"We were busy on the other side of the shop, I guess," repli

TOM SWIFT AND HIS SUBMARINE BOAT

or

Under the Ocean for Sunken Treasure

by

VICTOR APPLETON

CONTENTS

I News of a Treasure Wreck

II Finishing the Submarine

III Mr. Berg Is Astonished

IV Tom Is Imprisoned

V Mr. Berg Is Suspicious

VI Turning the Tables

VII Mr. Damon Will Go

VIII Another Treasure Expedition

IX Captain Weston's Advent

X Trial of the Submarine

XI On the Ocean Bed

XII For a Breath of Air

XIII Off for the Treasure

XIV In the Diving Suits

XV At the Tropical Island

XVI "We'll Race You For It!"

XVII The Race

XVIII The Electric Gun

XIX Captured

XX Doomed to Death

XXI The Escape

XXII At the Wreck

XXIII Attacked by Sharks

XXIV Ramming the Wreck

XXV Home with the Gold

TOM SWIFT AND HIS SUBMARINE BOAT

Chapter One

News of a Treasure Wreck

There was a rushing, whizzing, throbbing noise in the air. A great

body, like that of some immense bird, sailed along, casting a grotesque

shadow on the ground below. An elderly man, who was seated on the

porch of a large house, started to his feet in alarm.

"Gracious goodness! What was that, Mrs. Baggert?" he called to a

motherly-looking woman who stood in the doorway. "What happened?"

"Nothing much, Mr. Swift," was the calm reply "I think that was Tom and

Mr. Sharp in their airship, that's all. I didn't see it, but the noise

sounded like that of the Red Cloud."

"Of course! To be sure!" exclaimed Mr. Barton Swift, the well-known

inventor, as he started down the path in order to get a good view of

the air, unobstructed by the trees. "Yes, there they are," he added.

"That's the airship, but I didn't expect them back so soon. They must

have made good time from Shopton. I wonder if anything can be the

matter that they hurried so?"

He gazed aloft toward where a queerly-shaped machine was circling about

nearly five hundred feet in the air, for the craft, after swooping down

close to the house, had ascended and was now hovering just above the

line of breakers that marked the New Jersey seacoast, where Mr. Swift

had taken up a temporary residence.

"Don't begin worrying, Mr. Swift," advised Mrs. Baggert, the

housekeeper. "You've got too much to do, if you get that new boat done,

to worry."

"That's so. I must not worry. But I wish Tom and Mr. Sharp would land,

for I want to talk to them."

As if the occupants of the airship had heard the words of the aged

inventor, they headed their craft toward earth. The combined aeroplane

and dirigible balloon, a most wonderful traveler of the air, swung

around, and then, with the deflection rudders slanted downward, came on

with a rush. When near the landing place, just at the side of the

house, the motor was stopped, and the gas, with a hissing noise, rushed

into the red aluminum container. This immediately made the ship more

buoyant and it landed almost as gently as a feather.

No sooner had the wheels which formed the lower part of the craft

touched the ground than there leaped from the cabin of the Red Cloud a

young man.

"Well, dad!" he exclaimed. "Here we are again, safe and sound. Made a

record, too. Touched ninety miles an hour at times--didn't we, Mr.

Sharp?"

"That's what," agreed a tall, thin, dark-complexioned man, who followed

Tom Swift more leisurely in his exit from the cabin. Mr. Sharp, a

veteran aeronaut, stopped to fasten guy ropes from the airship to

strong stakes driven into the ground.

"And we'd have done better, only we struck a hard wind against us about

two miles up in the air, which delayed us," went on Tom. "Did you hear

us coming, dad?"

"Yes, and it startled him," put in Mrs. Baggert. "I guess he wasn't

expecting you."

"Oh, well, I shouldn't have been so alarmed, only I was thinking deeply

about a certain change I am going to make in the submarine, Tom. I was

day-dreaming, I think, when your ship whizzed through the air. But tell

me, did you find everything all right at Shopton? No signs of any of

those scoundrels of the Happy Harry gang having been around?" and Mr.

Swift looked anxiously at his son.

"Not a sign, dad," replied Tom quickly. "Everything was all right. We

brought the things you wanted. They're in the airship. Oh, but it was a

fine trip. I'd like to take another right out to sea."

"Not now, Tom," said his father. "I want you to help me. And I need

Mr. Sharp's help, too. Get the things out of the car, and we'll go to

the shop."

"First I think we'd better put the airship away," advised Mr. Sharp. "I

don't just like the looks of the weather, and, besides, if we leave the

ship exposed we'll be sure to have a crowd around sooner or later, and

we don't want that."

"No, indeed," remarked the aged inventor hastily. "I don't want people

prying around the submarine shed. By all means put the airship away,

and then come into the shop."

In spite of its great size the aeroplane was easily wheeled along by

Tom and Mr. Sharp, for the gas in the container made it so buoyant that

it barely touched the earth. A little more of the powerful vapor and

the Red Cloud would have risen by itself. In a few minutes the

wonderful craft, of which my readers have been told in detail in a

previous volume, was safely housed in a large tent, which was securely

fastened.

Mr. Sharp and Tom, carrying some bundles which they had taken from the

car, or cabin, of the craft, went toward a large shed, which adjoined

the house that Mr. Swift had hired for the season at the seashore. They

found the lad's father standing before a great shape, which loomed up

dimly in the semi-darkness of the building. It was like an immense

cylinder, pointed at either end, and here and there were openings,

covered with thick glass, like immense, bulging eyes. From the number

of tools and machinery all about the place, and from the appearance of

the great cylinder itself, it was easy to see that it was only partly

completed.

