water. We can rise, when needful, by forcing outthis water by means of compressed air. When we are on the ocean we cango down by using our diving rudders, and in much quicker time than byfilling our tanks. "

"How is that?" asked the seeker after the Pandora's gold. 

"Filling the tanks is slow work in itself, " replied Tom, "and they haveto be filled very carefully and evenly, so we don't stand on our sternor bow in going down. We want to sink on an even keel, and sometimesthis is hard to accomplish. But we are doing it now, " and he calledattention to an indicator which told how much the M. N. 1 might belisting to one side or to one end or the other. 

A submarine, as everyone knows, is essentially a water-tight tank, shaped like a cigar, with a propeller on one end. It can sink below thesurface and move along under water. It sinks because rudders force itdown, and water taken into tanks in its interior hold it to a certaindepth. It can rise by ejecting this extra water and by setting therudders in the proper position. 

A submarine moves under water by means of electric motors, the currentof which is supplied by storage batteries. On the surface when thehatches can be opened, oil or gasolene engines are used. These enginescannot be used under water because they depend on a supply of air, oroxygen, and when the submarine is tightly sealed all the air possibleis needed for her crew to breathe. While cruising on the surface asubmarine recharges her storage batteries to give her motive power whenshe is submerged. 

There are many types of submarines, some comparatively simple andsmall, and others large and complex. In some it is possible for thecrew to live many days without coming to the surface. 

Tom Swift's reconstructed craft compared favorably with the best andlargest ever made, though she was not of exceptional size. She was verystrong, however, to allow her to go to a great depth, for the fartherdown one goes below the surface of the sea, the greater the pressureuntil, at, say, six miles, the greatest known depth of the ocean, thepressure is beyond belief. And yet is possible that marine monstersmay live in that pressure which would flatten out a block of solidsteel into a sheet as thin as paper. 

"Well, we are as deep down as it is safe to go in the river, " announcedTom, as the gauge showed a distance below the surface of a little lessthan twenty-nine feet. "Now we'll move into the bay. How do you likeit, Mr. Hardley?"

"Very well, so far. But it isn't very exciting yet. "

"Bless my accident policy!" exclaimed Mr. Damon, "I hope you aren'tlooking for excitement. "

"I'm used to it, " was the answer. "The more there is the better I likeit. "

"Well, you may get your wish, " said Tom. 

He turned a lever, and those on board the submarine became conscious ofa forward motion. She was no longer sinking. 

She trembled and vibrated as the powerful electric motors turned herpropellers, and Tom, having seen that all was running smoothly in themain engine room, called Mr. Damon, Ned, and Mr. Hardley to him. 

"We'll go into the forward pilot house and give Mr. Hardley a viewunder water, " he announced. "Of course, you'll see nothing like whatyou'll view when we're in the ocean, " added the young inventor, "but itmay interest you. "

The four were soon in the forward compartment of the craft. She couldbe directed and steered from here when occasion arose, but now Tom wasletting his navigator direct the craft from the controls in the mainengine room. A conning tower, rising just above the deck of the craft, gave the pilot the necessary view. 

"Here you are!" exclaimed Tom, as he switched out the lights in thecabin. For a moment they were in darkness, and then, with a click, steel plates, guarding heavy plate glass bull's-eyes, moved back, andMr. Hardley for the first time looked out on an underwater scene. Hesaw the murky waters of river down which they were proceeding to thebay moving past the glass windows. Now and then a fish swam up, looking in, and, with a swirl of its tail, shot away again, apparentlyfrightened well-nigh to death. 

"Bless my shoe laces, Tom!" exclaimed Mr. Damon, "this isn't a markercompared to some of the sights we've seen, is it?"

"I can imagine not, " said Mr. Hardley. "But it is interesting. I shallbe anticipating more wonderful sights. "

"And you'll get them!" exclaimed Ned. "Do you remember, Tom, the timethe big octopus tried to hold us back?"

"Yes, indeed, " answered the young inventor. "That gave us a scare forthe time being. "

Steadily the M. N. 1 kept on her way under water. Her path wasilluminated to a considerable degree by a broad, diffused beam of lightfrom a powerful searchlight that was fixed just back of the conningtower, giving the helmsman a certain degree of vision. This light alsoserved to illuminate the water, so that those in the forward cabincould see what was going on around them. 

"There isn't much of interest in the river, " said Tom. "No big fish, oranything else of moment. Even in the bay we won't see much to attractour attention. But I want to make sure everything is working smoothlybefore we start for the West Indies. "

"That's right!" agreed Mr. Hardley. "We want to make a success of thistrip. "

He remained at the glass bull's-eyes, now and then exclaiming as someshad or other fair-sized fish came into view. Suddenly, however, hisexclamation was sharper than usual. 

"Look!" he exclaimed. "There's part of a wreck!"

Ned, Mr. Damon, and Tom looked out and saw, sweeping past them, theribs and worm-eaten timbers of some craft, lying on the bottom of theriver. 

"Yes, that's the remains of an old brick scow, " the young inventorexplained. "That's one of our water-marks, so to speak. It is at thebend of the river. We turn now, and head for the bay. "

As he spoke they all became aware of a sudden swerve in the course ofthe submarine. The helmsman had, doubtless, noted the "water-mark, " asTom termed it, and as an automobilist on land might swing at thecross-roads, the steersman was changing the course of his craft. 

"We'll go deeper, " said Tom a moment later, as the wreck passed out ofview. "We can go about fifty feet down now. Yes, he's sinking her, " headded, as a gauge showed the craft to be descending. "Nelson knows hisbusiness all right. "

"He is your captain?" asked Mr. Hardley. 

"One of the best, yes. He'll go with us on the search for the Pandora. "

They talked of various matters, Tom relating to Mr. Hardley how a tughad rammed the brick scow some years ago, and sunk it in the river. 

The submarine was now about forty-eight feet below the surface, andsuddenly they all became aware that her speed had increased. 

"Guess he's going to give the motors a good try-out, " observed Tom. "Ithink I'll go back to the engine room. You may remain here, if youlike, and you'll probably see--"

A cry from Mr. Damon interrupted him. 

"Bless my rubber boots, Tom! Look!" cried the eccentric man. "We'regoing to ram a mud bank!"

As he spoke they all became aware of a solid black mass looming infront of the bull's-eye window. An instant later the submarine came toa jarring stop, as if she had struck some soft, yielding substance. There was a confused shouting throughout the craft, the noise ofmachinery, a trembling and vibration, and then ominous quiet. 

CHAPTER IX

READY TO START

Characteristic it was of Tom Swift to act calmly in times of stress anddanger, and he ran true to form now. Only for an instant did he showany sign of perturbation. Then with calmness and deliberation the younginventor quickly did a number of things to the controls within hisreach. 

First of all he signaled to the engine room that he was going to takecharge of the boat. This meant that the navigator in the conning towerwas to keep his hands off the various levers and wheel-valves. It waspossible to operate the M. N. 1 from three positions, but Tom wanted notriplicate handling of his craft now. 

Almost the instant Tom signaled that he would take charge back cameflashing the electrical signal from the conning tower that his orderswere understood. The next thing that those aboard the craft becameaware of was a tremor that seemed to run through the whole under-seaship. The quiet had changed to a subdued humming, and the ominous lackof motion was succeeded by violent vibration. 

"Backing her up, Tom?" asked Ned, in a low voice. 

"Trying to, " was the answer. "But I'm afraid her nose has gone inpretty deep. I've reversed the propellers. "

For perhaps a minute this vibration continued, showing that thepowerful electric motors were turning over the twin propellers at theblunt stern of the craft. But she did not change her position. 

With a touch of his hand, and still almost as cool as the proverbialcucumber (though why they should be cool it is hard to say), Tomstopped the motors. Once again the craft was quiet, but now, instead ofthe occupants being able to see clearly from the thick, glass windowsin the forward cabin, the water showed muddy and murky in the glare ofthe underwater searchlight. 

"Bless my postage stamps, Tom! what has happened?" exclaimed Mr. Damon. "Has a giant squid attacked us, as one did some time ago, and is heroiling up the water?"

"No, it isn't a squid, Mr. Damon, " replied the young inventor easily;"though the water does look as if a squid had spilled a lot of his inkin it. This is just the effect of mud stirred up by our propellers. There may be more of it. "

Ned looked toward Mr. Hardley to see how he was taking it. The seekerafter gold apparently had good control of his nerves, or else he wasignorant of what was going on. For he asked, casually enough:

"Have we stopped?"

"We have, " answered Tom. "I thought I'd give you a view of the scenery. "

Perhaps he spoke sarcastically, but, if he did, Mr. Damon's friend didnot seem to be aware of it. Coolly enough he replied:

"Well, if this is a fair sample of underwater scenery I prefersomething up above, though I appreciate that this may be needful. "

"We'll soon be traveling along, " announced Tom. "Koku, " he added to thegiant, who had been calmly sitting during the excitement, "go to theengine room and help with the big levers. "

"Yes, Master, " was the answer. Koku had implicit faith in Tom. 

Waiting a moment for his faithful servant to reach the post assigned tohim, Tom again signaled to his helpers and then quickly turned a wheelwhich produced startling results. For all within the submarine suddenlyslid forward across the cabin floor. 

"Bless my hammock hooks, Tom! are you standing her on her head?" criedMr. Damon. 

"That's exactly what I'm doing, " was the answer. "I've started to emptyone of the after ballast tanks, and that, naturally, raises the sternwhile the nose is held down. "

The submarine was indeed in a peculiar position. She was on a slant inthe water, her nose held fast in the soft mud bank, and it was Tom'sidea that by making the stern buoyant it might help to pull her free. 

To this end he also gave what assistance the propellers were capable ofadding by starting the motors again, so that the craft once moretrembled and vibrated. 

But it all seemed to no purpose. Aside from the slanting position, there was no change in the M. N. 1. Ned, looking out into the murkywater, which had cleared slightly, saw that the craft was still heldfast. And then, for the first time, Mr. Hardley seemed to become awarethat something serious was the matter. Up to now he seemed to thinkthat all that had occurred was done for the purpose of testing thenewly outfitted underseas boat. 

"Is there anything wrong?" he asked sharply of Tom. "Why are we in thisposition, and why don't we go on out to the open ocean and make a testat considerable depth? We'll have to go down deeper than this if wefind the Pandora!"

"I suppose so, " agreed Tom. "But we have had an accident, and--"

"An accident!" interrupted the gold-seeker, and then Ned saw him turnpale. "Do you mean to say this is not part of the test?"

"We have run into a mud bank, " said Tom. "The steersman must havebecome confused, or else, since we last used the submarine, there hasbeen a shift of the mud banks in this river and one exists where therewas none before. At any rate, we ran our nose deep into it, and here weare--stuck!"

"Can't we get loose--go up to the surface?" demanded Mr. Hardley. 

"I'm trying to bring that about, " announced Tom calmly. "So far herengines haven't been able to pull her loose. "

"But Great Scott, man, we can't stay here!" cried the now excitedadventurer. "We'll be drowned like rats in a trap! Let me out! Isn'tthere some way? I'll be shot through a torpedo tube, if necessary! Imust get out! I can't stay here to be drowned! I have too much atstake!"

"Now wait a minute!" calmly advised Tom Swift. "You haven't any more atstake than the rest of us. None of us wants to be drowned, and there isonly a remote possibility that we shall be. I haven't played all mycards yet. We can live on this boat for a week, if need be. "

"You mean under water as we are now?" asked Mr. Hardley. 

"Yes. I always keep the boat provisioned and with plenty of air andwater for a long stay, if need be, " replied Tom. "And I did notoverlook the fact that we might have an accident on the trial trip. "

"I don't see how you let an accident happen before we even gotstarted, " complained the gold-seeker. "I should think your steersmanwould have been more careful. "

"He is very careful, " explained Tom. "But we have not used the craftfor some time, and, meanwhile, there have been changes in the river, due, I suppose, to heavy tides. But we may get out of the grip of themud bank soon. "

"And if we don't, what then?" asked Mr. Hardley. 

"Then there is always the torpedo tube, " said Tom calmly. "And we arenot very deep down. I think I can save you all. "

"I certainly hope so!" was the fretful comment of the adventurer. "Ihave too much at stake to be drowned like a rat in a trap! You mustsend me up first if it becomes necessary to use the tube. "

Tom did not answer. But as he looked out of the observation windows tosee if possible the conformation of the mud bank, the young inventorwhispered to Ned one word. And that word was:

"Yellow!"

"You said it!" was Ned's whispered rejoinder. 

Tom Swift arrived at a sudden determination. Once again the motors werestopped, and the boat gradually assumed an even keel. 

"What are you going to try, Tom?" asked Ned. 

"I'm going to shove her farther into the mud bank, " announced the younginventor. "I think that's the only way to get her loose. "

"Bless my apple pie, Tom!" cried Mr. Damon, "doesn't that seem afoolish thing to do?"

"It's the only thing to do, I believe, " was the answer. "This mud is ofa peculiar sticky and holding kind. The sub's nose is in it like a pegin a hole. What I propose to do now is to enlarge the hole, and thenour nose will come loose--I hope. "

"But you haven't any right to shove our nose further in!" cried Mr. Hardley. "I won't allow it! I demand to be put on the surface! I won'tbe drowned down here before I get the gold that's coming to me--thegold and--"

"Now look here!" suddenly cried Tom. "I'm in command of this boat, andyou'll do as I say. I'll gladly set you on the surface if I can, andthis is the only way it can be brought about--it's the only way to saveall of us. I'm going to enlarge the mud hole so we can pull out. Pleasekeep still!"

Mr. Hardley stared at the young inventor a moment, seemed about to saysomething, and then changed his mind. 

"Hold fast, everybody!" suddenly called Tom. The next moment the M. N. 1 began behaving in a most peculiar manner. 

She appeared to be acting like a corkscrew. While her bow wascomparatively steady, her stern described a circle in the water whichwas churned to mud by the two propellers, each being revolved in adifferent direction. 

"I'm trying to make the hole bigger just as an amateur carpenter makesa nail hole bigger, so he can pull out the nail, by twisting itaround, " explained Tom. "The motion may be a bit unpleasant, but it isneedful. "

And indeed the motion was unpleasant. Tom, veteran airman and sailorthat he was, began to feel a trifle seasick, and Mr. Hardley was invery evident distress. 

Suddenly, however, something happened. The M. N. 1 gave a lurch to oneside and then shot upward so quickly that Ned and Mr. Damon lost theirbalance and slumped over on the bench that ran around three sides ofthe room. 

"Are we free?" cried Mr. Hardley. 

"We have come loose from the mud bank, " said Tom quietly. "By boringinto it the hole was enlarged sufficiently to enable us to pull loose. There is no more danger!"

His announcement was received in momentary silence, and then Nedexclaimed:

"Hurray!"

"Bless my accident policy!" voiced Mr. Damon. 

Mr. Hardley appeared dazed, and then, as the submarine was again movingthrough the water, seemingly none the worse for the accident, the goldseeker approached Tom Swift. 

"I want to apologize, Mr. Swift, for my actions and words, " said Mr. Hardley frankly. "I admit that I lost my head. But it's my first tripin a submarine. "

"I realize that, " said Tom, equally frank, "and we'll forget all aboutit. It was a strain on you--on all of us--though there really was novery great danger. Now, are you game enough to continue the trip?"

"Try me!" exclaimed the adventurer. "You won't find me acting so like ababy again. "

Nor did he, even when the craft reached the open ocean and went down toa considerable depth, where, had any accident occurred, there wouldhave been grave danger to all. But Mr. Hardley seemed to enjoy it. 

"Maybe I've misjudged him, " Tom said to Ned, when they were gettingready to go back. 

"It's possible, " agreed the financial manager. This trial, which sonearly ended disastrously, was only one of several. No damage resultedfrom the collision with the river mud bank, and that trip and the onesfollowing gave Tom some new ideas in interior construction which hefollowed out. 

About a month later all was ready for the trip to the West Indies tolook for the ill-fated Pandora. Tom's affairs were put in shape, thesubmarine was laden with stores and provisions, the new diving bell andother wonderful apparatus were put aboard, and the crew and officerspicked. Ned, Mr. Damon, Koku, and Tom were, of course, together, andthough Mr. Hardley was a stranger, he seemed to become more friendly asthe days passed. 

"Well, we start in the morning, " said Tom to Ned one evening. "I'mgoing over to tell Mary goodbye. "

"Give her my regards, " requested Ned, and Tom said he would. 

CHAPTER X

STARTLING REVELATIONS

"Oh, Tom! And so you are really ready to start on that perilous trip!"exclaimed Mary Nestor, a little later that same evening, when Tomcalled at Mary's house in his speedy electric runabout, a car in whichhe had once made a sensational ride. 

"Perilous? I don't know why you call it that!" exclaimed the younginventor. 

"Didn't you tell me you were stuck in a mud bank away down under theriver and had hard work to get loose?" asked the young lady, as shemade a place for Tom on the sofa beside her. 

"Oh, that! Why, that wasn't anything!" he declared. 

"It would have been if you hadn't come up. "

"Ah, but we did come up, Mary. "

"Suppose you get in a similar position when you find the wreck of thePandora? You won't get up so easily, will you?"

"No. But there aren't any mud banks in that part of the Atlantic, so Ican't be stuck in one, " answered Tom. 

For some time Tom Swift and Mary talked of mutual friends andhappenings in which they were both interested. Mr. And Mrs. Nestorstepped into the room for a minute, to wish the young inventor goodluck on his voyage, and when they had gone out, promising to see Tombefore he left for the night, the latter remarked to Mary:

"Did your uncle ever find the oil-well papers and get his affairsstraightened out?"

"No, " was the answer, "he never did. And we feel very sorry for him. Just think, he had a fortune in his grasp, and now it is slipping away. "

"Just what happened?" asked Tom, hoping there might be some way inwhich he could aid Mary's uncle. Of course, Tom wanted to help Mary, and this was one of the ways. 

"Well, I don't exactly understand it all, " she replied. "Father saysI'll never have a head for business. But as nearly as I can tell, myuncle, Barton Keith, went into partnership with a man to prospect foroil in Texas. My uncle has been in that business before, and he wasvery successful. He supplied the working knowledge about oil wells, Ibelieve, and the other man put up the money. My uncle was to have ahalf share in whatever oil wells he located, and his partner suppliedthe cash for putting down the pipe, or whatever is done. "

"I believe putting down a pipe is the proper term, " said Tom. 

"Well, anyhow, " went on Mary, "my uncle spent many weary monthsprospecting in Texas. In fact, he made himself ill, being out in allsorts of weather, looking after the drilling. At last they struck oil, as I believe they call it. They drilled down until they brought in whatmy uncle called a 'gusher, ' and there was a chance of him and hispartner getting rich. "

"Why didn't he?" asked Tom. "A gusher, I believe, is one of the bestsort of oil wells. Why didn't your uncle clean up a fortune, to use aslang term?"

