TOM SWIFT AND HIS GIANT CANNON

OR

The Longest Shots on Record

 

 

 

 

CONTENTS

 

CHAPTER

      I  ON A LIVE WIRE

     II  "WE'LL TAKE A CHANCE!"

    III  PLANNING A BIG GUN

     IV  KOKU'S BRAVE ACT

      V  OFF TO SANDY HOOK

     VI  TESTING THE WALLER GUN

    VII  THE IMPOSSIBLE OCCURS

   VIII  A BIG PROBLEM

     IX  THE NEW POWDER

      X  SOMETHING WRONG

     XI  FAILURE AND SUCCESS

    XII  A POWERFUL BLAST

   XIII  CASTING THE CANNON

    XIV  A NIGHT INTRUDER

     XV  READY FOR THE TEST

    XVI  A WARNING

   XVII  THE BURSTING DAM

  XVIII  THE DOPED POWDER

    XIX  BLOWING DOWN THE BARRIER

     XX  THE GOVERNMENT ACCEPTS

    XXI  OFF FOR PANAMA

   XXII  AT GATUN LOCKS

  XXIII  NEWS OF THE MINE

   XXIV  THE LONGEST SHOT

    XXV  THE LONG-LOST MINE

 

 

 

 

TOM SWIFT AND HIS GIANT CANNON

 

 

 

CHAPTER I

 

ON A LIVE WIRE

 

 

"Now, see here, Mr. Swift, you may think it all a sort of

dream, and imagine that I don't know what I'm talking about; but

I do! If you'll consent to finance this expedition to the extent

of, say, ten thousand dollars, I'll practically guarantee to give

you back five times that sum

 

"I don't know, Alec, I don't know," slowly responded the aged

inventor. "I've heard those stories before, and in my experience

nothing ever came of them. Buried treasure, and lost vessels

filled with gold, are all well and good, but hunting for an opal

mine on some little-heard-of island goes them one better."

 

"Then you don't feel like backing me up in this matter, Mr.

Swift?"

 

"No, Alec, I can't say I do. Why, just stop and think for a

minute. You're asking me to put ten thousand dollars into a

company, to fit out an expedition to go to this island--somewhere

down near Panama, you say it is--and try to locate the lost mine

from which, some centuries ago, opals and other precious stones

came. It doesn't seem reasonable."

 

"But I'm sure I can find the mine, Mr. Swift!" persisted Alec

Peterson, who was almost as elderly a man as the one he

addressed. "I have the old documents that tell how rich the mine

once was, how the old Mexican rulers used to get their opals from

it, and how all trace of it was lost in the last century. I have

all the landmarks down pat, and I'm sure I can find it. Come on

now, take a chance. Put in this ten thousand dollars. I can

manage the rest. You'll get back more than five times your

investment."

 

"If you find the mine--yes."

 

"I tell you I will find it! Come now, Mr. Swift," and the

visitor's voice was very pleading, "you and your son Tom have

made a fortune for yourselves out of your different inventions.

Be generous, and lend me this ten thousand dollars."

 

Mr. Swift shook his head.

 

"I've heard you talk the same way before, Alec," he replied.

"None of your schemes ever amounted to anything. You've been a

fortune-hunter all your life, nearly; and what have you gotten

out of it? Just a bare living."

 

"That's right, Mr. Swift, but I've had bad luck. I did find the

lost gold mine I went after some years ago, you remember."

 

"Yes, only to lose it because the missing heirs turned up, and

took it away from you. You could have made more at straight

mining in the time you spent on that scheme."

 

"Yes, I suppose I could; but this is going to be a success--I

feel it in my bones."

 

"That's what you say, every time, Alec. No, I don't believe I

want to go into this thing."

 

"Oh, come--do! For the sake of old times. Don't you recall how

you and I used to prospect together out in the gold country; how

we shared our failures and successes?"

 

"Yes, I remember that, Alec. Mighty few successes we had,

though, in those days."

 

"But now you've struck it rich, pardner," went on the pleader.

"Help me out in this scheme--do!"

 

"No, Alec. I'd rather give you three or four thousand dollars

for yourself, if you'd settle down to some steady work, instead

of chasing all over the country after visionary fortunes. You're

getting too old to do that."

 

"Well, it's a fact I'm no longer young. But I'm afraid I'm too

old to settle down. You can't teach an old dog new tricks,

pardner. This is my life, and I'll have to live it until I pass

out. Well, if you won't, you won't, I suppose. By the way, where

is Tom? I'd like to see him before I go back. He's a mighty fine

boy."

 

"That's what he is!" broke in a new voice. "Bless my overshoes,

but he is a smart lad! A wonderful lad, that's what! Why, bless

my necktie, there isn't anything he can't invent; from a button-

hook to a battleship! Wonderful boy--that's what!"

 

"I guess Tom's ears would burn if he could hear your praises,

Mr. Damon," laughed Mr. Swift. "Don't spoil him."

 

"Spoil Tom Swift? You couldn't do it in a hundred years!" cried

Mr. Damon, enthusiastically. "Bless my topknot! Not in a thousand

years--no, sir!"

 

"But where is he?" asked Mr. Peterson, who was evidently unused

to the extravagant manner of Mr. Damon.

 

"There he goes now!" exclaimed the gentleman who frequently

blessed himself, some article of his apparel, or some other

object. "There he goes now, flying over the house in that Humming

Bird airship of his. He said he was going to try out a new

magneto he'd invented, and it seems to be working all right. He

said he wasn't going to take much of a flight, and I guess he'll

soon be back. Look at him! Isn't he a great one, though!"

 

"He certainly is," agreed Mr. Peterson, as he and Mr. Swift

went to the window, from which Mr. Damon had caught a glimpse of

the youthful Inventor in his airship. "A great lad. I wish he

could come on this mine-hunt with me, though I'd never consent to

go in an airship. They're too risky for an old man like me."

 

"They're as safe as a church when Tom Swift runs them!"

declared Mr. Damon. "I'm no boy, but I'd go anywhere with Tom."

 

"I'm afraid you wouldn't get Tom to go with you, Alec," went on

Mr. Swift, as he resumed his chair, the young inventor in his

airship having passed out of sight. "He's busy on some new

invention now, I believe. I think I heard him say something about

a new rifle."

 

"Cannon it was, Mr. Swift," said Mr. Damon. "Tom has an idea

that he can make the biggest cannon in the world; but it's only

an idea yet."

 

"Well, then I guess there's no hope of my interesting him in my

opal mine," said the fortune-hunter, with rather a disappointed

smile. "Nor you either, Mr. Swift."

 

"No, Alec, I'm afraid not. As I said, I'd rather give you

outright three or four thousand dollars, if you wanted it,

provided that you used it for your own personal needs, and

promised not to sink it in some visionary search."

 

Mr. Peterson shook his head.

 

"I'm not actually in want," he said, "and I couldn't accept a

gift of money, Mr. Swift. This is a straight business

proposition."

 

"Not much straight business in hunting for a mine that's been

lost for over a century," replied the aged inventor, with a

glance at Mr. Damon, who was still at the window, watching for a

glimpse of Tom on his return trip in the air craft.

 

"If Tom would go, I'd trail along," said the odd man. "We

haven't done anything worth speaking of since he used his great

searchlight to detect the smugglers. But I don't believe he'll

go. That mining proposition sounds good."

 

"It is good!" cried Mr. Peterson, with fervor, hoping he had

found a new "prospect" in Mr. Damon.

 

"But not business-good," declared Mr. Swift, and for some time

the three argued the matter, Mr. Swift continuing to shake his

head.

 

Suddenly into the room there ran an aged colored man, much

excited.

 

"Fo' de land sakes!" he cried. "Somebody oughter go out an'

help Massa Tom!"

 

"Why, what's the matter, Eradicate?" asked Mr. Swift, leaping

to his feet, an example followed by the other two men. "What has

happened to my son?"

 

"I dunno, Massa Swift, but I looked up jest now, an' dere he

be, in dat air-contraption ob his'n he calls de Hummin' Burd.

He's ketched up fast on de balloon shed roof, an' dere he's

hangin' wif sparks an' flames a-shootin' outer de airship suffin'

scandalous! It's jest spittin' fire, dat's what it's a-doin', an'

ef somebody don't do suffin' fo' Massa Tom mighty quick, dere

ain't gwin t' be any Massa Tom; now dat's what I'se aÄtellin'

you!"

 

"Bless my shoe buttons!" gasped Mr. Damon. "Come on out,

everybody! We've got to help Tom!"

 

"Yes!" assented Mr. Swift. "Call someone on the telephone! Get

a doctor! Maybe he's shocked! Where's Koku, the giant? Maybe he

can help!"

 

"Now doan't yo' go t' gittin' all excited-laik," objected

Eradicate Sampson, the aged colored man. "Remember yo' all has

got a weak heart, Massa Swift!"

 

"I know it; but I must save my son. Hurry!"

 

Mr. Swift ran from the room, followed by Mr. Damon and Mr.

Peterson, while Eradicate trailed after them as fast as his

tottering limbs would carry him, murmuring to himself.

 

"There he is!" cried Mr. Damon, as he caught sight of the young

inventor in his airship, in a position of peril. Truly it was as

Eradicate had said. Caught on the slope of the roof of his big

balloon shed, Tom Swift was in great danger.

 

From his airship there shot dazzling sparks, and streamers of

green and violet fire. There was a snapping, cracking sound that

could be heard above the whir of the craft's propellers, for the

motor was still running.

 

"Oh, Tom! Tom! What is it? What has happened?" cried his

father.

 

"Keep back! Don't come too close!" yelled the young inventor,

as he clung to the seat of the aeroplane, that was tilted at a

dangerous angle. "Keep away!"

 

"What's the matter?" demanded Mr. Damon. "Bless my pocket comb

--what is it?"

 

"A live wire!" answered Tom. "I'm caught in a live wire! The

trailer attached to the wireless outfit on my airship is crossed

with the wire from the power plant. There's a short circuit

somewhere. Don't come too close, for it may burn through any

second and drop down. Then it will twist about like a snake!"

 

"Land ob massy!" cried Eradicate.

 

"What can we do to help you?" called Mr. Swift. "Shall I run

and shut off the power?" for in the shop where Tom did most of

his inventive work there was a powerful dynamo, and it was on one

of the wires extending from it, that brought current into the

house, that the craft had caught.

 

"Yes, shut it off if you can!" Tom shouted back. "But be

careful. Don't get shocked! Wow! I got a touch of it myself that

time!" and he could be seen to writhe in his seat.

 

"Oh, hurry! hurry! Find Koku!" cried Mr. Swift to Mr. Damon,

who had started for the power house on the run.

 

The sparks and lances of fire seemed to increase around the

young inventor. The airship could be seen to slip slowly down the

sloping roof.

 

"Land ob massy! He am suah gwine t' fall!" yelled Eradicate.

 

"Oh, he'll never get that current shut off in time!" murmured

Mr. Swift, as he started after Mr. Damon.

 

"Wait! I think I have a plan!" called Mr. Peterson. "I think I

can save Tom!"

 

He did not waste further time in talk, but, running to a nearby

shed, he got a long ladder that he saw standing under it. With

this over his shoulder he retraced his steps to the balloon

hangar and placed the ladder against the side. Then he started to

climb up.

 

"What are you going to do?" yelled Tom, leaning over from his

seat to watch the elderly fortune-hunter.

 

"I'm going to cut that wire!" was the answer.

 

"Don't! If you touch it you'll be shocked to death! I may be

able to get out of here. So far I've only had light shocks, but

the insulation is burning out of my magneto, and that will soon

stop. When it does I can't run the motor, and--"

 

"I'm going to cut that wire!" again shouted Mr. Peterson.

 

"But you can't, without pliers and rubber gloves!" yelled Tom.

"Keep away, I tell you!"

 

The man on the ladder hesitated. Evidently he had not thought

of the necessity of protecting his hands by rubber covering, in

order that the electricity might be made harmless. He backed down

to the ground.

 

"I saw a pair of old gloves in the shed!" he cried. "I'll get

them--they look like rubber."

 

"They are!" cried Tom, remembering now that he had been putting

up a new wire that day, and had left his rubber gloves there.

"But you haven't any pliers!" the lad went. "How can you cut wire

without them? There's a pair in the shop, but--"

 

"Heah dey be! Heah dey be!" cried Eradicate, as he produced a

heavy pair from his pocket. "I--I couldn't find de can-opener fo'

Mrs. Baggert, an' I jest got yo' pliers, Massa Tom. Oh, how glad

I is dat I did. Here's de pincers, Massa Peterson."

 

He handed them to the fortune-hunter, who came running back

with the rubber gloves. Mr. Damon was no more than half way to

the power house, which was quite a distance from the Swift

homestead. Meanwhile Tom's airship was slipping more and more,

and a thick, pungent smoke now surrounded it, coming from the

burning insulation. The sparks and electrical flames were worse

than ever.

 

"Just a moment now, and I'll have you safe!" cried the fortune-

hunter, as he again mounted the ladder. Luckily the charged wire

was near enough to be reached by going nearly to the top of the

ladder.

 

Holding the pincers in his rubber-gloved hands, the old man

quickly snipped the wire. There was a flash of sparks as the

copper conductor was severed, and then the shower of sparks about

Tom's airship ceased.

 

In another second he had turned on full power, the propellers

whizzed with the quickness of light, and he rose in the air, off

the shed roof, the live wire no longer entangling him. Then he

made a short circuit of the work-shop yard, and came to the

ground safely a little distance from the balloon hangar.

 

"Saved! Tom is saved!" cried Mr. Swift, who had seen the act of

Mr. Peterson from a distance. "He saved my boy's life!"

 

"Thanks, Mr. Peterson!" exclaimed the young inventor, as he

left his seat and walked up to the fortune-hunter. "You certainly

did me a good turn then. It was touch and go! I couldn't have

stayed there many seconds longer. Next time I'll know better than

to fly with a wireless trailer over a live conductor," and he

held out his hand to Mr. Peterson.

 

"I'm glad I could help you, Tom," spoke the other, warmly. "I

was afraid that if you had to wait until they shut off the power

it would be too late."

 

"It would--it would--er--I feel--I--"

 

Tom's voice trailed off into a whisper and he swayed on his

feet.

 

"Cotch him!" cried Eradicate. "Cotch him! Massa Tom's hurt!"

and only just in time did Mr. Peterson clutch the young inventor

in his arms. For Tom, white of face, had fallen back in a dead

faint.

 

 

 

CHAPTER II

 

"WE'LL TAKE A CHANCE!"

 

 

"Carry him into the house!" cried Mr. Swift, as he came running

to where Mr. Peterson was loosening Tom's collar.

 

"Git a doctor!" murmured Eradicate. "Call someone on de

tellifoam! Git fo' doctors!"

 

"We must get him into the house first," declared Mr. Damon,

who, seeing that Tom was off the shed roof, had stopped mid-way

to the powerhouse, and retraced his steps. "Let's carry him into

the house. Bless my pocketbook! but he must have been shocked

worse than he thought."

 

They lifted the inert form of our hero and walked toward the

mansion with him, Mrs. Baggert, the housekeeper, standing in the

doorway in dismay, uncertain what to do.

 

And while Tom is being cared for I will take just a moment to

tell my new readers something more about him and his inventions,

as they have been related in the previous books of this series.

 

The first volume was called "Tom Swift and His Motor-Cycle,"

and this machine was the means of his becoming acquainted with

Mr. Wakefield Damon, the odd gentleman who so often blessed

things. On his motor-cycle Tom had many adventures.

 

The lad was of an inventive mind, as was his father, and in the

succeeding books of the series, which you will find named in

detail elsewhere, I related how Tom got a motorboat, made an

airship, and later a submarine, in all of which craft he had

strenuous times and adventures.

 

His electric runabout was quite the fastest car on the road,

and when he sent his wonderful wireless message he saved himself

and others from Earthquake Island. He solved the secret of the

diamond makers, and, though he lost a fine balloon in the caves

of ice, he soon had another air craft--a regular sky-racer. His

electric rifle saved a party from the red pygmies in Elephant

Land, and in his air glider he found the platinum treasure. With

his wizard camera, Tom took wonderful moving pictures, and in the

volume immediately preceding this present one, called "Tom Swift

and His Great Searchlight," I had the pleasure of telling you how

the lad captured the smugglers who were working against Uncle Sam

over the border.

 

Tom, as you will see, had, with the help of his father,

perfected many wonderful inventions. The lad lived with his aged

parent, his mother being dead, in the village of Shopton, in New

York State.

 

While the house, which was presided over by the motherly Mrs.

Baggert, was large, it was almost lost now amid the many

buildings surrounding it, from balloon and airship hangars, to

shops where varied work was carried on. For Tom did most of his

labor himself, of course with men to help him at the heavier

tasks. Occasionally he had to call on outside shops.

 

In the household, beside his father, himself and Mrs. Baggert,

was Eradicate Sampson, an aged colored man-of-all-work, who said

he was called "Eradicate" because he eradicated dirt. There was

also Koku, a veritable giant, one of two brothers whom Tom had

brought with him from Giant Land, when he escaped from captivity

there, as related in the book of that name.

 

Mr. Damon was, with Ned Newton, Tom's chum, the warmest friend

of the family, and was often at Tom's home, coming from the

neighboring town of Waterford, where he lived.

 

Tom had been back some time now from working for the government

in detecting the smugglers, but, as you may well suppose, he had

not been idle. Inventing a number of small things, including

useful articles for the house, was a sort of recreation for him,

but his mind was busy on one great scheme, which I will tell you

about in due time.

 

Among other things he had just perfected a new style of magneto

for one of his airships. The magneto, as you know, is a sort of

small dynamo, that supplies the necessary spark to the cylinder,

to explode the mixture of air and gasoline vapor. He was trying

out this magneto in the Humming Bird when the accident I have

related in the first chapter occurred.

 

"There! He's coming to!" exclaimed Mrs. Baggert, as she leaned

over Tom, who was stretched out on the sofa in the library. "Give

him another smell of this ammonia," she went on, handing the

bottle to Mr. Swift.

 

"No--no," faintly murmured Tom, opening his eyes. "I--I've had

enough of that, if you please! I'm all right."

 

"Are you sure, Tom?" asked his father. "Aren't you hurt

anywhere?"

 

"Not a bit, Dad! It was foolish of me to go off that way; but I

couldn't seem to help it. It all got black in front of me, and--

well, I just keeled over."

 

"I should say you did," spoke Mr. Peterson.

 

"An' ef he hadn't a-been there to cotch yo' all," put in

Eradicate, "yo' all suah would hab hit de ground mighty hard."