"Well, how goes it, dad?" asked the youth, as he deposited his bundle

on a bench. "Do you think you can make it work?"

"I think so, Tom. The positive and negative plates are giving me

considerable trouble, though. But I guess we can solve the problem. Did

you bring me the galvanometer?"

"Yes, and all the other things," and the young inventor proceeded to

take the articles from the bundles he carried.

Mr. Swift looked them over carefully, while Tom walked about examining

the submarine, for such was the queer craft that was contained in the

shed. He noted that some progress had been made on it since he had

left the seacoast several days before to make a trip to Shopton, in New

York State, where the Swift home was located, after some tools and

apparatus that his father wanted to obtain from his workshop there.

"You and Mr. Jackson have put on several new plates," observed the lad

after a pause.

"Yes," admitted his father. "Garret and I weren't idle, were we,

Garret?" and he nodded to the aged engineer, who had been in his employ

for many years.

"No; and I guess we'll soon have her in the water, Tom, now that you

and Mr. Sharp are here to help us," replied Garret Jackson.

"We ought to have Mr. Damon here to bless the submarine and his liver

and collar buttons a few times," put in Mr. Sharp, who brought in

another bundle. He referred to an eccentric individual who had recently

made an airship voyage with himself and Tom, Mr. Damon's peculiarity

being to use continually such expressions as: "Bless my soul! Bless my

liver!"

"Well, I'll be glad when we can make a trial trip," went on Tom. "I've

traveled pretty fast on land with my motorcycle, and we certainly have

hummed through the air. Now I want to see how it feels to scoot along

under water."

"Well, if everything goes well we'll be in position to make a trial

trip inside of a month," remarked the aged inventor. "Look here, Mr.

Sharp, I made a change in the steering gear, which I'd like you and Tom

to consider."

The three walked around to the rear of the odd-looking structure, if an

object shaped like a cigar can be said to have a front and rear, and

the inventor, his son, and the aeronaut were soon deep in a discussion

of the technicalities connected with under-water navigation.

A little later they went into the house, in response to a summons from

the supper bell, vigorously rung by Mrs. Baggert. She was not fond of

waiting with meals, and even the most serious problem of mechanics was,

in her estimation, as nothing compared with having the soup get cold,

or the possibility of not having the meat done to a turn.

The meal was interspersed with remarks about the recent airship flight

of Tom and Mr. Sharp, and discussions about the new submarine. This

talk went on even after the table was cleared off and the three had

adjourned to the sitting-room. There Mr. Swift brought out pencil and

paper, and soon he and Mr. Sharp were engrossed in calculating the

pressure per square inch of sea water at a depth of three miles.

"Do you intend to go as deep as that?" asked Tom, looking up from a

paper he was reading.

"Possibly," replied his father; and his son resumed his perusal of the

sheet.

"Now," went on the inventor to the aeronaut, "I have another plan. In

addition to the positive and negative plates which will form our motive

power, I am going to install forward and aft propellers, to use in case

of accident."

"I say, dad! Did you see this?" suddenly exclaimed Tom, getting up from

his chair, and holding his finger on a certain place in the page of the

paper.

"Did I see what?" asked Mr. Swift.

"Why, this account of the sinking of the treasure ship."

"Treasure ship? No. Where?"

"Listen," went on Tom. "I'll read it: 'Further advices from Montevideo,

Uruguay, South America, state that all hope has been given up of

recovering the steamship Boldero, which foundered and went down off

that coast in the recent gale. Not only has all hope been abandoned of

raising the vessel, but it is feared that no part of the three hundred

thousand dollars in gold bullion which she carried will ever be

recovered. Expert divers who were taken to the scene of the wreck state

that the depth of water, and the many currents existing there, due to a

submerged shoal, preclude any possibility of getting at the hull. The

bullion, it is believed, was to have been used to further the interests

of a certain revolutionary faction, but it seems likely that they will

have to look elsewhere for the sinews of war. Besides the bullion the

ship also carried several cases of rifles, it is stated, and other

valuable cargo. The crew and what few passengers the Boldero carried

were, contrary to the first reports, all saved by taking to the boats.

It appears that some of the ship's plates were sprung by the stress in

which she labored in a storm, and she filled and sank gradually.'

There! what do you think of that, dad?" cried Tom as he finished.

"What do I think of it? Why, I think it's too bad for the

revolutionists, Tom, of course."

"No; I mean about the treasure being still on board the ship. What

about that?"

"Well, it's likely to stay there, if the divers can't get at it. Now,

Mr. Sharp, about the propellers--"

"Wait, dad!" cried Tom earnestly.

"Why, Tom, what's the matter?" asked Mr. Swift in some surprise.

"How soon before we can finish our submarine?" went on Tom, not

answering the question.

"About a month. Why?"

"Why? Dad, why can't we have a try for that treasure? It ought to be

comparatively easy to find that sunken ship off the coast of Uruguay.

In our submarine we can get close up to it, and in the new diving suits

you invented we can get at that gold bullion. Three hundred thousand

dollars! Think of it, dad! Three hundred thousand dollars! We could

easily claim all of it, since the owners have abandoned it, but we

would be satisfied with half. Let's hurry up, finish the submarine, and

have a try for it."