"Because he lost the papers showing that he had a right to half the oilwell, " answered Mary. "At least my uncle thinks he lost them, but hewas so ill, directly after the well proved a success, that he says heisn't sure what happened. At any rate, his partner claims everythingand my uncle can do nothing. He has been hoping he might find thepapers somewhere, or that something would happen to prove the rights ofhis claim. "

"And nothing has?" inquired Tom. 

"Not yet. My father and mother have been trying to help him, and dadengaged a lawyer, but he says nothing can be done unless my unclerecovers the partnership and other papers. As it stands now, it is myuncle's word against the word of his partner, and both are equally goodin a court of law. But if Uncle Barton could find the documentseverything would come out all right. He could claim his half of the oilwell then. "

"Is it still producing?" Tom questioned. 

"Yes, better than ever. But that's all the good it does my uncle. He isill, discouraged, and despondent. All his fortune was eaten up inprospecting, and he depended on the gusher to make him rich again. Andnow, because of a rascally partner, he may be doomed to die a poor man. Of course we will always help him, but you know what it is to bedependent on relatives. "

"I can imagine, " conceded Tom. "It is tough luck! I wish I could help, and perhaps I can after I get back from this trip. "

"The only way you or any one could help, would be to get back myuncle's missing papers, " said Mary. "And as he himself isn't sure whatbecame of them, it seem hopeless. "

"It does, " Tom agreed. "But wait until I get back. "

"I wish you weren't going, " sighed Mary. 

"So do I--more than a little, " was Tom's remark. "I'm sorry I ever letMr. Damon persuade me to go into this deal with Dixwell Hardley!"

Mary sat bolt upright on the couch. 

"What name did you say?" she cried. 

"Dixwell Hardley, " repeated Tom. "That's he name of the man who claimsto know where the wreck of the Pandora lies. He says she has twomillions or more in gold on board, and I'm to get half. "

"Well!" exclaimed Mary, with spirit, "if you don't get any bigger shareout of the wreck than my uncle got out of the oil well, you won't bedoing so very nicely, Tom. "

"What do you mean?" asked the young inventor. "What has the oil well todo with recovering gold from the wreck?"

"A good deal, I should say, " answered the girl, "seeing that the sameman is mixed up in both. "

"What same man?"

"Dixwell Hardley!"

"Is he the man who cheated your uncle?" cried Tom. 

"I won't say that he cheated him, " said Mary. "But Dixwell Hardley isthe man who furnished the money when my uncle went into partnershipwith him to locate oil wells in Texas. The oil wells were located, Mr. Hardley got his share, and my uncle got nothing. And just because hecan't prove there was a legal partnership! I hope you won't have thesame experience with Mr. Hardley, Tom. "

"Whew!" whistled the young inventor. "This is news to me! I can say onething, though. Mr. Hardley doesn't take a dollar out of that wreckunless I get one to match it. I think I hold the best cards on thisdeal. But, Mary, are you sure it's the same man?"

"Pretty sure. Wait, I'll call my father and make certain, " sheanswered, and as she went from the room to summon Mr. Nestor, Tom felta vague sense of uneasiness. 

CHAPTER XI

BARTON KEITH'S STORY

"What's this Mary tells me, Tom?" asked Mr. Nestor, as he followed hisdaughter back into the room. 

"You mean about Dixwell Hardley?"

"Yes. Do you suppose he can be the same man who has so meanly treatedmy brother-in-law?"

"I wouldn't want to say, Mr. Nestor, until you describe to me the Mr. Hardley you know. Then I can better tell. But from what little I haveseen of the man to whom I was introduced by my friend Mr. Damon, I'dsay, off hand, that he was capable of such action. "

"Does Mr. Damon know this Mr. Hardley well?" asked Mrs. Nestor, whoaccompanied her husband. 

"I wouldn't say that he did, " Tom replied. "I don't know just how Mr. Damon met this chap--I think it was in a financial way, though. "

"Well, if it's the same Mr. Hardley, I'll say he has some queerfinancial ways, " said Mr. Nestor. "Now let's see if we can make the twojibe. Describe him, Tom. "

This the young inventor did, and when this description had beencompared with one given of the Mr. Hardley with whom Mr. Keith once wasassociated, Mrs. Nestor said:

"It surely is the same man! The Mr. Hardley who wants you to get wealthfrom the bottom of the ocean, Tom, is the same fellow who is keeping mybrother out of the oil well property! I'm sure of it!"

"It does seem so, " Tom agreed. "Dixwell Hardley is not a usual name;but we must be careful In spite of its unusualness there may be twovery different men who have that name. I think the only way to find outfor certain is to see Mr. Keith. He'd know a picture of the DixwellHardley who, he claims, cheated him, wouldn't he?"

"Indeed he would!" exclaimed Mrs. Nestor. "But where could we get apicture of your Mr. Hardley? I call him that, though I don't supposeyou own him, Tom, " and she smiled at her future son-in-law. 

"No, I don't own him, and I don't want to, " was Tom's answer. "But Ihappen to have a picture of him. I made him furnish me with proofs thathe was on the Pandora at the time she foundered in a gale, and amongthe documents he gave was his passport. It has his picture on. I haveit here. "

Tom drew the paper from his pocket. In one corner was pasted aphotograph of the man who had been introduced to Tom by Mr. Damon. 

"It looks like the same man my brother described, " said Mrs. Nestor, "but of course I couldn't be sure. "

"There is only one way to be, " Tom stated, "and that is to show thispicture to Mr. Keith. Where is he?"

"Ill at his home in Bedford, " answered Mrs. Nestor. 

"Then we'll go there and see him!" declared Tom. 

"But it's a hundred miles from here!" exclaimed Mary. "And you areleaving on your submarine trip the first thing in the morning, Tom!"

"No, I'm not leaving until I settle this matter, " declared the younginventor. "I'm not going on an undersea voyage with a man who may be acheater. I want this matter settled. I'll postpone this trip until Ifind out. A day's delay won't matter. "

"But it will take longer than that, " said Mr. Nestor. "Bedford is asmall place, and there's only one train a day there. You'll lose atleast three days Tom, if you go there. "

"Not necessarily, " was the quick answer. "I can go by airship, and makethe trip in a little over an hour. I can be back the same day, perhapsnot in time to start our submarine trip, as Mr. Keith may be too ill tosee me. But I won't lose much time in my Air Scout. 

"Mary, will you go with me to see your uncle? We'll start the firstthing in the morning and I'll show him this picture. Will you go?"

"I will!" exclaimed the girl. 

"Good!" cried Tom. "Then I'll make preparations. I don't want to formany rash judgment, so we'll make certain; but it wouldn't surprise me abit to have it turn out that the Dixwell Hardley who wants me to helphim recover the Pandora treasure is the same one who is trying to cheatMr. Keith. "

Early the next morning, when Tom arose in his own home, he met Mr. Damon and Mr. Hardley, both of whom were guests at the Swift house, pending the beginning of the undersea trip. 

"Well, Tom, " began the eccentric man, "we have good weather for thestart. Bless my rubber boots! Not that it much matters, though, whatsort of weather we have when we're in the submarine. But I always liketo start in the sunshine. "

"So do I, " agreed Mr. Hardley. "I suppose we'll get off early thismorning, " he added. 

"We'll go to the dock in the auto, as usual, shall we not?" he asked. 

"We aren't going to start this morning, " said Tom, as he sat down tobreakfast. 

"Not going to start this morning!" exclaimed Mr. Hardley. "Why--why--"

"Bless my alarm clock!" voiced Mr. Damon, "has anything happened, Tom?No accident to the M. N. 1 is there? You aren't backing out now, at thelast minute, are you?"

"Oh, no, " was the easy answer. "We'll go, as arranged, but not today. Ihad some unexpected news last night which necessitates making a tripthis morning. I expect to be back tonight, if all goes well, and we'llstart tomorrow morning instead of this. It's a matter of importantbusiness. "

"Well, I don't know that we can find fault with Mr. Swift for attendingto business, " said Mr. Hardley, with a short laugh. "Business is whatkeeps the world moving. And we are a little ahead of our schedule, as amatter of fact. May I ask where you are going, Mr. Swift?"

"To Bedford, to call on a Mr. Barton Keith, " answered Tom quickly, looking the adventurer straight in the eyes. 

Mr. Hardley was a good actor, or else he was a perfectly innocent man, for he showed not the least sign of perturbation. 

"Oh, Bedford, " he remarked. "Don't know that I ever heard of the place. "

"Or Mr. Keith, either?" asked Tom, a bit sharply. 

"No, certainly not. Why should I?" he asked, boldly. 

"I didn't know, " Tom replied. "I'm sorry to postpone our trip, but it'snecessary, " he added. "I'll be back as soon as I can. Everything is inreadiness, so there will be no delay. "

Tom made a hurried meal, and then, giving Ned a hint of what was in thewind, but cautioning him to say nothing about it, Tom had the small AirScout brought out, and in that he flew over to Mary's home. 

He found her waiting for him, and, after being duly cautioned by hermother to "be careful, " though whether that was of any value or not ispossibly debatable, the small, speedy craft again took the air. 

"You haven't heard anything from your uncle since last night, haveyou?" asked Tom, as they flew along. 

"Yes, " answered Mary, "mother had a letter. He is worse, if anything, and the doctor says the only thing that will save him is the knowledgethat the oil-well matter has turned out right and that my uncle willget his share of the wealth. "

"That's too bad!" sympathized Tom. "I hope we can make it turn out thatway. If the two Dixwell Hardley chaps are the same it may be that I cando something for your uncle. If not--we'll have to wait and see. "

It was not difficult for Tom and Mary to talk while in the aeroplane, as it was almost noiseless. In due time, Bedford was reached withoutmishap, and Tom and Mary were soon at the home of her uncle. 

An explanation to the housekeeper and an inspection on the part of thenurse, brought forth permission for Tom to see the patient. Though hehad never known Mr. Keith he could see that the man's health was indeedfast waning. 

Wasting little time in preliminaries, the object of the visit was toldand Tom showed the passport photograph of Dixwell Hardley. 

"Is that the man who cheated you on the oil-well deal?" asked the younginventor. 

"I won't admit he has yet cheated me, but he is trying to!" exclaimedMr. Keith, with something of a return of his former spirit. "If I everget off my back I'm going to fight him tooth and nail. But that's thesame scoundrel! He got me to locate the wells, and when they panned outbig--bigger than either of us dreamed--he turned me out cold. He deniedhe had ever offered to share with me, and said I was only working formonthly wages! Why, sometimes I didn't get even that!"

"How did he get the best of you?" asked Tom. 

"By making away with or hiding the papers by which I could prove ourpartnership and my right to half a share in all the wells, " answeredMary's uncle. "Yes, that's the same man all right. I'd know his faceanywhere, and he ha& the same name. "

"He isn't going under a false name, that's sure, " agreed Tom. "He mustbe a bold chap. "

"He is--bold and unscrupulous! That's what makes him so successful inhis own way!" declared Mr. Keith. "And so you are working with him!Well, I'm sorry for you. "

"I'm not exactly working with him, " replied Tom. "As a matter of fact, I'm sorry I ever agreed to look for this wreck. "

He told the details of the pending treasure-trove expedition, andmentioned it as his belief that Mr. Damon had been mistaken in hisestimate of Mr. Hardley. 

"But, so far, Mr. Damon is quite taken with him, " Tom went on. "Now, Mr. Keith, if it isn't too much for you, I should like to hear all theparticulars. "

Thereupon Mary's uncle told his story. It was a long one. After manyhardships in life, which Mr. Keith related in some detail to Tom, theoil-well prospector at last fell in with Dixwell Hardley. Then followedthe combination of interests. 

"We are actually partners, " declared Mr. Keith. "I agreed to do thework, and he agreed to furnish the money. I must say this for him, thathe kept to that end of the bargain. He supplied the money to locate anddrill the wells, but I got very little of it personally. And Ifulfilled my end of it. I discovered the wells. Then, when the breakcame, and I wanted to be rid of the man--for I caught him in somecrooked transactions--he surprised me by telling me to get out. I askedfor my share of the oil-well stock, and was told I was not entitled toany. 

"I put up a fight, naturally, and took the matter to court. But when itcame to trial Dixwell Hardley did not appear, and, though I won atechnical victory over him, I never got any money. "

"Where was he during the trial?" asked Tom. 

"At sea, I believe. "

"At sea?"

"Yes, he was mixed up in some South American revolution, I heard. "

"A South American revolution!" exclaimed Tom, and a great light came tohim. 

"Yes, " went on Mary's uncle. "He was always that kind--mixing up inanything he thought would produce money. He didn't make out very wellin the revolution business, so I understood. The revolutionary partywas beaten, or they lost their shipment of arms, or something likethat. At any rate, Dixwell Hardley had a narrow escape with his lifewhen a ship went down, and from then on I've been trying to get him torestore my rights to me. "

"Did he have the papers that would prove you were entitled to a halfshare in the oil wells?" asked Tom. 

"He certainly did!" said the sick man, who was obviously being weakenedby this long and exhausting talk. "At first I was not sure of whathappened, but now I am positive he stole the papers and took them tosea with him. What happened to them after that I don't know. But if Ihad Dixwell Hardley here--now--I--I'd--"

Mr. Keith fell back in a faint on the bed, and, in great alarm, Tomsummoned the nurse. 

CHAPTER XII

IN DEEP WATERS

Mary Nestor, as well as Tom Swift, felt great alarm over the conditionof Mr. Keith. But the nurse, after reviving him, said:

"He is in no special immediate danger. Talking about his troubleoverstrained him, but in the end it may do him good. "

"Then will he get well?" asked Mary. 

"He may, " was the noncommittal answer. "His recovery would be hastened, however, if his mind could be relieved. He keeps worrying about theloss of his papers that proved his share in the Texas oil wells. Untilthey can be given back to him he is bound to suffer mentally, and ofcourse that effects him physically. "

"Oh, if we only could do something!" murmured Mary. 

"Perhaps we can, " said Tom in a low voice. "I've learned somethingthese last few hours. I don't want to promise too much, but I think Ibegin to see how matters lie. There, he's rousing. Speak to him, Mary. "

Mr. Keith opened his eyes, and smiled at his niece. 

"Did I dream it, " he asked in a low voice, "or was there some young manwith you, Mary, my dear, to whom I was telling my troubles about theoil-well papers?"

"You didn't dream it, Uncle, " Mary answered. "You were talking to TomSwift. Here he is, " and Tom came forward. 

"Oh, yes, I remember now, " said Mr. Keith passing his hand wearily overhis eyes. "I thought, for a moment, that he had recovered my papers forme. But that was a dream, I'm sure. "

"It may not be, Mr. Keith!" exclaimed Tom. 

"May not be? What do you mean?"

"I mean, " replied the young inventor, "that I am much interested inwhat you have told me. Now that I have proved that the Dixwell Hardleywho is to sail with me is the same one who has treated you so shabbily, I think I understand the truth. I don't want to make a promise that Imay not be able to carry out, but I am going to watch this man whilehe's on the submarine with me. "

"Then you are going on with the voyage, Tom?" asked Mary. 

"I shall have to, " he said. "I have entered into an agreement with thisman and I'm not going to break my contract, no matter what he does. ButI think I know what his game is. Mr. Keith, I'm going to ask you tokeep quiet about this matter until I come back from the treasuresearch. I may then have some news for you. "

"I hope you do, young man, I hope you do!" exclaimed the oilcontractor, with more energy than he had previously shown. "It means alot, at my age, to lose a small fortune. If I were well and strong I'dtackle this Dixwell Hardley myself, and make him give up the papers I'msure he has hidden away. He has them, I'm positive. "

"Well, he may not have them, but perhaps he knows where they are, " saidTom. "And I'm going to make it my business to watch him and see if Ican find out his secret. I won't let him know I've heard from you. I'llapply the old saying of giving him plenty of rope, and I'll watch whathappens. 

"Now, Mr. Keith, take care of yourself. Mary and I must be gettingback. Try not to worry, and I'll do my best for you, " Tom concluded. 

Mary added a few words of comfort and encouragement to her uncle, andthen she and Tom took leave of him, flying back to Shopton in thespeedy Air Scout. 

"What are you going to do, Tom?" asked Mary, as he left her at herhome, having told Mr. And Mrs. Nestor his part in the visit to BartonKeith. 

"I'm going to start on the submarine voyage tomorrow, " was the answerof the young inventor. 

"Do you really believe there is a treasure ship?"

"Well, I've satisfied myself that a ship named the Pandora sunk aboutwhere Hardley says it did, and she had some treasure on board. Whetherit's just the kind he has told me it was I don't know. But I'm going tofind out. "

"Then you'll be saying goodbye for a long time, " observed Mary, ratherwistfully. 

"Oh, it may not be for so very long, " and Tom tried to speakcheerfully. "I'll bring you back some souvenirs from the bottom of thesea, " he added with a laugh. 

"Bring me back--yourself!" said Mary in a low voice, and then shehurried away. 

By appointment Tom met Mr. Damon and Mr. Hardley at the submarine dockthe next morning. Everything had been made ready for the start, postponed from the day before. Mr. Hardley's estimated share of theexpenses had been deposited in a bank, to be paid over later. 

"Well, are we really going this time, or are you going to delay again?"asked the gold seeker, and his voice lacked a pleasant tone. 

"Oh, were going this time!" exclaimed Tom. "And I hope everything turnsout the way I want it to, " he added meaningly. 

"We'll find the treasure on the ship all right, if we can find theship, " said Mr. Hardley. "That part is your job, Mr. Swift. "

"And I'll find her if she's where you say she went down, " answered Tom. "Now then, as soon as Ned comes we'll start. "

Ned Newton had been intrusted with some last-moment messages, but hearrived a little later, and hurried on board the M. N. 1 which lay ather dock, just afloat. 

"All aboard!" called Tom, when he saw his financial manager coming downthe pier. "We're ready to start now. "

"Bless my fountain pen!" exclaimed Mr. Damon, "but we ought to dosomething, Tom--sing a song, make a speech or something, oughtn't we?"

"We'll sing a song of victory when we come back, " replied Tom, with alaugh. "Everything all right at home, Ned?" he asked, for his chum hadjust come on from Shopton. 

"Yes; your father sent his regards, but he told me to make a lastappeal to you to install a gyro-scope rudder. "

"It's too late for that now, " said Tom. "He attaches, I think, too muchimportance to that device. I shan't need it with the improvements Ihave made to the craft. Get aboard!"

Ned climbed down the hatchway, which, however, was not closed, as itwas decided to navigate the craft on the surface until it was necessaryto submerge her because of too rough water, or when the vicinity of thewreck was reached. 

"Though we will go down to the bottom when we get to the Atlantic forthe purpose of testing her in deep water, " decided Tom. "Most of thetime we'll steam on the surface, for we'll save our batteries that way, and it's more comfortable breathing natural air. "

So, with part of her deck above the surface, the M. N. 1 began hervoyage, sent on her way by the cheers of the small force of Tom'sworkmen at the submarine plant. The general public was not admitted, for the object of the quest was kept secret from all save thoseimmediately interested. 