 

"That's two services he did for me today," said Tom, as he

managed to sit up. "Cutting that wire--well, it saved my life,

that's certain."

 

"I believe you, Tom," said Mr. Swift, solemnly, and he held out

his hand to his old mining partner.

 

"Do you need the doctor?" asked Mr. Damon, who was at the

telephone. "He says he'll come right over--I can get him in Tom's

electric runabout, if you say so. He's on the wire now."

 

"No, I don't need him," replied the young inventor. "Thank him

just the same. It was only an ordinary faint, caused by the

slight electrical shocks, and by getting a bit nervous, I guess.

I'm all right--see," and he proved it by standing up.

 

"He's ail right--don't come, doctor," said Mr. Damon into the

telephone. "Bless my keyring!" he exclaimed, "but that was a

strenuous time!"

 

"I've been in some tight places before," went on Tom, as he sat

down in an easy chair, "and I've had any number of shocks when

I've been experimenting, but this was a sort of double

combination, and it sure had me guessing. But I'm feeling better

every minute."

 

"A cup of hot tea will do you good," said motherly Mrs.

Baggert, as she bustled out of the room. "I'll make it for you."

 

"You cut that wire as neatly as any lineman could," went on

Tom, glancing from Mr. Peterson out of the window to where one of

his workmen was repairing the break. "When I flew over it in my

airship I never gave a thought to the trailer from my wireless

outfit. The first I knew I was caught back, and then pulled down

to the balloon shed roof, for I tilted the deflecting rudder by

mistake.

 

"But, Mr. Peterson," Tom went on, "I haven't seen you in some

time. Anything new on, that brings you here?" for the fortune-

hunter had called at the Swift house after Tom had gone out to

the shop to get his airship ready for the flight to try the

magneto.

 

"Well, Tom, I have something rather new on," replied Mr.

Peterson. "I hoped to interest your father in it, but he doesn't

seem to care to take a chance. It's a lost opal mine on a little-

known island in the Caribbean Sea not far from the city of Colon.

I say not far--by that I mean about twenty miles. But your father

doesn't want to invest, say, ten thousand dollars in it, though I

can almost guarantee that he'll get five times that sum back. So,

as long as he doesn't feel that he can help me out, I guess I'd

better be traveling on."

 

"Hold on! Wait a minute. Don't be in a hurry," said Mr. Swift.

 

Mr. Peterson was an old friend, and when he and Mr. Swift were

young men they had prospected and grub-staked together. But Mr.

Swift soon gave that up to devote his time to his inventions,

while Mr. Peterson became a sort of rolling stone.

 

He was a good man, but somewhat visionary, and a bit inclined

to "take chances"--such as looking for lost treasure--rather than

to devote himself to some steady employment. The result was that

he led rather a precarious life, though never being actually in

want.

 

"No, pardner," he said to Mr. Swift. "It's kind of you to ask

me to stay; but this mine business has got a grip on me. I want

to try it out. If you won't finance the project someone else may.

I'll say good-bye, and--"

 

"Now just a minute," said Mr. Swift. "It's true, Alec, I had

about made up my mind not to go into this thing, when this

accident happened to Tom. Now you practically saved his life.

You--"

 

"Oh, pshaw! I only acted on the spur of the moment. Anyone

could have done what I did," protested the fortune-hunter.

 

"Oh, but you did it!" insisted Mr. Swift, "and you did it in

the nick of time. Now I wouldn't for a moment think of offering

you a reward for saving my son's life. But I do feel mighty

friendly toward you--not that I didn't before--but I do want to

help you. Alec, I will go into this business with you. We'll take

a chance! I'll invest ten thousand dollars, and I'm not so awful

worried about getting it back, either--though I don't believe in

throwing money away."

 

"You won't throw it away in this case!" declared Mr. Peterson,

eagerly. "I'm sure to find that mine; but it will take a little

capital to work it. That's what I need--capital!"

 

"Well, I'll supply it to the extent of ten thousand dollars,"

said Mr. Swift. "Tom, what do you think of it? Am I foolish or

not?"

 

"Not a bit of it, Dad!" cried the young man, who was now

himself again. "I'm glad you took that chance, for, if you

hadn't--well, I would have supplied the money myself--that's

all," and he smiled at the fortune-hunter.

 

 

 

CHAPTER III

 

PLANNING A BIG GUN

 

 

"BUT, Tom, I don't see how in the world you can ever hope to

make a bigger gun than that."

 

"I think it can be done, Ned," was the quiet answer of the

young inventor. He looked up from some drawings on the table in

the office of one of his shops. "Now I'll just show you--"

 

"Hold on, Tom. You know I have a very poor head for figures,

even if I do help you out once in a while on some of your work.

Skip the technical details, and give me the main facts."

 

The two young men--Ned Newton being Tom's special chum--were

talking together over Tom's latest scheme.

 

It was several days after Tom's accident in the airship, when

he had been saved by the prompt action of Mr. Peterson. That

fortune-hunter, once he had the promise of Mr. Swift to invest in

his somewhat visionary plan of locating a lost opal mine near the

Panama Canal, had left the Swift homestead to arrange for fitting

out the expedition of discovery. He had tried to prevail on Tom

to accompany him, and, failing in that, tried to work on Mr.

Damon.

 

"Bless my watch chain!" exclaimed that odd gentleman. "I would

like to go with you first rate. But I'm so busy--so very busy--

that I can't think of it. I have simply neglected all my affairs,

chasing around the country with Tom Swift. But if Tom goes I--

ahem! I think perhaps I could manage it--ahem!"

 

"I thought you were busy," laughed Tom.

 

"Oh, well, perhaps I could get a few weeks off. But I'm not

going--no, bless my check book, I must get back to business!"

 

But as Mr. Damon was a retired gentleman of wealth, his

"business" was more or less of a joke among his friends.

 

So then, a few days after the departure of Mr. Peterson, Tom

and Ned sat in the former's office, discussing the young

inventor's latest scheme.

 

"How big is the biggest gun ever made, Tom?" asked his chum. "I

mean in feet, in inches, or in muzzle diameter, however they are

measured."

 

"Well," began Tom, "of course some nation may, in secret, be

making a bigger gun than any I have ever heard of. As far as I

know, however, the largest one ever made for the United States

was a sixteen-inch rifled cannon--that is, it was sixteen inches

across at the muzzle, and I forget just how long. It weighed many

tons, however, and it now lies, or did a few years ago, in a

ditch at the Sandy Hook proving grounds. It was a failure."

 

"And yet you are figuring on making a cannon with a muzzle

thirty inches across--almost a yard--and fifty feet long and to

weigh--"

 

"No one can tell exactly how much it will weigh," interrupted

Tom. "And I'm not altogether certain about the muzzle

measurement, nor of the length. It's sort of in the air at

present. Only I don't see why a larger gun than any that has yet

been made, can't be constructed."

 

"If anybody can invent one, you can, Tom Swift!" exclaimed Ned,

admiringly.

 

"You flatter me!" exclaimed his chum, with a mock bow.

 

"But what good will it be?" went on Ned. "Making big guns

doesn't help any in war, that I can see."

 

"Ned!" exclaimed Tom, "you don't look far enough ahead. Now

here's my scheme in a nutshell. You know what Uncle Sam is doing

down in his big ditch; don't you?"

 

"You mean digging the Panama Canal?"

 

Yes, the greatest engineering feat of centuries. It is going

to make a big change in the whole world, and the United States is

going to become--if she is not already--a world-power. Now that

canal has to be protected--I mean against the possibility of

war. For, though it may never come, and the chances are it never

will, still it may.

 

"Uncle Sam has to be ready for it. There never was a more true

saying than 'in time of peace prepare for war.' Preparing for

war is, in my opinion, the best way not to have one.

 

"Once the Panama Canal is in operation, and the world-changes

incidental to it have been made, if it should pass into the hands

of some foreign country--as it very possibly might do--the United

States would not only be the laughing-stock of the world, but she

would lose the high place she holds.

 

"Now, then, to protect the canal, several things are necessary.

Among them are big guns--cannon that can shoot a long distance--

for if a foreign nation should send some of their new

dreadnaughts over here--vessels with guns that can shoot many

miles--where would the canal be once a bombardment was opened? It

would be ruined in a day--the immense lock-gates would be

destroyed. And, not only from the guns aboard ships would there

be danger, but from siege cannon planted in Costa Rica, or some

South American country below the canal zone.

 

"Now, to protect the canal against such an attack we need guns

that can shoot farther, straighter and more powerfully than any

at present in use, and we've got to have the most powerful

explosive. In other words, we've got to beat the biggest guns

that are now in existence. And I'm going to do it, Ned!"

 

"You are?"

 

"Yes, I'm going to invent a cannon that will make the longest

shots on record. I'm going to make a world-beater gun; or,

rather, I'm going to invent it, and have it made, for I guess it

would tax this place to the limit.

 

"I've been thinking of this for some time, Ned. I've been

puttering around inventing new magnetos, potato-parers and the

like, but this is my latest hobby. The Panama Canal is a big

thing--one of the biggest things in the world. We need the

biggest guns in the world to protect it.

 

"And, listen: Uncle Sam thinks the same way. I understand that

the best men in the service--at West Point, Annapolis and Sandy

Hook, as well as elsewhere--are working in the interest of the

United States to perfect a bigger cannon than any ever before

made. In fact, one has just been constructed, and is going to be

tried at the Sandy Hook proving grounds soon. I'm going to see

the test if I can.

 

"And here's another thing. Foreign nations are trying to steal

Uncle Sam's secrets. If this country gets a big cannon, some

other nation will want a bigger one. It's a constant warfare. I'm

going to devote my talents--such as they are--to Uncle Sam. I'm

going to make the biggest cannon in the world--the one that will

shoot the farthest and knock into smithereens all the other big

guns. That's the only way to protect the canal. Do you

understand, Ned?"

 

"Somewhat, Tom. Since I gave up my place in the bank, and

became a sort of handy-lad for you, I know more about your work.

But isn't it going to be dangerous to make a cannon like that?"

 

"Well, in a way, yes, Ned. But we've got to take chances, just

as father did when he invested ten thousand dollars in that opal

mine. He'll never see his money again."

 

"Don't you think so?"

 

"No, Ned."

 

"And when do you expect to start on your gun, Tom?"

 

"Right away. I'm making some plans now. I'm going down to Sandy

Hook and witness the test of this new big cannon. You can come

along, if you like."

 

"Well, I sure will like. When is it?"

 

"Oh, in about a week. I'll have to look--"

 

"'Scuse me, Massa Tom," broke in Eradicate, as he put his head

through the half-opened office door. "'Scuse me, but dere's a

express gen'men outside, wif his auto truck, an' he's got some

packages fo' yo' all, marked 'dangerous--explosive--an' keep away

fom de fire.' He want t' know what he all gwine t' do wif 'em,

Massa Tom?"

 

"Do with 'em? Oh, I guess it's that new giant powder I sent

for. Why, Eradicate, have him bring 'em right in here."

 

"Yais, sah, Massa Tom. Dat's all right; but he jest can't bring

'em in," and Eradicate looked behind him somewhat apprehensively.

 

"Can't bring 'em in? Why not, I'd like to know?" exclaimed Tom.

"He's paid for it."

 

"'Scuse me, Massa Tom," said the colored man, "but dat express

gen'men can't bring dem explosive powder boxes in heah, 'case as

how his autermobile hab done ketched fire an' he cain't get near

it nohow. Dat's why, Massa Tom!"

 

"Caesar's ghost!" yelled the young inventor. "The auto on fire,

and that powder in it! Come on Ned!" and he made a rush for the

door.

 

 

 

CHAPTER IV

 

KOKU'S BRAVE ACT

 

 

"Tom! Tom!" cried Ned, as he watched the disappearing figure of

his chum. "Come back here! If there's going to be an explosion we

ought to run out of the back door!"

 

"I'm not running away!" flashed back Tom. "I'm going to get

that powder out of the auto before it goes up! If it does we'll

be blown to kingdom come, back door or front door! Come on!"

 

"Bacon and eggs!" yelled Ned. "He's running an awful risk! But

I can't let him go alone! I guess we're in for it!"

 

Then he, too, rushed from the office toward the front of the

shop, before which, in a sort of private road, stood the blazing

auto. And Ned, who had now lost sight of Tom, because of our hero

having turned a corner in the corridor, heard excited shouts

coming from the seat of trouble.

 

"If that's some new kind of powder Tom's sent for, to test for

his new big gun, and it goes up," Ned said to himself, as he

rushed on, "this place will be blown to smithereens. All Tom's

valuable machinery and patents will be ruined!"

 

Ned had now reached the front door of the shop. He had a

glimpse of the burning auto--a small express truck, well loaded

with various packages. And, through the smoke, which from the

odor must have been caused by burning gasoline, Ned could see

several boxes marked in red letters:

 

 

DANGEROUS            EXPLOSIVE

 

 

     KEEP AWAY FROM FIRE

 

 

"Keep away from fire!" murmured the panting lad. "If they can

get any nearer fire I don't see how."

 

"Oh, mah golly!" gasped Eradicate, who had lumbered on behind

Ned. "Oh, mah golly! Oh, good land ob massy! Look at Massa Tom!"

 

"I've got to help him!" cried Ned, for he saw that his chum had

rushed to the rear of the auto, and was endeavoring to drag one

of the powder boxes across the lowered tail-board. Tom was

straining and tugging at it, but did not seem able to move the

case. It was heavy, as Ned learned later, and was also held down

by the weight of other express packages on top of it.

 

"Oh, mah golly!" cried Eradicate. "Git some watah, somebody,

an' put out dat fire!"

 

"No--no water!" yelled Tom, who heard him. "Water will only

make it worse--it'll scatter the blazing gasoline. The feed pipe

from the tank must have burst. Throw on sand--sand is the only

thing to use!"

 

"I'll git a shubble!" cried Eradicate. "I'll git a sand-

shubble!" and he tottered off.

 

"Wait, Tom, I'll give you a hand!" cried Ned, as he saw his

chum step away from the end of the auto for a moment, as a burst

of flame, and choking smoke, driven by the wind, was blown almost

in his face. "I'll help you!"

 

"We've got to be lively, then, Ned!" gasped Tom. "This is

getting hotter every minute! Where's that Koku? He could yank

these boxes out in a jiffy!"

 

And indeed a giant's strength was needed at that moment.

 

Ned glanced around to see if he could catch a glimpse of the

big man whom Tom had brought from Giant Land, but Koku was not in

sight.

 

"Let's have another try now, Ned!" suggested Tom, when a shift

in the wind left the rear of the auto comparatively free from

smoke and flame.

 

"You fellows had better skip!" cried the expressman, who had

been throwing light packages off his vehicle from in front,

where, as yet, there was no fire. "That powder'll go up in

another minute. Some of the boxes are beginning to catch now!" he

yelled. "Look out!"

 

"That's right!" shouted Tom, as he saw that the edge of one of

the wooden cases containing the powder was blazing slightly.

"Lively, Ned!"

 

Ned held back only for a second. Then, realizing that the time

to act was now or never, and that even if he ran he could hardly

save himself, he advanced to Tom's side. The smoke was choking

and stifling them, and the flames, coming from beneath the auto

truck, made them gasp for breath.

 

Together Tom and Ned tugged at the nearest case of powder--the

one that was ablaze.

 

"We--we can't budge it!" panted Tom.

 

"It--it's caught somewhere," added Ned. "Oh, if Koku were only

here!"

 

There was a sound behind the lads. A voice exclaimed:

 

"Master want shovel, so Eradicate say--here it is!"

 

They turned and saw a big, powerful man, with a simple, child-

like face, standing calmly looking at the burning auto.

 

"Koku!" cried Tom. "Quick! Never mind the shovel! Get those

powder boxes out of that cart before they go up! Yank 'em out!

They're too much for Ned and me! Quick!"

 

"Oh, of a courseness I will so do!" said Koku, to whom, even

yet, the English language was somewhat of a mystery. He dropped

the shovel, and, heedless of the thick smoke from the burning

gasoline, reached over and took hold of the nearest box. It

seemed as though he pulled it from the auto truck as easily as

Tom might have lifted a cork.

 

Then, carrying the box, which was now burning quite fiercely on

one corner, over toward Tom and Ned, who had moved back, the

giant asked:

 

"What you want of him, Master?"

 

"Put it down, Koku, and get out all the others! Lively, now,

Koku!"

 

"I do," was the simple answer. The giant put the box on the

grass and ran back toward the auto.

 

"Quick, Ned!" shouted Tom. "Throw some sand on this burning

box! That will put out the fire!"

 

A few handfuls of earth served to extinguish the little blaze,

and by this time Koku had come back with another box of powder.

 

"Get 'em all, Koku, get 'em all! Then we can put out the fire

on the auto."

 

For the giant it was but child's play to carry the heavy boxes

of powder, and soon he had them all removed from the truck. Then,

with the danger thus narrowly averted, they all, including the

expressman, turned in and began throwing sand on the fire, which

now had a good hold on the body of the auto. The shovel, which

Eradicate had sent by Koku, who could use more speed than could

the aged colored man, came in handy.

 

Soon the fire was out, though not before the truck had been

badly damaged, and some of its load destroyed. But, beyond a

charring of some of the powder boxes, the explosive was intact.

 

"Whew! That was a lucky escape," murmured Tom, as he sat down

on one of the boxes, and wiped the smoke and sweat from his face.

"A little later and there'd only been a hole in the ground to

tell what happened. hot work; eh, Ned?"

 

"I guess yes, Tom."

 

"I thought of the powder as soon as I saw that the truck was on

fire," explained the expressman; "but I didn't know what to do. I

was kinder flustered, I guess. This is the second time this old

truck has caught fire from a leaky gasoline pipe. I guess that

will be the last--it will for me, anyhow. I'll resign if they

don't give me another machine. Will you sign for your stuff?" he

asked Tom, holding out the receipt book, which had escaped the

flames.

 

"Yes, and I'm mighty glad I'm here to sign for it," replied the

young inventor. "Now, Koku, I guess you can take that stuff up to

the shop; but be careful where you put it."

 

"I do, Master," replied the giant.

 

"What sort of powder is that, Tom?" asked Ned a little later,

when they were again back in the office, the excitement having

calmed down. The expressman had gone back to town afoot, to

arrange about getting another vehicle for what remained of his

load. "Is it the kind they use in big guns?"

 

"One of the kinds," replied Tom. "I sent for several samples,

and this is one. I'm going to conduct some tests to see what kind

I'll need for my own big gun. But I expect I'll have to invent an

explosive as well as a cannon, for I want the most powerful I can

get. Want to look at some of this powder?"