"But, Tom, you forget that I am to enter my new ship in the trials for

the prize offered by the United States Government."

"How much is the prize if you win it?" asked Tom.

"Fifty thousand dollars."

"Well, here's a chance to make three times that much at least, and

maybe more. Dad, let the Government prize go, and try for the treasure.

Will you?"

Tom looked eagerly at his father, his eyes shining with anticipation.

Mr. Swift was not a quick thinker, but the idea his son had proposed

made an impression on him. He reached out his hand for the paper in

which the young inventor had seen the account of the sunken treasure.

Slowly he read it through. Then he passed it to Mr. Sharp.

"What do you think of it?" he asked of the aeronaut.

"There's a possibility," remarked the balloonist "We might try for it.

We can easily go three miles down, and it doesn't lie as deeply as

that, if this account is true. Yes, we might try for it. But we'd have

to omit the Government contests."

"Will you, dad?" asked Tom again.

Mr. Swift considered a moment longer.

"Yes, Tom, I will," he finally decided. "Going after the treasure will

be likely to afford us a better test of the submarine than would any

Government tests. We'll try to locate the sunken Boldero."

"Hurrah!" cried the lad, taking the paper from Mr. Sharp and waving it

in the air. "That's the stuff! Now for a search for the submarine

treasure!"

Chapter Two

Finishing the Submarine

"What's the matter?" cried Mrs. Baggert, the housekeeper, hurrying in

from the kitchen, where she was washing the dishes. "Have you seen some

of those scoundrels who robbed you, Mr. Swift? If you have, the police

down here ought to--"

"No, it's nothing like that," explained Mr. Swift. "Tom has merely

discovered in the paper an account of a sunken treasure ship, and he

wants us to go after it, down under the ocean."

"Oh, dear! Some more of Captain Kidd's hidden hoard, I suppose?"

ventured the housekeeper. "Don't you bother with it, Mr. Swift. I had a

cousin once, and he got set in the notion that he knew where that

pirate's treasure was. He spent all the money he had and all he could

borrow digging for it, and he never found a penny. Don't waste your

time on such foolishness. It's bad enough to be building airships and

submarines without going after treasure." Mrs. Baggert spoke with the

freedom of an old friend rather than a hired housekeeper, but she had

been in the family ever since Tom's mother died, when he was a baby,

and she had many privileges.

"Oh, this isn't any of Kidd's treasure," Tom assured her. "If we get

it, Mrs. Baggert, I'll buy you a diamond ring."

"Humph!" she exclaimed, as Tom began to hug her in boyish fashion. "I

guess I'll have to buy all the diamond rings I want, if I have to

depend on your treasure for them," and she went back to the kitchen.

"Well," went on Mr. Swift after a pause, "if we are going into the

treasure-hunting business, Tom, we'll have to get right to work. In the

first place, we must find out more about this ship, and just where it

was sunk."

"I can do that part," said Mr. Sharp. "I know some sea captains, and

they can put me on the track of locating the exact spot. In fact, it

might not be a bad idea to take an expert navigator with us. I can

manage in the air all right, but I confess that working out a location

under water is beyond me."

"Yes, an old sea captain wouldn't be a bad idea, by any means,"

conceded Mr. Swift. "Well, if you'll attend to that detail, Mr. Sharp,

Tom, Mr. Jackson and I will finish the submarine. Most of the work is

done, however, and it only remains to install the engine and motors.

Now, in regard to the negative and positive electric plates, I'd like

your opinion, Tom."

For Tom Swift was an inventor, second in ability only to his father,

and his advice was often sought by his parent on matters of electrical

construction, for the lad had made a specialty of that branch of

science.

While father and son were deep in a discussion of the apparatus of the

submarine, there will be an opportunity to make the reader a little

better acquainted with them. Those of you who have read the previous

volumes of this series do not need to be told who Tom Swift is. Others,

however, may be glad to have a proper introduction to him.

Tom Swift lived with his father, Barton Swift, in the village of

Shopton, New York. The Swift home was on the outskirts of the town, and

the large house was surrounded by a number of machine shops, in which

father and son, aided by Garret Jackson, the engineer, did their

experimental and constructive work. Their house was not far from Lake

Carlopa, a fairly large body of water, on which Tom often speeded his

motor-boat.

In the first volume of this series, entitled "Tom Swift and His

Motor-Cycle," it was told how he became acquainted with Mr. Wakefield

Damon, who suffered an accident while riding one of the speedy

machines. The accident disgusted Mr. Damon with motor-cycles, and Tom

secured it for a low price. He had many adventures on it, chief among

which was being knocked senseless and robbed of a valuable patent model

belonging to his father, which he was taking to Albany. The attack was

committed by a gang known as the Happy Harry gang, who were acting at

the instigation of a syndicate of rich men, who wanted to secure

control of a certain patent turbine engine which Mr. Swift had invented.

Tom set out in pursuit of the thieves, after recovering from their

attack, and had a strenuous time before he located them.

In the second volume, entitled "Tom Swift and His Motor-Boat," there

was related our hero's adventures in a fine craft which was recovered

from the thieves and sold at auction. There was a mystery connected

with the boat, and for a long time Tom could not solve it. He was

aided, however, by his chum, Ned Newton, who worked in the Shopton

Bank, and also by Mr. Damon and Eradicate Sampson, an aged colored

whitewasher, who formed quite an attachment for Tom.