"Rad, him be plenty mad he not come, " said Koku to Tom, as the giantmoved about the cabin, putting things to rights. 

"Well, don't start crowing over him until we get back, " warned theyoung inventor. "He may have the laugh on us. "

"Rad no laugh, " declared Koku. "Rad him too mad dat I come on trip. "

"A submarine voyage is no place for old, faithful Eradicate, " murmuredTom. "He's better off looking after my father. "

The first part of the trip was without incident of moment. No mishapattended the voyage of the M. N. 1 down the river, out into the bay, and so on to the great Atlantic. 

Fairly good time was made, as there was no particular object inspeeding, and on the second day after leaving the dock Tom gave ordersfor the hatch to be closed, the deck cleared, and everything made tightand fast. 

"What's up?" asked Ned, hearing the instructions passed around. 

"We're approaching deep water, " was the answer. "I'm going to submerge. "

A little later, by means of her diving rudders, aided also by thetanks, the M. N. 1 began to sink. Down, down, down she went. 

"Now I'll be able to show you some pretty sights, Mr. Hardley, " saidTom, as he and his friends entered the forward compartment, while thesteel shutters were rolled back from the heavy glass windows. "We'll bein deep waters presently. "

Ten minutes later the depth gauge showed that they were down aboutthree hundred feet, and that is pretty deep for a submarine. But Tom'sboat was capable of even greater depths than that. 

At first there was nothing much to observe save the opal-tinted waterilluminated by the powerful lights of the submarine. Small, andevidently frightened, fish darted to and fro, but there was nothingespecially to attract the attention of Tom and his friends, who hadmade much more sensational trips than this under water. 

Mr. Hardley, however, was fascinated, and kept close to the observationwindows. 

"Are there any wrecks around here?" he asked Tom. 

"Possibly, " was the answer. "Though they do not contain any treasure, Iimagine--brick schooners or cargo boats would be about all. "

The submarine went deeper, plowing her way through the Atlantic at adepth of more than three hundred and fifty feet, for Tom wanted tosubject her to a good test. 

Suddenly Mr. Hardley, who was now alone at the window on the port side, uttered a cry of alarm. 

"Look! Look!" he fairly shouted. "We're surrounded by a school ofsharks! What monsters! Are we in danger?"

CHAPTER XIII

THE SEA MONSTER

Tom Swift, who had been making readings of the various gauges, takingnotes for future use, and otherwise busying himself about thenavigation of his reconstructed craft, turned quickly from theinstrument board at the cry from Mr. Hardley. The gold-seeker, with alook of terror on his face, had recoiled from the observation windows. 

"Bless my hat band!" cried Mr. Damon. "Look, Tom!"

They all turned their attention to the glass, and through the platescould be seen a school of giant fishes that seemed to be swimming infront of the submarine, keeping pace with it as though waiting for achance to enter. 

"Are we well protected against sharks, Mr. Swift?" demanded theadventurer. "Are these sea monsters likely to break, the glass and getin at us?"

"Indeed not!" laughed Tom. "There is absolutely no danger from thesefish--they aren't sharks, either. "

"Not sharks?" cried Mr. Hardley. "What are they, then?"

"Horse mackerel, " Tom answered. "At least that is the common name forthe big fish. But they are far from being sharks, and we are in nodanger from them. "

"Oh!" exclaimed Mr. Hardley, and he seemed a little ashamed of theexhibition of fear he had manifested. "Well, they certainly seemdetermined to follow us, " he added. 

The big fish were, indeed, following the submarine, and it required noexertion on their part to maintain their speed, since below the surfacethe M. N. 1 could not move very fast, as indeed no submarine can, dueto the resistance of the water. 

"They do look as though they'd like to take a bite or two out of us, "observed Ned. "Are they dangerous, Tom?"

"Not as a rule, " was the answer. "I don't doubt, though, but if a loneswimmer got in a school of horse mackerel he'd be badly bitten. Infact, some years ago, when there was a shark scare along the New Jerseycoast, some fishermen declared that it was horse mackerel that wereresponsible for the death and injury of several bathers. A number ofhorse mackerel were caught and exhibited as sharks, but, as you caneasily see, their mouths lack the under-shot arrangement of the shark, and they are not built at all as are the man-eaters. "

"Bless my toothbrush!" exclaimed Mr. Damon. "Still, between a horsemackerel and a shark there isn't much choice!"

Mr. Hardley, with a shudder, turned away from the glass windows, andTom glanced significantly at Ned. It was another exhibition of theman's lack of nerve. 

"We'll have trouble with him before this voyage is over, " declared theyoung inventor to his chum, a little later. 

"What makes you think so?" asked Ned. 

"Because he's yellow; that's why. I thought him that once before, andthen I revised my opinion. Now I'm back where I started. Youwatch--we'll have trouble. "

"Well, I guess we can handle him, " observed the financial manager. 

"I'm going a little deeper, " announced Tom, toward evening on the firstday of the voyage on the open ocean. "I want to see how she stands thepressure at five hundred feet. I feel certain she will, and even at agreater depth. But if there's anything wrong we want to correct itbefore we get too far away from home. We're going down again, deeperthan before. "

A little later the submarine began the descent into the lower oceandepths. From three hundred and fifty feet she went to four hundred, andwhen the hand on the gauge showed four hundred and fifty there was atense moment. If anything went wrong now there would be serious trouble. 

But Tom Swift and his men had done their work well. The M. N. 1 stoodthe strain, and when the gauge showed four hundred and ninety feet Mr. Damon gave a faint cheer. 

"Bless my apple dumpling, Tom!" he replied, "this is wonderful. "

"Oh, we've been deeper than this, " replied the young inventor, "butunder different conditions. I'm glad to see how well she is standingit, though. "

Suddenly, as the needle pointer on the depth gauge showed five hundredand two feet, there came a slight jar and vibration that was feltthroughout the craft. 

"What's that?" suddenly and nervously cried Mr. Hardley. "Have westruck something?"

"Yes, the bottom of the ocean, " answered Tom quietly. "We are now onthe floor of the Atlantic, though several hundred miles, and perhaps athousand, from the treasure ship. We bumped the bottom, that's all, "and as he spoke he brought the submarine to a stop by a signal to theengine room. 

And there, as calmly and easily as some of the masses of seaweedgrowing on the ocean floor around her, rested the M. N. 1. It was atest of her powers, and well had she stood the test, though harder oneswere in store for her. 

And inside the submarine Tom and his party were under scarcely greaterdiscomfort than they would have been on the surface. True, they wereconfined to a restricted space, and the air they breathed came fromcompression tanks, and not from the open sky. The lights had to bekept aglow, of course, for it was pitch dark at that depth. Thesunlight cannot penetrate to more than a hundred feet. But sunlight wasnot needed, for the craft carried powerful electric lights that couldilluminate the sea in the immediate vicinity of the submarine. 

"Are you going to stay here long?" asked Mr. Hardley, when Tom hadspent some time making accurate readings of the various instruments ofthe boat. "Of course, I realize that you are the commander, but if wedon't get to the treasure ship soon some one else may loot her beforewe have a chance. She's been given up as a hopeless task more thanonce, but the lure of the millions may attract another gang. "

"I want to stay here until I make sure that nothing is leaking and thateverything is all right, " answered the young inventor. "This is a testI have not given her since the rebuilding. But I think she is comingthrough it all right, and we can soon start off again. Before we do, though, I want to try the new diving outfit. Ned, are you game for itnow? This is a little deeper than you have gone out in for some time, but--"

"Oh, I'm game!" exclaimed the young financial manager. "Get out thesuit, Tom, and I'll put it on. I'll go for a stroll on the bottom ofthe sea. Who knows? Perhaps I may pick up a pearl. "

"Pearls aren't found in these northern waters, any more than aresharks, " said Tom with a laugh. "However, I'll have the suits madeready. I'll send Koku with you, and I'll stay in this time. Mr. Damon, do you want to go out?"

"Not this time, Tom, " answered the eccentric man. "My heart actionisn't what it used to be. The doctor said I mustn't strain it. At adepth not quite so great I may take a chance. "

"How about you, Mr. Hardley?" asked Tom. "Do you want to put on one ofmy portable diving suits and walk around on the bottom of the sea?"

"I--I don't believe I've had enough experience, " was the hesitatinganswer. "I'll watch the others first. "

Tom felt that it would be this way, but he said nothing. He ordered thediving suits made ready, a special size having been built for thegiant, and soon preparations were under way for the two to step outsidethe craft. 

Those who have read of Tom Swift's submarine boat know how his specialdiving outfit was operated. Instead of the diver being supplied withthe air through a hose connected with a pump on the surface, there wasattached to the suit a tank of compressed air, which was supplied asneeded through special reducing valves. 

The diving dress, too, was exceptionally strong, to withstand the awfulpressure of water at more than five hundred feet below the surface. Theusual rubber was supplemented by thin, reinforced sheets of steel, andthis feature, together with an auxiliary air pressure, kept the wearersafe. 

Thus Ned and Koku could leave the submarine, walk about on the floor ofthe ocean as they pleased, and return, unhampered by an air hose orlife line. In dangerous waters, infested by sea monsters, weapons couldbe carried that were effective under water. The diving suit was alsoprovided with a powerful electric light operated by a new form ofstorage current, compact and lasting. 

"Well, I think we're all ready, " announced Ned, as he and Koku werehelped into their suits and they waited for the glass-windowed helmetsto be put on. Once these were fastened in place talk would have to becarried on with the outside world by means of small telephones or bysignals. 

"Give me axe!" exclaimed Koku, as some of the sailors were about to puthis helmet in place. 

"What do you want of an axe?" Tom asked. 

"Maybe so one them cow fish come along, " explained the giant. "Kokuwhack him with axe. "

"He means horse mackerel, " laughed Ned. "Give him the axe, Tom. Idon't like the looks of those fish, either. I'll take a weapon myself. "

Two keen axes were handed to the divers, their helmets were screwed on, and they immediately began breathing the compressed air carried in atank on their shoulders. 

Slowly and laboriously they walked to the diving chamber. Theirprogress would be easier in the water, which would buoy them up in ameasure. Now they were heavily weighted. 

To leave the submarine the divers had to enter a steel chamber in theside of the craft. This craft contained double doors. Once the diverswere inside the door leading to the interior of the submarine washermetically closed. Water from outside was then admitted until thepressure was equalized. Then the outer door was opened and Ned and Kokucould step forth. 

They entered the chamber, the door was closed tightly and then TomSwift turned the valve that admitted the sea water. With a hiss theAtlantic began rushing in, and in a short time the outer door would beopened. 

"If you'll come around to the observation windows you can see them, "said Tom, when a look at the indicators told him Ned and Koku hadstepped forth. 

To the front cabin he and the others betook themselves, and when theinterior lights were turned out and the exterior ones turned on theywaited for a sight of the two divers. 

"Bless my pickle bottle!" cried Mr. Damon, "there they are, Tom. "

As he spoke there came into view, moving slowly, Ned and Koku. Theirportable lights were glowing, and then, in order to see them better, Tom turned out the exterior searchlights. This made the two forms, intheir rather grotesque dress, stand out in bold relief amid theswirling green waters of the Atlantic. 

Ned and the giant moved slowly, for it was impossible to progress withany speed wader that terrific pressure. They looked toward thesubmarine and waved their hands in greeting. They had no special objecton the ocean floor, except to try the new diving dress, and it seemedto operate successfully. Ned made a pretense of looking for treasureamid the sand and seaweed, and once he caught and held up by its tail aqueer turtle. Koku stalked about behind Ned, looking to right and left, possibly for a sight of some monster "cow fish. "

"They're coming back in, I think, " remarked Tom, when he saw Ned turnand start back for the side of the craft, where, amidships, was locatedthe diving chamber. "They're satisfied with the test. "

Suddenly Koku was seen to glide to the side of Ned, and point atsomething which none of the observers in the M. N. 1 could see. Thegiant was evidently perturbed, and Ned, too, showed some agitation. 

"Bless my rubber shoes! what's the matter?" cried Mr. Damon. 

"I don't know, " answered Tom. "Perhaps they have sighted a wreck, orsomething like that. "

"Look! It's a sea monster!" cried Mr. Hardley. "I can see the form ofsome great fish, or something. Look! It's coming right at them!"

As he spoke all in the observation chamber saw a great, black form, asif of some monster, move close to the two divers. 

CHAPTER XIV

IN STRANGE PERIL

"What is it, Tom? What is it?" cried Mr. Damon, not stopping in thismoment of excitement to bless anything. "What is going to attack Nedand Koku?"

"I don't know, " answered the young inventor. "It's some big fishevidently. I must get to the diving chamber!"

He gave a quick glance through the observation windows. Ned and thegiant were moving as fast as they could toward the side of the craftwhere they could enter. The black, shadowy form was nearer now, but itsnature could not be made out. 

Calling to his force of assistants, Tom stood ready to let his chum andKoku out of the diving chamber as soon as the water should have beenpumped from it. 

A little later, as they all stood waiting in tense eagerness, therecame a signal that the two divers had entered the side chamber. QuicklyTom turned the lever that closed the outer door. 

"They're safe!" he exclaimed, as he started the pumps to working. Buteven as he spoke they felt a jar, and the submarine rolled partly overas if she had collided with some object. Yet this could not be, as shewas stationary on the floor of the ocean. 

"Bless my cake of soap, Tom!" cried Mr. Damon, "what in the world isthat?"

"If it's an accident!" exclaimed Mr. Hardley, "I think it ought to beprevented. There have been too many happenings on this trip already. Ithought you said your submarine was safe for underwater trips!" hefairly snapped at Tom. 

The young inventor gave one look at the irate man who was coming out inhis true colors. But it was no time to rebuke him. Too much yetremained to be done. Ned and Koku were still in the chamber andprotected from some unknown sea monster by only a comparatively thindoor. They must be inside to be perfectly safe. 

Tom speeded up the pumps that were forcing the water from the chamberso the inner door could be opened. Eagerly he and his men watched thegauges to note when the last gallon should have been forced out by thecompressed air. Not until then would it be safe to let Ned and Kokustep into the interior of the craft. 

The submarine had not ceased rolling from the force of the blow she hadreceived when there came another, and this time on the opposite side. Once more she rolled to a dangerous angle. 

"Bless my tea biscuit!" cried Mr. Damon, "what is it all about, TomSwift?"

"I don't know, " was the low-voiced answer, "unless a pair of monstersare attacking us on both sides alternately. But we'll soon learn. Theregoes the last of the water!"

The gauge showed that the diving chamber was empty. Quickly the innerdoors were opened, stud, with their suits still dripping from theirimmersion in the salty sea, Ned and Koku stepped forth. In anothermoment their helmets were loosed from the bayonet catches, and theycould speak. 

"What was it, Ned?" cried Tom. 

"Big fish!" answered Koku. 

"Two monster whales!" gasped Ned. "We barely got away from them!They're ramming the sub, Tom!"

As he spoke there came a blow on the port side, greater than either ofthe two preceding ones. Those in the M. N. 1 staggered about, and hadto hold on to objects to preserve their footing. 

"Both at the same time!" cried Ned. "The two whales are coming at usboth at once!"

This was evidently the case. Tom Swift quickly hurried to the engineroom. 

"What are you going to do?" asked Mr. Hardley. "You ought to dosomething! I'm not going to be killed down here by a whale. You've gotto do something, Swift! I've had enough of this!"

Tom did not deign an answer, but hurried on. Mr. Damon followed him, having seen that some of the sailors were helping Ned and Koku out ofthe diving suits. 

"Are we in any danger, Tom?" asked the eccentric man. 

"Yes; but I think it is easily remedied, " was the answer. "We'll go upto the surface. I don't believe the whales will follow us. Or, if theydo, they can't do much damage when we are in motion. It's because weare stationary and they are moving that the blows seem so violent. Unless they collide head on with us, in the opposite direction to ours, we ought to be able to get clear of them. If they persist in followingus--"

He paused as he pulled over the lever that would send the M. N. 1 tothe surface. 

"Well, what then?" asked Mr. Damon. 

"Then we'll have to use some weapon, and I have several, " finished theyoung inventor. 

A few moments later the craft was in motion, not before, however, shewas struck another blow, but only a glancing one. 

"We're puzzling them!" cried Tom. 

Having done all that was possible for the time being, Tom hurried tothe observation chamber, followed by the ethers. There Tom switched onthe powerful lights. For a moment nothing was to be seen but theswirling, green water. Then, suddenly, a great shape came into view ofthe glass windows, followed by another. 

"Whales!" cried Tom Swift. "And the largest I've ever seen. "

It was true. Two immense specimens of the cetacean species were infront of the submarine, one on either bow, evidently much puzzled overthe glaring lights. They were bow-heads, and immense creatures, and itwould not take many blows from them to disable even a stouter craftthan was the submarine. 

But the motion of the undersea ship, the bright lights, and possiblythe feel of her steel skin was evidently not to the liking of the seamonsters. One, indeed, came so close to the glass that he seemed aboutto try to break it, but, to the relief of all, he veered off, evidentlynot liking the look of what he saw. 

Just once again, before the craft reached the surface, was thereanother blow, this time at the stern. But it was a parting tap, andnone others followed. 

"They've gone!" exclaimed Mr. Damon, as the whales vanished from thesight of those in the forward cabin. 

"Have you any adequate protection against these monsters of the deep?"asked Mr. Hardley in a fault-finding voice. "I should think you wouldhave taken precautions, Swift!"

He had dropped the formal "Mr. " and seemed to treat Tom as an inferior. 

"We have other protection than running away, " said the young inventorquietly. "There are guns we can use, and, if the whales had been farenough away, I could have sent a small torpedo at them. Close by itwould be dangerous to use that, as it would operate on us just as thedepth bombs operated on the German submarines. However, I fancy we havenothing more to fear. "

And Tom was right. When the surface was reached and the main hatchopened, the sea was calm and there was no sight of the whales. Theyevidently had had enough of their encounter with a steel fish, largereven than themselves. 

"But they surely were monsters, " said Ned, as he told of how he andKoku had sighted the animals; for a whale is an animal, and not a fish, though often mistakenly called one. 

"Koku was for attacking them with his axe, " went on Ned, "but Imotioned to him to beat it. We wouldn't have stood a show against suchcreatures. They were on us before we noticed their coming, but Ipresume the big submarine attracted them away from us. "

"It might have been the lights you carried that drew them, " suggestedTom. "I am glad you came out of it so well. "

Mr. Hardley seemed to recover some of his former manners, once theperil was passed, but his conduct had been a revelation to Mr. Damon. 

"Tom, " said the eccentric man in private to the young inventor, "I'mdisgusted with that fellow. I don't see how I was ever bamboozled intotaking up his offer. "

"I don't, either, " replied Tom frankly. "But we're in for it now. We'veagreed to do certain things, and I'll carry out my end of the bargain. However, I won't put up with any of his nonsense. He's got to obeyorders on this ship! I know more than he thinks I do!"