 

"Yes, if you think it's safe."

 

"Oh, it's safe enough if you treat it right. I'll show you,"

and working carefully Tom soon had one of the boxes open.

Reaching into the depths he held up a handful of something that

looked like sticks of macaroni. "There it is," he said.

 

"That powder?" cried Ned. "That's a queer kind. I've seen the

kind they use in some guns on the battleships. That powder was in

hexagonal form, about two inches across, and had a hole in the

centre. It was colored brown."

 

"Well, powder is made in many forms," explained Tom. "A person

who has only seen black gunpowder, with its little grains, would

not believe that this was one grain of the new powder."

 

"That macaroni stick a grain of powder?" cried Ned.

 

"Yes, we'll call it a grain," went on the young inventor, "just

as the brown, hexagonal cube you saw was a grain. You see, Ned,

the idea is to explode all the powder at once--to get

instantaneous action. It must all burn up at once as soon as it

is detonated, or set off.

 

"To do that you have to have every grain acted on at the same

moment, and that could not be done if the powder was in one solid

chunk, or closely packed. For that reason they make it in

different shapes, so it will lie loose in the firing chamber,

just as a lot of jack-straws are piled up. In fact, some of the

new powder looks like jack-straws. Some, as this, for instance,

looks like macaroni. Other is in cubes, and some in long

strings."

 

As he spoke Tom struck a match and held the flames near the end

of one of the "macaroni" sticks.

 

"Caesar's grandmother!" yelled Ned. "Are you crazy, Tom?" as he

started to leap for a window.

 

"Don't get excited," spoke Tom, quietly. "There's no danger,"

and he actually set fire to the stick of queer powder, which

burned like some wax taper.

 

"But--but--" stammered Ned.

 

"It is only when powder is confined that it explodes," Tom

explained. "If it can burn in the open it's as harmless as water,

provided you don't burn too much at once. But put it in something

where the resulting gases accumulate and can't escape, and then--

why, you have an explosion--that's all."

 

"Yes--that's all," remarked Ned, grimly, as he nervously

watched the burning stick of powder. Tom let it flame for a few

seconds, and then calmly blew it out.

 

"You know what a little puff black gunpowder gives, if you burn

some openly on the ground," went on Tom; "don't you, Ned?"

 

"Sure, I've often done that."

 

"But put that same powder in a tight box, and set fire to it,

and you have a bang instead of a puff. It's the same way with

this powder, only it doesn't even puff, for it burns more slowly.

 

"An explosion, you see, is the sudden liberation at one time of

the gases which result when the powder is burned. If the gases

are given off gradually, and in the open, no harm is done. But

put a stick like this in, say, a steel box, all closed up, save a

hole for the fuse, and what do you have? An explosion. That's the

principle of all guns and cannon.

 

"But say, Ned, I'm getting to be a regular lecturer. I didn't

know I was running on so. Why didn't you stop me?"

 

"Because I was interested. Go on, tell me some more."

 

"Not now. I want to get this powder in a safe place. I'm a

little nervous about it after that fire. You see if it had

caught, when tightly packed in the boxes, there would have been a

terrific explosion, though it does burn so harmlessly in the open

air. Now let me see--"

 

Tom was interrupted by the postman's whistle, and a little

later Eradicate came in with the mail that had been left in the

box at the shop door. Tom rapidly looked over the letters.

 

"Here's the note I want, I think," he said, Selecting one.

"Yes, this is it. 'Permission is hereby granted,' he read, 'to

Thomas Swift to visit,' and so on, and so on. This is the stuff,

Ned!" he cried.

 

"What is it?"

 

"A permit to visit the government proving grounds at Sandy

Hook, Ned, and see 'em test that new big gun I was telling you

about. Hurray! We'll go down there, and I'll see how my ideas fit

in with those of the government's experts."

 

"Did you say 'we' would go down, Tom?"

 

"I sure did. You'll go with me; won't you?"

 

"Well, I hadn't thought very much about it, but I guess I will.

When is it?"

 

"A week from today, and I'm going to need all that time to get

ready. Now let's get busy, and we'll arrange to go to Sandy Hook.

I've had trouble enough to get this permit--I guess I'll put it

where it won't get lost," and he locked it in a secret drawer of

his desk.

 

Then the lads stored the powder in a safe place, and soon were

busy about several matters in the shop.

 

 

 

CHAPTER V

 

OFF TO SANDY HOOK

 

 

"What's the idea of this government test of the big gun, Tom?"

asked Ned. "I got so excited about that near-explosion the other

day, that I didn't think to ask you all the particulars."

 

"Why, the idea is to see if the gun will work, and do all that

the inventor claims for it," was the answer. "They always put a

new gun through more severe tests than anything it will be called

on to stand in actual warfare. They want to see just how much

margin of safety there is."

 

"Oh I see. And is this one of the guns that are to be used in

fortifying the Panama Canal?"

 

"Well, Ned, I don't know, exactly. You see, the government

isn't telling all its secrets. I assume that it is, and that's

why I'm anxious to see what sort of a gun it is.

 

"As a matter of fact, I'm going into this thing on a sort of

chance, just as dad did when he invested in Mr. Peterson's opal

mine."

 

"Do you think anything will come of that, Tom?"

 

"I don't know. If we get down to Panama, after I have made my

big gun, we may take a run over, and see how he is making out.

But, as I said, I'm going into this big cannon business on a sort

of gamble. I have heard, indirectly, that Uncle Sam intends to

use a new type of gun in fortifying the Panama Canal. It's about

forty-nine miles long, you know, and it will take many guns to

cover the whole route, as well as to protect the two entrances."

 

"Not so very many if you make a gun that will shoot thirty

miles," remarked Ned, with a smile.

 

"I'm not so sure I can do it," went on Tom. "But, even at that,

quite a number of guns will be needed. For if any foreign nation,

or any combination of nations, intend to get the canal away from

us, they won't make the attack from one point. They'll come at us

seven different ways for Sunday, and I've never heard yet of a

gun that can shoot seven ways at once. That's why so many will be

needed.

 

"But, as I said, I don't know just what type the Ordnance

Department will favor, and I want to get a line. Then, even if I

invent a cannon that will outshoot all the others, they may not

take mine. Though if they do, and buy a number of them, I'll be

more than repaid for my labor, besides having the satisfaction of

helping my country."

 

"Good for you, Tom! I wish it was time to go to Sandy Hook now.

I'm anxious to see that big gun. Do you know anything about it?"

 

"Not very much. I have heard that it is not quite as large as

the old sixteen-inch rifle that they had to throw away because of

some trouble, I don't know just what. It was impractical, in

spite of its size and great range. But this new gun they are

going to test is considerably smaller, I understand.

 

"It was invented by a General Wailer, and is, I think, about

twelve inches across at the muzzle. In spite of that

comparatively small size, it fires a projectile weighing a

thousand pounds, or half a ton, and takes five hundred pounds of

powder. Its range, of course, no one knows yet, though I have

heard it said that General Wailer claims it will shoot twenty

miles."

 

"Whew! Some shot!"

 

"I'm going to beat it," declared Tom, "and I want to do it

without making such a monstrous gun that it will be difficult to

cast it.

 

"You see, Ned, there is, theoretically, nothing to prevent the

casting of a steel rifled cannon that would be fifty inches

across at the muzzle, and making it a hundred feet long. I mean

it could be done on paper--figured out and all that. But whether

you would get a corresponding increase in power or range, and be

able to throw a relatively larger projectile, is something no one

knows, for there never has been such a gun made. Besides, the

strain of the big charge of powder needed would be enormous. So I

don't want merely to make a giant cannon. I want one that will do

a giant's work, and still be somewhere in the middle-sized

class."

 

"I see. Well, you'll probably get some points at Sandy Hook."

 

"I think so. We go day after tomorrow."

 

"Is Mr. Damon going?'

 

"I think not. If he does I'll have to get another pass, for

mine only calls for two persons. I got it through a Captain

Badger, a friend of mine, stationed at the Sandy Hook barracks.

He doesn't have anything to do with the coast defense guns, but

he got the pass to the proving grounds for me."

 

Tom and his chum talked for some time about the prospects for

making a giant cannon, and then the young inventor, with Ned's

aid, made some powder tests, using some of the explosive that had

so nearly caught fire.

 

"It isn't just what I want," Tom decided, after he had put

small quantities in little steel bombs, and exploded them, at a

safe distance, and under a bank of earth, by means of an electric

primer.

 

"Why, Tom, that powder certainly burst the bombs all to

pieces," said Ned, picking up a shattered piece of steel.

 

"I know, but it isn't powerful enough for me. I'm going to send

for samples of another kind, and if I can't get what I want I'll

make my own powder. But come on now, this stuff gives me a

headache. Let's take a little flight in the Humming Bird. We'll

go see Mr. Damon," and soon the two lads were in the speedy

little monoplane, skimming along like the birds. The fresh air

soon blew away their headaches, caused by the fumes from the

nitro-glycerine, which was the basis of the powder. Dynamite will

often produce a headache in those who work with it.

 

Two days later Tom and Ned set off for Sandy Hook.

 

This long, neck-like strip of land on the New Jersey coast is,

as most of you know, one of the principal defenses of our

country.

 

Foreign vessels that steam into New York harbor first have to

pass the line of terrible guns that, back of the earth and

concrete defenses, look frowningly out to sea. It is a wonderful

place.

 

On the Sandy Hook Bay side of the Hook there is a life-saving

station. Right across, on the sea side, are the big guns. Between

are the barracks where the soldiers live, and part of the land is

given over to a proving ground, where many of the big guns are

taken to be tested.

 

Tom and Ned reached New York City without incident of moment,

and, after a night spent at a hotel, they went to the Battery,

whence the small government steamer leaves every day for Sandy

Hook. It is a trip of twenty-one miles, and as the bay was rather

rough that day, Tom and Ned had a taste of a real sea voyage. But

they were too experienced travelers to mind that, though some

other visitors were made quite ill.

 

A landing was made on the bay side of the Hook, it being too

rough to permit of a dock being constructed on the ocean side.

 

"Now we'll see what luck we have," spoke Tom, as he and Ned,

inquiring the way to the proving grounds from a soldier on duty,

started for them. On the way they passed some of the

fortifications.

 

"Look at that gun!" exclaimed Ned, pointing to a big cannon

which seemed to be crouched down in a sort of concrete pit. "How

can they fire that, Tom? The muzzle points directly at the stone

wall. Does the wall open when they want to fire?"

 

No, the gun raises up, peeps over the wall, so speak, shoots

out its projectile, and then crouches down again."

 

"Oh, you mean a disappearing gun."

 

"That's it, Ned. See, it works by compressed air," and Tom

showed his chum how, when the gun was loaded, the projectile in

place, and the breech-block screwed fast, the officer in charge

of the firing squad would, on getting the range from the soldier

detailed to calculate it, make the necessary adjustments, and

pull the lever.

 

The compressed air would fill the cylinders, forcing the gun to

rise on toggle-jointed arms, so that the muzzle was above the

bomb-proof wall. Then it would be fired, and sink back again, out

of sight of the enemy.

 

The boys looked at several different types of big rifled

cannon, and then passed on. They could hear firing in the

distance, some of the explosions shaking the ground.

 

"They're making some tests now," said Tom, hurrying forward.

 

Ned followed until, passing a sort of machine shop, the lads

came to where a sentry paced up and down a concrete walk.

 

"Are these the proving grounds?" asked Tom. "This is the

entrance to them," replied the soldier, bringing his rifle to

"port," according to the regulations. "What do you want?"

 

"To go in and watch the gun tests," replied Tom. "I have a

permit," and he held it out so the soldier could see it.

 

"That permit is no good here;" the sentry exclaimed.

 

"No good?" faltered Tom.

 

"No, it has to be countersigned by General Wailer. And, as he's

on the proving grounds now, you can't see him. He's getting ready

for the test of his new cannon."

 

"But that's just what we want to see!" cried Tom. "We want to

get in there purposely for that. Can't you send word to General

Wailer?"

 

"I can't leave my post," replied the sentry, shortly. "You'll

have to come another time, when the General isn't busy. You can't

get in unless he countersigns that permit."

 

"Then it may be too late to witness the test," objected the

young inventor. "Isn't there some way I can get word to him?"

 

"I don't think so," replied the sentry. "And I'll have to ask

you to leave this vicinity. No strangers are allowed on the

proving grounds without a proper pass."

 

 

 

CHAPTER VI

 

TESTING THE WALLER GUN

 

 

Tom looked at Ned in dismay. After all their work and planning,

to be thus thwarted, and by a mere technicality! As they stood

there, hardly knowing what to do, the sound of a tremendous

explosion came to their ears from behind the big pile of earth

and concrete that formed the bomb-proof around the testing

ground.

 

"What's that?" cried Ned, as the earth shook.

 

"Just trying some of the big guns," explained the sentry, who

was not a bad-natured chap. He had to do his duty. "You'd better

move on," he suggested. "If anything happens the government isn't

responsible, you know."

 

"I wish there was some way of getting in there," murmured Tom.

 

"You can see General Waller after the test, and he will

probably countersign the permit," explained the sentry.

 

"And we won't see the test of the gun I'm most interested in,"

objected Tom. "If I could only--"

 

He stopped as he noticed the sentry salute someone coming up

from the rear. Tom and Ned turned to behold a pleasant-faced

officer, who, at the sight of the young inventor, exclaimed:

 

"Well, well! If it isn't my old friend Tom Swift! So you got

here on my permit after all?"

 

"Yes, Captain Badger," replied the lad, and then with a rueful

face he added: "But it doesn't seem to be doing me much good. I

can't get into the proving grounds."

 

"You can't? Why not?" and he looked sharply at the sentry.

 

"Very sorry, sir," spoke the man on guard, "but General Wailer

has left orders, Captain Badger, that no outsiders can enter the

proving grounds when his new gun is being tested unless he

countersigns the permits. And he's engaged just now. I'm sorry,

but--"

 

"Oh, that's all right, Flynn," said Captain Badger. "It isn't

your fault, of course. I suppose there is no rule against my

going in there?" and he smiled.

 

"Certainly not, sir. Any officer may go in," and the guard

stepped to one side.

 

"Let me have that pass, Tom, and wait here for me," said the

Captain. "I'll see what I can do for you," and the young officer,

whose acquaintance Tom had made at the tests when the government

was purchasing some aeroplanes for the army, hurried off.

 

He came back presently, and by his face the lads knew he had

been successful.

 

"It's all right," he said with a smile. "General Waller

countersigned the pass without even looking at it. He's so

excited over the coming test of his gun that he hardly knows what

he is doing. Come on in, boys. I'll go with you."

 

"Then they haven't tested his gun yet?" Asked Tom, eagerly,

anxious to know whether he had missed anything.

 

"No, they're going to do so in about half an hour. You'll have

time to look around a bit. Come on," and showing the sentinel the

counter-signed pass, Captain Badger led the two youths into the

proving grounds.

 

Tom and Ned saw so much to interest them that they did not know

at which to look first. In some places officers and firing squads

were testing small-calibre machine guns, which shot off a round

with a noise like a string of firecrackers on the Chinese New

Year's. On other barbettes larger guns were being tested, the

noise being almost deafening.

 

"Stand on your tiptoes, and open your mouth when you see a big

cannon about to be fired," advised Captain Badger, as he walked

alongside the boys.

 

"What good does that do?" inquired Ned.

 

"It makes your contact with the earth as small as possible--

standing on your toes," the officer explained, "and so reduces

the tremor. Opening your mouth, in a measure, equalizes the

changed air pressure, caused by the vacuum made when the powder

explodes. In other words, you get the same sort of pressure down

inside your throat, and in the tubes leading to the ear--the same

pressure inside, as outside.

 

"Often the firing of big guns will burst the ear drums of the

officers near the cannon, and this may often be prevented by

opening the mouth. It's just like going through a deep tunnel, or

sometimes when an elevator descends quickly from a great height.

There is too much outside air pressure on the ear drums. By

opening your mouth and swallowing rapidly, the pressure is nearly

equaled, and you feel no discomfort."

 

The boys tried this when the next big gun was fired, and they

found it true. They noticed quite a crowd of officers and men

about a certain large barbette, and Captain Badger led them in

that direction.

 

"Is that General Wailer's gun?" asked Tom.

 

"That's where they are going to test it," was the answer.

 

Eagerly Tom and Ned pressed forward. No one of the many

officers and soldiers grouped about the new cannon seemed to

notice them. A tall man, who seemed very nervous and excited, was

hurrying here and there, giving orders rapidly.

 

"How is that range now?" he asked. "Let me take a look! Are you

sure the patrol vessels are far enough out? I think this

projectile is going farther than any of you gentlemen have

calculated."

 

"I believe we have correctly estimated the distance," answered

someone, and the two entered into a discussion.

 

"That excited officer is General Wailer," explained Captain

Badger, in a low voice, to Tom and Ned.

 

"I guessed as much," replied the young inventor. Then he went

closer to get a better look at the big cannon.

 

I say big cannon, and yet it was not the largest the government

had. In fact, Tom estimated the calibre to be less than twelve

inches, but the cannon was very long--much longer in proportion

than guns of greater muzzle diameter. Then, too, the breech, or

rear part, was very thick and heavy.

 

"He must be going to use a tremendous lot of powder," said Tom.

 

"He is," answered Captain Badger. "Some of us think he is going

to use too much, but he says it is impossible to burst his gun.

He wants to make a long-range record shot, and maybe he will."

 

"That's a new kind of breech block," commented Tom, as he

watched the mechanism being operated.

 

"Yes, that's General Waller's patent, too. They're going to

fire soon."

 

I might explain, briefly, for the benefit of you boys who have

never seen a big, modern cannon, that it consists of a central

core of cast steel. This is rifled, just as a small rifle is

bored, with twisted grooves throughout its length. The grooves,

or rifling, impart a twisting motion to the projectiles, and keep

them in a straighter line.

 

After the central core is made and rifled, thick jackets of

steel are "shrunk" on over the rear part of the gun. Sometimes

several jackets are put on, one over the other, to make the gun

stronger.

 

If you have ever seen a blacksmith put a tire on a wheel you

will understand what I mean. The tire is heated, and this expands

it, or makes it larger. It is put on hot, and when it cools it

shrinks, getting smaller, and gripping the rim of the wheel in a

strong embrace. That is what the jackets of steel do to the big

guns.

 

A big rifled cannon is loaded from the rear, or breech, just as

is a breech-loading shotgun or rifle. That is, the cannon is

opened at the back and the projectile is put in by means of a

derrick, for often the projectiles weigh a thousand pounds or

more. Next comes the powder--hundreds of pounds of it--and then

it is necessary to close the breech.