In his motor-boat Tom had more than one race with Andy Foger, a rich

lad of Shopton, who was a sort of bully. He had red hair and squinty

eyes, and was as mean in character as he was in looks. He and his

cronies, Sam Snedecker and Pete Bailey, made trouble for Tom, chiefly

because Tom managed to beat Andy twice in boat races.

It was while in his motor-boat, Arrow, that Tom formed the acquaintance

of John Sharp, a veteran balloonist. While coming down Lake Carlopa on

the way to the Swift home, which had been entered by thieves, Tom, his

father and Ned Newton, saw a balloon on fire over the lake. Hanging

from a trapeze on it was Mr. Sharp, who had made an ascension from a

fair ground. By hard work on the part of Tom and his friends the

aeronaut was saved, and took up his residence with the Swifts.

His advent was most auspicious, for Tom and his father were then

engaged in perfecting an airship, and Mr. Sharp was able to lend them

his skill, so that the craft was soon constructed.

In the third volume, called "Tom Swift and His Airship," there was set

down the doings of the young inventor, Mr. Sharp and Mr. Damon on a

trip above the clouds. They undertook it merely for pleasure, but they

encountered considerable danger, before they completed it, for they

nearly fell into a blazing forest once, and were later fired at by a

crowd of excited people. This last act was to effect their capture, for

they were taken for a gang of bank robbers, and this was due directly

to Andy Foger.

The morning after Tom and his friends started on their trip in the air,

the Shopton Bank was found to have been looted of seventy-five thousand

dollars. Andy Foger at once told the police that Tom Swift had taken

the money, and when asked how he knew this, he said he had seen Tom

hanging around the bank the night before the vault was burst open, and

that the young inventor had some burglar tools in his possession.

Warrants were at once sworn out for Tom and Mr. Damon, who was also

accused of being one of the robbers, and a reward of five thousand

dollars was offered.

Tom, Mr. Damon and Mr. Sharp sailed on, all unaware of this, and unable

to account for being fired upon, until they accidentally read in the

paper an account of their supposed misdeeds. They lost no time in

starting back home, and on the way got on the track of the real bank

robbers, who were members of the Happy Harry gang.

How the robbers were captured in an exciting raid, how Tom recovered

most of the stolen money, and how he gave Andy Foger a deserved

thrashing for giving a false clue was told of, and there was an account

of a race in which the Red Cloud (as the airship was called) took part,

as well as details of how Tom and his friends secured the reward, which

Andy Foger hoped to collect.

Those of you who care to know how the Red Cloud was constructed, and

how she behaved in the air, even during accidents and when struck by

lightning, may learn by reading the third volume, for the airship was

one of the most successful ever constructed.

When the craft was finished, and the navigators were ready to start on

their first long trip, Mr. Swift was asked to go with them. He

declined, but would not tell why, until Tom, pressing him for an

answer, learned that his father was planning a submarine boat, which he

hoped to enter in some trials for Government prizes. Mr. Swift remained

at home to work on this submarine, while his son and Mr. Sharp were

sailing above the clouds.

On their return, however, and after the bank mystery had been cleared

up, Tom and Mr. Sharp, aided Mr. Swift in completing the submarine,

until, when the present story opens, it needed but little additional

work to make the craft ready for the water.

Of course it had to be built near the sea, as it would have been

impossible to transport it overland from Shopton. So, before the keel

was laid, Mr. Swift rented a large cottage at a seaside place on the

New Jersey coast and there, after erecting a large shed, the work on

the Advance, as the under-water ship was called, was begun.

It was soon to be launched in a large creek that extended in from the

ocean and had plenty of water at high tide. Tom and Mr. Sharp made

several trips back and forth from Shopton in their airship, to see that

all was safe at home and occasionally to get needed tools and supplies

from the shops, for not all the apparatus could be moved from Shopton

to the coast.

It was when returning from one of these trips that Tom brought with him

the paper containing an account of the wreck of the Boldero and the

sinking of the treasure she carried.

Until late that night the three fortune-hunters discussed various

matters.

"We'll hurry work on the ship," said Mr. Swift at length. "Tom, I

wonder if your friend, Mr. Damon, would care to try how it seems under

water? He stood the air trip fairly well."

"I'll write and ask him," answered the lad. "I'm sure he'll go."

Securing, a few days later, the assistance of two mechanics, whom he

knew he could trust, for as yet the construction of the Advance was a

secret, Mr. Swift prepared to rush work on the submarine, and for the

next three weeks there were busy times in the shed next to the seaside

cottage. So busy, in fact, were Tom and Mr. Sharp, that they only found

opportunity for one trip in the airship, and that was to get some

supplies from the shops at home.

"Well," remarked Mr. Swift one night, at the close of a hard day's

work, "another week will see our craft completed. Then we will put it

in the water and see how it floats, and whether it submerges as I hope

it does. But come on, Tom. I want to lock up. I'm very tired to-night."

"All right, dad," answered the young inventor coming from the darkened

rear of the shop. "I just want to--"

He paused suddenly, and appeared to be listening. Then he moved softly

back to where he had come from.

"What's the matter?" asked his father in a whisper. "What's up, Tom?"

The lad did not answer Mr. Swift, with a worried look on his face,

followed his son. Mr. Sharp stood in the door of the shop.

"I thought I heard some one moving around back here," went on Tom

quietly.