The next two days the M. N. 1 progressed along on the surface, andnothing of moment occurred. Then, as they neared southern waters, andTom desired to make some observations of the character of the bottom, it was decided to submerge. Accordingly, one day the order was given. 

Not until the gauge showed a hundred fathoms, or six hundred feet, didthe craft cease descending, and then she came to rest on the bottom ofthe sea--a greater depth than she had yet attained on this voyage. 

"How beautiful!" exclaimed Mr. Damon, when Tom turned on the lights andthey looked out of the forward cabin windows. "How wonderful andbeautiful!"

Well might he say that, for they were resting on pure white sand, andabout them, growing on the bottom of this warm, tropical sea were greatcorals, purple and white, of wondrous shapes, waving plants like fernsand palms, and, amid it all, swam fish of queer shapes and beautifulcolors. 

"This is worth waiting for!" murmured Ned. "If only moving pictures ofthis could be taken in colors, it would create a sensation. "

"Perhaps I may try that some day, " said Tom with a smile. "But just nowI have something else to do. Ned, are you game for another try in thediving dress? I want to see how it operates with a new air tank I'vefitted on. Want to try?"

"Sure I'll go out, " was the ready answer. "It's nicer walking around onthis white sand than on the black mud where we saw the whales. You cansee better, too. "

A little later he and one of the sailors were outside the submarine, walking around in the diving dress, while Tom and the others watchedthrough the glass windows. The new air tank seemed to be working well, for Ned, coming close to the window, signaled that he was verycomfortable. 

He walked around with the sailor, breaking off bits of odd-shaped coralto bring back to Tom. Suddenly, as those inside the craft looked out, they saw the sailor turn from Ned's side, and with a warning hand, point to something evidently approaching. The next instant a queershape seemed to envelope Ned Newton, coming out from behind a ledge ofweed-draped coral. And a cry went up from those in the submarine as Nedwas seen to be enveloped in long, waving arms. 

"An octopus!" cried Mr. Damon. "Bless my soul, Tom, an octopus has Ned!"

"No, it isn't that!" cried the young inventor hoarsely. "It's someother monster. It has only five arms--an octopus has eight! I've gotto save Ned!"

And he hurried toward the diving chamber, while the others, infascinated horror, looked at the diver who was in such strange peril. 

CHAPTER XV

TOM TO THE RESCUE

Mr. Damon came to a pause in the compartment from which the divingchamber gave access to the ocean outside. Tom, standing before thesliding steel door, had summoned to him several of his men and wasrapidly giving them directions. 

"What are you going to do, Tom Swift?" asked the eccentric man. 

"I'm going out there to save Ned!" was the quick answer. "He's in thegrip of some strange monster of the sea. What it is I don't know, butI'm going to find out. Koku, you come with me!"

"Yes, Master, me come!" said the giant simply, as if Tom had told himto go for a pail of water instead of risking his life. 

"Barnes, the electric gun!" cried the young inventor to one of hishelpers, while others were getting out the diving suits. 

"The electric gun!" exclaimed the man. "Do you mean the small one?"

"No, the largest. The improved one. "

"Right, sir! Here you are!"

"Do you mean to say you are going out there, where that monster is, andattack it with a gun?" asked Mr. Hardley. 

"That's what I'm going to do!" answered Tom, as he began to put on thesuit of steel and rubber, an example followed by Koku. 

"But you may be attacked by the monster! You may be killed! You arerisking your life!" cried the gold seeker. 

"I know it. " Tom spoke simply. "Ned would do the same for me!"

"But hold on!" cried Mr. Hardley. "If you are killed there will be noone to navigate this boat to the place of the wreck! You can't desertthis way!"

Tom gave the man one look of contempt. "You need have, no fears, " hesaid. "This submarine is under international maritime laws. If I die, Captain Nelson, the next in command, takes charge, and the originalorders will be carried out. If it is possible to get the gold for youit will be done. Now let me alone. I've got work to do!"

"Bless my apple cart, Tom, that's the way to talk!" exclaimed Mr. Damon, and he, too, for the first time, seemed ready to break withHardley. "If I were a bit younger I'd go out with you myself and helpsave Ned. "

"Koku and I can do it--if he's still alive!" murmured the younginventor. "Lively now, boys! Is that gun ready?"

"Yes, and doubly charged, " was the answer. "Good! I may need it. Koku, take a gun also!"

"Me take axe, Master, " replied the giant. 

"Well, perhaps that will be better, " Tom agreed. "If two of us get toshooting under the water we may hit one another. Quick, now! Thehelmets. And, Nash, you work the big searchlight!"

"Aye, aye, sir!" answered the sailor. 

The helmets were now put on, and any further orders Tom had to givemust come through the telephone, and it was by that same medium that hemust listen to the talk of his friends. It was possible for the diversto talk and listen to one another while in the water by means of thesepeculiarly constructed telephones. 

"All ready, Koku?" asked Tom. 

"All ready, Master, " answered the giant, as he grasped his keen axe. 

The inner door of the diving chamber was now opened, and, the waterhaving been pumped out of the chamber since Ned and the sailor hademerged, it was ready for Tom and Koku. They entered, the door wasclosed, and presently they felt the pressure of water all about them, the sea being admitted through valves in the outer door. 

While this was going on Mr. Damon, the gold-seeker, and some of thecrew and officers went into the forward chamber to observe the underseafight against the monster that had attacked Ned. 

Suddenly the waters glowed with a greatly increased light, and in thisillumination it was seen that the monster, whatever it was, had almostcompletely enveloped Tom's chum with its five arms. 

"What makes it possible to see better?" asked Mr. Damon. 

"I've turned on the big searchlight, " was the answer. "Mr. Swift had itinstalled at the last moment. It's the same kind he invented and gaveto the government, but he retained the right to use it himself. "

"It's a good thing he did!" exclaimed the eccentric man. "Now he cansee what he's doing! Poor Ned! I'm afraid he's done for!"

"Look!" exclaimed one of the crew. "Norton, the sailor who went outwith Mr. Newton, is trying to kill the monster with his spear!"

This was so. Ned's companion, armed with a lone pole to which he hadlashed a knife, was stabbing and jabbing at the black form which almostcompletely hid Ned from sight. But the efforts of the sailor seemed toproduce little effect. 

"What in the world can it be?" asked Mr. Damon. "Tom says it isn't anoctopus, and it can't be, unless it has lost three of its arms. Butwhat sort of monster is it?"

No one answered him. The powerful searchlight continued to glow, and inthe gleam Ned could be seen trying to break away from the grip of theAtlantic beast. But his efforts were unavailing. It was as if he wasenveloped in a sort of sack, made in segments, so that they opened andclosed over his head. About all that could be seen of him was his feet, encased in the heavy lead-laden boots. The form of the other sailor, who had gone out of the submarine with him, could be seen moving hereand there, stabbing at the huge creature. 

"Here comes Tom!" suddenly exclaimed Mr. Damon, and the young inventor, followed by the giant Koku, came into view. They had emerged from thediving chamber, walked around the submarine as it rested on the oceanfloor, and were now advancing to the rescue. Tom carried his electricrifle, and Koku an axe. 

So desperately was Norton engaged in trying to kill the sea beast thathad attacked Ned, that for the moment he was unaware of the approach ofTom and Koku. Then, as a swirl of the water apprised him of this, heturned and, seeing them, hastened toward them. 

"What is it?" Tom asked through the telephone, this information beinggiven to the watchers in the submarine later, as all they could gatherthen was by what they saw. "What sort of monster is it?"

"A giant starfish!" answered Norton, speaking into his mouthpiece andthe water serving as a transmitting medium instead of wires. "I neverknew they grew so big! This one has its five arms all around Mr. Newton!"

"A starfish!" murmured Tom. This accounted for it, and, as he looked atthe monster from closer quarters, he saw that Norton had spoken thetruth. 

Small starfish, or even large ones, two feet or more in diameter, maybe seen at the seashore almost any time. Nearly always the specimenscast up on the beach are in extended form, either limp, or dead anddried. In almost every instance they are spread out just as their nameindicates, in the conventional form of a star. 

But a starfish alive, and at its business of eating oysters or othershell animals in the sea, is not at all this shape. Instead, itassumes the form of a sack, spreading its five radiating arms aroundthe object of its meal. It then proceeds to suck the oyster out of itsshell, and so powerful a suction organ has the starfish that he canpull an oyster through its shell, by forcing the bivalve to open. 

And it was a gigantic starfish, a hundred times as large as any Tom hadever seen, that had Ned in its grip. The creature had doubtless takenthe diver for a new kind of oyster, and was trying to open it. Anoctopus has suckers on the inner sides of its eight arms. A starfishhas little feelers, or "fingers, " arranged parallel rows on the innerside of its arms--thousands of little feelers, and these exert a sortof sucking action. 

The gigantic starfish had attacked Ned from above, settling down on himso that the head of the diver was at the middle of the creature's body, the five arms, dropping over Ned in a sort of living canopy. And thearms held tightly. 

"Come on, Koku, and you, too, Norton!" called Tom through his headpiecetelephone. "We'll all attack it at once. I'll fire, and then you beginto hack it. The electric charge ought to stun it, if it doesn't killthe beast!"

Tom's new electric gun, unlike one kind he had first invented, did notfire an electrically charged bullet. Instead it sent a powerful chargeof electricity, like a flash of lightning, in a straight line towardthe object aimed at. And the current was powerful enough to kill anelephant. 

Bracing his feet on the white sand, which gleamed and sparkled in theglare of the searchlight, Tom aimed at the gigantic starfish which hadenveloped Ned. Standing on either side of him, ready to rush in andattack with axe and lance, were Koku and Norton. 

For an instant Tom hesitated. He was wondering whether the powerfulelectric charge might not penetrate the body of the starfish and killhis chum. 

"But the rubber suit ought to insulate and protect him, " mused theyoung inventor. "Here goes!"

Taking quick aim, Tom pulled the switch, and the deadly charge shot outof the rifle toward the sea monster. 

CHAPTER XVI

GASPING FOR AIR

For an instant after the electrical charge had been fired nothing seemto happen. The giant starfish still enveloped Ned Newton in its grip, while Tom and his two companions stood tensely waiting and those in thesubmarine looked anxiously out through the thick glass windows. 

Then, as the powerful current made itself felt, those watching saw oneof the arms slowly loosen its grip. Another floated upward, as a strandof rope idly drifts in the current. Tom saw this, and called throughhis telephone:

"He's feeling it! Go to him, boys! Koku, you with the axe!"

They needed no second urging. 

Springing toward the monster, Koku with upraised axe and Norton withthe lance, they attacked the starfish. Hacking and stabbing, theycompleted the work begun by Tom's electric gun. With one powerfulstroke, even hampered as he was by the heavy medium in which heoperated, Koku lopped off one of the legs. Norton thrust his lance deepinto the body of the monster, but this was hardly needed, for thestarfish was now dead, and gradually the remaining arms relaxed theirhold. 

Pushing with their weapons, the giant and the sailor now freed Ned fromthe bulk of the creature, which floated away. It was almost immediatelyattacked by a school of fish that seemed to have been waiting for justthis chance. Ned Newton was freed, but for a moment he staggered abouton the floor of the sea, hardly able to stand. 

"Are you all right, Ned? Did he pierce your suit?" asked Tom, anxiouslythrough the telephone. 

"Yes, I'm all right, " came back the reassuring answer. "I'm a bitcramped from the way he held me, but that's all. Guess he found thissuit of rubber and steel too much for his digestion. "

Slowly, for Ned was indeed a bit stiff and cramped, they made their wayback to the submarine, passing through a vast horde of small fisheswhich had been attracted by the dismemberment of the monster that hadbeen killed. 

"There'll be sharks along soon, " said Tom to Ned through the telephone. "They're not going to miss such a gathering of food as these small frypresent. And sharks will present a different emergency from starfish. "

Tom spoke truly, for a little later, when they were all once moresafely within the submarine, looking through the windows, they saw aschool of hungry sharks feeding on the millions of small fish thatgathered to eat the creature that had attacked Ned. 

"What did you think was happening to you out there?" asked Tom, whenthe diving suits had been put away. 

"I didn't know what to think, " was the answer. "I was prospectingaround, and I leaned over to pick up a particularly beautiful bit ofcoral. All at once I felt something over me, as a cloud sometimes hidesthe sun. I looked up, saw a big black shape settling down, and then Ifelt my arms pinned to my sides. At first I thought it was an octopus, but in a moment I realized what it was. Though I never thought beforethat starfish grew so large. "

"Nor I, " added Tom. "Well, you've had an experience, to say the least. "

They remained a little longer in the vicinity, Tom and his officersmaking observations they thought would be useful to them later, andthen the submarine went up to the surface. 

They cruised in the open the rest of that day, recharging the storagebatteries and getting ready for the search which, Tom calculated, wouldtake them some time. As he had explained, it would not be easy tolocate the Pandora in the fathomless depths of the sea. 

Ned and Mr. Damon did some fishing while they were on the surface, and, as their luck was good, there was a welcome change from the usual foodof the M. N. 1. Though, as Tom had installed a refrigerating plant, fresh meat could be kept for some time, and this, in addition to thetinned and preserved foods, gave them an ample larder. 

"When are we going to begin the real search for the gold?" asked Mr. Hardley that evening. 

"I should say in another day or two, " Tom answered, after he hadconsulted the charts and made calculations of their progress sinceleaving their dock. "We shall then be in the vicinity of the placewhere you say the Pandora went down, and, if you are sure of yourlocation, we ought to be able to come approximately near to thelocation of the gold wreck. "

"Of course I am sure of my figures, " declared Mr. Hardley. "I had themdirectly from the first mate, who gave them to the captain. "

"Well, it remains to be seen, " replied Tom Swift. "We'll know in a fewdays. "

"And I hope there will be no more taking chances, " went on thegold-seeker. "I don't see any sense in you people going out in divingsuits to fight starfish. We need those suits to recover the gold with, and it's foolish to take needless risks. "

His tone and manner were dictatorial, but Tom said nothing. Only whenhe and Mr. Damon were alone a little later the eccentric man said:

"Tom will you ever forgive me for introducing you to such a pest?"

"Oh, well, you didn't know what he was, " said Tom good-naturedly. "You're as badly taken in as I am. Once we get the gold and give himhis share, he can get off my boat. I'll have nothing more to do withhim!"

Not wishing to navigate in the darkness, for fear of not being able tokeep an accurate record of the course and the distance made Tomsubmerged the craft when night came and let her come to rest on thebottom of the sea. He calculated that two days later they would be inthe vicinity of the Pandora. 

The night passed without incident, situated, as they were, on the sandabout three hundred feet below the surface; and after breakfast Tomannounced that they would go up and head directly for the place wherethe Pandora had foundered. 

The ballast tanks were emptied, the rising rudder set, and the M. N. 1began to ascend. She was still several fathoms from the surface whenall on board became aware of a violent pitching and tossing motion. 

"Bless my postage stamp, Tom!" exclaimed Mr. Damon, "what's the matternow?"

"Has anything gone wrong?" demanded Mr. Hardley. 

"Nothing, except that we are coming up into a storm, " answered theyoung inventor. "The wind is blowing hard up above and the waves arehigh. The swell makes itself felt even down here. "

Tom's explanation of the cause of the pitching and rolling of thesubmarine proved correct. When they reached the surface and anobservation was taken from the conning tower, it was seen that aterrific storm was raging. It was out of the question to open thehatches, or the M. N. 1 would have been swamped. The waves were high, it was raining hard and the wind blowing a hurricane. 

"Well, here's where we demonstrate the advantage of traveling in asubmarine, " announced Tom, when it was seen that journeying on thesurface was out of the question. "The disturbance does not go far belowthe top. We'll submerge and be in quiet waters. "

He gave the orders, and soon the craft was sinking again. The deepershe went the more untroubled the sea became, until, when half way tothe bottom, there was no vestige of the storm. 

"Are we going to lie here on the bottom all day, or make some progresstoward our destination?" asked the gold-seeker, when Tom came into themain cabin after a visit to the engine room. "It seems to me, " went onMr. Hardley, "that we've wasted enough time! I'd like to get to thewreck, and begin taking out the gold. "

"That is my plan, " said Tom quietly. "We will proceed presently--justas soon as navigating calculations can be made and checked up. If wetravel under water we want to go in the right direction. "

His manner toward the gold-seeker was cool and distant. It was easy tosee that relations were strained. But Tom would fulfill his part of thecontract. 

A little later, after having floated quietly for half an hour or so, the craft was put in motion, traveling under water by means of herelectric motors. All that day she surged on through the salty sea, nomore disturbed by the storm above than was some mollusk on the sandybottom. 

It was toward evening, as they could tell by the clocks and not by anychange in daylight or darkness, that, as the submarine traveled on, there came a sudden violent concussion. 

"What's that?" cried Mr. Damon. 

"We've struck something!" replied Tom, who was with the others in thecabin, the navigation of the craft having been entrusted to one of theofficers. "Keep cool, there's no danger!"

"Perhaps we have struck the wreck!" exclaimed Mr. Hardley. 

"We aren't near her, " answered the young inventor. "But it may be someother half-submerged derelict. I'll go to see, and--"

Tom's words were choked off by a sudden swirl of the craft. She seemedabout to turn completely over, and then, twisted to an uncomfortableangle, so that those within her slid to the side walls of the cabin, the M. N. 1 came to an abrupt stop. At the same time she seemed tovibrate and tremble as if in terror of some unknown fate. 

"Something has gone wrong!" exclaimed Tom, and he hurried to the engineroom, walking, as best he could with the craft at that grotesque angle. The others followed him. 

"What's the matter, Earle?" asked Tom of his chief assistant. 

"One of the rudders has broken, sir, " was the answer. "It's thrown usoff our even keel. I'll start the gyroscope, and that ought tostabilize us. "

"The gyroscope!" cried Tom. "I didn't bring it. I didn't think we'dneed it!"

For a moment Earle looked at his commander. Then he said:

"Well, perhaps we can make a shift if we can repair the broken rudder. We must have struck a powerful cross current, or maybe a whirlpool, that tore the main rudder loose. We've rammed a sand bank, or stuck hernose into the bottom in some shallow place, I'm afraid. We can't goahead or back up. "

"Do you mean we're stuck, as we were in the mud bank?" asked Mr. Hardley. 

"Yes, " answered Tom, and Earle nodded to confirm that version of it. 

"But we'll get out!" declared Tom. "This is only a slight accident. Itdoesn't amount to anything, though I'm sorry now I didn't take myfather's advice and bring the gyroscope rudder along. It would haveacted automatically to have prevented this. Now, Mr. Earle, we'll seewhat's to be done. "

All night long they worked, but when morning came, as told by theclocks, they were still in jeopardy. 

And then a new peril confronted them!

Earle, coming from the crew's quarters, spoke to Tom quietly in themain cabin. 