 

The breech block does this. That block is a ponderous piece of

steel, quite complicated, and it swings on a hinge fastened to

one side of the rear of the gun. Once it is swung back into

place, it is made fast by means of screw threads, wedges or in

whatever way the inventor of the gun deems best.

 

The breech block must be very strong, and held firmly in place,

or the terrific force of the powder would blow it out, wreck the

gun and kill those behind it. You see, the breech block really

stands a great part of the strain. The powder is between it and

the projectile, and there is a sort of warfare to see which will

give way--the projectile or the block. In most cases the

projectile gracefully bows, so to speak, and skips out of the

muzzle of the gun, though sometimes the big breech block will be

shattered.

 

With eager eyes Tom and Ned watched the preparations for firing

the big gun. The charge of powder was hoisted out of the bomb-

proof chamber below the barbette, and then the great projectile

was brought up in slings. At the sight of that Tom realized that

the gun was no ordinary one, for the great piece of steel was

nearly three feet long, and must have weighed nearly a thousand

pounds. Truly, much powder would be needed to send that on its

way.

 

"I'm afraid, General, that you are using too much of that

strong powder," Tom heard one officer say to the inventor of the

gun. "It may burst the breech."

 

"Nonsense, Colonel Washburn. I tell you it is impossible to

burst my gun--impossible, sir! I have allowed for every

emergency, and calculated every strain. I have a margin of safety

equal to fifty per cent."

 

"Very well, I hope it proves a success."

 

"Of course it will. It is impossible to burst my gun! Now, are

we ready for the test."

 

The gun was rather crude in form, not having received its final

polish, and it was mounted on a temporary carriage. But even with

that Tom could see that it was a wonderful weapon, though he

thought he would have put on another jacket toward the muzzle, to

further strengthen that portion.

 

"I'm going to make a gun bigger than that," said Tom to Ned. He

spoke rather louder than he intended, and, as it was at a moment

when there was a period of silence, the words carried to General

Waller, who was at that moment near Tom.

 

"What's that?" inquired the rather fiery-tempered officer, as

he looked sharply at our hero.

 

"I said I was going to make a larger gun than that," repeated

Tom, modestly.

 

"Sir! Do you know what you are saying? How did you come in

here, anyhow? I thought no civilians were to be admitted today!

Explain how you got here!"

 

Tom felt an angry flush mounting to his cheeks.

 

"I came in here on a pass countersigned by you," he replied.

 

"A pass countersigned by me? Let me it."

 

Tom passed it over.

 

"Humph, it doesn't seem to be forged," went on the pompous

officer. "Who are you, anyhow?"

 

"Tom Swift."

 

"Hum!"

 

"General Waller, permit me to introduce Tom Swift to you,"

spoke Captain Badger, stepping forward, and trying not to smile.

"He is one of our foremost inventors. It is his type of monoplane

that the government has adopted for the coming maneuvers at

Panama, you may recall, and he was very helpful to Uncle Sam in

stopping that swindling on the border last year--Tom and his big

searchlight. Mr. Swift, General Waller," and Captain Badger bowed

as he completed the introduction.

 

"What's that. Tom Swift here? Let me meet him!" exclaimed an

elderly officer coming through the crowd. The others parted to

make way for him, as he seemed to be a person of some importance,

to judge by his uniform, and the medals he wore.

 

"Tom Swift here!" he went on. "I want to shake hands with you,

Tom! I haven't seen you since I negotiated with you for the

purchase of those submarines you invented, and which have done

such splendid service for the government. Tom, I'm glad to see

you here today."

 

The face of General Waller was a study in blank amazement.

 

 

 

CHAPTER VII

 

THE IMPOSSIBLE OCCURS

 

 

There were murmurs throughout the throng about the big gun, as

the officer approached Tom Swift and shook hands with him.

 

"What have you in mind now, Tom, that you come to Sandy Hook?"

the much-medaled officer asked.

 

"Nothing much, Admiral," answered our hero.

 

"Oh, yes, you have!" returned Admiral Woodburn, head of the

naval forces of Uncle Sam. "You've got some idea in your head, or

you wouldn't come to see this test of my friend's gun. Well, if

you can invent anything as good for coast defense, or even

interior defense, as your submarines, it will be in keeping with

what you have done in the past. I congratulate you, General

Waller, on having Tom Swift here to give you the benefit of some

of his ideas."

 

"I--I haven't had the pleasure of meeting Mr. Swift before,"

said the gun inventor, stiffly. "I did not recognize his name

when I countersigned his pass."

 

It was plain that the greeting of Tom by Admiral Woodburn had

had a marked effect in changing sentiment toward our hero.

Captain Badger smiled as he noticed with what different eyes the

gun inventor now regarded the lad.

 

"Well, if Tom Swift gives you any points about your gun, you

want to adopt them," went on the Admiral. "I thought I knew

something about submarines, but Tom taught me some things, too;

didn't you, Tom?"

 

"Oh, it was just a simple matter, Admiral," said Tom, modestly.

"Just that little point about the intake valves and the ballast

tanks."

 

"But they changed the whole matter. Yes, General, you take

Tom's advice--if he gives you any."

 

"I don't know that I will need any--as yet," replied General

Waller. "I am confident my gun will be a success as it is at

present constructed. Later, however, if I should decide to make

any changes, I will gladly avail myself of Mr. Swift's counsel,"

and he bowed stiffly to Tom. "We will now proceed with the test,"

he went on. "Kindly send a wireless to the patrol ships that we

are about to fire, and ask them to note carefully where the

projectile falls."

 

"Very good, sir," spoke the officer in immediate charge of the

matter, as he saluted. Soon from the aerials snapped the vicious

sparks that told of the wireless telegraph being worked.

 

I might explain that near the spot where the projectile was

expected to fall into the sea--about fifteen miles from Sandy

Hook--several war vessels were stationed to warn shipping to give

the place a wide berth. This was easy, since the big gun had been

aimed at a spot outside of the steamship lanes. Aiming the rifle

in a certain direction, and giving it a definite angle of

inclination, made it practically certain just where the shot

would fall. This is called "getting the range," and while, of

course, the exact limit of fire of the new gun was not known, it

had been computed as nearly as possible.

 

"Is everything ready now?" asked General Waller, while Tom was

conversing with his friends, Captain Badger and Admiral Woodburn,

Ned taking part in the conversation from time to time.

 

"All ready, sir," was the assurance. The inventor was plainly

nervous as the crucial moment of the test approached. He went

here and there upon the barbette, testing the various levers and

gear wheels of the gun.

 

The projectile and powder had been put in, the breech-block

screwed into place, the primer had been inserted, and all that

remained was to press the button that would make the electrical

connection, and explode the charge. This act of firing the gun

had been intrusted to one of the soldiers, for General Waller and

his brother officers were to retire to a bomb-proof, whence they

would watch the effect of the fire, and note the course of the

projectile.

 

"It seems to me," remarked Ned, "that the soldier who is going

to fire the gun is in the most danger."

 

"He would be--if it exploded," spoke Tom, for his officer

friends had joined their colleagues, most of whom were now

walking toward the shelter. "But I think there is little danger.

 

"You see, the electric wires are long enough to enable him to

stand some distance from the gun. And, if he likes, he can crouch

behind that concrete wall of the next barbette. Still, there is

some chance of an accident, for, no matter how carefully you

calculate the strain of a bursting charge of powder, and how

strongly you construct the breech-block to stand the strain,

there is always the possibility of a flaw in the metal. So, Ned,

I think we'll just go to the bombÄproof ourselves, when we see

General Waller making for the same place."

 

"I suppose," remarked Ned, "that in actual warfare anyone who

fired one of the big guns would have to stand close to it--closer

than that soldier is now."

 

"Oh, yes--much," replied Tom, as he watched General Waller

giving the last instructions to the private who was to press the

button. "Only, of course, in war the guns will have been tested,

and this one has not. Here he comes; I guess we'd better be

moving."

 

General Waller, having assured himself that everything was as

right as possible, had given the last word to the private and was

now making his way toward the bomb-proof, within which were

gathered his fellow-officers and friends.

 

"You had better retire from the immediate vicinity of the gun,"

said its inventor to Tom and Ned, as he passed them. "For, while

I have absolute confidence in my cannon, and I know that it is

impossible to burst it, the concussion may be unpleasant at such

close range."

 

"Thank you," said Tom. "We are going to get in a safe place."

 

He could not refrain from contrasting the general's manner now

with what it had been at first.

 

As for Ned, he could not help wondering why, if the inventor

had such absolute faith in his weapon, he did not fire it

himself, even at the risk of a "concussion."

 

How it happened was never accurately known, as the soldier

declared positively--after he came out of the hospital--that he

had not pressed the button. The theory was that the wires had

become crossed, making a short circuit, which caused the gun to

go off prematurely.

 

But suddenly, while Tom, Ned and General Waller were still some

distance away from the bomb-proof, there was a terrific

explosion. It seemed as if the very foundations of the

fortifications would be shattered There was a roaring in the air

--a hot burst of flame, and instantly such a vacuum was created

that Tom and Ned found themselves gasping for breath.

 

Dazed, shaken in every bone, with their muscles sore, they

picked themselves up from the ground, along which they had been

blown with great force in the direction of the bomb-proof. Even

as Tom struggled to his feet, intending to run to safety in fear

of other explosions, he realized what had happened.

 

"What--what was it?" cried Ned, as he, too, arose.

 

"The gun burst!" yelled Tom.

 

He looked to the left and saw General Waller picking himself

up, his uniform torn, and blood streaming from a cut on his face.

At the same instant Tom was aware of the body of a man flying

through the air toward a distant grass plot, and the young

inventor recognized it as that of the soldier who had been

detailed to fire the great cannon.

 

Almost instantaneously as everything happened, Tom was aware of

noticing several things, as though they took place in sequence.

He looked toward where the gun had stood. It was in ruins. The

young inventor saw something, which he took to be the projectile,

skimming across the sea waves, and he had a fleeting glimpse of

the greater portion of the immense weapon itself sinking into the

depths of the ocean.

 

Then, coming down from a great height in the air, he saw a dark

object. It was another piece of the cannon that had been hurled

skyward.

 

"Look out!" Tom yelled, instinctively, as he staggered toward

the bomb-proof, Ned following.

 

He saw a number of officers running out to assist General

Waller, who seemed too dazed to move. Many of them had torn

uniforms, and not a few were bleeding from their injuries. Then

the air seemed filled with a rain of small missilesÄstones, dirt,

gravel and pieces of metal.

 

 

 

CHAPTER VIII

 

A BIG PROBLEM

 

 

"Are you much hurt, Ned?"

 

Tom Swift bent anxiously over the prostrate form of his chum. A

big piece of the burst gun had fallen close to Ned--so close, in

fact, that Tom, who saw it as he neared the entrance to the bomb-

proof, shuddered as he raced back. But there was no sign of

injury on his chum.

 

"Are you much hurt, Ned?"

 

The lad's eyes opened. He seemed dazed.

 

"No--no, I guess not," he answered, slowly. "I--I guess I'm as

much scared as hurt, Tom. It was the wind from that big piece

that knocked me down. It didn't actually hit me."

 

"No, I should say not," put in Captain Badger, who had run out

toward the two lads. "If it had hit you there wouldn't have been

much of you left to tell the tale," and he nodded toward the big

piece of metal Tom had seen coming down from the sky. That part

of the cannon forming a portion of the breech had buried itself

deep in the earth. It had landed close to Ned--so close that, as

he said, the wind of it, as well as the concussion, perhaps, had

thrown him with enough force to send the breath from him.

 

"Glad to hear that, old man!" exclaimed Tom, with a sigh of

relief. "If you'd been hurt I should have blamed myself."

 

"That would have been foolish. I took the same chance that you

did," answered Ned, as he arose, and limped off between the

captain and Tom.

 

A great silence seemed to have followed the terrific report.

And now the officers and soldiers began to recover from the

stupor into which the accident had thrown them. Sentries began

pouring into the proving grounds from other portions of the

barracks, and an ambulance call was sent in.

 

General Waller's comrades had hurried out to him, and were now

leading him away. He did not seem to be much hurt, though, like

many others, he had received numerous cuts and scratches from

bits of stone and gravel scattered by the explosion, as well as

from small bits of metal that were thrown in all directions.

 

"Are you hurt, General?" asked Admiral Woodburn, as he put his

arm about the shoulder of the inventor.

 

"No--that is to say, I don't think so. But what happened? Did

they fire some other gun in our direction by mistake?"

 

For a moment they all hesitated. Then the Admiral said, gently:

 

"No, General. It was your own gun--it burst."

 

"My gun! My gun burst?"

 

"That was it. Fortunately, no one was killed."

 

"My gun burst! How could that happen? I drew every plan for

that gun myself. I made every allowance. I tell you it was

impossible for it to burst!"

 

"But it did burst, General," went on the Admiral. "You can see

for yourself," and he turned around and waved his hand toward the

barbette where the gun had been mounted. All that remained of it

now was part of the temporary carriage, and a small under-portion

of the muzzle. The entire breech, with the great block, had been

blown into fragments, so powerful was the powder used. The

projectile one watcher reported, had gone about three hundred

yards over the top of the barbette and then dropped into the sea,

very little of the force of the explosive having been expended on

that. A large piece of the gun had also been lost in the water

off shore.

 

"My gun burst! My gun burst!" murmured General Waller, as if

unable to comprehend it. "My gun burst--it is impossible!"

 

"But it did," spoke Admiral Woodburn, softly. "Come, you had

better see the surgeon. You may be more seriously injured than

you think."

 

"Was anyone else hurt?" asked the inventor, listlessly. He

seemed to have lost all interest, for the time being.

 

"No one seriously, as far as we can learn," was the answer.

 

"What of the man who fired the gun?" inquired the General.

 

"He was blown high into the air," said Tom. "I saw him."

 

"But he is not injured beyond some bruises," put in one of the

ambulance surgeons. "We have taken him to the hospital. He fell

on a pile of bags that had held concrete, and they saved him. It

was a miraculous escape."

 

"I am glad of it," said General Waller. "It is bad enough to

feel that I made some mistake, causing the gun to burst; but I

would never cease to reproach myself if I felt that the man who

fired it was killed, or even hurt."

 

His friends led him away, and Tom and Ned went over to look at

what remained of the great gun. Truly, the powder, expending its

force in a direction not meant for it, had done terrific havoc.

Even part of the solid concrete bed of the barbette had been torn

up.

 

An official inquiry was at once started, and, while it would

take some time to complete it (for the parts of the gun remaining

were to be subjected to an exhaustive test to determine the cause

of the weakness), it was found that there was some defect in the

wiring and battery that was used to fire the charge.

 

The soldier who was to press the button was sure he had not

done so, as he had been ordered to wait until General Waller gave

the signal from the bomb-proof. But the gun went off before its

inventor reached that place of safety. Just what had caused the

premature discharge could never be learned, as part of the firing

apparatus had been blown to atoms.

 

"Well, Tom, what do you think of it?" asked Ned, who had now

fully recovered from the shock. The two were about to leave the

proving grounds, having seen all that they cared to.

 

"I don't know just what to think," was the answer. "It sure was

a big explosion, and it goes to prove that, no matter how many

calculations you make, when you try a new powder in a new gun you

don't know what's going to happen, until after it has happened--

and then it's too late. It's a big problem, Ned."

 

"Do you think you can solve it? Are you still going on with

your plan to build the biggest cannon ever made?"

 

"I sure am, Ned, though I don't know that I'll make out any

better than General Waller did. It's too bad his was a failure;

but I think I see where he made some mistakes."

 

"Oh, you do; eh?" suddenly exclaimed a voice, and from a nearby

parapet, where he had gone to look at one of the pieces of his

gun, stepped General Waller. "So you think I made some mistakes,

Tom Swift? Where, pray?"

 

"In making the breech. The steel jackets were of uneven

thickness, making the strain unequal. Then, too, I do not think

the powder was sufficiently tested. It was probably of uneven

strength. That is only my opinion, sir."

 

"Well, you are rather young to give opinions to men who have

devoted almost all their lives to the study of high explosives."

 

"I realize that, sir; but you asked me for my opinion. I shall

hope to profit by your mistakes, too. That is one reason I wanted

to see this test."

 

"Then you are seriously determined to make a gun that you think

will rival mine."

 

"I am, General Wailer."

 

"For what purpose--to sell to some foreign government?"

 

"No, sir!" cried Tom, with flashing eyes. "If I am successful

in making a cannon that will fire the longest shots on record, I

shall offer it to Uncle Sam first of all. If he does not want it,

I shall not dispose of it to any foreign country!"

 

"Hum! Well, I don't believe you'll succeed. I intend to rebuild

my gun at once, though I may make some changes in it. I am sure I

shall succeed the next time. But as for you--a mere youth--to

hope to rival men who have made this problem a life-study--it is

preposterous, sir! Utterly preposterous!" and he uttered these

words much as he had declared that it was impossible for his gun

to burst, even after it was in fragments."

 

"Come on, Ned," said Tom, in a low voice. "We'll go back home."

 

 

 

CHAPTER IX

 

THE NEW POWDER

 

 

"Bless my cartridge belt, Tom, you don't really mean to say

that stuff is powder!" exclaimed Mr. Damon.

 

"That's what I hope it will prove to be--and powerful powder at

that."

 

"Why, it looks more like excelsior than anything else," went on

the odd man, gingerly taking up some yellowish shreds in his

fingers.

 

"And it will burn as harmlessly as excelsior in the open air,"

went on Tom. "But I hope to prove, when it is confined in a

chamber, that it will be highly explosive. I'm going to make a

test of it soon."

 

"Give me good notice, so I can get over in the next State!"

exclaimed Ned Newton, with a laugh.

 

This was several days after our friends had returned from the

disastrous gun test at Sandy Hook. Tom had at once gotten to work

on the problem that confronted him--a problem of his own making--

to build a giant cannon that would make the longest shots on

record. And he had first turned his attention to the powder, or

explosive, to be used.

 

"For," he said, "there is no use having a big gun unless you

can fire it. And the gun I am planning will need something more

powerful in the powder line than any I've ever heard of."

 

"Stronger than the kind General Wailer used?" inquired Ned.

 

"Yes, but I'll make my cannon correspondingly stronger, too, so

there will be no danger."

 

"Bless my shoe buttons!" exclaimed Mr. Damon. "You boys must

have had your nerve with you to stay around Sandy Hook after that

gun went up in the air."