"Some one in this shop!" exclaimed the aged inventor excitedly. "Some

one trying to steal my ideas again! Mr. Sharp, come here! Bring that

rifle! We'll teach these scoundrels a lesson!"

Tom quickly darted back to the extreme rear of the building. There was

a scuffle, and the next minute Tom cried out:

"What are you doing here?"

"Ha! I beg your pardon," replied a voice. "I am looking for Mr. Barton

Swift."

"My father," remarked Tom. "But that's a queer place to look for him.

He's up front. Father, here's a man who wishes to see you," he called.

"Yes, I strolled in, and seeing no one about I went to the rear of the

place," the voice went on. "I hope I haven't transgressed."

"We were busy on the other side of the shop, I guess," replied Tom, and

he looked suspiciously at the man who emerged from the darkness into

the light from a window. "I beg your pardon for grabbing you the way I

did," went on the lad, "but I thought you were one of a gang of men

we've been having trouble with."

"Oh, that's all right," continued the man easily. "I know Mr. Swift,

and I think he will remember me. Ah, Mr. Swift, how do you do?" he

added quickly, catching sight of Tom's father, who, with Mr. Sharp, was

coming to meet the lad.

"Addison Berg!" exclaimed the aged inventor as he saw the man's face

more plainly. "What are you doing here?"

"I came to see you," replied the man. "May I have a talk with you

privately?"

"I--I suppose so," assented Mr. Swift nervously. "Come into the house."

Mr. Berg left Tom's side and advanced to where Mr. Swift was standing.

Together the two emerged from the now fast darkening shop and went

toward the house.

"Who is he?" asked Mr. Sharp of the young inventor in a whisper.

"I don't know," replied the lad; "but, whoever he is, dad seems afraid

of him. I'm going to keep my eyes open."

Chapter Three

Mr. Berg is Astonished

Following his father and the stranger whom the aged inventor had

addressed as Mr. Berg, Tom and Mr. Sharp entered the house, the lad

having first made sure that Garret Jackson was on guard in the shop

that contained the submarine.

"Now," said Mr. Swift to the newcomer, "I am at your service. What is

it you wish?"

"In the first place, let me apologize for having startled you and your

friends," began the man. "I had no idea of sneaking into your workshop,

but I had just arrived here, and seeing the doors open I went in. I

heard no one about, and I wandered to the back of the place. There I

happened to stumble over a board--"

"And I heard you," interrupted Tom.

"Is this one of your employees?" asked Mr. Berg in rather frigid tones.

"That is my son," replied Mr. Swift.

"Oh, I beg your pardon." The man's manner changed quickly. "Well, I

guess you did hear me, young man. I didn't intend to bark my shins the

way I did, either. You must have taken me for a burglar or a sneak

thief."

"I have been very much bothered by a gang of unscrupulous men," said

Mr. Swift, "and I suppose Tom thought it was some of them sneaking

around again."

"That's what I did," added the lad. "I wasn't going to have any one

steal the secret of the submarine if I could help it."

"Quite right! Quite right!" exclaimed Mr. Berg. "But my purpose was an

open one. As you know, Mr. Swift, I represent the firm of Bentley &

Eagert, builders of submarine boats and torpedoes. They heard that you

were constructing a craft to take part in the competitive prize tests

of the United States Government, and they asked me to come and see you

to learn when your ship would be ready. Ours is completed, but we

recognize that it will be for the best interests of all concerned if

there are a number of contestants, and my firm did not want to send in

their entry until they knew that you were about finished with your

ship. How about it? Are you ready to compete?"

"Yes," said Mr. Swift slowly. "We are about ready. My craft needs a few

finishing touches, and then it will be ready to launch."

"Then we may expect a good contest on your part," suggested Mr. Berg.

"Well," began the aged inventor, "I don't know about that."

"What's that?" exclaimed Mr. Berg.

"I said I wasn't quite sure that we would compete," went on Mr. Swift.

"You see, when I first got this idea for a submarine boat I had it in

mind to try for the Government prize of fifty thousand dollars."

"That's what we want, too," interrupted Mr. Berg with a smile.

"But," went on Tom's father, "since then certain matters have come up,

and I think, on the whole, that we'll not compete for the prize after

all."

"Not compete for the prize?" almost shouted the agent for Bentley &

Eagert. "Why, the idea! You ought to compete. It is good for the trade.

We think we have a very fine craft, and probably we would beat you in

the tests, but--"

"I wouldn't be too sure of that," put in Tom. "You have only seen the

outside of our boat. The inside is better yet."

"Ah, I have no doubt of that," spoke Mr. Berg, "but we have been at the

business longer than you have, and have had more experience. Still we

welcome competition. But I am very much surprised that you are not

going to compete for the prize, Mr. Swift. Very much surprised, indeed!

You see, I came down from Philadelphia to arrange so that we could both

enter our ships at the same time. I understand there is another firm of

submarine boat builders who are going to try for the prize, and I want

to arrange a date that will be satisfactory to all. I am greatly

astonished that you are not going to compete."

"Well, we were going to," said Mr. Swift, "only we have changed our

minds, that's all. My son and I have other plans."

"May I ask what they are?" questioned Mr. Berg.

"You may," exclaimed Tom quickly; "but I don't believe we can tell you.

They're a secret," he added more cordially.