"We'll have to turn on one of the auxiliary air tanks, " he said. "We'veconsumed more than the usual amount on account of the men working sohard, and we used one of the compressed air motors to aid theelectrics. We'll have to open up the reserve tank. "

"Very well, do so, " ordered Tom. 

But a grim look came to his face when Earle, returning a little later, reported with blanched cheeks:

"The extra tank hasn't an atom of air in it, sir!"

"What do you mean?" asked Tom, in fear and alarm. 

"I mean that the valve has been opened in some way--broken perhaps byaccident--and all the air we have is what's in the submarine now. Notan atom in reserve, sir!"

"Whew!" whistled Tom, and then he stood up and began breathing quickly. 

Already the atmosphere was beginning to be tainted, as it alwaysbecomes in a closed place when no fresh oxygen can enter. Without morefresh air the lives of all in the submarine were in imminent peril. Andeven as Tom listened to the report of his officer, he and the othersbegan gasping for breath. 

CHAPTER XVII

WHERE IS IT?

"Down on your faces!" called Tom to those with him in the cabin. "Liedown, every one! The freshest air is near the floor; the bad air rises, being lighter with carbonic acid. Lie down!"

All obeyed, Tom following the advice he himself gave. It was a littleeasier to breathe, lying on the tilted cabin floor, but how long couldthis be kept up? That was a question each one asked himself. 

"Is every bit of our reserve air used?" asked Tom, speaking to Earle. 

"As far as I can learn, yes, sir. If I had known that the auxiliarytank was empty I wouldn't have ordered the compressed air motor used. But I didn't know. "

"No one is to blame, " said Tom in a low voice. "It is one of theaccidents that could not be foreseen. If there is any blame it attachesto me for not installing the gyroscope rudder. If we had had that whenwe were caught in the cross current, or the whirlpool swirl, ourequilibrium would have been automatically maintained. As it is--"

He did not finish, but they all knew what he meant. 

"Bless my soda fountain, Tom!" murmured Mr. Damon, "but isn't there anyway of getting fresh air?"

"None without rising to the top, " Tom answered. "We'll have to trythat. Come with me to the engine room, Mr. Earle. It may be possible wecan pull her loose. "

They started to crawl on their hands and knees, to take advantage ofthe purer air at the floor level. The situation of the M. N. 1 wasexactly the same as it had been when she ran into the mud bank in theriver, with the exception that now she was in graver danger, for thesupply of air for breathing was almost exhausted. 

Reaching the engine room, where he found the crew lying down to takeadvantage of the better air near the floor, Tom made a hastyexamination of the apparatus. There was still plenty of power left inthe storage batteries, but, so far, the motors they operated had notbeen able to pull the craft loose from where her nose was stuck fast. 

"Are the tanks completely emptied?" asked Tom. 

"As nearly so as we could manage with the pumps not acting to theirfull capacity, " answered Earle. "If we could turn the craft on a morelevel keel we might empty them further, and then her natural buoyancywould send her up. "

"Then that's the thing to try to do!" exclaimed Tom, his head beginningto feel the heaviness due to the impure air. "We'll move everystationary object over to the port side, and we'll all stand there, orlie there, ourselves. That may heel her over, and help loosen the gripof the sand. "

"It's worth trying, " said Earle. "Get ready, men!" he called to thecrew. 

Tom crawled back to the main cabin and told Mr. Damon and the otherswhat was to be attempted. 

"Koku, you come and help move things, " requested Tom. 

"Me move anything!" boasted the giant, who, because of his greatstrength and reserve power did not seem as greatly affected as were theothers. 

Going back to the engine room with Koku, Tom assisted, as well as hecould, in the shifting of pieces of apparatus, stores and other thingsthat were movable. They all worked at a great disadvantage except Koku, and he did not seem to feel the lack of vitalizing air. 

One thing after another was shifted, and still the M. N. 1 maintainedthe dangerous angle. 

"It isn't going to work!" gasped Tom, as he noticed the indicator whichtold to what angle the craft was still off an even keel. "We'll have totry something else. "

"Is there anything to try?" asked Earle, in a faint voice. He was onthe point of fainting for lack of air. 

Tom looked desperately around. There was one piece of heavy machinerythat might be moved to the other side of the engine room. It was boltedto the floor, but its added weight, with that of the crew andpassengers, together with what had already been shifted, might turn thetrick. 

"Let's try to move that!" said Tom faintly, pointing to it. 

"It will take an hour to unbolt it, " said one of the men. 

"Koku!" gasped Tom, pointing to the heavy apparatus. "See if--see ifyou--"

Tom's breath failed him, and he sank down in a heap. But he had managedto make the giant understand what was wanted. 

"Koku do!" murmured the big man. Striding to the piece of machinery, the legs of which were bolted to the floor, Koku got his arms under it. Bending over, and arching his back, so as to take full advantage of hisenormous muscles, the giant strained upward. 

There was a cracking of bone and sinew, a rasping sound, but themachinery did not leave the floor. 

"Him must come!" gasped the giant. "One more go!"

He took a hold lower down. Tom's eyes were dim now, and he could notsee well. Some of the men were unconscious. 

Then, suddenly, there was a loud, breaking sound, and something tinkledon the steel floor of the submarine engine room. It was the heads ofthe bolts which Koku had torn loose. Like hail they fell about thegiant, and in another instant the big man had pulled loose the machine, weighing several hundreds of pounds. In another moment he shoved itacross the floor, toward the elevated side of the craft. 

For a second or two nothing happened. Then slowly, very slowly, the M. N. 1 began to heel over. 

"She's turning!" some one gasped. 

An instant later, freed by this turning motion from the grip of thesand bank, the submarine shot to the surface. Up and up she went, breaking out on the open sea as a great fish darts upward from thehidden depths. 

It was the work of only a few seconds for the man nearest it to openthe hatch, and then in rushed the life-giving air. Tom and hiscompanions were saved, and by Koku's strength. 

"Me say him machine got to come up--him come up!" said the giant, smiling in happy fashion, when, after they had all gulped down greatmouthfuls of the precious oxygen, they were talking of their experience. 

"Yes, you certainly did it, " said Tom, and due credit was given to Koku. 

"Never again will I travel without a gyroscope, " declared Tom. "I'malmost ready to go back and have one installed now. "

"No, don't!" exclaimed the gold-seeker. "We are almost at the place ofthe wreck. "

"Well, I suppose we can travel more slowly and not run a risk like thatagain, " decided Tom. "I'll put double valves on the emergency air tank, so no accident will release our supply again. "

This was done, after the broken valves had been repaired, and then, when the machine Koku had torn loose was fastened down again, and thesubmarine restored to her former condition, a consultation was held asto what the next step should be. 

They were in the neighborhood of the West Indies, and another day, orperhaps less, of travel would bring them approximately to the placewhere the Pandora had foundered. The latitude and longitude had beencomputed, and then, with air tanks filled, with batteries fullycharged, and everything possible done to insure success, the craft wassent on the last leg of her journey. 

For two days they made progress, sometimes on the surface, and againsubmerged, and, finally, on the second noon, when the sun had been"shot, " Tom said:

"Well, we're here!"

"You mean at the place of the wreck?" asked Mr. Hardley. 

"At the place where you say it was, " corrected Tom. 

"Well, if this is the place of which I gave you the longitude andlatitude, then it's down below here, somewhere, " and the gold-seekerpointed to the surface of the sea. It was a calm day and the ocean wasthe proverbial mill pond. 

"Let's go down and try our luck, " suggested Tom. 

The orders were given, the tanks filled, the rudders set, and, withhatches closed, the M. N. 1 submerged. Then, with the powerfulsearchlight aglow, the search was begun. Moving along only a few feetabove the floor of the ocean, those in the submarine peered from theglass windows for a sight of the sunken Pandora. 

All the rest of that day they cruised about below the surface. Thenthey moved in ever widening circles. Evening came, and the wreck hadnot been found. The search was kept up all night, since darkness anddaylight were alike to those in the undersea craft. 

But when three days had passed and the Pandora had not been seen, norany signs of her, there was a feeling of something like dismay. 

"Where is it?" demanded Mr. Hardley. "I don't see why we haven't foundit! Where is that wreck?" and he looked sharply at Tom Swift. 

CHAPTER XVIII

A SEPARATION

"Mr. Hardley, " began Tom calmly, as he took a seat in the main cabin, "when we started this search I told you that hunting for something onthe bottom of the sea was not like locating a building at theintersection of two streets. "

"Well, what if you did?" snapped the gold-seeker. "You're supposed todo the navigating, not I! You said if I gave you the latitude andlongitude, down to seconds, as well as degrees and minutes, which Ihave done, that you could bring your submarine to that exact point. "

"I said that, and I have done it, " declared Tom. "When we computed ourposition the other day we were at the exact location you gave me asbeing the spot where the Pandora foundered. "

"Then why isn't she here?" demanded the unpleasant adventurer. "Wewent down to the bottom at the exact spot, and we've been cruisingaround it ever since, but there isn't a sign of the wreck. Why is it?"

"I'm trying to explain, " replied Tom, endeavoring to keep his temper. "As I said, finding a place on the open sea is not like going to theintersection of two streets. There everything is in plain sight. Buthere our vision is limited, even with my big searchlight. And being afew feet out of the way, as one is bound to be in making nauticalcalculations, makes a lot of difference. We may have been close to thewreck, but may have missed it by a few yards. "

"Then what's to be done?" asked Mr. Hardley. 

"Keep on searching, " Tom answered. "We have plenty of food andsupplies. I came out equipped for a long voyage, and I'm notdiscouraged yet. Another thing. The ship may have moved on severalfathoms, or even a mile or two, after her last position was takenbefore she went down. In that case she'd be all the harder to find. Andeven granting that she sank where you think she did, the ocean currentssince then may have shifted her. Or she may be covered by sand. "

"Covered by sand!" exclaimed the gold-seeker. 

"Yes, " replied Tom. "The bottom of the ocean is always changing andshifting. Storms produce changes in currents, and currents wash thesand on the bottom in different directions. So that a wreck which mayhave been exposed at one time may be covered a day or so later. We'llhave to keep on searching. I'm not ready to give up. "

"Maybe not. But I am!" snapped out Mr. Hardley. 

"What do you mean?" asked the young inventor. 

"Just what I said, " was the quick answer. "I'm not going to stay downhere, cruising about without knowing where I'm going. It looks to meas if you were hunting for a needle in a haystack. "

"That's just about what we are doing, " and Tom tried to speakgood-naturedly. 

"Then do you know what I think?" the gold-seeker fairly shot forth. 

"Not exactly, " Tom replied. 

"I think that you don't understand your business, Swift!" was theinstant retort. "You pretend to be a navigator, or have men who are, and yet when I give you simple and explicit directions for finding asunken wreck you can't do it, and you cruise all around looking for itlike a dog that has lost the scent! You don't know your business, in myestimation!"

"Well, you are entitled to your opinion, of course, " agreed Tom, andboth Mr. Damon and Ned were surprised to see him so calm. "I admit wehaven't found the wreck, and may not, for some time. "

"Then why don't you admit you're incompetent?" cried Mr. Hardley. 

"I don't see why I should, " said Tom, still keeping calm. "But sinceyou feel that way about it, I think the best thing for us to do is toseparate. "

"What do you mean?" stormed the other. 

"I mean that I will set you ashore at the nearest place, and that allarrangements between us are at an end. "

"All right then! Do it! Do it!" cried Mr. Hardley, shaking his fist, but at no one in particular. "I'm through with you! But this is yourown decision. You broke the contract--I didn't, and I'll not pay a centtoward the expenses of this trip, Swift! Mark my words! I won't pay acent! I'll claim the money I deposited in the bank, and I won't pay acent!"

"I'm not asking you to!" returned Tom, with a smile that showed how hehad himself in command. "You put up a bond, secured by a deposit, toinsure your share of the expenses--yours and Mr. Damon's. Very well, we'll consider that bond canceled. I won't charge you a cent for thistrip. But, mark this, Hardley: What I find from now on, is my own! Youdon't share in it!"

"You mean that--"

"I mean that if I discover the wreck of the Pandora and take the goldfrom her, that it is all my own. I will share it with Mr. Damon, provided he remains with me--"

"Bless my silk hat, Tom, of course I'll stay with you!" broke in theeccentric man. 

"But you don't share with me, " went on the young inventor, lookingsternly at the gold-seeker. "What I find is my own!"

"All right--have it that way!" snapped the adventurer. "Set me ashoreas soon as you can--the sooner the better. I'm sick of the way you dobusiness!"

"Nothing like being honest!" murmured Ned. But, as a matter of fact, hewas glad the separation had come. There had been a strain ever sinceHardley came aboard. Mr. Damon, too, looked relieved, though a trifleworried. He had considerable at stake, and he stood to lose the moneyhe had invested with Dixwell Hardley. 

"This is final, " announced Tom. "If we separate we separate for good, and I'm on my own. And I warn you I'll do my best to discover thatwreck, and I'll keep what I find. "

"Much good may it do you!" sneered the other. "Perhaps two can playthat game. "

No one paid much attention to his words then, but later they wererecalled with significance. 

"Get ready to go up!" Tom called the order to the engine room. 

"Where are you going to land me?" asked Mr. Hardley. "I have a right toknow that?"

"Yes, " conceded Tom, "you have. I'll tell you in a moment. "

He consulted a chart, made a few calculations and then spoke. 

"I shall land you at St. Thomas, " answered the young inventor. "I donot wish to bring my submarine to a place that is too public, as toomany questions may be asked. From St. Thomas you can easily reach PortoRico, and from there you can go anywhere you wish. "

"Very well, " murmured the malcontent. "But I don't consider that I oweyou a cent, and I'm not going to pay you. "

"I wouldn't take your money, " Tom answered. "And don't forget what Isaid--that what I find is my own. "

The other answered nothing. Nor from then on did he hold muchconversation with Tom or any others in the party. He kept to himself, and a day later he was landed, at night, at a dock, and if he said"good-bye" or wished Tom and his friends a safe voyage, they did nothear him. 

They were steaming along on the surface the next day, and at noon thesubmarine suddenly halted. 

"What's on now, Tom?" asked Ned, as he saw his chum prepare to go up ondeck with some of the craft's officers. 

"We're going to 'shoot the sun' again, " was the answer. "I want to makesure that we were right in our former calculations as to the positionof the Pandora. The least error would throw us off. "

Using the sextant and other apparatus, some of which Tom had inventedhimself, the exact position of the submarine was calculated. As thelast figure was set down and compared with their previous location, oneof the men who had been doing the computing gave an exclamation. 

"What's the matter?" asked Tom. 

"Look!" was the answer, and he pointed to the paper. "There's where amistake was made before. We were at least two miles off our course. "

"You don't say so!" exclaimed Tom, and, taking the sheet, he wentrapidly over the results. 

CHAPTER XIX

THE SERPENT WEED

All waited eagerly for Tom Swift to verify the statement of the othermathematician, and the young inventor was not long in doing this, forhe had what is commonly known as a "good head for figures. "

"Yes, I see the mistake, " said Tom. "The wrong logarithm was taken, andof course that threw out all the calculations. I should say we werenearer three miles off our supposed location than two miles. "

"Does that mean, " asked Mr. Damon, "that we began a search for thewreck of the Pandora three miles from the place Hardley told us shewas. "

"That's about it, " Tom said. "No wonder we couldn't find her. "

"What are you going to do?" Ned wanted to know. 

"Get to the right spot as soon as possible and begin the search there, "Tom answered. "You see, before we submerged as nearly as possible atthe place where we thought the Pandora might be on the ocean bottom. From there we began making circles under the sea, enlarging thediameter each circuit. 

"That didn't bring us anywhere, as you all know. Now we will start ourseries of circles with a different point as the center. It will bringus over an entirely different territory of the ocean floor. "

"Just a moment, " said Ned, as the conference was about to break up. "Isit possible, Tom, that in our first circling that we covered any of theground which we may cover now? I mean will the new circles we proposemaking coincide at any place with the previous ones?"

"They won't exactly coincide, " answered the young inventor. "You can'tmake circles coincide unless you use the same center and the sameradius each time. But the two series of circles will intersect atcertain places. "

"I guess intersect is the word I wanted, " admitted Ned. 

"What's the idea?" Tom wanted to know. 

"I'm thinking of Hardley, " answered his chum. "He might assert that wepurposely went to the wrong location with him to begin the search, andif we afterward find the wreck and the gold, he may claim a share. "

"Not much he won't!" cried Tom. 

"Bless my check book, I should say not!" exclaimed Mr. Damon. 

"Hardley broke off relations with us of his own volition, " said Tom. "He 'breached the contract, ' as the lawyers say. It was his own doing. 

"He has put me to considerable expense and trouble, not to say danger. He was aware of that, and yet he refused to pay his share. He accusedme of incompetence. Very well. That presuggested that I must have madean error, and it was on that assumption that he said I did not know mybusiness. Instead of giving me a chance to correct the error, which hedeclared I had made, he quit--cold. Now he is entitled to no furtherconsideration. 

"An error was made--there's no question of that. We are going tocorrect it, and we may find the gold. If we do I shall feel I have alegal and moral right to take all of it I can get. Mr. Hardley, to usea comprehensive, but perhaps not very elegant expression, may go fishfor his share. "

"That's right!" asserted Mr. Damon. 

"I guess you're right, Tom, " declared Ned. "There's only one more thingto be considered. "

"What's that?" asked the young inventor. 

"Why, Hardley himself may find out in some way that we were barking upthe wrong tree, so to speak. That is, learn we started at the wrongnautical point. He may get up another expedition to come and search forthe gold and--"

"Well, he has that right and privilege, " said Tom coolly. "But I don'tbelieve he will. Anyhow, if he does, we have the same chance, and abetter one than he has. We're right here, almost on the ground, youmight say, or we shall be in half an hour. Then we'll begin our search. If he beats us to it, that can't be helped, and we'll be as fair to himas he was to us. This treasure, as I understand it, is available towhoever first finds it, now that the real owners, whoever they were, have given it up. "

"I guess you're right there, " said Mr. Damon. "I'm no sea lawyer, but Ibelieve that in this case finding is keeping. "

"And there isn't one chance in a hundred that Hardley can get anothersubmarine here to start the search, " went on Tom. "Of course it'spossible, but not very probable. "

"He might get an ordinary diving outfit and try, " Ned suggested. 

"Not many ordinary divers would take a chance going down in the opensea to the depth the Pandora is supposed to lie, " Tom said. "But, withall that, we have the advantage of being on the ground, and I'm goingto make use of that advantage right away. "

He gave orders at once for the M. N. 1 to proceed, and this she did onthe surface. It was decided to steam along on the open sea until theexact nautical position desired was reached. This position was the sameMr. Hardley had indicated, but that position was not before attained, owing to an error in the calculations. 