 

"Oh, the danger was all over soon after it began," spoke Tom,

with a smile. "But now I'm going to test some of this powder. If

you want to run away, Mr. Damon, I'll have Koku take you up in

one of the airships, and you'll certainly be safe a mile or so in

the air," for Tom had instructed his giant servant how to run one

of the simpler biplanes.

 

"No--no, Tom, I'll stick!" exclaimed the eccentric man. "I'll

not promise not to hide behind the fence, or something like that,

though, Tom; but I'll stick."

 

"So will I," added Ned. "How are you going to make the test,

Tom?"

 

"I'll tell you in a minute. I want to do a little figuring

first."

 

Tom had, before going to Sandy Hook, made some experiments in

powder manufacturing, but they had not been very satisfactory. He

had not been able to get power enough. On his return he had

undertaken rather a daring innovation. He had mingled two

varieties of powder, and the resulting combination would, he

hoped, prove just what he wanted.

 

The powder was in gelatin form, being made with nitro-glycerine

as a base. It looked, as Mr. Damon had said, like a bunch of

excelsior, only it was yellow instead of white, and it felt not

unlike pieces of dry macaroni.

 

"I have shredded the powder in this manner," Tom explained, "so

that it will explode more evenly and quickly. I want it to burn

as nearly instantaneously as possible, and I think it will in

this form."

 

"But how are you going to tell how powerful it is unless you

fire it in a cannon?" asked Ned. "And you haven't even started

your big gun yet."

 

"Oh, I'll show you," declared Tom. "There are several ways of

making a test, but I have one of my own. I am going to take a

solid block of steel, of known weight--say about a hundred

pounds. This I will put into a sort of square cylinder, or well,

closed at the bottom somewhat like the breech of a gun. The block

of steel fits so closely in the square well that no air or powder

gas can pass it.

 

"In the bottom of this well, which may be a foot square, I will

put a small charge of this new powder. On top of that will come

the steel block. Then by means of electric wires I can fire the

charge.

 

"Attached to the steel well, or chamber, will be a gauge, a

pressure recorder and other apparatus. When the powder, of which

I will use only a pinch, carefully weighing it, goes off, it will

raise the hundred-pound weight a certain distance. This will be

noted on the scale. There will also be shown the amount of

pressure released in the gas given off by the powder. In that way

I can make some calculations."

 

"How?" asked Ned, who was much interested.

 

"Well, for instance, if one ounce of powder raises the weight

three feet, and gives a muzzle pressure of, say, five hundred

pounds, I can easily compute what a thousand pounds of powder,

acting on a projectile weighing two tons and a half, would do,

and how far it would shoot it."

 

"Bless my differential gear!" cried Mr. Damon. "A projectile

weighing two and a half, tons! Tom, it's impossible!"

 

"That's what General Waller said about his gun; but it burst,

just the same," declared Ned. "Poor man, I felt sorry for him. He

seemed rather put out at you, Tom."

 

"I guess he was--a bit--though I didn't mean anything

disrespectful in what I said. But now we'll have this test. Koku,

take the rest of this powder back. I'll only keep a small

quantity."

 

The giant, who, being more active than Eradicate, had rather

supplanted the aged colored man, did as he was bid, and soon Tom,

with Ned and Mr. Damon to help him, was preparing for the test.

 

They went some distance away from any of the buildings, for,

though Tom was only going to use a small quantity of the

explosive, he did not just know what the result would be, and he

wanted to take no chances.

 

"I know from personal experience what the two kinds of powder

from which I made this sample will do," he said; "but it is like

taking two known quantities and getting a third unknown one from

them. There is an unequal force between the two samples that may

make an entirely new compound."

 

The steel chamber that was to receive the hundred-pound steel

block had been prepared in advance, as had the various gauges and

registering apparatus.

 

"Well, I guess we'll start things moving now," went on Tom, as

he looked over the things he had brought from his shops to the

deserted meadow. The fact of the test had been kept a secret, so

there were no spectators. "Ned, give me a hand with this block"

Tom went on. "It's a little too heavy to lift alone." He was

straining and tugging at the heavy piece of steel.

 

"Me do!" exclaimed Koku the giant, gently pushing Tom to one

side. Then the big man, with one hand, raised the hundred-pound

weight as easily as if it were a loaf of bread, and deposited it

where Tom wanted it.

 

"Thanks!" exclaimed our hero, with a laugh. "I didn't make any

mistake when I brought you home with me, Koku."

 

"Huh! I could hab lifted dat weight when I was a young feller!"

exclaimed Eradicate, who was, it is needless to say, jealous of

the giant.

 

The powder had been put in the firing chamber. The steel socket

had been firmly fixed in the earth, so that if the force of the

explosion was in a lateral direction, instead of straight up, no

damage would result. The weight, even if it shot from the muzzle

of the improvised "cannon," would only go harmlessly up in the

air, and then drop back. The firing wires were so long that Tom

and his friends could stand some distance away.

 

"Are you all ready?" cried Tom, as he looked to see that the

wiring was clear.

 

"As ready as we ever shall be," replied Mr. Damon, who, with

Ned and the others, had taken refuge behind a low hill.

 

"Oh, this isn't going to be much of an explosion," laughed Tom.

"It won't be any worse than a Fourth of July cannon. Here she

goes!"

 

He pressed the electric button, there was a flash, a dull,

muffled report and, for a moment, something black showed at the

top of the steel chamber. Then it dropped back inside again.

 

"Pshaw!" cried Tom, in disappointed tones. "It didn't even blow

the weight out of the tube. That powder's no good! It's a

failure!"

 

Followed by the others, the young inventor started toward the

small square "cannon." Tom wanted to read the records made by the

gases.

 

Suddenly Koku cried:

 

"There him be, master! There him be!" and he pointed toward a

distant path that traversed the meadow.

 

"He? Whom do you mean?" asked Tom, startled the giant's excited

manner.

 

"That man what come and look at Master's new powder," was the

unexpected answer. "Him say he want to surprise you, and he come

today, but no speak. He run away. Look--him go!" and he pointed

toward a figure of distinctly military bearing hurrying along the

road that led to Shopton.

 

 

 

CHAPTER X

 

SOMETHING WRONG

 

 

"Bless my buttons!" cried Mr. Damon.

 

"Let's chase after him!" yelled Ned.

 

"Koku kin run de fastest oh any oh us," put in Eradicate. "Let

him go."

 

"Hold on--wait a minute!" exclaimed Tom. "We want to know who

that man is--and why we're going to chase after him. Koku, I

guess it's up to you. Something has been going on here that I

don't know anything about. Explain!"

 

"Well, it's no use to chase after him now," said Ned. "There he

goes on his motor-cycle."

 

As he spoke the man, who, even from a rear view, presented all

the characteristics of an army man, so straight was his carriage,

leaped upon a motor-cycle that he pulled from the roadside

bushes, and soon disappeared in a cloud of dust.

 

"No, he's gone," spoke Tom, half-regretfully. "But who was he,

Koku? You seemed to know him. What was he doing out here,

watching my test?"

 

"Me tell," said the giant, simply. "Little while after Master

come back from where him say big gun all go smash, man come to

shop when Master out one day. Him very nice man, and him say him

know you, and want to help you make big cannon. I say, 'Master no

be at home.' Man say him want to give master a little present of

powder for use in new cannon. Master be much pleased, man say.

Make powder better. I take, and I want Master to be pleased. I

put stuff what man gave me in new powder. Man go away--he laugh--

he say he be here today see what happen --I tell him you go to

make test today. Man say Master be much surprised. That all I

know."

 

Silence followed Koku's statement. To Ned and Mr. Damon it was

not exactly clear, but Tom better understood his giant servant's

queer talk.

 

"Is that what you mean, Koku?" asked the young inventor, after

a pause. "Did some stranger come here one day when I was out,

after I had made my new powder, and did he give you some 'dope'

to put in it?"

 

"What you mean by 'dope'?"

 

"I mean any sort of stuff."

 

"Yes, man give me something like sugar, and I sprinkle it on

new powder for to surprise Master."

 

"Well, you've done it, all right," said Tom, grimly. "Have you

any of the stuff left?"

 

"I put all in iron box where Master keep new powder."

 

"Well, then some of it must be there yet. Probably it sifted

through the excelsior-like grains of my new explosive, and we'll

find it on the bottom of the powder-case. But enough stuck to the

strands to spoil my test. I'll just take a reading of the gauges,

and then we'll make an investigation."

 

Tom, with Ned to help him, made notes of how far the weight had

risen in the tube, and took data of other points in the

experiment.

 

"Pshaw!" exclaimed Tom. "There wasn't much more force to my new

powder, doped as it apparently has been, than to the stuff I can

buy in the open market. But I'm glad I know what the trouble is,

for I can remedy it. Come on back to the shop. Koku, don't you

ever do anything like this again," and Tom spoke severely.

 

"No, Master," answered the giant, humbly.

 

"Did you ever see this man before, Koku?"

 

"No, Master."

 

"What kind of a fellow was he?" asked Ned.

 

"Oh, him got whiskers on him face, and stand very straight,

like stick bending backwards. Him look like a soldier, and him

blink one eye more than the other."

 

Tom and Ned started and looked at one another.

 

"That description fits General Waller," said Ned, in a low

voice to his chum.

 

"Yes, in a way; but it would be out of the question for the

General to do such a thing. Besides, the man who ran away, and

escaped on his motor-cycle, was larger than General Waller."

 

"It was hard to tell just what size he was at the distance,"

spoke Ned. "It doesn't seem as though he would try to spoil your

experiments. though."

 

"Maybe he hoped to spoil my cannon," remarked Tom, with a laugh

that had no mirth in it. "My cannon that isn't cast yet. He

probably misunderstood Koku's story of the test, and had no idea

it was only a miniature, experimental, gun.

 

"This will have to be looked into. I can't have strangers

prowling about here, now that I am going to get to work on a new

invention. Koku, I expect you, after this, not to let strangers

approach unless I give the word. Eradicate, the same thing

applies to you. You didn't see anything of this mysterious man;

did you?"

 

"No, Massa 'Tom. De only s'picious man I see was mab own cousin

sneakin' around mah chicken coop de odder night. I tooks mah ole

shot gun, an' sa'ntered out dat way. Den in a little while dere

wasn't no s'picious man any mo'."

 

"You didn't shoot him; did you, Rad?" cried Tom, quickly.

 

"No, Massa Tom--dat is, I didn't shoot on puppose laik. De gun

jest natchelly went off by itself accidental-laik, an' it

peppered him good an' proper."

 

"Why, Rad!" cried Ned. "You didn't tell us about this."

 

"Well, I were 'shamed ob mah cousin, so I was. Anyhow, I only

had salt an' pepper in de gun--'stid ob shot. I 'spect mah cousin

am pretty well seasoned now. But dat's de only s'picious folks I

see, 'ceptin' maybe a peddler what wanted t' gib me a dish pan

fo' a pair ob ole shoes; only I didn't hab any."

 

"There are altogether too many strangers coming about here,"

went on Tom. "It must be stopped, if I have to string charged

electric wires about the shops as I once did."

 

They hurried back to the shop where the new powder was kept,

and Tom at once investigated it. Taking the steel box from where

it was stored he carefully removed the several handfuls of

excelsior-like explosive. On the bottom of the box, and with some

of it clinging to some of the powder threads, was a sort of white

powder. It had a peculiar odor.

 

"Ha!" cried Tom, as soon as he saw it. "I know what that is.

It's a new form of gun-cotton, very powerful. Whoever gave it to

Koku to put on my powder hoped to blow to atoms any cannon in

which it might be used. There's enough here to do a lot of

damage."

 

"How is it that it didn't blow your test cylinder to bits?"

asked Ned.

 

"For the reason that the stuff I use in my powder and this new

gun-cotton neutralized one another," the young inventor

explained. "One weakened the other, instead of making a stronger

combination. A chemical change took place, and lucky for us it

did. It was just like a man taking an over-dose of poison--it

defeated itself. That's why my experiment was a failure. Now to

put this stuff where it can do no harm. Is this what that man

gave you, Koku?"

 

"That's it, Master."

 

There came a tap on the door of the private room, and

instinctively everyone started. Then came the voice of Eradicate,

saying:

 

"Dere's a army gen'men out here to see you. Massa Tom; but I

ain't gwine t' let him in lessen as how you says so."

 

"An army gentleman!" repeated Tom.

 

"Yais, sah! He say he General Waller, an' he come on a motor-

cycle."

 

"General Waller!" exclaimed Tom. "What can he want out here?"

 

"And on a motor-cycle, too!" added Ned. "Tom, what's going on,

anyhow?"

 

The young inventor shook his head.

 

"I don't know," he replied; "but I suppose I had better see

him. Here. Koku, put this powder away, and then go outside. Mr.

Damon, you'll stay; won't you?"

 

"If you need me, Tom. Bless my finger nails! But there seems to

be something wrong here."

 

"Show him in, Rad!" called Tom.

 

"Massa Gen'l Herodotus Waller!" exclaimed the colored man in

pompous tones, as he opened the door for the officer, clad in

khaki, whom Tom had last seen at Sandy Hook.

 

"Ah, how do you do, Mr. Swift!" exclaimed General Waller,

extending his hand. "I got your letter inviting me to a test of

your new explosive. I hope I am not too late."

 

Tom stared at him in amazement.

 

 

 

CHAPTER XI

 

FAILURE AND SUCCESS

 

 

"You--you got my letter!" stammered Tom, holding out his hand

for a missive which the General extended. "I--I don't exactly

understand. My letter?"

 

"Yes, certainly," went on the officer. "It was very kind of you

to remember me after--well, to be perfectly frank with you, I did

resent, a little, your remarks about my unfortunate gun. But I

see you are of a forgiving spirit."

 

"But I didn't write you any letter!" exclaimed Tom, feeling

more and more puzzled.

 

"You did not? What is this?" and the General unfolded a paper.

Tom glanced over it. Plainly it was a request for the General to

be present at the test on that day, and it was signed with Tom

Swift's name.

 

But as soon as the young inventor saw it, he knew that it was a

forgery.

 

"I never sent that letter!" he exclaimed. "Look, it is not at

all like my handwriting," and he took up some papers from a near-

by table and quickly compared some of his writing with that in

the letter. The difference was obvious.

 

"Then who did send it?" asked General Waller. "If someone has

been playing a joke on me it will not be well for him!" and he

drew himself up pompously.

 

"If a joke has been played--and it certainly seems so," spoke

Tom, "I had no hand in it. And did you come all the way from

Sandy Hook because of this letter?"

 

"No, I am visiting friends in Waterford," said the officer,

naming the town where Mr. Damon lived. "My cousin is Mr. Pierce

Watkins."

 

"Bless my doorbell!" exclaimed Mr. Damon, "I know him! He lives

just around the corner from me. Bless my very thumb prints!"

 

General Waller stared at Mr. Damon in some amazement, and

resumed:

 

"Owing to the unfortunate accident to my gun, and to some

slight injuries I sustained, I found my health somewhat impaired.

I obtained a furlough, and came to visit my cousin. The doctor

recommended open air exercise, and so I brought with me my

motor-cycle, as I am fond of that means of locomotion."

 

"I used to be," murmured Mr. Damon; "but I gave it up."

 

"After his machine climbed a tree," Tom explained, with a

smile, remembering how he had originally met Mr. Damon, and

bought the damaged machine from him, as told in the first volume

of this series.

 

"So, when I got your letter," continued the General, "I

naturally jumped on my machine and came over. Now I find that it

is all a hoax."

 

"I am very sorry, I assure you," said Tom. "We did have a sort

of test today; but it was a failure, owing to the fact that

someone tampered with my powder. From what you tell me, I am

inclined to the belief that the same person may have sent you

that letter. Let me look at it again," he requested.

 

Carefully he scanned it.

 

"I should say that was written in a sort of German hand; would

you not also?" he asked of Mr. Damon.

 

"I would, Tom."

 

"A German!" exclaimed General Waller.

 

At the mention of the word "German" Koku, the giant, who had

entered the room, to be stared at in amazement by the officer,

exclaimed:

 

"That he, Master! That he!"

 

"What do you mean?" inquired Tom.

 

"German man give me stuff for to put in your powder. I 'member

now, he talk like Hans who make our garden here; and he say 'yah'

just the same like. That man German sure."

 

"What does this mean?" inquired the officer.

 

Quickly Tom told of the visit of an unknown man who had

prevailed on the simple-minded giant to "dope" Tom's new powder

under the impression that he was doing his master a favor. Then

the flight of the spy on a motor-cycle, just as the experiment

failed, was related.

 

"We have a German gardener," went on Tom, "and Koku now recalls

that our mysterious visitor had the same sort of speech. This

ought to give us a clue."

 

"Let me see," murmured General Waller. "In the first place your

test fails--you learn, then, that your powder has been tampered

with--you see a man riding away in haste after having, in all

likelihood, spied on your work--your giant servant recalls the

visit of a mysterious man, and, when the word 'German' is

pronounced in his hearing he recalls that his visitor was of that

nationality. So far so good.

 

"I come to this vicinity for my health. That fact, as are all

such regarding officers, was doubtless published in the Army and

Navy Journal, so it might easily become known to almost anyone. I

receive a letter which I think is from Tom Swift, asking me to

attend the test. As the distance is short I go, only to find that

the letter has been forged, presumably by a German.

 

"Question: Can the same German be the agent in both cases?"

 

"Bless my arithmetic! how concisely you put it!" exclaimed Mr.

Damon.

 

"It is part of my training, I suppose," remarked the officer.

"But it strikes me that if we find your German spy, Tom, we will

find the man who played the joke on me. And if I do find him--

well, I think I shall know how to deal with him," and General

Waller assumed his characteristic haughty attitude.

 

"I believe you are right, General," spoke Tom. "Though why any

German would want to prevent my experiments, or even damage my

property, and possibly injure my friends, I cannot understand."

 

"Nor can I," spoke the officer.

 

"I am sorry you have had your trouble for nothing," went on

Tom. "And, if you are in this vicinity when I conduct my next

test, I shall be glad to have you come. I will send word by Mr.

Damon, and then there will be no chance of a mistake."

 

"Thank you, Tom, I shall be glad to come I do not know how long

I shall remain in this vicinity. If I knew where to look for the

German I would make a careful search. As it is, I shall turn this

letter over to the United States Secret Service, and see what its

agents can do. And, Tom, if you are annoyed again, let me know.

You are a sort of rival, so to speak, but, after all, we are both

working to serve Uncle Sam. I'll do my best to protect you."

 

"Thank you, sir," replied Tom. "On my part, I shall keep a good

lookout. It will be a bold spy who gets near my shop after this.