"Oh, I see," retorted Mr. Berg. "Well, of course I don't wish to

penetrate any of your secrets, but I hoped we could contest together

for the Government prize. It is worth trying for I assure you--fifty

thousand dollars. Besides, there is the possibility of selling a number

of submarines to the United States. It's a fine prize."

"But the one we are after is a bigger one," cried Tom impetuously, and

the moment he had spoken he wished he could recall the words.

"Eh? What's that?" exclaimed Mr. Berg. "You don't mean to say another

government has offered a larger prize? If I had known that I would not

have let my firm enter into the competition for the bonus offered by

the United States. Please tell me."

"I'm sorry," went on Tom more soberly. "I shouldn't have spoken. Mr.

Berg, the plans of my father and myself are such that we can't reveal

them now. We are going to try for a prize, but not in competition with

you. It's an entirely different matter."

"Well, I guess you'll find that the firm of Bentley & Eagert are

capable of trying for any prizes that are offered," boasted the agent.

"We may be competitors yet."

"I don't believe so," replied Mr. Swift.

"We may," repeated Mr. Berg. "And if we do, please remember that we

will show no mercy. Our boats are the best."

"And may the best boat win," interjected Mr. Sharp. "That's all we

ask. A fair field and no favors."

"Of course," spoke the agent coldly. "Is this another son of yours?" he

asked.

"No but a good friend," replied the aged inventor. "No, Mr. Berg, we

won't compete this time. You may tell your firm so."

"Very good," was the other's stiff reply. "Then I will bid you good

night. We shall carry off the Government prize, but permit me to add

that I am very much astonished, very much indeed, that you do not try

for the prize. From what I have seen of your submarine you have a very

good one, almost as good, in some respects, as ours. I bid you good

night," and with a bow the man left the room and hurried away from the

house.

Chapter Four

Tom is Imprisoned

"Well, I must say he's a cool one," remarked Tom, as the echoes of Mr.

Berg's steps died away. "The idea of thinking his boat better than

ours! I don't like that man, dad. I'm suspicious of him. Do you think

he came here to steal some of our ideas?"

"No, I hardly believe so, my son. But how did you discover him?"

"Just as you saw, dad. I heard a noise and went back there to

investigate. I found him sneaking around, looking at the electric

propeller plates. I went to grab him just as he stumbled over a board.

At first I thought it was one of the old gang. I'm almost sure he was

trying to discover something."

"No, Tom. The firm he works for are good business men, and they would

not countenance anything like that. They are heartless competitors,

however, and if they saw a legitimate chance to get ahead of me and

take advantage, they would do it. But they would not sneak in to steal

my ideas. I feel sure of that. Besides, they have a certain type of

submarine which they think is the best ever invented, and they would

hardly change at this late day. They feel sure of winning the

Government prize, and I'm just as glad we're not going to have a

contest."

"Do you think our boat is better than theirs?"

"Much better, in many respects."

"I don't like that man Berg, though," went on Tom.

"Nor do I," added his father. "There is something strange about him.

He was very anxious that I should compete. Probably he thought his

firm's boat would go so far ahead of ours that they would get an extra

bonus. But I'm glad he didn't see our new method of propulsion. That is

the principal improvement in the Advance over other types of

submarines. Well, another week and we will be ready for the test."

"Have you known Mr. Berg long, dad?"

"Not very. I met him in Washington when I was in the patent office. He

was taking out papers on a submarine for his firm at the same time I

got mine for the Advance. It is rather curious that he should come all

the way here from Philadelphia, merely to see if I was going to

compete. There is something strange about it, something that I can't

understand."

The time was to come when Mr. Swift and his son were to get at the

bottom of Mr. Berg's reasons, and they learned to their sorrow that he

had penetrated some of their secrets.

Before going to bed that night Tom and Mr. Sharp paid a visit to the

shed where the submarine was resting on the ways, ready for launching.

They found Mr. Jackson on guard and the engineer said that no one had

been around. Nor was anything found disturbed.

"It certainly is a great machine," remarked the lad as he looked up at

the cigar-shaped bulk towering over his head. "Dad has outdone himself

this trip."

"It looks all right," commented Mr. Sharp. "Whether it will work is

another question."

"Yes, we can't tell until it's in the water," conceded Tom. "But I

hope it does. Dad has spent much time and money on it."

The Advance was, as her name indicated, much in advance of previous

submarines. There was not so much difference in outward construction as

there was in the means of propulsion and in the manner in which the

interior and the machinery were arranged.

The submarine planned by Mr. Swift and Tom jointly, and constructed by

them, with the aid of Mr. Sharp and Mr. Jackson, was shaped like a

Cigar, over one hundred feet long and twenty feet in diameter at the

thickest part. It was divided into many compartments, all water-tight,

so that if one or even three were flooded the ship would still be

useable.

Buoyancy was provided for by having several tanks for the introduction

of compressed air, and there was an emergency arrangement so that a

collapsible aluminum container could be distended and filled with a

powerful gas. This was to be used if, by any means, the ship was

disabled on the bottom of the ocean. The container could be expanded

and filled, and would send the Advance to the surface.

Another peculiar feature was that the engine-room, dynamos and other

apparatus were all contained amidships. This gave stability to the

craft, and also enabled the same engine to operate both shafts and

propellers, as well as both the negative forward electrical plates, and

the positive rear ones.

These plates were a new idea in submarine construction, and were the

outcome of an idea of Mr. Swift, with some suggestions from his son.