As all know, to get to a certain point on the surface of the ocean, where there is no land to give location, a navigator has to depend onmathematical calculations. The earth's surface is divided by imaginarylines. The lines drawn from the north to the south poles are calledmeridians of longitude. They are marked in degrees, and indicatedistance east or west of the meridian of, say, Greenwich, England, which is taken as one of the centers. The degrees are further dividedinto minutes and seconds, each minute being a sixtieth of a degree andeach second, naturally, the sixtieth of a minute. 

Now, if a navigator had to depend only on the meridian lines indicatingdistance east and west, he might be almost any distance north or southof where he wanted to go. So the earth is further divided into sectionsby other imaginary lines called parallels of latitude. As all know, these indicate the distance north or south of the middle line, or theequator. The equator goes around the earth at the middle, so to speak, running from east to west, or from west to east, according as it islooked at. The meridian of Greenwich may be regarded as a sort of halfequator, running half way around the earth in exactly the oppositedirection, or from north to south. 

The place where any two of these imaginary lines, crossing at rightangles, meet may be exactly determined by the science of navigation. Itis a complicated and difficult science, but by calculating the distanceof the sun above the horizon, sometimes by views of stars, by knowingthe speed of the ship, and by having the exact astronomical time athand, shown on an accurate chronometer, the exact position of a ship atany hour may be determined. 

By this means, if a navigator wants to get to a place where two certainlines cross, indicating an exact spot in the ocean, he is able to doso. He can tell for instance when he has reached the place where theseventy-second degree of longitude, west from Greenwich, meets andcrossed the twentieth parallel of latitude. This spot is just off thenorthern coast of Haiti. Other positions are likewise determined. 

It was after about an hour of rather slow progress on the surface ofthe calm sea, no excess speed being used for fear of over-running themark, that Tom and his associates gathered on deck again to makeanother calculation. 

Long and carefully they worked out their position, and when, at last, the figures had been checked and checked again, to obviate the chanceof another error, the young inventor exclaimed:

"Well, we're here!"

"Really?" cried Ned. 

"No doubt of it, " said his chum. 

"Bless my doormat!" cried Mr. Damon. "And do you mean to say, TomSwift, that if we submerge now we'll be exactly where the Pandora lies, a wreck on the floor of the ocean. 

"I mean to say that we're at exactly the spot Where Hardley said shewent down, " corrected Tom, "and we weren't there before--that is not sothat we actually knew it. Now we are, and we're going down. But thatdoesn't guarantee that we'll find the wreck. She may have shifted, orbe covered with sand. All that I said before in reference to thedifficulty in locating something under the surface of the sea stillholds good. "

Once more, to make very certain there was no error, the figures weregone over, Then, as one result checked the other, Tom put away thepapers, the nautical almanac, and said:

"Let's go!"

Slowly the tanks of the M. N. 1 began to fill. It was decided to lether sink straight down, instead of descending by means of the verticalrudders. In that way it was hoped to land her as nearly as possible onthe exact spot where the Pandora was supposed to be. 

"How deep will it be, Tom?" asked Ned, as he stood beside his chum inthe forward observation cabin and watched the needle of the gauge movehigher and higher. 

"About six hundred feet, I judge, going by the character of the seabottom around here. Certainly not more than eight hundred I shouldsay. " And Tom was right. At seven hundred and eighty-six feet the gaugestopped moving, and a slight jar told all on board that the submarinewas again on the ocean floor. 

"Now to look for the wreck!" exclaimed Tom. "And it will be a realsearch this time. We know we are starting right. "

"Are you going to put on diving suits and walk around looking for her?"asked Ned. 

"No, that would take too long, " answered Tom. "We'll just cruise about, beginning with small circles and gradually enlarging them, spiralfashion. We'll have to go up a few feet to get off the bottom. "

As Tom was about to give this order Ned looked from the glass windows. The powerful searchlight had been switched on and its gleamsilluminated the ocean in the immediate vicinity of the craft. 

As was generally the case, the light attracted hundreds of fish ofvarious shapes, sizes, and, since the waters were tropical, beautifulcolors. They swarmed in front of the glass windows, and Ned was glad tonote that there were no large sea creatures, like horse mackerel or bigsharks. Somehow or other, Ned had a horror of big fish. There weresharks in the warm waters, he well knew, but he hoped they would keepaway, even though he did not have to encounter any in the diving suit. 

Slowly the submarine began to move. And as she was being elevatedslightly above the ocean bed, to enable her to proceed, Ned uttered anexclamation and pointed to the windows. 

"Look, Tom!" he cried. 

"What is it?" the young inventor asked. 

"Snakes!" whispered his chum. "Millions of 'em! Out there in the water!Look how they're writhing about!"

Tom Swift laughed. 

"Those aren't snakes!" he said. "That's serpent grass--a form of verylong seaweed which grows on certain bottoms. It attains a length offifty feet sometimes, and the serpent weed looks a good deal like anest of snakes. That's how it got its name. I didn't know there was anyhere. But we must have dropped down into a bed of it. "

"Any danger?" asked Ned. 

"Not that I know of, only it may make it more difficult for us to seethe wreck of the Pandora. "

As Tom turned to leave the cabin the submarine suddenly ceased moving. And she came to a gradual stop as though she had been "snubbed" by amooring line. 

"I wonder what's the matter!" exclaimed Tom. "We can't have come uponthe wreck so soon. "

At that moment a man entered the cabin. 

"Trouble, Mr. Swift!" he reported. 

"What kind?" asked Tom. 

"Our propellers are tangled with a mass of serpent weed, " was theanswer. "They're both fouled, and we can't budge. "

"Bless my anchor chain!" ejaculated Mr. Damon. "Stuck again!"

CHAPTER XX

THE DEVIL FISH

It was true. The long sinuous strands of ocean grass, known under thename of "serpent weed, " had caught around the whirling propellers andthere had been wound and twisted very tightly. Just as sometimes thestern line gets so tightly twisted around a motor boat propeller as torequire hours of work with an axe to free it, the seaweed was twistedaround the blades of the M. N. 1. 

Slowly the undersea craft came to a stop, and there she remained, floating freely enough, but a few feet above the bottom of the ocean. There was a look of alarm on the faces of Ned and Mr. Damon, but TomSwift smiled. 

"This is annoying, and may cause us delay, " he announced, "but there isno danger. "

"How are we to get free from the weed?" asked Mr. Damon. "We can't moveif it's wound around our propellers, can we?"

"Not very well, " Tom answered. "But all that will have to be done willbe for some of us to put on diving suits, go out and chop the strandsof weed away. We can do it more easily than could an ordinary vessel, for they would have to go into dry dock for the purpose. I think I'llgo out myself. I want to look around a little. "

"I'll go with you, " said Ned. "As long as we haven't seen any sharks Idon't mind. "

"Nor gigantic starfish, either, " added Tom with a smile, and Ned noddedin agreement. 

"We might try reversing the propellers, " suggested the man from theengine room, who had come in with the information about the serpentweed. "The chief didn't like to try that. We saw the weed from ourobservation windows and stopped as soon as we felt we had fouled it. "

"That was right, " commended Tom. "Well, try reversing. It can't do anyharm, and it may make it easier for us to free the propellers when wego out. "

He went to the engine room himself to see that everything was properlyattended to. Slowly the motors were reversed, and only a slight currentwas given them, as, with the resistance of the tightly wound weed, toopowerful a force might burn out the insulation. 

Slowly the starting lever was thrown over. There was a low humming andwhining as the current jumped from the batteries, and a slightvibration of the craft. Tom looked at the movable pointer which showedthe speed and direction of the propellers. The hand oscillatedslightly and then stopped. 

"Shut off the current!" cried Tom. "It's of no use. The propellers areheld as tight as a drum! We've got to go out and cut loose the serpentweed!"

The experiment of reversing the propellers had failed. But still Tomdid not believe his craft was in danger. He gave orders for the engineroom force to stand by and then arranged for himself, Ned, and Koku togo outside in diving dress and cut the weed off the shafts. There weretwin propellers on the submarine, each revolving independently byseparate motors, and each capable of being sent in forward or reversedirection. 

"Start the engines as soon as we give the signal, " Tom told themachinist. "Two knocks on the hull with an axe will mean go ahead, andthree will mean reverse. "

"I understand, " said Weyth, the machinist. "But stand away from thepropellers after you give the signal. I'll give you three minutes tomove clear. "

"That will be enough, " Tom said. "But better make it half speed ineither case. My idea is that if we can partly cut the weed off, starting the propellers, either forward or in reverse, will finish thetrick. "

"It may, " agreed Weyth. 

Armed with axes and sharp steel bars, Tom, Ned, and Koku were soonready to step outside the submarine. 

They entered the diving chamber. In the usual manner water wasadmitted, and, when the pressure was equalized, the outer door wasopened and they walked out on the floor of the ocean, the submarinehaving been allowed to settle down again on the bottom of the Atlantic. 

The powerful searchlight had been turned so that the beams werediffused toward the stern. In addition to this Tom and his twocompanions carried, attached to their suits, small, but brilliant, electric torches. Of course they had their air tanks with them, andalso the telephones, by means of which they could communicate with oneanother. 

As they emerged into the warm waters surrounding the submarine theydisturbed thousands of small fish which were feeding all about. Likeocean swallows, the creatures scattered in all directions, some evenbrushing the divers as they slowly made their way toward the stern ofthe craft. 

"Nice place here, " said Ned to Tom, as they walked along, Koku comingjust behind them. 

"Yes. If we could take this up above and exhibit it in some city parkit would make a hit all right, " answered the young inventor. 

They were walking on the pure, white, sandy floor of the ocean, someseven hundred feet below the surface, protected from the awful pressureof the water by means of the specially constructed suits which Tom hadinvented. About them, growing as if in a garden, were great masses ofcoral, some so thin and sinuous that it waved as do palms and ferns inthe open air. Other coral was in great rock masses. 

Then, too, there was the unpleasant serpent weed. It did not grow allover, but in patches here and there, as rank grass springs up in ameadow. 

And it had been the misfortune of the M. N. 1 that she poked her tailinto a mass of this long, tough grass, which was now wound about herpropellers. 

In addition to the many wonderful vegetable forms that grew on theocean floor, some rivalling in beauty the orchids of the tropics, andalmost as delicate, there were the fishes, which darted to and fro, nowswiftly swimming beneath some coral arch, and again poising around somemass of waving sea fronds. 

"Well, let's get busy, " called Tom to Ned through the telephone. "Wewant to free the propellers and find the wreck of the Pandora. She maybe a hundred feet from us, or a mile away, and in that case it's goingto take longer to locate her. "

Together they walked to the stern of the disabled craft. One look atthe propeller shafts, the examination being made by the diffused glowfrom the searchlight, as well as from the electric torches carried, showed that the diagnosis of the trouble was correct. 

Wound around both propellers was a mass of the serpent weed, tightlybound because the machinery had whirled it around and around after thegrass had once been caught. It was almost as bad as though manila cablehad been thus accidentally fastened. 

"Well, might as well begin to cut it loose, " said Tom to hiscompanions. "Koku, you take the port propeller, and Ned and I will workon the other. You ought to be able to beat us at this game. "

"Me do, " said the giant, as he got his axe ready for work. 

Blows struck in water lose much of their force. This can easily beproved by filling a bathtub full of water, rolling up the sleeves, andthen taking a hammer in the hand, immersing it fully, and trying tostrike some object held in the other hand. The water hampers the blows. 

It was this way with Tom and his friends. Nearly half of Koku's greatstrength was wasted. But they knew they could take their time, thoughthey did not want to waste many hours. 

The streamers of weed were like strands of tightly wound rope, andthis, under certain circumstances, acquires almost the density of wood. Tom and Ned, working together, had managed to chop a little off theirpropeller shaft, and Koku had done somewhat better with his task, whenNed became aware of a shadow passing above him. 

Instinctively he looked up, and as he did so he could not repress astart of horror. Tom, too, as well as Koku, saw the menacing shadow. Ned grasped more tightly his sharp, steel bar and spoke through thetelephone to his companions. 

"Devil fish!" he said. "The devil fish are after us. "

CHAPTER XXI

A WAR REMINDER

To a large number of people the name devil fish brings to mind aconception of an octopus, squid, cuttle fish, or a member of thatspecies. This is, however, a mistake. 

The true devil fish of the tropics is a member of the sting ray family, and the common name it bears is given to it because of two prongs, orhorns, which project just in front of its mouth. His Satanic Majestyis popularly supposed to have horns, together with a tail, hoofs andother appendages, and the horns of this sting ray fish are what give itthe name it bears. 

The devil fish, some specimens of which grow to the weight of a ton andmeasure fifteen feet from wing tip to wing tip, are armed with a longtail, terminating in a tough, horny substance, like many of the rayfamily members. This horn-tipped tail, lashing about in the water, becomes a terrible weapon of defense. Possibly it is used for offense, as the devil fish feeds on small sea animals, sweeping them into itsmouth by movements of the horns mentioned. These horns, swirled aboutin the water, create a sort of suction current, and on that the foodfishes are borne into the maw of the gigantic creature. 

A whale rushes through a school of small sea animals with open mouth, takes in a great quantity of water, and the fringe of whalebone acts asa strainer, letting out the water and retaining the food. In likemanner the devil fish feeds, except that it has no whalebone. Its"horns" help it to get a meal. 

The "wing tips" of the devil fish have been spoken of. They are notreally wings, though when one of these fish breaks water and shootsthrough the air, it appears to be flying. The wings are merely fins, enormously enlarged, and these give the fish its great size, ratherthan does the body itself. It is the whipping spike-armed tail of thedevil fish that is to be feared, aside from the fact that the rush of amonster might swamp a small boat. 

It was two or three of these devil fish that were now floating in thewater above Tom and his companions, who were grouped about the stern ofthe disabled submarine. 

"They won't attack us unless we disturb them, " said Tom through histelephone, speaking to Ned and Koku. "Keep still and they'll swim away. I guess they're trying to find out what new kind of fish our boat is. "

All might have gone well had not Koku acted precipitately. One of thedevil fish, the smallest of the trio, measuring about ten feet across, swam down near the giant. It was an uncanny looking creature, with itshorns swirling about in the water and its bone-tipped tail lashing toand fro like a venomous serpent. 

"Look out!" cried Tom. But he was too late. Koku raised his axe andstruck with all his force at the sea beast. He hit it a glancing blow, not enough to kill it, but to wound it, and immediately the sea wascrimsoned with blood. 

The devil fish was able to observe under water better than its humanenemies, and it was in no doubt as to its assailant. In an instant itattacked the giant, seeking to pierce him with the deadly tail. 

These tails are not only armed with a tip of horn-like hardness, theyare also poisonous, and their penetrating power is great. Fishermenhave sometimes caught small sting rays, which are a sort of devil fish. Lashing about in the bottom of a boat a sting ray can send its tail tipthrough the sole of a heavy boot and inflict a painful wound which maycause serious results. 

The beast Koku had wounded was trying to sting the giant, and thelatter, aware of his peril, was striking out with the axe. 

"Look out, Tom!" called Ned through his telephone, as he saw one of thetwo unwounded devil fish swirl down toward the young inventor. Tomlooked up, saw the big, horrible shape above him, and jabbed it withthe sharp, steel bar. He inflicted a wound which added further to thecrimson tinge in the sea, and that fish now attacked Tom Swift. 

In another instant all three divers were fighting the terriblecreatures, that, knowing by instinct they were in danger, were usingthe weapon with which nature had provided them. They lashed about withtheir sharp-pointed tails, and more than one blow fell on the suits ofthe divers. 

Had there been the least penetration, of course almost instant deathwould have followed. For the sea, at that depth and pressure, enteringthe suits would have ended life suddenly. But Tom had seen to it thatthe suits were well made and strong, with a lining of steel. Andhowever great a thickness of leather the devil fish could send hissting through, it could not overcome steel. 

There was danger, though, that the slender tip might slip through thesteel bars across the windows in the helmets and shatter the glass. Andthat would be as great a danger as if the suits themselves werepenetrated. 

"We've got to fight 'em!" gasped Tom through his instrument, and, seeing his chance, he gave another jab to the devil fish attacking him. Koku, too, was standing up well under the attack of the monster he hadfirst wounded. Ned, watching his chance, got in several blows, first atone and then at the other of the huge creatures. The third devil fish, which had not been wounded, had disappeared. Finally Koku, with adesperate blow, succeeded in severing the tail from the beast attackinghim, and that battle was over. 

As if realizing that it had lost its power to harm, the devil fish atonce swam off, grievously wounded. Then Koku turned his attention toTom's enemy. Ned, too, lent his aid, and they succeeded in wounding thecreature in several places, so that it sank to the bottom of the seaand lay there gasping. 

Slowly the red waters cleared and the three divers, exhausted by thefight, could view the remaining creature--the one wounded to death. Itwas the largest of the three, and truly it was a monster. But it waspast the power to harm, and in a few minutes an under sea currentcarried it slowly away. Later it would float, doubtless, or be devouredby sharks or other ocean pirates before reaching the surface. 

"Thank goodness that's over!" said Ned to Tom. "I don't want to see anymore of them. "

"There may be more about, " Tom said. "We'd better keep watch. Ned, youlay off and Koku and I will work on the propellers. Then you can takeyour turn. "

This plan was followed. Koku, not being tired, did not need to stopworking, and he was the first to free his shaft partially of theentangling weeds. Tom rapped a signal, the blades were slowly revolvedand then came free. A little later the second was in like condition. 

"Now we can move!" said Tom, as they started back toward the divingchamber. "I hope we don't run into another patch of that serpent grass. "

"Nor see any more devil fish, " added Ned. 

"Same here!" echoed the young inventor. 

Luck seemed to be with the gold-seekers after that, for as thesubmarine was sent ahead, no more of the long, entangling grass wasencountered. 

The search for the sunken Pandora was now begun in earnest, since theywere positive that they were at the right spot. 

No immediate sign of her was found. But Tom and his friends hardlyexpected to be as lucky as that. They were willing to make a search. For, as Tom had said, a current might have shifted the position of thewreck. 

They followed the plan of moving about in ever-widening circles. Onlyin this way could they successfully cover the ground. It was the thirdday after the encounter with the devil fish that Tom, Ned and Mr. Damonwere in the forward observation cabin. The eccentric man suddenlypointed to something visible from the starboard window. 

"There's a wreck, Tom!" he cried. "Maybe it's the Pandora!"

Tom and the others hurried to Mr. Damon's side and peered out into thesea, illuminated by the great searchlight. 

"That isn't the Pandora!" said the young inventor. 

"But it's a wreck, isn't it?" asked Ned. 

"Yes, it's a sunken vessel, all right, " Tom assented. "But it's areminder of the Great War. Look! She has been blown up by a torpedo!"

CHAPTER XXII

STUDYING CURRENTS

There was no question about Tom's statement. They had approached closeto the side of a small, sunken and wrecked steamer, and in her side wastorn a great hole. In the light from the submarine it could be seenthat the plates bent inward, indicating that the explosion was fromoutside. 