I'm going to put up my highly-charged protecting electric wires

again. We were just talking about them when you came in. Would

you like to look about here, General?"

 

"I would, indeed, Tom. Have you made your big gun yet?"

 

"No, but I am working on the plans. I want first to decide on

the kind of explosive I am to use, so I can make my gun strong

enough to stand it."

 

"A wise idea. I think there is where I made my mistake. I did

not figure carefully enough on the strength of material. The

internal pressure of the powder I used, as well as the muzzle

velocity of my projectile, were both greater than they should

have been. Take a lesson from my failure. But I am going to start

on another gun soon, and--Tom Swift--I am going to try to beat

you!"

 

"All right, General," answered Tom, genially. "May the best gun

win!"

 

"Bless my powder box!" cried Mr. Damon. "That's the way to

talk."

 

General Waller was much interested in going about Tom's shop,

and expressed his surprise at the many inventions he saw. While

ordnance matters, big guns and high explosives were his hobby,

nevertheless the airships were a source of wonder to him.

 

"How do you do it, Tom?" he asked.

 

"Oh, by keeping at it," was the modest answer. "Then my good

friends here--Ned and Mr. Damon--help me."

 

"Bless my check book!" exclaimed the odd gentleman. "It is very

little help I give, Tom."

 

General Waller soon took his departure, promising to call

again, to see Tom's test if one were held. He also repeated his

determination to set the Secret Service men at work to discover

the mysterious German.

 

"I can't imagine who would want to injure you or me, Tom

Swift," he said.

 

"Do you think they wanted to injure you, General?" asked Mr.

Damon.

 

"It would seem so," remarked Ned. "That man doped Tom's powder,

hoping to make it so powerful that it would blow up everything.

Then he sends word to the General to be present. If there had

been a blow-up he would have gone with it."

 

"Bless my gaiters, yes!" exclaimed Mr. Damon.

 

"Well, we'll see if we can ferret him out!" spoke the officer

as he took his leave.

 

Tom, Ned and the others talked the matter over at some length.

 

"I wonder if we could trace that man who rode away on the

motor-cycle?" said Ned.

 

"We'll try," decided Tom, energetically, and in the electric

runabout, that had once performed such a service to his father's

bank, the young inventor and his chum were soon traversing the

road taken by the spy. They got some traces of him--that is,

several persons had seen him pass--but that was all. So they had

to record one failure at least.

 

"I wonder if the General himself could have sent that letter?"

mused Ned, as they returned home.

 

"What! To himself?" cried Tom, in amazement.

 

"He might have," went on Ned, coolly. "You see, Tom, he admits

that he was jealous of you. Now what is there to prevent him from

hiring someone to dope your powder, and then, to divert suspicion

from himself, faking up a letter and inviting himself to the

blowout."

 

"But if he did that--which I don't believe--why would he come

when there was danger, in case his trick worked, of the whole

place being blown to kingdom come

 

"Ah, but you notice he didn't arrive until after danger of an

explosion had passed," commented Ned.

 

"Oh, pshaw!" cried Tom. "I don't take any stock in that

theory."

 

"Well, maybe not," replied Ned. "But it's worth thinking about.

I believe if General Waller could prevent you from inventing your

big gun, he would."

 

The days that followed were busy ones for Tom. He worked on the

powder problem from morning to night, scoring many failures and

only a few successes. But he did not give up, and in the

meanwhile drew tentative plans for the big gun.

 

One evening, after a hard day's work, he went to the library

where his father was reading.

 

"Tom," said Mr. Swift, "do you remember that old fortune

hunter, Alec Peterson, who wanted me to go into that opal mine

scheme?"

 

"Yes, Dad. What about him? Has he found it?"

 

"No, he writes to say he reached the island safely, and has

been working some time. He hasn't had any success yet in locating

the mine; but he hopes to find it in a week or so."

 

"That's just like him," murmured Tom. "Well, Dad, if you lose

the ten thousand dollars I guess I'll have to make it up to you,

for it was on my account that you made the investment."

 

"Well, you're worth it, Tom," replied his father, with a smile.

 

 

 

CHAPTER XII

 

A POWERFUL BLAST

 

 

"Look out with that box, Koku! Handle it as though it contained

a dozen eggs of the extinct great auk, worth about a thousand

dollars apiece.

 

"Eradicate! Don't you dare stumble while you're carrying that

tube. If you do, you'll never do it again!"

 

"By golly, Massa Tom! I--I's gwine t' walk on mah tiptoes all

de way!"

 

Thus Eradicate answered the young inventor, while the giant,

Koku, who was carrying a heavy case, nodded his head to show that

he understood the danger of his task.

 

"So you think you've got the right stuff this time, Tom?" asked

Ned Newton.

 

"I'm allowing myself to hope so, Ned."

 

"Bless my woodpile!" cried Mr. Damon. "I--I really think I'm

getting nervous."

 

It was one afternoon, about two weeks after Tom had made his

first test of the new powder. Now, after much hard work, and

following many other tests, some of which were more or less

successful, he had reached the point where he believed he was on

the threshold of success. He had succeeded in making a new

explosive that, in the preliminary tests, in which only a small

quantity was used, gave promise of being more powerful than any

Tom had ever experimented with--his own or the product of some

other inventor.

 

And his experiments had not always been harmless. Once he came

within a narrow margin of blowing up the shop and himself with

it, and on another occasion some of the slow-burning powder,

failing to explode, had set ablaze a shack in which he was

working.

 

Only for the prompt action of Koku, Tom might have been

seriously injured. As it was he lost some valuable patterns and

papers.

 

But he had gone on his way, surmounting failure after failure,

until now he was ready for the supreme test. This was to be the

explosion of a large quantity of the powder in a specially

prepared steel tube of great thickness. It was like a miniature

cannon, but, unlike the first small one, where the test had

failed, this one would carry a special projectile, that would be

aimed at an armor plate set up on a big hill.

 

Tom's hope was that this big blast would show such pressure in

foot-tons, and give such muzzle velocity to the projectile, and

at the same time such penetrating power, that he would be

justified in taking it as the basis of his explosive, and using

it in the big gun he intended to make.

 

The preliminaries had been completed. The special steel tube

had been constructed, and mounted on a heavy carriage in a

distant part of the Swift grounds. A section of armor plate, a

foot and a half in thickness, had been set up at the proper

distance. A new projectile, with a hard, penetrating point, had

been made--a sort of miniature of the one Tom hoped to use in his

giant cannon.

 

Now the young inventor and his friends were on their way to the

scene of the test, taking the powder and other necessaries,

including the primers, with them. Tom, Ned and Mr. Damon had some

of the gauges to register the energy expended by the improvised

cannon. There were charts to be filled in, and other details to

be looked after.

 

"So General Waller won't be here?" remarked Ned, as they walked

along, Tom keeping a watchful eye on Koku.

 

"No," was the reply. "He has gone back to Sandy Hook. He wrote

that his health was better, and that he wanted to resume work on

a new type of gun."

 

"I guess he's afraid you'll beat him out, Tom," laughed Ned.

"You take my advice, and look out for General Waller."

 

"Nonsense! I say, Rad! Look out with those primers!"

 

"I'se lookin' out, Massa Tom. Golly, I don't laik dis yeah job

at all! I--I guess I'd better be gittin' at dat whitewashin',

Massa Tom. Dat back fence suah needs a coat mighty bad."

 

"Never you mind about the whitewashing, Rad. You just stick

around here for a while. I may need you to sit on the cannon to

hold it down."

 

"Sit on a cannon, Massa Tom! Say, looky heah now! You jest take

dese primary things from dish yeah coon. I--I'se got t' go!"

 

"Why, what's the matter, Rad? Surely you're not afraid; are

you?" and Tom winked at Ned.

 

"No, Massa Tom, I'se not prezactly 'skeered, but I done jest

'membered dat I didn't gib mah mule Boomerang any oats t'day, an'

he's suahly gwine t' be desprit mad at me fo' forgettin' dat. I--

I'd better go!"

 

"Nonsense, Rad! I was only fooling. You can go as soon as we

get to my private proving grounds, if you like. But you'll have

to carry those primers, for all the rest of us have our hands

full. Only be careful of 'em!"

 

"I--I will, Massa Tom."

 

They kept on, and it was noticed that Mr. Damon gave nervous

glances from time to time in the direction of Koku, who was

carrying the box of powder. The giant himself, however, did not

seem to know the meaning of fear. He carried the box, which

contained enough explosive to blow them all into fragments, with

as much composure as though it contained loaves of bread.

 

"Now you can go, Rad," announced Tom, when they reached the

lonely field where, pointing toward a big hill, was the little

cannon.

 

"Good, Massa Tom!" cried the colored man, and from the way in

which he hurried off no one would ever suspect him of having

rheumatic joints.

 

"Say, that stuff looks just like Swiss cheese," remarked Ned,

as Tom opened the box of explosive. It would be incorrect to call

it powder, for it had no more the appearance of gunpowder, or any

other "powder," than, as Ned said, swiss cheese.

 

And, indeed, the powerful stuff bore a decided resemblance to

that peculiar product of the dairy. It was in thin sheets, with

holes pierced through it here and there, irregularly.

 

"The idea is," Tom explained, "to make a quick-burning

explosive. I want the concussion to be scattered through it all

at once. It is set off by concussion, you see," he went on. "A

sort of cartridge is buried in the middle of it, after it has

been inserted in the cannon breech. The cartridge is exploded by

a primer, which responds to an electric current. The thin plates,

with holes corresponding to the centre hole in a big grain of the

hexagonal powder, will, I hope, cause the stuff to burn quickly,

and give a tremendous pressure. Now we'll put some in the steel

tube, and see what happens."

 

Even Tom was a little nervous as he prepared for this latest

test. But he was not nervous enough to drop any of those queer,

cheese-like slabs. For, though he knew that a considerable

percussion was needed to set them off, it would not do to take

chances. High explosives do not always act alike, even under the

same given conditions. What might with perfect safety be done at

one time, could not be repeated at another. Tom knew this, and

was very careful.

 

The powder, as I shall occasionally call it for the sake of

convenience, though it was not such in the strict sense of the

word--the powder was put in the small cannon, together with the

primer. Then the wires were attached to it, and extended off for

some distance.

 

"But we won't attach the battery until the last moment," Tom

said. "I don't want a premature explosion."

 

The projectile was also put in, and Tom once more looked to see

that the armor plate was in place. Then he adjusted the various

gauges to get readings of the power and energy created by his new

explosive.

 

"Well, I guess we're all ready," he announced to his friends.

"I'll hook on the battery now, and we'll get off behind that

other hill. I had Koku make a sort of cave there--a miniature

bomb-proof, that will shelter us."

 

"Do you think the blast will be powerful enough to make it

necessary?" asked Mr. Damon.

 

"It will, if this larger quantity of explosive acts anything

like the small samples I set off," replied the young inventor.

 

The electric wires were carried behind the protecting hill,

whither they all retired.

 

"Here she goes!" exclaimed Tom, after a pause.

 

His thumb pressed the electric button, and instantly the ground

shook with the tremor of a mighty blast, while a deafening sound

reared about them. The earth trembled, and there was a big sheet

of flame, seen even in the powerful sunlight.

 

"Something happened, anyhow!" yelled Tom above the

reverberating echoes.

 

 

 

CHAPTER XIII

 

CASTING THE CANNON

 

 

"Come on!" yelled Ned. "We'll see how this experiment came

out!" and he started to run from beneath the shelter of the hill.

 

"Hold on!" shouted Tom, laying a restraining hand on his chum's

shoulder.

 

"Why, what's the matter?" asked Ned in surprise.

 

"Some of that powder may not have exploded," went on the young

inventor. "From the sound made I should say the gun burst, and,

if it did, that gelatin is bound to be scattered about. There may

be a mass of it burning loose somewhere, and it may go off. It

ought not to, if my theory about it being harmless in the open is

correct, but the trouble is that it's only a theory. Wait a few

seconds."

 

Anxiously they lingered, the echoes of the blast still in their

ears, and a peculiar smell in their nostrils.

 

"But there's no smoke," said Mr. Damon. "Bless my spyglass! I

always thought there was smoke at an explosion."

 

"This is a sort of smokeless powder," explained Tom. "It throws

off a slight vapor when it is ignited, but not much. I guess it's

safe to go out now. Come on!"

 

He dropped the pushbutton connected with the igniting battery,

and, followed by the others, raced to the scene of the

experiment. A curious sight met their eyes.

 

A great hole had been torn in the hillside, and another where

the improvised gun had stood. The gun itself seemed to have

disappeared.

 

"Why--why--where is it?" asked Ned.

 

"Burst to pieces I guess," replied Tom. "I was afraid that

charge was a bit too heavy."

 

"No, here it is!" shouted Mr. Damon, circling off to one side.

"It's been torn from the carriage, and partly buried in the

ground," and he indicated a third excavation in the earth.

 

It was as he had said. The terrific blast had sheared the gun

from its temporary carriage, thrown it into the air, and it had

come down to bury itself in the soft ground. The carriage had

torn loose from the concrete base, and was tossed off in another

direction.

 

"Is the gun shattered?" asked Tom, anxious to know how the

weapon had fared. It was, in a sense, a sort of small model of

the giant cannon he intended to have cast.

 

"The breech is cracked a little," answered Mr. Damon, who was

examining it; "but otherwise it doesn't seem to be much damaged."

 

"Good cried Tom. "Another steel jacket will remedy that defect.

I guess I'm on the right road at last. But now to see what became

of that armor plate."

 

"Dinner plate not here," spoke Koku, who could not understand

how there could be two kind of plates in the world. "Dinner plate

gone, but big hole here, and he indicated one in the side of the

hill.

 

"I expect that is where the armor plate is," said Tom, trying

not to laugh at the mistake of his giant servant. "Take a look in

there, Koku, and, if you can get hold of it, pull it out for us.

I'm afraid the piece of nickel-steel armor proved too much for my

projectile. But we'll have a look."

 

Koku disappeared into the miniature cave that had been torn in

the side of the bill. It was barely large enough to allow him to

go in. But Tom knew none other of them could hope to loosen the

piece of steel, imbedded as it must be in the solid earth.

 

Presently they heard Koku grunting and groaning. He seemed to

be having quite a struggle.

 

"Can you get it, Koku?" asked Torn. "Or shall I send for picks

and shovels."

 

"Me get, Master," was the muffled answer.

 

Then came a shout, as though in anger Koku had dared the buried

plate to defy him. There was a shower of earth at the mouth of

the cave, and the giant staggered out with the heavy piece of

armor plate. At the sight of it Tom uttered a cry.

 

"Look!" he shouted. "My projectile went part way through and

then carried the plate with it into the side of the hill. Talk

about a powerful explosive! I've struck it, all right!"

 

It was as he had said. The projectile, driven with almost

irresistible force, had bitten its way through the armor plate,

but a projection at the base of the shell had prevented it from

completely passing through. Then, with the energy almost

unabated, the projectile had torn the plate loose and hurled it,

together with its own body, into the solid earth of the hillside.

There, as Koku held them up, they could all see the shell

imbedded in the plate, the point sticking out on the other side,

as a boy might spear an apple with a sharp stick.

 

"Bless my spectacle case!" cried Mr. Damon. "This is the

greatest ever!"

 

"It sure is," agreed Ned. "Tom, my boy, I guess you can now

make the longest shots on record."

 

"I can as soon as I get my giant cannon, perhaps," admitted the

young inventor. "I think I have solved the problem of the

explosive. Now to work on the cannon."

 

An examination of the gauges, which, being attached to the

cannon and plate by electric wires, were not damaged when the

blast came, showed that Tom's wildest hopes had been confirmed.

He had the most powerful explosive ever made--or at least as far

as he had any knowledge, and he had had samples of all the best

makes.

 

Concerning Tom's powder, or explosive, I will only say that he

kept the formula of it secret from all save his father. All that

he would admit, when the government experts asked him about it,

later, was that the base was not nitro-glycerine, but that this

entered into it. He agreed, however, in case his gun was accepted

by the government, to disclose the secret to the ordnance

officers.

 

But Tom's work was only half done. It was one thing to have a

powerful explosive, but there must be some means of utilizing it

safely--some cannon in which it could be fired to send a

projectile farther than any cannon had ever sent one. And to do

this much work was necessary.

 

Tom figured and planned, far into the night, for many weeks

after that. He had to begin all over again, working from the

basis of the power of his new explosive. And he had many new

problems to figure out.

 

But finally he had constructed--on paper--a gun that was to his

liking. The most exhaustive figuring proved that it had a margin

of safety that would obviate all danger of its bursting, even

with an accidental over-charge.

 

"And the next thing is to get the gun cast," said Tom to Ned

one day.

 

"Are you going to do it in your shops?" his chum asked.

 

"No; it would be out of the question for me. I haven't the

facilities. I'm going to give the contract to the Universal Steel

Company. We'll pay them a visit in a day or two."

 

But even the great facilities of the steel corporation proved

almost inadequate for Tom's giant cannon. When he showed the

drawings, on which he had already secured a patent, the manager

balked.

 

"We can't cast that gun here!" he said.

 

"Oh, yes, you can!" declared Tom, who had inspected the plant.

"I'll show you how."

 

"Why, we haven't a mould big enough for the central core," was

another objection.

 

"Then we'll make one," declared Tom "We'll dig a pit in the

earth, and after it is properly lined we can make the cast

there."

 

"I never thought of that!" exclaimed the manager. "Perhaps it

can be done."

 

"Of course it can!" cried Tom. "Do you think you can shrink on

the jackets, and rifle the central tube?"

 

"Oh, yes, we can do that. The initial cast was what stumped me.

But we'll go ahead now."

 

"And you can wind the breech with wire, and braze it on; can't

you?" persisted Tom.

 

"Yes, I think so. Are you going to have a wire-wound gun?"

 

"That, in combination with a steel-jacketed one. I'm going to

take no chances with 'Swiftite'!" laughed Tom, for so he had

named his new explosive, in honor of his father, who had helped

him with the formula.

 

"It must be mighty powerful," exclaimed the manager.

 

"It is," said Tom, simply.

 

I am not going to tire my readers with the details leading up

to the casting of Tom's big cannon. Sufficient to say that the

general plan, in brief, was this: A hole would be dug in the

earth, in the center of the largest casting shop--a hole as deep

as the gun was to be long. This was about one hundred feet,

though the gun, when finished, would be somewhat shorter than

this. An allowance was to be made for cutting.

 

In the center of this hole would be a small "core" made of

asbestos and concrete mixed. Around this would be poured the

molten steel from great caldrons. It would flow into the hole.