The aged inventor did not want to depend on the usual screw propellers

for his craft, nor did he want to use a jet of compressed air, shooting

out from a rear tube, nor yet a jet of water, by means of which the

creature called the squid shoots himself along. Mr. Swift planned to

send the Advance along under water by means of electricity.

Certain peculiar plates were built at the forward and aft blunt noses

of the submarine. Into the forward plate a negative charge of

electricity was sent, and into the one at the rear a positive charge,

just as one end of a horseshoe magnet is positive and will repel the

north end of a compass needle, while the other pole of a magnet is

negative and will attract it. In electricity like repels like, while

negative and positive have a mutual attraction for each other.

Mr. Swift figured out that if he could send a powerful current of

negative electricity into the forward plate it would pull the boat

along, for water is a good conductor of electricity, while if a

positive charge was sent into the rear plate it would serve to push the

submarine along, and he would thus get a pulling and pushing motion,

just as a forward and aft propeller works on some ferry boats.

But the inventor did not depend on these plates alone. There were

auxiliary forward and aft propellers of the regular type, so that if

the electrical plates did not work, or got out of order, the screws

would serve to send the Advance along.

There was much machinery in the submarine. There were gasolene motors,

since space was too cramped to allow the carrying of coal for boilers.

There were dynamos, motors and powerful pumps. Some of these were for

air, and some for water. To sink the submarine below the surface large

tanks were filled with water. To insure a more sudden descent,

deflecting rudders were also used, similar to those on an airship.

There were also special air pumps, and one for the powerful gas, which

was manufactured on board.

Forward from the engine-room was a cabin, where meals could be served,

and where the travelers could remain in the daytime. There was also a

small cooking galley, or kitchen, there. Back of the engine-room were

the sleeping quarters and the storerooms. The submarine was steered

from the forward compartment, and here were also levers, wheels and

valves that controlled all the machinery, while a number of dials

showed in which direction they were going, how deep they were, and at

what speed they were moving, as well as what the ocean pressure was.

On top, forward, was a small conning, or observation tower, with

auxiliary and steering and controlling apparatus there. This was to be

used when the ship was moving along on the surface of the ocean, or

merely with the deck awash. There was a small flat deck surrounding

the conning tower and this was available when the craft was on the

surface.

There was provision made for leaving the ship when it was on the bed of

the ocean. When it was desired to do this the occupants put on diving

suits, which were provided with portable oxygen tanks. Then they

entered a chamber into which water was admitted until it was equal in

pressure to that outside. Then a steel door was opened, and they could

step out. To re-enter the ship the operation was reversed. This was

not a new feature. In fact, many submarines to-day use it.

At certain places there were thick bull's-eye windows, by means of

which the under-water travelers could look out into the ocean through

which they were moving. As a defense against the attacks of submarine

monsters there was a steel, pointed ram, like a big harpoon. There were

also a bow and a stern electrical gun, of which more will be told later.

In addition to ample sleeping accommodations, there were many

conveniences aboard the Advance. Plenty of fresh water could be

carried, and there was an apparatus for distilling more from the sea

water that surrounded the travelers. Compressed air was carried in

large tanks, and oxygen could be made as needed. In short, nothing that

could add to the comfort or safety of the travelers had been omitted.

There was a powerful crane and windlass, which had been installed when

Mr. Swift thought his boat might be bought by the Government. This was

to be used for raising wrecks or recovering objects from the bottom of

the ocean. Ample stores and provisions were to be carried and, once the

travelers were shut up in the Advance, they could exist for a month

below the surface, providing no accident occurred.

All these things Tom and Mr. Sharp thought of as they looked over the

ship before turning in for the night. The craft was made immensely

strong to withstand powerful pressure at the bottom of the ocean. The

submarine could penetrate to a depth of about three miles. Below that

it was dangerous to go, as the awful force would crush the plates,

powerful as they were.

"Well, we'll rush things to-morrow and the next day," observed Tom as

he prepared to leave the building. "Then we'll soon see if it works."

For the next week there were busy times in the shop near the ocean.

Great secrecy was maintained, and though curiosity seekers did stroll

along now and then, they received little satisfaction. At first Mr.

Swift thought that the visit of Mr. Berg would have unpleasant results,

for he feared that the agent would talk about the craft, of which he

had so unexpectedly gotten a sight. But nothing seemed to follow from

his chance inspection, and it was forgotten.

It was one evening, about a week later, that Tom was alone in the shop.

The two mechanics that had been hired to help out in the rush had been

let go, and the ship needed but a few adjustments to make it ready for

the sea.

"I think I'll just take another look at the water tank valves," said

Tom to himself as he prepared to enter the big compartments which

received the water ballast. "I want to be sure they work properly and

quickly. We've got to depend on them to make us sink when we want to,

and, what's more important, to rise to the surface in a hurry. I've got

time enough to look them over before dad and Mr. Sharp get back."

Tom entered the starboard tank by means of an emergency sliding door

between the big compartments and the main part of the ship. This was

closed by a worm and screw gear, and once the ship was in the water

would seldom be used.

The young inventor proceeded with his task, carefully inspecting the

valves by the light of a lantern he carried. The apparatus seemed to

be all right, and Tom was about to leave when a peculiar noise

attracted his attention. It was the sound of metal scraping on metal,

and the lad's quick and well-trained ear told him it was somewhere

about the ship.