"What are you going to do, Tom?" asked Ned, as he saw his chum move theengine room telegraph signal to the stop position. 

"Going to investigate, " was the answer. "We might as well take thetime. We may learn something of value. "

"Do you think there is any treasure in her?" asked Mr. Damon. 

"There might be, " answered Tom. "We'll put on the diving suits and gooutside. "

"I hope there aren't any devil fish, " remarked Ned. 

"Same here, " Tom agreed. "But I don't believe we'll meet with any. Willyou take a chance, Ned?"

"I surely will! I'd like to find out what sort of ship that is--orrather, was, for there isn't much left of her. "

He spoke truly, for indeed the torpedo had created fearful havoc. Thefull extent of it was not observed until Tom, Ned, Koku and two of thecrew had put on diving suits and approached the hulk. She lay on herside on the sandy bottom, heeled over somewhat, and when theinvestigators had walked around her, as they were able to do, they sawa second, and even larger hole in the opposite side. 

"Two submarines must have attacked her, " said Ned, speaking through histelephone to Tom. 

"Either that, or else one sent a torpedo into her, dived, came up onthe other side and sent another. "

"Well, let's see if she has any treasure aboard, " Ned proposed. "Wouldn't it be queer if we should discover two treasure ships?"

"More queer than likely, " Tom answered. "We've got to be careful goinginside her. "

"Why?" asked Ned. "Do you think we'll set off a hidden mine?"

"No, but part of the wreckage might be loosened if we climbed over it, and we might fall and be pinned down. I've read of divers being caughtthat way. We must be careful. "

"Do you suppose a German sub did this?" Ned asked. 

"I think very likely, " Tom answered. "Maybe we can tell if we candiscover the nationality of this craft. "

They made their way to a position just outside the gaping hole in thestarboard side of the craft. Evidently; it was, or had been, a trampsteamer, and the torpedo hole on her starboard side was aboutamidships. She must have filled and sunk quickly with two such greatholes torn in her. 

Standing near the wound in the steel skin, Tom and his companions triedto see what was inside. Their portable torches did not give lightenough to make out clearly the character of the cargo carried, and itwas too risky to venture into the mass of wreckage that must be theresult of the explosion of the torpedo. 

"Let's try the other side, " suggested Tom, and they moved around thestern of the craft. When they reached the place where the name wasvisible Tom raised his electric torch and, in the glow of it, they allread the painted inscription, Blakesly, New York. 

"That's the vessel that disappeared so mysteriously!" exclaimed Ned, speaking through his instrument. "I remember reading about her. Shesailed from New York for Brest, but was never heard of. At last wehave solved the mystery!"

"Yes, " agreed Tom, "but without much avail. We are too late to do anygood. "

"Not one of her crew or passengers was ever heard of, " went on Ned. "Itwas surmised that a German sub attacked her, and that she was eithersunk 'without a trace' or else her survivors were taken aboard thesubmarine and carried to Germany. "

"Perhaps we may learn something to that end, " said Tom, as they gotaround to the other side. The hole there was not quite so big, and asit seemed safe to enter Tom and Ned prepared to do so, the othersremaining outside to give them aid in case of necessity. 

It was comparatively easy to enter by this wound in the side of theBlakesly, and, proceeding cautiously, Tom and Ned made the attempt. They found they could not penetrate far, however, because of the massof wreckage scattered about by the explosion. They could see throughinto the engine room, and there the machinery was in every stage ofdestruction, while below the boilers were disrupted. 

"She must have gone down in a hurry, " remarked Tom. 

"Yes, and with part of her crew, " added Ned, as he pointed to where aheap of white bones lay--grim reminders of the Great War. The engineroom forces had been trapped and carried down to death. 

"I wonder if, by any chance, she did carry gold, " suggested Ned. 

"It wouldn't be down here if she did, " asserted Tom. "And if she was atreasure ship, and the huns knew it, they wouldn't leave any on board. "

"That's just it, " went on his chum. "They may not have known it, andhave ripped a couple of torpedoes at her without any warning. It wouldbe just like them. "

"Granted, " assented the young inventor. "Well, we can take another lookaround outside. Maybe there's a way of getting on deck, and so goingbelow from there. I wouldn't chance it from here. "

"Me, either, " Ned answered. 

They looked around a little more, a further view showing how dangerousit would be to attempt to enter the shattered engine room, where amisstep or a sudden change of equilibrium might cause disaster. 

"Nothing there, " Tom reported to Koku and the others waiting for himoutside. 

"Rope by up go him stern, " said Koku, motioning toward the after partof the wreck. 

"What does he mean?" Tom asked one of his crew. 

"Oh, he went walking around outside while you were inside, sir, " wasthe answer, "and he seems to have found a rope ladder or a chain, orsomething hanging from the stern. "

"Let's go and see it, " proposed Tom. "I've been wondering if we couldget on deck. "

"Are we going to spend much time here?" Ned wanted to know. 

"Not much longer, " Tom replied. "Why?"

"Well, I was thinking we'd better keep on looking for the Pandora. Idon't want that fellow Hardley to get the bulge on us. "

"Oh, " laughed Tom, "he isn't likely to. But we won't take any chances. As soon as I see if we can learn anything that may be useful from thishulk, we'll go back and start on our way again. "

The party of divers, led by Koku, who wanted to point out hisdiscovery, walked slowly along on the bottom of the sea, around to thestern of the Blakesly. 

"See!" said the giant through his telephone, and, as the instrumentswere interchanging, all heard him. 

Koku pointed to several ropes and chains that were dangling from thestern of the sunken craft. Evidently they had been used by those whosought to escape from the sinking ship after she had been torpedoed. 

"Wait a minute!" Tom telephoned, as he saw Koku grasp a chain, evidently with the object of hoisting himself up on deck by the simplemethod of going up hand over hand. He could easily do this by adjustingthe air pressure inside his diving suit to make himself more buoyant. 

"Koku go up!" said the giant. 

"Better make sure that chain will hold you, " cautioned Tom. The giantproved it by several powerful tugs, and then began to raise himselffrom the sandy bed of the ocean. 

"Well, if it will hold him it will hold us, " asserted Tom. "Ned, we'llgo up. You two stay here, " he said to the members of his crew. "Wecan't take any chances of all getting in the same accident if thereshould be one. "

A little later Tom, Ned, and Koku stood on the deck of the sunkencraft. Much of what she had carried had been swept off, either in theexplosions or by reason of currents generated by storms since thefatality. But what seemed to be the cabin of the captain, or of some ofthe officers, was in plain view and easy of access from this level. 

"Let's take a look!" said Tom. 

Ned followed him to the door. It had been torn off, and inside was atable made fast to the floor. From the appearance of the room it wasevidently the compartment where the charts were kept, and where thecaptain or his officers worked out the reckoning. But it wastenantless now, and if any maps or papers had been out they weredissolved in sea water some time since. 

"Let's see if we can find the log book, " proposed Ned. 

"Good idea, " assented Tom. 

Using the iron bars they carried, they forced open some of the lockers, but aside from pulp, which might have been charts or almost anything inthe way of documents, nothing was come upon that would tell anything. 

"Unless the log book was kept in a water-tight case the ink would allrun, once it was wet, " Tom said, when they were about ready to give uptheir search. 

"I suppose so, " agreed Ned. "But I would like to know whether shecarried treasure. "

However, it was impossible to discover this, and dangerous to look toofar into the interior. So Tom and his party were forced to leavewithout discovering the secret of the Blakesly, if she possessed one. 

Later, however, when they had returned home, Tom and Ned made a reportof what they had seen, and so cleared up the fate of the vessel. Theylearned that she carried no treasure, and they were glad they had notrisked their lives looking for it. What had happened to her crew wasnever learned. 

They returned to the submarine and told what they had viewed. Andthen, with a last look at the wreck, they passed on in their search forthe Pandora. 

Several fruitless days followed, and though a careful search was madein the vicinity of the true location given by Mr. Hardley, nothing wasdiscovered. 

"How long will you keep at it before you give up?" asked Ned oneevening, as they went aloft to replenish the air tanks and charge thebatteries. 

"Oh, another week, anyhow. I have a new theory, Ned. "

"What's that?"

"Ocean currents. I believe there are powerful currents in these waters, and that they may have shifted the position of the Pandoraconsiderably. I'm going to study the currents. "

"Good idea!" cried his chum. 

And the next day they began observations which were destined to havesurprising results. 

CHAPTER XXIII

AN UNDERSEA COLLISION

Under the warm, tropical sun the submarine floated idly on the surfaceof the calm sea. She had risen from the depths, her hatches had beenopened, and now the crew, the owner, and his guests were breathing freeair. The men were taking advantage of the period above water to washout some of their garments, hanging them on improvised lines stretchedalong the deck. For Tom Swift had said he would remain above thesurface all day. 

Some slight repairs were necessary to the electric motors, and theycould be made only when the craft was on the open sea. This, too, wouldafford a chance to recharge the batteries and repair one of them. 

For the time being the search under the sea for the treasure shipPandora had been abandoned. But it was not given up entirely. As Tomhad announced to Ned, a new theory would be worked out. So far, cruising about in the place where the fillibuster ship was supposed tohave gone down had resulted in nothing. 

Mr. Damon, who had been below, shaving, came up on deck to see Tom andNed tossing into the water large pieces of cork taken from spare lifepreservers. Tom tossed his in from one side of the deck, and Ned fromthe other. Then, as the eccentric man listened, he heard Tom say:

"I think mine is going to beat yours, Ned!"

"Then you've got another guess coming, " declared the young financialman. "Mine's going twice as fast as yours is now, though yours didstart off better. "

"Bless my beefsteak!" exclaimed Mr. Damon, "what's this, Tom Swift? Ithought we came on a treasure-hunting expedition, and here I find youand Ned playing some childish game! I hope you aren't laying any wagerson it!" Mr. Damon did not approve of gambling in any form. 

"No, we aren't doing that, " laughed Tom, as he dropped another bit ofcork into the ocean. 

"We are trying to arrive at some valuable scientific facts, Mr. Damon. "

"Scientific facts--that childish play?"

"It isn't play, " said Tom, turning to remark to Ned: "I think we'vesettled it. The current has a decided twist to the north. "

"Yes, " agreed his chum. "You were right, Tom. "

"If you don't mind explaining, " began Mr. Damon, "I should like toknow--"

"We're trying to determine the drift of the ocean currents in thislocality, " Tom said. 

"So we'll know better where to look for the Pandora, " added Ned. 

"Oh, so you haven't given up the hunt, then?" asked the eccentric man. 

"By no means!" exclaimed Tom. "It's this way, Mr. Damon. We went downat as nearly the exact spot where the treasure-ship was sunk as wecould determine by means of calculations. She wasn't there, nor couldwe find her by going around in circles. Then it occurred to me, and tosome of the others also, including Ned, that the ocean currents mighthave shifted the position of the craft after she had sunk. There arepowerful currents in the ocean, as you know, the Gulf Stream being oneand the Japan Current another. Now there may be smaller ones in thesewaters that would produce a local effect. 

"So Ned and I have been dropping bits of cork of different shapes intothe water and watching which way they drifted. Our conclusion is thatthe currents here have a decided set toward the north. "

"And what does that indicate?" asked Mr. Damon. 

"That we should have begun our search some distance north of the pointwhere we actually did begin, " answered Tom. 

"How far north?" the eccentric man wanted to know. 

"That's just what we have yet to ascertain, " the young inventorreplied. "So far our conclusions have been arrived at merely fromsurface data. Now we've got to go below. "

"And play with bits of cork there?" asked Mr. Damon. 

"No, we'll have to use something heavier than cork, " Tom said. "We'llprobably use weights, and see how far they move along the bottom in agiven time. But we have established one thing, and I begin to havehopes now that we may locate the Pandora. "

The remainder of the day was spent in various ways aboard thesubmarine, which continued to float idly on the waves. 

It was toward evening, when the red, setting sun gave promise of a fairday on the morrow that the submarine's deck lookout approached Tom, and, waiting until he had the attention of the young inventor, reported:

"There is a smudge of smoke dead astern, sir. "

"Is there?" exclaimed Tom. "Let me have the glasses. "

He took them from the lookout and made a long and careful study of theslight, black smudge which was low down on the horizon. 

"A steamer, " decided Tom, "and coming on fast. We'll go below!" headded. "Please make ready, " he said to the officer in charge. 

"What's up, Tom?" asked Ned, as his chum gathered up the papers onwhich he had been figuring on an improvised table set under an awningon deck. 

"Some craft is coming, and I'd just as soon she wouldn't sight us, " wasthe answer. 

"You mean she might interfere with our search for the treasure-ship?"

"Not exactly. But she might want to start a search on her own account, and there's no use of giving our presence away, or letting them guessat what might be right conclusions as to the location of the Pandora. "

"But, Tom, no one knows of the wreck! At least, no one is supposed tobut our party and--"

"Hardley. Exactly!" exclaimed Tom, as he saw his chum about to utterthe name. 

"And you think he is coming?"

"I shouldn't be a bit surprised. Anyhow, it's just as easy for us tosubmerge and let them do their own guessing. I was going down soon, anyhow, and another hour won't make any difference. Here, take a look, if you like. "

Ned peered through the glasses, but his eyes not being trained in seainterpretation, as were Tom's, he could make out nothing but a blacksmudge, now larger and darker. 

"It might be a cloud for all I can tell, " he said, as he handed thebinoculars back to Tom. 

"Well, it's a steamer all right, and she's under forced draft, too, ifI'm any judge. We'll go below before she sights us. "

"Perhaps she has already, " suggested Ned, as the crew began clearingthe submarine's deck. 

"No, we lie too low in the water for that. Well, now we can start ourunderwater observations of current trends. "

It did not take long, once she started, for the M. N. 1 to go down. Just as the sun sank below the horizon, and while the smudge of smokewas becoming more distinct, the waves closed over the steel deck of thesubmarine. Half an hour later she was nearly a quarter of a mile belowthe surface, resting on the bottom of the sea again. 

On this trip Tom did not go to any such depths as he did on his formervoyage in the Advance. Not that the reconstructed submarine was notcapable of it, for she was even stronger than when first built. But thewreck they were seeking did not lie in so great a depth of water, andthere was no need of running useless risks. 

"Well, " remarked Ned, when they came to a stop, "I don't believe anyone will find us here. "

"Not an ordinary diver, at any rate, " Tom agreed. "And after supper I'mgoing to have another go at the currents. "

The meal was served as usual, and a very good one it was, consideringthe fact that not as many supplies could be carried in the ratherlimited space of a submarine as may be transported in an ocean liner. Then, as it was still early, Tom and Ned, with the help of some of theofficers, got ready for a new series of experiments. 

The big searchlight was set aglow, and, going out on the ocean bed indiving suits, Tom and his friends dropped on the sand various weightedobjects. 

These were made in the shape of the hull of a steamer, and inproportion. Once they were on the sand, an iron rod was thrust into theocean bed near each object. 

"Now, " remarked Tom, as they all went into the submarine again, "we'lllet them drift until morning. Then we'll make new calculations. I thinkwe'll arrive at some results, too. "

"Just what are you aiming to do?" asked Mr. Damon. 

"See how far each one of those weighted objects drifts, " Tom replied. "We have planted them in different spots on the ocean bed. Some willdrift farther than others. Some are large and some are small. Bystriking an average we may be able to tell about how far from thesupposed location of the Pandora we ought to look for her. "

The night passed without incident and as calmly and peacefully asthough they were all in some deep cave beneath a great mountain. In themorning after breakfast Tom and his friends went outside the submarineagain and noted the weighted objects. Some had drifted farther thanothers. Measurements were carefully taken, and then began a series ofintricate calculations. 

The distance each object had drifted from the iron bar marker wasconsidered in reference to its size and shape. Also the elapsed timewas computed. The results were then compared, an average struck, andthen the size and weight of the Pandora, as nearly as they could beascertained, were figured. The resultant figures were compared, and Tomannounced:

"If we are anywhere near right in our conclusions we ought to begin tosearch for the treasure-ship about four miles from here, in a generalnortherly direction. "

"Do you think she has drifted that far?" asked Ned. 

"Fully that, " Tom answered. "That is only our starting point--thecenter of a new series of circles. "

A moment later Tom gave the order to rise to the surface. 

"Going up?" exclaimed Ned. 

"Yes, I want to make some observations to determine our exact nauticalposition. "

"But suppose that other steam--"

"We'll have to take a chance. We can submerge quickly if we have to, and I don't believe she's able to do that. "

An observation was taken through the conning tower, however, before theM. N. 1 went all the way up, and there was not a sail nor a smudge ofsmoke on the horizon. 

"So far so good, " murmured Tom. "Now we'll 'shoot the sun, ' and afterwe submerge we'll begin our search in earnest. I think we are on theright track now. "

The observation was made at noon, and then, as nearly as possible, thesubmarine was moved to a position approximately four miles north of theplace where the Pandora was supposed to have foundered. 

"Down we go!" exclaimed Tom, and down they went. 

The depth gauge showed more than a thousand feet below the surface whenthe M. N. 1 came to rest. This was deeper than Tom had thought to findthe wreck, but his craft was able to withstand the pressure. A briefwait, to make sure that everything was in readiness, was followed bythe beginning of the new search. In gradually widening circles thecraft moved about under water. 

If the voyagers had expected to locate at once the treasure-ship, theywould have been disappointed. For the first day gave no signs. But Tomhad not promised immediate results, and no one gave up hope. 

It was shortly after noon on the second day of the search at the newlocation that, as they were proceeding at rather greater speed thanusual, something happened. 

Ned had just suggested that he and Tom might go out and try thecurrent-setting experiments again, when suddenly they were both thrownoff their feet by a terrific jar and concussion. The M. N. 1 seemed toreel back, as if from a great blow. 

"Bless my safety razor!" cried Mr. Damon, "what's the matter, Tom?"

"I think we've had a collision!" was the answer. "I must see how badlywe are damaged!"

CHAPTER XXIV

THE TREASURE-SHIP

Sudden and forceful had been the underwater collision in which the M. N. 1 had participated. Either the lookout, aided though he was by thefocused rays of the great searchlight, had failed to notice someobstruction in time to signal to avoid it, or there was an errorsomewhere else. At any rate the submarine had rammed something--what itwas remained to be discovered. 

"Bless my shotgun, " cried Mr. Damon, "perhaps it was one of those bigwhales, Ned!"

"It didn't feel like a whale, " answered the young financial man. 

"And it wasn't!" declared Tom, who was hastening to the engine room. "It was too solid for that. "

Following the collision there had been considerable confusion aboardthe vessel. But discipline prevailed, and now it was necessary todetermine the extent of the damage. This, Tom and his officers and crewproceeded to do. 