The sides of earth--lined with fire-clay--would hold it in, and

the middle core would make a hole throughout the length of the

central part of the gun. Afterward this hole would be bored and

rifled to the proper calibre.

 

After this central part was done, steel jackets or sleeves

would be put on, red-hot, and allowed to shrink. Then would come

a winding of wire, to further strengthen the tube, and then more

sleeves or jackets. In this way the gun would be made very

strong.

 

As the greatest pressure would come at the breech, or in the

powder chamber there, the gun would be thickest at this point,

decreasing in size to the muzzle.

 

It took many weary weeks to get ready for the first cast, but

finally Tom received word that it was to be made, and with Ned,

and Mr. Damon, he proceeded to the plant of the steel concern.

 

There was some delay, but finally the manager gave the word.

Tom and his friends, standing on a high gallery, watched the

tapping of the combined furnaces that were to let the molten

steel into the caldrons. There were several of these, and their

melted contents were to be poured into the mould at the same

time.

 

Out gushed the liquid steel, giving off a myriad of sparks. The

workers, as well as the visitors, had to wear violet-tinted

glasses to protect their eyes from the glare.

 

"Hoist away!" cried the manager, and the electric cranes

started off with the caldrons of liquid fire, weighing many tons.

 

"Pour!" came the command, and into the pit in the earth

splashed the melted steel that was to form the big cannon. From

each caldron there issued a stream of liquid metal of intense

heat. There were numerous explosions as the air bubbles burst--

explosions almost like a battery in action.

 

"So far so good!" exclaimed the manager, with a sigh of relief

as the last of the melted stuff ran into the mould. "Now, when it

cools, which won't be for some days, we'll see what we have."

 

"I hope it contains no flaws," spoke Tom, "That is the worst of

big guns--you never can tell when a flaw will develop. But I

hope--"

 

Tom was interrupted by the sound of a dispute at one of the

outer doors of the shop.

 

"But I tell you I must go in--I belong here in!" a voice cried.

It had a German accent, and at the sound of it Tom and Ned looked

at each other.

 

"Who is there?" asked the manager sharply of the foreman..

 

"Oh, a crazy German. He belongs in one of the other shops, and

I guess he's mixed up. He thinks he belongs here. I sent him

about his business."

 

"That is right," remarked the manager. "I gave orders, at your

request," he said to Tom, "that no one but the men in this part

of the plant were to be present at the casting. I cant understand

what that fellow wanted."

 

"I think I can," murmured Tom, to himself.

 

 

 

CHAPTER XIV

 

A NIGHT INTRUDER

 

 

"Tom, aren't you going to try to get a look at that German?"

whispered Ned, as he and his chum came down from the elevated

gallery at the conclusion of the cast. "I mean the one who tried

to get in!"

 

"I'd like to, Ned, but I don't want to arouse any suspicion,"

replied Tom. "I've got to stay here a while yet, and arrange

about shrinking on the jackets, after the core is rifled. I don't

see how--"

 

"I'll slip out and see if I can get a peep at him," went on

Ned. "If it's like the one Koku described, we'll know that he's

still after you."

 

"All right, Ned. Do as you like, only be cautious."

 

"I will," promised Tom's chum. So, while the young inventor was

busy arranging details with the steel manager, Ned slipped out of

a side door of the casting shop, and looked about the yard. He

saw a little group of workmen surrounding a man who appeared to

be angry.

 

"I dell you dot is my shop!" one of the men was heard to

exclaim--a man whom the others appeared to dragging away with

main force.

 

"And I tell you, Baudermann, that you're mistaken!" insisted

one, evidently a foreman. "I told you to work in the brazing

department. What do you want to try to force your way into the

heavy casting department for? Especially when we're doing one of

the biggest jobs that we ever handled--making the new Swift

cannon."

 

"Oh, iss dot vot vas going on in dere?" asked the man addressed

as Baudermann. "Shure den, I makes a misdake. I ask your pardon,

Herr Blackwell. I to mine own apartment will go. But I dinks my

foreman sends me to dot place," and he indicated the casting shop

from which he had just been barred.

 

"All right!" exclaimed the foreman. "Don't make that mistake

again, or I'll dock you for lost time."

 

"Only just a twisted German employee, I guess," thought Ned, as

he was about to turn back. "I was mistaken. He probably didn't

understand where he was sent."

 

He passed by the group of men, who, laughing and jeering at the

German, were showing him where to go. He seemed to be a new hand

in the works.

 

But as Ned passed he got one look at the man's face. Instead of

a stupid countenance, for one instant he had a glimpse of the

sharpest, brightest eyes he had ever looked into. And they were

hard, cruel eyes, too, with a glint of daring in them. And, as

Ned glanced at his figure, he thought he detected a trace of

military stiffness--none of the stoop-shouldered slouch that is

always the mark of a moulder. The fellow's hands, too, though

black and grimy, showed evidences of care under the dirt, and Ned

was sure his uncouth language was assumed.

 

"I'd like to know more about you," murmured Ned, but the man,

with one sharp glance at him, passed on, seemingly to his own

department of the works.

 

"Well, what was it?" asked Tom, as his chum rejoined him.

 

"Nothing very definite, but I'm sure there was something back

of it all, Tom. I wouldn't be surprised but what that fellow--

whoever he was--whatever his object was--hoped to get in to see

the casting; either to get some idea about your new gun, or to do

some desperate deed to spoil it."

 

"Do you think that, Ned?"

 

"I sure do. You've got to be on your guard, Tom."

 

"I will. But I wonder what object anyone could have in spoiling

my gun?"

 

"So as to make his own cannon stand in a better light."

 

"Still thinking of General Waller, are you?"

 

"I am, Tom."

 

There was nothing more to be done at present, and, as it would

take several days for the big mass of metal to properly cool,

Tom, Ned and Mr. Damon returned to Shopton.

 

There Tom busied himself over many things. Ned helping him, and

Mr. Damon lending an occasional hand. Koku was very useful, for

often his great strength did what the combined efforts of Tom and

his friends could not accomplish.

 

As for Eradicate, he "puttered around," doing all he could,

which was not much, for he was getting old. Still Tom would not

think of discharging him, and it was pitiful to see the old

colored man try to do things for the young inventor--tasks that

were beyond his strength. But if Koku offered to help, Eradicate

would draw himself up, and exclaim:

 

"Git away fom heah! I guess dish yeah coon ain't forgot how t'

wait on Massa Tom. Go 'way, giant. I ain't so big as yo'-all, but

I know de English language, which is mo' 'n yo' all does. Go on

an' lemme be!"

 

Koku, good naturedly, gave place, for he, too, felt for

Eradicate.

 

"Well, Ned," remarked Tom one day, after the visit of the

postman, "I have a letter from the steel people. They are going

to take the gun out of the mould tomorrow, and start to rifle it.

We'll take a run down in the airship, and see how it looks. I

must take those drawings, too, that show the new plan of

shrinking on the jackets. I guess I'll keep them in my room, so I

won't forget them."

 

Tom and Ned occupied adjoining and connecting apartments, for,

of late, Ned had taken up his residence with his chum. It was

shortly after midnight that Ned was awakened by hearing someone

prowling about his room. At first he thought it was Tom, for the

shorter way to the bath lay through Ned's apartment, but when the

lad caught the flash of a pocket electric torch he knew it could

not be Tom.

 

"Who's there?" cried Ned sharply, sitting up in bed.

 

Instantly the light went out, and there was

silence.

 

"Who's there?" cried Ned again.

 

This time he thought he heard a stealthy footstep.

 

"What is it?" called Tom from his chamber.

 

"Someone is in here!" exclaimed Ned. "Look out, Tom!"

 

 

 

CHAPTER XV

 

READY FOR THE TEST

 

 

Tom Swift acted promptly, for he realized the necessity. The

events that had hedged him about since he had begun work on his

giant cannon made him suspicious. He did not quite know whom to

suspect, nor the reasons for their actions, but he had been on

the alert for several days, and was now ready to act.

 

The instant Ned answered as he did, and warned Tom, the young

inventor slid his hand under his pillow and pressed an auxiliary

electric switch he had concealed there. In a moment the rooms

were flooded with a bright light, and the two lads had a

momentary glimpse of an intruder making a dive for the window.

 

"There he is, Tom!" cried Ned.

 

"What do you want?" demanded Tom, instinctively. But the

intruder did not stay to answer.

 

Instead, he made a dive for the casement. It was one story

above the ground, but this did not cause him any hesitation. It

was summer, and the window was open, though a wire mosquito net

barred the aperture. This was no hindrance to the man, however.

 

As Ned and Tom leaped from their beds, Ned catching up the

heavy, empty water pitcher as a weapon, and Tom an old Indian war

club that served as one of the ornaments of his room, the fellow,

with one kick, burst the screen.

 

Then, clambering out on the sill, he dropped from sight, the

boys hearing him land with a thud on the turf below. It was no

great leap, though the fall must have jarred him considerably,

for the boys heard him grunt, and then groan as if in pain.

 

"Quick!" cried Ned. "Ring the bell for Koku, Ned. I want to

capture this fellow if possible."

 

"Who is he?" asked Ned.

 

"I don't know, but we'll see if we can size him up. Signal for

the giant!"

 

There was an electric bell from Tom's room to the apartment of

his big servant, and a speaking tube as well. While Ned was

pressing the button, and hastily telling the giant what had

happened, urging him to get in pursuit of the intruder, Tom had

taken from his bureau a powerful, portable, electric flash lamp,

of the same variety as that used by the would-be thief. Only

Tom's was provided with a tungsten filament, which gave a glaring

white pencil of light, increased by reflectors.

 

And in this glare the young inventor saw, speeding away over

the lawn, the form of a big man.

 

"There he goes, Ned!" he shouted.

 

"So I see. Koku will be right on the job. I told him not to

dress. Can you make out who the fellow is?"

 

"No, his back is toward us. But he's limping, all right. I

guess that jump jarred him up a bit. Where is Koku?"

 

"There he goes now!" exclaimed Ned, as a figure leaped from the

side door of the house--a gigantic figure, scantily clad.

 

"Get to him, Koku!" cried Tom.

 

"Me git, Master!" was the reply, and the giant sped on.

 

"Let's go out and lend a hand!" suggested Ned, looking at the

water pitcher as though wondering what he had intended to do with

it.

 

"I'm with you," agreed Tom. "Only I want to get into something

a little more substantial than my pajamas."

 

As the two lads hurriedly slipped on some clothing they heard

the voice of Mr. Swift calling:

 

"What is it, Tom? Has anything happened?"

 

"Nothing much," was the reassuring answer. "It was a near-

happening, only Ned woke up in time. Someone was in our rooms--a

burglar, I guess."

 

"A burglar! Good land a massy!" cried Eradicate, who had also

gotten up to see what the excitement was about. "Did you cotch

him, Massa Tom?"

 

"No, Rad; but Koku is after him."

 

"Koku? Huh, he nebber cotch anybody. I'se got t' git out dere

mahse'f! Koku? Hu! I s'pects it's dat no-'count cousin ob mine,

arter mah chickens ag'in! I'll lambaste dat coon when I gits him,

so I will. I'll cotch him for yo'-all, Massa Tom," and, muttering

to himself, the aged colored man endeavored to assume the

activity of former years.

 

"Hark!" exclaimed Ned, as he and Tom were about ready to take

part in the chase. "What's that noise, Tom?"

 

"Sounds like a motor-cycle."

 

"It is. That fellow--"

 

"It's the same chap!" interrupted Tom. "No use trying to chase

him on that speedy machine. He's a mile away from here by now. He

must have had it in waiting, ready for use. But come on, anyhow."

 

"Where are you going?"

 

"Out to the shop. I want to see if he got in there."

 

"But the charged wires?"

 

"He may have cut them. Come on."

 

It was as Tom had suspected. The deadly, charged wires, that

formed a protecting cordon about his shops, had been cut, and

that by an experienced hand, probably by someone wearing rubber

gloves, who must have come prepared for that very purpose. During

the night the current was supplied to the wires from a storage

battery, through an intensifying coil, so that the charge was

only a little less deadly than when coming direct from a dynamo.

 

"This looks bad, Tom," said Ned.

 

"It does, but wait until we get inside and look around. I'm

glad I took my gun-plans to the house with me."

 

But a quick survey of the shop did not reveal any damage done,

nor had anything been taken, as far as Tom could tell. The office

of his main shop was pretty well upset, and it looked as though

the intruder had made a search for something, and, not finding

it, had entered the house.

 

"It was the gun-plans he was after, all right," decided Tom.

"And I believe it was the same fellow who has been making trouble

for me right along."

 

"You mean General Waller?"

 

"No, that German--the one who was at the machine shop."

 

"But who is he--what is his object?"

 

"I don't know who he is, but he evidently wants my plans.

Probably he's a disappointed inventor, who has been trying to

make a gun himself, and can't. He wants some of my ideas, but he

isn't going to get them. Well, we may as well get back to bed,

after I connect these wires again. I must think up a plan to

conceal them, so they can't be cut."

 

While Tom and Ned were engaged on this, Koku came back, much

out of breath, to report:

 

"Me not git, Master. He git on bang-bang machine and go off--

puff!"

 

"So we heard, Koku. Never mind, we'll get him yet."

 

"Hu! Ef I had de fust chanst at him, I'd a cotched dat coon

suab!" declared Eradicate, following the giant. "Koku he done git

in mah way!" and he glared indignantly at the big man.

 

"That's all right, Rad," consoled Tom. "You did your best. Now

we'll all get to bed. I don't believe he'll come back." Nor did

he.

 

Tom and Ned were up at the first sign of daylight, for they

wanted to go to the steel works, some miles away, in time to see

the cannon taken out of the mould, and preparations made for

boring the rifle channels. They found the manager, anxiously

waiting for them.

 

"Some of my men are as interested in this as you are," he said

to the young inventor. "A number of them declare that the cast

will be a failure, while some think it will be a success."

 

"I think it will be all right, if my plans were followed," said

Tom. "However, we'll see. By the way, what became of that German

who made such a disturbance the day we cast the core?"

 

"Oh, you mean Baudermann?"

 

"Yes."

 

"Why, it's rather queer about him. The foreman of the shop

where he was detailed, saw that he was an experienced man, in

spite of his seemingly stupid ways, and he was going to promote

him, only he never came back."

 

"Never came back? What do you mean?"

 

"I mean the day after the cast of the gun was made he

disappeared, and never came back."

 

"Oh!" exclaimed Tom. He said nothing more, but he believed that

he understood the man's actions. Failing to obtain the desired

information, or perhaps failing to spoil the cast, he realized

that his chances were at an end for the present.

 

With great care the gun was hoisted from the mould. More eyes

than Tom's anxiously regarded it as it came up out of the casting

pit.

 

"Bless my buttonhook!" cried Mr. Damon, who had gone with the

lads. "It's a monster; isn't it?"

 

"Oh, wait until you see it with the jackets on exclaimed Ned,

who had viewed the completed drawings. "Then you'll open your

eyes."

 

The great piece of hollow steel tubing was lifted to the boring

lathe. Then Tom and the manager examined it for superficial

flaws.

 

"Not one!" cried the manager in delight.

 

"Not that I can see," added Tom.. "It's a success--so far."

 

"And that was the hardest part of the work," went on the

manager of the steel plant. "I can almost guarantee you success

from now on."

 

And, as far as the rifling was concerned, this was true. I will

not weary you with the details of how the great core of Tom

Swift's giant cannon was bored. Sufficient to say that, after

some annoying delays, caused by breaks in the machinery, which

had never before been used on such a gigantic piece of work, the

rifling was done. After the jackets had been shrunk on, it would

be rifled again, to make it true in case of any shrinkage.

 

Then came the almost Herculean task of shrinking on the great

red-hot steel jackets and wire-windings, that would add strength

to the great cannon. To do this the central core was set up on

end, and the jackets, having been heated in an immense furnace,

were hoisted by a great crane over the core, and lowered on it as

one would lower his napkin ring over the rolled up napkin.

 

It took weeks of hard work to do this, and Tom and Ned, with

Mr. Damon occasionally for company, remained almost constantly at

the plant. But finally the cannon was completed, the rifling was

done over again to correct any imperfections, and the manager

said:

 

"You cannon is completed, Mr. Swift. I want to congratulate you

on it. Never have we done such a stupendous piece of work. Only

for your plans we could not have finished it. It was too big a

problem for us. Your cannon is completed, but, of course, it will

have to be mounted. What about the carriage?"

 

"I have plans for that," replied Tom; "but for the present I am

going to put it on a temporary one. I want to test the gun now.

It looks all right, but whether it will shoot accurately, and for

a greater distance than any cannon has ever sent a projectile

before, is yet to be seen."

 

"Where will you test it?"

 

"That is what we must decide. I don't want to take it too far

from here. Perhaps you can select a place where it would be safe

to fire it, say with a range of about thirty miles."

 

"Thirty miles! why, my dear sir--"

 

"Oh, I'm not altogether sure that it will go that distance,"

interrupted Tom, with a smile; "but I'm going to try for it, and

I want to be on the safe side. Is there such a place near here?"

 

"Yes, I guess we can pick one out. I'll let you know."

 

"Then I must get back and arrange for my powder supply," went

on the young inventor. "We'll soon test my giant cannon!"

 

"Bless my ear-drums!" cried Mr. Damon. "I hope nothing bursts.

For if that goes up, Tom Swift--"

 

"I'm not making it to burst," put in Tom, with a smile. "Don't

worry. Now, Ned, back to Shopton to get ready for the test."

 

 

 

CHAPTER XVI

 

A WARNING

 

 

"Whew, how it rains!" exclaimed Ned, as he looked out of the

window.

 

"And it doesn't seem to show any signs of letting up," remarked

Tom. "It's been at it nearly a week now, and it is likely to last

a week longer."

 

"It's beastly," declared his chum. "How can you test your gun

in this weather?"

 

"I can't. I've got to wait for it to clear."

 

"Bless my rubber boots! it's just got to stop some time,"

declared Mr. Damon. "Don't worry, Tom."

 

"But I don't like this delay. I have heard that General Waller

has perfected a new gun--and it's a fine one, from all accounts.

He has the proving grounds at Sandy Hook to test his on, and I'm

handicapped here. He may beat me out."

 

"Oh, I hope not, Tom!" exclaimed Ned. "I'm going to see what

the weather reports say," and he went to hunt up a paper.

 

It was several weeks after the completion of Tom's giant

cannon. In the meanwhile the gun had been moved by the steel

company to a little-inhabited part of New York State, some miles

from the plant. The gun had been mounted on an improvised

carriage, and now Tom and his friends were waiting anxiously for

a chance to try it.