He turned to leave the tank, but as he wheeled around his light flashed

on a solid wall of steel back of him. The emergency outlet had been

closed! He was a prisoner in the water compartment, and he knew, from

past experience, that shout as he would, his voice could not be heard

ten feet away. His father and Mr. Sharp, as he was aware, had gone to a

nearby city for some tools, and Mr. Jackson, the engineer, was

temporarily away. Mrs. Baggert, in the house, could not hear his cries.

"I'm locked in!" cried Tom aloud. "The worm gear must have shut of

itself. But I don't see how that could be. I've got to get out mighty

soon, though, or I'll smother. This tank is airtight, and it won't take

me long to breath up all the oxygen there is here. I must get that

slide open."

He sought to grasp the steel plate that closed the emergency opening.

His fingers slipped over the smooth, polished surface. He was

hermetically sealed up--a captive! Blankly he set his lantern down and

leaned hopelessly against the wall of the tank.

"I've got to get out," he murmured.

As if in answer to him he heard a voice on the outside, crying:

"There, Tom Swift! I guess I've gotten even with you now! Maybe next

time you won't take a reward away from me, and lick me into the

bargain. I've got you shut up good and tight, and you'll stay there

until I get ready to let you out."

"Andy Foger!" gasped Tom. "Andy Foger sneaked in here and turned the

gear. But how did he get to this part of the coast? Andy Foger, you let

me out!" shouted the young inventor; and as Andy's mocking laugh came

to him faintly through the steel sides of the submarine, the imprisoned

lad beat desperately with his hands on the smooth sides of the tank,

vainly wondering how his enemy had discovered him.

Chapter Five

Mr. Berg is Suspicious

Not for long did the young inventor endeavor to break his way out of

the water-ballast tank by striking the heavy sides of it. Tom realized

that this was worse than useless. He listened intently, but could hear

nothing. Even the retreating footsteps of Andy Foger were inaudible.

"This certainly is a pickle!" exclaimed Tom aloud. "I can't understand

how he ever got here. He must have traced us after we went to Shopton

in the airship the last time. Then he sneaked in here. Probably he saw

me enter, but how could he know enough to work the worm gear and close

the door? Andy has had some experience with machinery, though, and one

of the vaults in the bank where his father is a director closed just

like this tank. That's very likely how he learned about it. But I've

got to do something else besides thinking of that sneak, Andy. I've got

to get out of here. Let's see if I can work the gear from inside."

Before he started, almost, Tom knew that it would be impossible. The

tank was made to close from the interior of the submarine, and the

heavy door, built to withstand the pressure of tons of water, could not

be forced except by the proper means.

"No use trying that," concluded the lad, after a tiring attempt to

force back the sliding door with his hands. "I've got to call for help."

He shouted until the vibrations in the confined space made his ears

ring, and the mere exertion of raising his voice to the highest pitch

made his heart beat quickly. Yet there came no response. He hardly

expected that there would be any, for with his father and Mr. Sharp

away, the engineer absent on an errand, and Mrs. Baggert in the house

some distance off, there was no one to hear his calls for help, even if

they had been capable of penetrating farther than the extent of the

shed, where the under-water craft had been constructed.

"I've got to wait until some of them come out here," thought Tom.

"They'll be sure to release me and make a search. Then it will be easy

enough to call to them and tell them where I am, once they are inside

the shed. But--" He paused, for a horrible fear came over him. "Suppose

they should come--too late?" The tank was airtight. There was enough

air in it to last for some time, but, sooner or later, it would no

longer support life. Already, Tom thought, it seemed oppressive, though

probably that was his imagination.

"I must get out!" he repeated frantically. "I'll die in here soon."

Again he tried to shove back the steel door. Then he repeated his cries

until he was weary. No one answered him. He fancied once he could hear

footsteps in the shed, and thought, perhaps, it was Andy, come back to

gloat over him. Then Tom knew the red-haired coward would not dare

venture back. We must do Andy the justice to say that he never realized

that he was endangering Tom's life. The bully had no idea the tank was

airtight when he closed it. He had seen Tom enter and a sudden whim

came to him to revenge himself.

But that did not help the young inventor any. There was no doubt about

it now--the air was becoming close. Tom had been imprisoned nearly two

hours, and as he was a healthy, strong lad, he required plenty of

oxygen. There was certainly less than there had been in the tank. His

head began to buzz, and there was a ringing in his ears.

Once more he fell upon his knees, and his fingers sought the small

projections of the gear on the inside of the door. He could no more

budge the mechanism than a child could open a burglar-proof vault.

"It's no use," he moaned, and he sprawled at full length on the floor

of the tank, for there the air was purer. As he did so his fingers

touched something. He started as they closed around the handle of a big

monkey wrench. It was one he had brought into the place with him.

Imbued with new hope he struck a match and lighted his lantern, which

he had allowed to go out as it burned up too much of the oxygen. By the

gleam of it he looked to see if there were any bolts or nuts he could

loosen with the wrench, in order to slide the door back. It needed but

a glance to show him the futility of this.

"It's no go," he murmured, and he let the wrench fall to the floor.

There was a ringing, clanging sound, and as it smote his ears Tom

sprang up with an exclamation.

"That's the thing!" he cried. "I wonder I didn't think of it before. I

can signal for help by pounding on the sides of the tank with the

wrench. The blows will carry a good deal farther than my voice would."

Every one knows how far the noise of a boiler shop, with hammers

falling on steel plates, can be heard; much farther than can a human

voice.