There were automatic devices in the various control cabins, as well asin the main engine room, which told instantly if a leak had been sprungin any part of the craft. In that serious difficulty automatic pumps, controlled by an electrical device, at once began forcing out thewater. Other apparatus rushed a supply of compressed air to the floodedcompartment in order to hold out the water if possible. For furthersecurity the submarine was divided into different compartments, as aremost ships in these days. The puncturing or flooding of one did notnecessarily mean the foundering of the craft, or, in the case of asubmarine, prevent her rising. 

But Tom had sensed that the collision was almost a head-on one, and inthat case it was likely that the plates might have started in severalsections at once. This he wanted to discover, and take means of safetyaccordingly. 

"How do you make it, Mr. Nelson?" cried the young inventor to thecaptain in the engine room. 

"Only a slight leak in compartment B 2, " he answered, as Tom's eyesrapidly scanned the tell-tale gauges. "The pumps and air are takingcare of that. "

"Good!" cried Tom. "It doesn't seem possible that there isn't more thanthat, though. We struck a terrible blow. "

"Yes, but a glancing one, I think, sir. "

"Send for the lookout, " ordered Tom. "I can't under stand why he didn'tsee whatever we've hit in time to avoid it. "

The lookout came in, very much frightened, it must be admitted. Onlyby a narrow margin had all escaped death. 

"It was impossible to see it, Mr. Swift, " he said. "We had a clearcourse, not a thing in sight. The bottom was white sand, and I couldalmost count the fishes. All at once there was a big swirl of waterthat threw our nose around, and before I could signal to slow down orreverse we were right into her. "

"Into what?" asked Tom. 

"Some sort of wreck, I took it to be. I shoved the wheel hard over asquickly as I could, and we struck only a glancing blow. "

"That's good, " murmured Tom. "I thought that must have been theexplanation. But what's that about a sudden swirl of water?"

"It seemed to me like a change in the current, " the lookout answered. "It threw us right over against the wreck. "

"I can very easily imagine something like that happening, " admittedTom. "Well, as long as we're not badly damaged I think we'll go outsideand take a look. If we hit a wreck--"

"Bless my looking glass!" cried Mr. Damon, "it may be the Pandora, Tom. "

"That's too good to be true!" cried Ned. "Anyhow, let's get out andtake a look. "

Tom first made sure that the slight leak was not likely to increase, and then arrangements were made for himself, Ned, Koku, and some of theothers to go outside in the diving suits. Mr. Damon wanted to be of theparty, but Tom was afraid to permit him in that depth of water. Mr. Damon, in spite of his jollity, was not as young as he had been. 

Shortly after the collision, which had missed being a disaster by anarrow margin, Tom and his companions were outside the submarine, walking on the white, sandy bottom of the sea. Around them was a myriadof fishes, some of large size, but seemingly harmless, as they scuddedrapidly away after a glance at the strange creatures who appeared tohave come to dispute with them for possession of Father Neptune'selement. 

Moving more slowly than usual, because of the greater pressure of waterat that depth, Tom and the others made their way around the nose of thesubmarine. And then, in the glow of the big searchlight, they saw thedim outlines of a steamer, partly imbedded in the sand. Her stern wastoward the undersea craft that had rammed her, and the name was not soobliterated but what the young inventor could read it. 

"The Pandora!" exclaimed Tom, speaking into his helmet telephonetransmitter, the others all hearing him. "We've found the treasure-shipat last!"

And so they had. An accident had brought them to the end of theirquest, though it is probable they would have found the Pandora anyhow, since they were making careful circles in her vicinity. 

"Yes, that's the Pandora, " said Ned. "And now the thing to do is tofind out if she really has any treasure on board. "

"That's what I'm going to do, " declared Tom. "But first I want toinvestigate this queer current. We can't feel it here, but we may if weget out beyond the wreck. We don't want to be swept off our feet. "

"Yes, we had better be careful, " said one of the officers. 

Accordingly they proceeded with caution along the length of the sunkenPandora. And as they neared her bow they all began to feel somepowerful force in the current. 

"This is far enough!" said Tom. "Don't get out beyond the protection ofthe hull. I see what it is. The steamer has drifted here from where shewas originally sunk. And here two currents meet, forming a very strongone. It was that which threw us off our course. As long as we remainbehind the wreck we'll be safe. But beyond her we may be in danger. She's firmly held in the sand, or, at best, is drifting only slightly. She'll be a sort of undersea breakwater for us. And now to see if wecan get on board!"

This proved comparatively easy. Several lengths of chain and one ironladder were over the stern, evidently having been used when the crewabandoned the ship in the storm that destroyed her. By means of theseTom and his companions gained the main deck near the stern. 

The Pandora was a typical tramp steamer. She was high in the bows andstern and low amidships, and it was evident that the quarters of theofficers and passengers, if any of the latter were carried, were in thestern. Tom was glad to find the vessel thus comparatively easy ofaccess. 

She lay on an almost even keel, and all he and his companions had to dowas to walk along the deck and enter the cabins. As they did not haveto look out for life lines or air hose they could enter, and even gobelow decks, in comparative safety. 

"Well, here's for it, " said Tom to the others. "Let's go in. 

"Where would the treasure be, if she had any?" asked Ned. 

"Captain's cabin or the purser's strong room, I imagine, " Tom answered. "Hardley didn't actually see it, but he said those two places wereconstantly guarded. I'm inclined to think the purser would have chargeof the gold. But we'll try both places. "

It was easy to learn which had been the commander's cabin. It had thename "Captain" on a brass plate over the door. Tom and Ned entered. Theplace was in confusion, and confusion not all caused by the oceancurrents. A small safe in the room stood with rusted door open, and thecontents of the strong box were gone. Drawers and lockers, too, wereopened and empty. 

"I guess the captain took as much with him as he could when he got intohis boat, " commented Tom. 

"And the gold, too, " added Ned, pointing to the empty safe. 

"That wouldn't have held two million dollars in gold, " Tom retorted. "Ibelieve the purser's cabin is the place to look. "

Making sure they were not missing anything in the captain's room, theycame out, to find Koku and the others waiting for them on deck. 

"Nothing there, " Tom reported. "Did any of you locate the purser'sstrong room?" One of the men pointed to an open door to the left. 

"That's it!" exclaimed Tom. "Yes, and there's a safe here big enough tohold gold for all the revolutions in South America, " he added. "I guesswe're on the right track at last. "

It needed but a look to show them that they had at last reached theplace of the treasure. The great safe stood open, and piled inside werea number of small boxes, such as are generally used to ship gold in. Ned, from his bank experience, recognized them at once. 

"There's the gold!" he exclaimed. "We've found the treasure!"

"They tried to take some of it with them, " said one of the submarineofficers, pointing to some opened boxes which were floating near thecabin ceiling. They were caught on some projections which had preventedthem from being washed out. 

"Maybe they looted the whole safe, " suggested Tom. "We'd better have alook. "

He tried to pull out one of the many boxes set in tiers in the safe, but it was beyond his strength. 

"Me do!" murmured Koku. 

It was easy for the giant to pry out one of the boxes with his ironbar, and with another blow from his bar he opened the cover. 

"Gold!" cried Ned, as he saw a gleam of yellow showing in the glow fromhis torch. "There's the gold!"

There was a table in the purser's cabin, made fast to the floor so ithad not floated away. At a sign from Tom, the giant turned the boxbottom side up on this table. 

And then a murmur of wonder came from all who saw the result. Foraside from the top layer of gold pieces, the box was filled with irondisks cut to the size of twenty-dollar gold pieces. In an instant itwas borne to all what this meant. 

"A fake!" exclaimed Tom Swift. "If all the boxes are like this thereisn't enough gold on the treasure ship to pay the expenses of thistrip! Somebody has been fooled! Open another box, Koku!"

CHAPTER XXV

THE STEEL BOX

Perhaps the least of all affected by what had taken place was thegiant. Gold meant nothing to him. To serve Tom Swift was his whole aimin life. Born in a savage country, he had not acquired an overwhelmingdesire for wealth. 

Consequently he was cool enough as he tore another box from the manythat were fitted into the safe. The water had swelled the wood, and itwas not easy to get them out. 

A pressure of the giant's iron bar broke the sealed lid. On top was thesame layer of gold pieces, but when the box was emptied the same trickwas discovered. Iron disks made up the remainder of the contents. 

"Bilked! That's what I call it! Regularly bilked!" exclaimed one of thedivers, an Englishman who had been in Tom's service several years. "Somebody's got the cream of this pudding before we did!"

"I'm inclined to agree with you, " said Tom. "Unless it transpires thatnot all the boxes have been thus camouflaged. We must take time toexamine. "

Then began a period of hard work. Laboring in relays of divers, everybox that had been locked in the purser's safe was brought out on thesubmerged cabin table, broken open, and the contents examined. The hoaxwas even worse than indicated at first. For after the front section ofboxes had been taken out none of the others remaining contained anygold at all. There were only iron disks. 

"Well, Tom, what do you think of it?" asked Ned of his chum, when theyhad returned to the cabin of the submarine, leaving some members of thecrew to complete the examination. For this the diving bell was used, aswell as the suits. 

"I don't think very much, " was the answer. "It looks as though we hadbeen sold. "

"Do you think Hardley knew that the gold had been changed to iron--thatis, all but a small part of it?"

"No, I don't believe he did, " Tom answered. "If he were here I'dwarrant he would be as much surprised as we are. He certainly believedthe Pandora was a regular treasure-ship. "

"Just how much did she really have in gold?" asked Mr. Damon, lookingat the double eagles on the table of the M. N. 1. 

"Well, at a rough guess I'd say ten thousand dollars, " Tom answered. "We haven't brought it all out yet, and it's possible they may find afull box in the safe. But, unless there is one, I guess ten or fifteenthousand dollars will cover it. "

"And Hardley said two millions!" exclaimed Ned. "Whew, what adifference!"

"Do you think he was in on the change?" asked one of the officers. 

"No, " replied Tom. "I guess it was like a good many of thesefilibustering plots. Somebody put up good money to be used to gaincontrol of a country--perhaps for the country's good. But somebody elsemade the substitution, and the patriots were left. I don't believeHardley knew this. "

"Well, you'll get a little out of it, Tom, " Ned remarked. 

"Nothing worth while, " was the answer. "But I'm not disappointed; thatis, very much. Of course I could use the money, but I don't really needit. The trip has been a wonderful experience, and I have learnedsomething I didn't know before. I'm sorry for you, though, Mr. Damon. You invested considerable with Hardley, didn't you?"

"About twenty thousand dollars, Tom. It will be hard to lose it, but Iguess I can stand it. "

Tom privately made up his mind to see that his old friend did notsuffer financially, for the gold discovered on the Pandora, while itwas far from the amount hoped for, would almost reimburse Mr. Damon. But the young inventor did not say anything about that just then. 

They were looking at the recovered gold and getting ready to store itin some of the boxes that had been brought from the wreck when thedivers that had remained on the Pandora to bring the last of thetreasure returned through the chamber. Two of them carried a smallsteel box. 

"What's that?" asked Tom, when they had their helmets off. 

"Don't know, " was the answer. "It was in the purser's safe. Stuck awayin the far corner. "

"Maybe it has jewels in it!" exclaimed Ned. "If it has--"

At that moment the lookout who had maintained his position in theconning tower called for Tom on the telephone. 

"What is it?" asked the young inventor. 

"There's some sort of grappling iron, or cable with a hook on it, beinglowered from the surface, and it's near the wreck, " was the answer. "Ifit isn't any of your apparatus it may be some other ship having a tryfor the gold. "

"It must be Hardley!" cried Tom. "He's come back with another ship, ashe half threatened to do, and, instead of diving for the wreck, whichhe can't get ordinary men to do in this depth, he's trying to grapplefor it. Come on, we'll have a look!"

Ned and Mr. Damon followed Tom to the conning tower. Looking outthrough the heavy glass windows, while the searchlight illuminated thewaters, the young inventor and his friends saw a great grappling ironswaying this way and that through the sea not far from the wreck, andonce, indeed, uncomfortably close to their own craft. 

"He's struck it uncommonly near, " remarked Tom. "I guess it's time forus to be leaving. "

"Suppose it's Hardley up above there?" suggested Ned. 

"I don't doubt but it is. "

"Well, are we going off and leave the wreck--and possibly other goldthat may be hidden on her?"

"I wouldn't give ten dollars for the chance of searching for any moregold!" Tom exclaimed. "We'll take this steel box--it may containsomething of value. The rest we'll leave to Hardley. "

Preparations for rising to the surface were quickly made. Up and upwent the M. N. 1, leaving the ill-starred Pandora to whatever else fatehad in store for her. 

Tom's craft broke water with gentle undulations of the waves. The topof the hatch was thrown back, admitting the bright sunshine on thosewho had been long in the shadow of the underseas. And, as the younginventor and his friends went out on deck, they saw a small steamerriding on the ocean not far away. 

One look was enough to tell them it was from this craft that thegrappling iron had been let down, and as the submarine drifted nearerthe form of Hardley was seen on deck. He was directing operations. 

Some one must have called his attention to the M. N. 1, for he hurriedto the rail of the craft which he had evidently chartered to seek thePandora, and he exclaimed:

"What are you doing here, Swift?"

"The same thing you are, I believe, " coolly answered Tom. "Cleaning upthe treasure ship. You might as well save your money though, for wehave all the gold there is!"

"Impossible!" cried the now irate man. "You cannot have found thePandora!"

"That's just what we did, though, " answered Tom. "And, for yourinformation, I'll say that we took all the gold we found, though it wasconsiderably less than you stated. "

"How dare you?" stormed the adventurer. "I'll have the law on you forthis!"

"I guess you forget, " replied Tom, "that we parted company at yourrequest and that I told you I was on my own. Finding is keeping. Ididn't find what I expected to, and, on the other hand, I got somethingI didn't look for. "

"What do you mean

"The Pandora was rightly named, " went on Tom. "If you recall the oldstory, Pandora had a box of treasures. They all flew out except Hope, which remained in the bottom. Well, most of the gold seems to haveflown away, but we found a box on the Pandora. What's in it I don'tknow yet, as I haven't opened it. Still, if it doesn't contain morethan Hope I shall be disappointed. "

The face of Hardley showed the rage felt. 

"Give me that box! Give me that box!" he cried, shaking his fist at Tom. 

"Not today, " was the cool answer of the young inventor. "I may let youknow what I find in it if you leave your address. Goodbye!"

Tom waved his hand, gave orders to close the hatches and submerge theM. N. 1, and a few moments later the sea closed over her, leaving theother vessel to grapple uselessly for the treasure-ship. 

"What are you going to do, Tom?" asked Ned of his chum, as they wereall gathered in the main cabin half an hour later. 

"Head for home as soon as we can. I've had enough of this, and I wantto get at something else I have in mind. But first I'm going to seewhat's in this box. "

It required the strength of Koku to open the small steel box, but whenit was torn apart, for the combination was impossible to guess at, allthat was seen were bundles of papers. The case having been hermeticallyclosed, no water had penetrated it, though it had been submerged a longtime. 

"What are they?" asked Ned of his chum. 

Tom did not answer for a moment. Then having quickly examined thepapers, he cried:

"We've struck it!"

"What?" they all wanted to know. 

"The very thing Hardley was after. These are the missing papers in theoil-well deal--the papers that prove Barton Keith has a half share inproperty worth many millions of dollars. It was these papers thatHardley was after. He may have thought he could get the gold, too, buthe wanted most these oil shares. Boys, we've found the fortune anyhow, in spite of the fellows who looted the gold boxes!"

There was no doubt about it. There were all the papers--thecertificates of shares, the partnership agreement and otherdocuments--to show that Mary's uncle was a rich man. The wreck of thePandora held a fortune after all. 

"How do you account for Hardley's acts?" asked Ned of his chum. 

"Well, there are several explanations. I think we may be certain thathe knew these papers were aboard the Pandora, for he must haveintrusted them to the purser himself when he made a trip on the ship. When she sank he had not time to get them to take with him. "

"He either knew then, or found out later, that the vessel carried, orwas supposed to carry, a large amount of gold. He may have beenhonestly mistaken in thinking it was two millions. In any case he wasplaying safe, for he only promised me half if the treasure was found. He could have claimed this box as his property, and that is probablywhat he was after from the beginning. He was using me as a cat's paw, so to speak. "

"Well, you beat him to it, " observed Ned. 

"Bless my necktie, I should say so!" agreed Mr. Damon. "Do you think hereally expected to find the gold?"

"Either that or the papers, " was Tom's answer. "He must have engagedthe vessel and the grappling apparatus, and, possibly, a diver, afterwe set him ashore at St. Thomas. Well, we'll leave him to his own fun. "

The M. N. 1 made good time back to her home port, nothing except aterrific storm occurring to mark the voyage. And as she submerged whenthat was on she did not feel it. After greeting his father, Tom lostlittle time in going to Mary's house with the box of securities andother papers. 

"I want you to hand these to your uncle with my compliments, " he said. "I've got the Air Scout out in the meadow. We'll go over in that. Howis Mr. Keith?"

"Not very well, " Mary answered, after she had got over her surprise atseeing Tom. "But this good news will restore him, I think. "

And it certainly was a great tonic. Mr. Keith could hardly believe thestory that Mary and Tom jointly told him. But at length he grasped theidea that he was a wealthy man again, and he exclaimed:

"Tom Swift, I'm going to share half with you!"

"Oh, no, " retorted the young inventor. "I couldn't think of that. Ifyou want to pay part of the expenses of the trip I shan't object tothat, as I intend giving the gold I recovered to Mr. Damon. But as fortaking any of the oil shares--"

"Then, Mary, you shall take half!" exclaimed Mr. Keith. "I have moremoney now than I'll ever spend. Mary, half of it is yours, and if youdon't let Tom Swift have a say in the spending of it-- Say, Mary, haveyou thanked him yet?" he asked with a twinkle of his eyes. "Well, UncleBarton, I--I don't know--"

"Then do it now!" cried her uncle. "Tom, if you could have any rewardyou wanted, what would it be?"

Tom took Mary in his arms and--But I refuse to betray any secrets. Anyhow, some time later when Ned asked his chum if he felt entirelysatisfied with the result of his undersea search, the young inventorreplied: "I certainly do!"

Tom admitted to his father that a mistake had been made in notinstalling the gyroscope rudder. There was no excuse for not taking it. Tom declared, as it was small and took up little room, and it mighthave saved them from what was a close call at one time. 

"I'll take it on my next submarine trip, " the young inventor promised. 

Ned wanted to bring suit against Hardley to recover half the expensesof the trip, but Tom would not consent to it. After all, the value ofthe oil well property was more than the gold the Pandora was reputed tohave carried. No attempt was made to take from Tom the comparativelysmall amount he had salvaged. Perhaps whoever had put it on board didnot want to admit the trick that had been played in filling the boxeswith iron disks. 

Dixwell Hardley made no further trouble. He could not, for he was soentirely in the wrong. He sold out his shares in the oil property, anda company took possession which gave fair treatment to Mary's uncle. 

And this is the end of the story. But the future holds furtheradventures for Tom Swift which, let it be hoped, he will see fit toorder recorded.