 

The work was not complete, for the steel company employees had

been hampered by the rain. Never before, it seemed, had there

been so much water coming down from the clouds. Nearly every day

was misty, with gradations from mere drizzles to heavy downpours.

There were occasional clear stretches, however, and during them

the men worked.

 

A few more days of clear weather would be needed before the gun

could be fastened securely to the carriage, and then Tom could

fire one of the great projectiles that had been cast for it. Not

until then would he know whether or not his cannon was going to

be a success.

 

Meanwhile nothing more had been heard or seen of the spy. He

appeared to have given up his attempts to steal Tom's secret, or

to spoil his plans, if such was his object.

 

The place of the test, as I have said, was in a deserted spot.

On one side of a great valley the gun was being set up. Its

muzzle pointed up the valley, toward the side of a mountain, into

which the gigantic projectile could plow its way without doing

any damage. Tom was going to fire two kinds of cannon balls--a

solid one, and one containing an explosive.

 

The gun was so mounted that the muzzle could be elevated or

depressed, or swung from side to side. In this way the range

could be varied. Tom estimated that the greatest possible range

would be thirty miles. It could not be more than that, he

decided, and he hoped it would not be much less. This extreme

range could be attained by elevating the gun to exactly the

proper pitch. Of course, any shorter range could, within certain

limits, also be reached.

 

The gun was pointed slantingly up the valley, and there was

ample room to attain the thirty-mile range without doing any

damage.

 

At the head of the valley, some miles from where the giant

cannon was mounted, was an immense dam, built recently by a water

company for impounding a stream and furnishing a supply of

drinking water for a distant city. At the other end of the valley

was the thriving village of Preston. A railroad ran there, and it

was to Preston station that Tom's big gun had been sent, to be

transported afterward, on specially made trucks, drawn by

powerful autos, to the place where it was now mounted.

 

Tom had been obliged to buy a piece of land on which to build

the temporary carriage, and also contract for a large slice of

the opposite mountain, as a target against which to fire his

projectiles.

 

The valley, as I have said, was desolate. It was thickly wooded

in spots, and in the centre, near the big dam, which held back

the waters of an immense artificial lake, was a great hill,

evidently a relic of some glacial epoch. This hill was a sort of

division between two valleys.

 

Tom, Ned, Mr. Damon, with Koku, and some of the employees of the

steel company, had hired a deserted farmhouse not far from the

place where the gun was being mounted. In this they lived, while

Tom directed operations.

 

"The paper says 'clear' tomorrow," read Ned, on his return.

"'Clear, with freshening winds.'"

 

"That means rain, with no wind at all," declared Tom, with a

sigh. "Well, it can't be helped. As Mr. Damon says, it will clear

some time."

 

"Bless my overshoes!" exclaimed the odd gentleman. "It always

has cleared; hasn't it?"

 

No one could deny this.

 

There came a slackening in the showers, and Tom and Ned,

donning raincoats, went out to see how the work was progressing.

They found the men from the steel concern busy at the great piece

of engineering.

 

"How are you coming on?" asked Tom of the foreman.

 

"We could finish it in two days if this rain

would only let up," replied the man.

 

"Well, let's hope that it will," observed Tom.

 

"If it doesn't, there's likely to be trouble up above," went on

the foreman, nodding in the direction of the great dam.

 

"What do you mean?"

 

"I mean that the water is getting too high. The dam is

weakening, I heard."

 

"Is that so? Why, I thought they had made it to stand any sort

of a flood."

 

"They evidently didn't count on one like this. They've got the

engineer who built it up there, and they're doing their best to

strengthen it. I also heard that they're preparing to dynamite it

to open breeches here and there in it, in case it is likely to

give way suddenly."

 

"You don't mean it! Say, if it does go out with a rush it will

wipe out the village."

 

"Yes, but it can't hurt us," went on the foreman. "We're too

high up on the side of the hill. Even if the dam did burst, if

the course of the water could be changed, to send it down that

other valley, it would do no harm, for there are no settlements

over there," and he pointed to the distant hill.

 

It was near this hill that Tom intended to direct his

projectiles, and on the other side of it was another valley,

running at right angles to the one crossed by the dam.

 

As the foreman had said, if the waters (in case the dam burst)

could be turned into this transverse valley, the town could be

saved.

 

"But it would take considerable digging to open a way through

that side of the mountain, into the other valley," went on the

man.

 

"Yes," said Tom, and then he gave the matter no further

thought, for something came up that needed his attention.

 

"Have you your explosive here?" asked the foreman of the young

inventor the next day, when the weather showed signs of clearing.

 

"Yes, some of it," said Tom. "I have another supply in a safe

place in the village. I didn't want to bring too much here until

the gun was to be fired. I can easily get it if we need it. Jove!

I wish it would clear. I want to get out in my Humming Bird, but

I can't if this keeps up." Tom had brought one of his speedy

little airships with him to Preston.

 

The following day the clouds broke a little, and on the next

the sun shone. Then the work on the gun went on apace. Tom and

his friends were delighted.

 

"Well, I think we can try a shot tomorrow!" announced Tom with

delight on the evening of the first clear day, when all hands had

worked at double time.

 

"Bless my powder-horn!" exclaimed Mr. Damon. "You don't mean

it!"

 

"Yes, the gun is all in place," went on the young inventor. "Of

course, it's only a temporary carriage, and not the disappearing

one I shall eventually use. But it will do. I'm going to try a

shot tomorrow. Everything is in readiness."

 

There came a knock on the door of the room Tom had fitted up as

an office in the old farmhouse.

 

"Who is it?" he asked.

 

"Me--Koku," was the answer.

 

"Well, what do you want, Koku?"

 

"Man here say him must see Master."

 

Tom and Ned looked at each other, suspicion in their eyes.

 

"Maybe it's that spy again," whispered Ned.

 

"If it is, we'll be ready for him," murmured his chum. "Show

him in, Koku, and you come in too."

 

But the man who entered at once disarmed suspicion. He was

evidently a workman from the dam above, and his manner was

strangely excited.

 

"You folks had better get out of here!" he exclaimed.

 

"Why?" asked Tom, wondering what was going to happen.

 

"Why? Because our dam is going to burst within a few hours.

I've been sent to warn the folks in town in time to let them take

to the hills. You'd better move your outfit. The dam can't last

twenty-four hours longer!"

 

 

 

CHAPTER XVII

 

THE BURSTING DAM

 

 

"Bless my fountain pen!" exclaimed Mr. Damon. "You don't mean

it!"

 

"I sure do!" went on the man who had brought the startling

news. "And the folks down below aren't going to have any more

time than they need to get out of the way. They'll have to lose

some of their goods, I reckon. But I thought I'd stop on my way

down and warn you. You'd better be getting a hustle on."

 

"It's very kind of you," spoke Torn; "but I don't fancy we are

in any danger."

 

"No danger!" cried the man. "Say, when that water begins to

sweep-down here nothing on earth can stop it. That big gun of

yours, heavy as it is, will be swept away like a straw, I know--I

saw the Johnstown flood!"

 

"But we're so high up on the side of the hill, that the water

won't come here," put in Ned. "We had that all figured out when

we heard the dam was weak. We're not in any danger; do you think

so, Tom?"

 

"Well, I hardly do, or I would not have set the gun where I

did. Tell me," he went on to the man, "is there any way of

opening the dam, to let the water out gradually?"

 

"There is, but the openings are not enough with such a flood as

this. The engineers never counted on so much rain. It's beyond

any they ever had here. You see, there was a small creek that we

dammed up to make our lake. Some of the water from the spillway

flows into that now, but its channel won't hold a hundredth part

of the flood if the dam goes out.

 

"You'd better move, I tell you. The dam is slowly weakening.

We've done all we can to save it, but that's out of the question.

The only thing to do is to run while there's time. We've tried to

make additional openings, but we daren't make any more, or the

wall will be so weakened that it will go out in less than twenty-

four hours.

 

"You've had your warning, now profit by it!" he added. "I'm

going to tell those poor souls down in the valley below. It will

be tough on them; but it can't be helped."

 

"If the dam bursts and the water could only be turned over into

the transverse valley, this one would be safe," said Tom, in a

low voice.

 

"Yes, but it can't be done!" the messenger exclaimed. "Our

engineers thought of that, but it would take a week to open a

channel, and there isn't time. It can't be done!"

 

"Maybe it can," spoke Tom, softly, but no one asked him what he

meant.

 

"Well, I must be off," the man went on. "I've done my duty in

warning you."

 

"Yes, you have," agreed Tom, "and if any damage comes to us it

will be our own fault. But I don't believe there will."

 

The man hastened out, murmuring something about "rash and

foolhardy people."

 

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

 

"Stay right here."

 

"But if the dam bursts?"

 

"It may not, but, if it does, we'll be safe. I have had a look

at the water, and there's no chance for it to rise here, even if

the whole dam went out at once, which is not likely. Don't worry.

We'll be all right."

 

"Bless my checkbook!" cried Mr. Damon. "But what about those

poor people in the valley?"

 

"They will have time to flee, and save their lives," spoke the

young inventor; "but they may lose their homes. They can sue the

water company for damages, though. Now don't do any more

worrying, but get to bed, and be ready for the test tomorrow. And

the first thing I do I'm going to have a little flight in the

Humming Bird to get my nerves in trim. This long rain has gotten

me in poor shape. Koku, you must be on the alert tonight. I don't

want anything to happen to my gun at the last minute."

 

"Me watch!" exclaimed the giant, significantly, as he picked up

a heavy club.

 

"Do you anticipate any trouble?" asked Ned, anxiously.

 

"No, but it's best to be on the safe side," answered Tom. "Now

let's turn in."

 

Certainly the next day, bright and sunshiny as it broke, had in

it little of impending disaster. The weather was fine after the

long-continued rains, and the whole valley seemed peaceful and

quiet. At the far end could be seen the great dam, with water

pouring over it in a thin sheet, forming a small stream that

trickled down the centre of the valley, and to the town below.

 

But, through great pipes that led to the drinking system,

though they were unseen, thundered immense streams of solid

water, reducing by as much as the engineers were able the

pressure on the concrete wall.

 

Tom and Ned, in the Humming Bird, took a flight out to the dam

shortly after breakfast, when the steel men were putting a few

finishing touches to the gun carriage, ready for the test that

was to take place about noon.

 

"It doesn't look as though it would burst," observed Ned, as

the aircraft hovered over the big artificial lake.

 

"No," agreed Tom. "But I suppose the engineers want to be on

the safe side in case of damage suits. I want to take a look at

the place where the other valley comes up to this at right

angles."

 

He steered his powerful little craft in that direction, and

circled low over the spot.

 

"A bursting projectile, about where that big white stone is,

would do the trick," murmured Tom.

 

"What trick?" asked Ned, curiously.

 

"Oh, I guess I was talking to myself," admitted Tom, with a

laugh. "I may not have to do it, Ned."

 

"Well, you're talking in riddles today, all right, Tom. When

you get ready to put me wise, please do."

 

"I will. Now we'll get back, and fire our first long shot. I do

hope I make a record."

 

There was much to be done, in spite of the fact that the

foreman of the steel workers assured Tom that all was in

readiness. It was some time that afternoon when word was given

for those who wished to retire to an improvised bomb-proof. Word

had previously been sent down the valley so that no one, unless

he was looking for trouble, need be in the vicinity of the gun,

nor near where the shots were to land.

 

Through powerful glasses Tom and Ned surveyed the distant

mountain that was to be the target. Several great squares of

white cloth had been put at different bare spots to make the

finding of the range easy.

 

"I guess we're ready now," announced the young inventor, a bit

nervously. "Bring up the powder, Koku."

 

"Me bring," exclaimed the giant, calmly, as he went to the

bomb-proof where the powerful explosive was kept.

 

The great projectile was in readiness to be slung into the

breech by means of the hoisting apparatus, for it weighed close

to two tons. It was carefully inserted under Tom's supervision.

It carried no bursting charge, for Tom's first shot was merely to

establish the extreme range that his cannon would shoot.

 

"Now the powder," called the young inventor. To avoid accidents

Koku handled this himself, the hoisting apparatus being dispensed

with. Tom figured out that five hundred pounds of his new,

powerful explosive would be about the right amount to use, and

this quantity, divided into several packages to make the handling

easier, was quickly inserted in the breech of the gun by Koku.

 

"Bless my doormat!" cried Mr. Damon, who stood near, looking

nervously on. "Don't drop any of that."

 

"Me no drop," was the answer.

 

Tom was busily engaged in figuring on a bit of paper, and Ned,

who looked over his shoulder, saw a complicated compilation that

looked to he a combination of geometry, algebra, differential

calculus and other higher mathematics.

 

"What are you doing, Tom?" he asked.

 

"I'm trying to confirm my own theories by means of figures, to

see if I can really reach that farthest target."

 

"What, not the one thirty miles away.

 

"That's it, Ned. I want to get a thirty-mile range if I can."

 

"It isn't possible, Tom."

 

"Bless my tape measure! I should say not!" cried Mr. Damon.

 

"We'll see," replied Tom, quietly. "Put in the primer, Ned;

and, Koku, close the breech and slot it home."

 

In a few seconds the great gun was ready for firing.

 

"Now," said Tom, "this thing may be all right, and it may not.

The only thing that can cause an accident will be a flaw in the

steel. No one can guard against that. So, in order to be on the

safe side, we will all go into the bomb-proof, and I will fire

the gun from there. The wires are long enough."

 

They all agreed that this was good advice, and soon the steel

men and Tom's friends were gathered in a sort of cave that had

been hollowed out in the side of the hill, and at an angle from

the big gun.

 

"If it does burst--which I hope it won't," said Tom, "the

pieces will fly in straight lines, so we will be safe enough

here. Ned, are you are ready at the instruments?"

 

"Yes, Tom."

 

"I want you to note the registered muzzle velocity. Mr. Damon,

you will please read the pressure gauge. After I press the button

I'm going to watch the landing of the projectile through the

telescope."

 

The gun had been pointed, as I have said, at the farthest

target--one thirty miles away, telescope sights on the giant

cannon making this possible.

 

"All ready!" cried Tom.

 

"All ready," answered Ned.

 

There was a tense moment; Tom's thumb pressed home the electric

button, and then came the explosion.

 

It seemed for a moment as if everyone was lifted from his feet.

They had all stood on their tiptoes, and opened their mouths to

lessen the shock, but even then it was terrific. The very ground

shook--from the roof of their cave small stones and gravel

rattled down on their heads. Their ear-drums were numbed from the

shock. And the noise that filled the valley seemed like a

thousand thunderbolts merged into one.

 

Tom rushed from the bombproof, dropping the electric button. He

caught sight of his gun, resting undisturbed on the improvised

carriage.

 

"Hurray!" he cried in delight. "She stood the charge all right.

And look! look!" he cried, as he pointed the glasses toward the

distant hillside. "There goes my projectile as straight as an

arrow. There! By Caesar, Ned! It landed within three feet of the

target! Oh, you beauty!" he yelled at his giant cannon. "You did

all I hoped you would! Thirty miles, Ned! Think of that! A two-

ton projectile being shot thirty miles!"

 

"It's great, Tom!" yelled his chum, clapping him on the back,

and capering about. "It's the longest shot on record."

 

"It certainly is," declared the foreman of the steel workers,

who had helped in casting many big guns. "No cannon ever made can

equal it. You win, Tom Swift!"

 

"Bless my armor plate!" gasped Mr. Damon. "What attacking ship

against the Panama Canal could float after a shot like that."

 

"Not one," declared Tom; "especially after I put a bursting

charge into the projectile. We'll try that next."

 

By means of compressed air the gases and some particles of the

unexploded powder were blown out of the big cannon. Then it was

loaded again, the projectile this time carrying a bursting charge

of another explosive that would be set off by concussion.

 

Once more they retired to the bombproof, and again the great

gun was fired. Once more the ground shook, and they were nearly

deafened by the shock.

 

Then, as they looked toward the distant hillside, they saw a

shower of earth and great rocks rise up. It was like a sand

geyser. Then, when this settled back again, there was left a

gaping hole in the side of the mountain.

 

"That does the business!" cried Tom. "My cannon is a success!"

 

The last shot did not go quite as far as the first, but it was

because a different kind of projectile was used. Tom was

perfectly satisfied, however. Several more trials were given the

gun, and each one confirmed the young inventor in his belief that

he had made a wonderful weapon.

 

"If that doesn't fortify the Panama Canal nothing will,"

declared Ned.

 

"Well, I hope I can convince Uncle Sam of that," spoke Tom,

simply.

 

The muzzle velocity and the pressure were equal to Tom's

highest hopes. He knew, now, that he had hit on just the right

mixture of powder, and that his gun was correctly proportioned.

It showed not the slightest strain.

 

"Now we'll try another bursting shell," he said, after a rest,

during which some records were made. "Then we'll call it a day's

work. Koku, bring up some more powder. I'll use a little heavier

charge this time."

 

It was while the gun was being loaded that a horseman was seen

riding wildly down the valley. He was waving a red flag in his

hand.

 

"Bless my watch chain!" cried Mr. Damon. "What's that?"

 

"It looks as though he was coming to give us a warning,"

suggested the steel foreman.

 

"Maybe someone has kicked about our shooting," remarked Ned.

 

"I hope not," murmured Tom.

 

He looked at the horseman anxiously. The rider came nearer and

nearer, wildly waving his flag. He seemed to be shouting

something, but his words could not be made out. Finally he came

near enough to be heard.

 

"The dam! The dam!" he cried. "It's bursting. Your shots have

hastened it. The cracks are widening. You'd better get away!" And

he galloped on.

 

"Bless my toilet soap!" gasped Mr. Damon.

 

"I was afraid of this!" murmured Tom. "But, since our shots

have hastened the disaster, maybe we can avert it."

 

"How?" demanded Ned.

 

"I'll show you. All hands come here and we'll shift this gun. I

want it to point at that big white stone!" and he indicated an

immense boulder, well up the valley, near the place where the two

great gulches joined.

 

 

 

CHAPTER XVIII

 

THE DOPED POWDER

 

 

"What are you going to do, Tom?" cried Ned, as he, with the

others, worked the hand gear that shifted the big gun. When it

was permanently mounted electricity would accomplish this work.

"What's your game, Tom?"

 

"Don't you remember, Ned? When we were talking about the chance

of the dam bursting, I said if the current of suddenly released

water could be turned into the other valley, the people below us

would be saved."

 

"Yes."

 

"Well, that's what I'm going to do. I'm going to fire a

bursting shell at the point where the two valleys come together.

I'll break down the barrier of rock and stone between them."

 

"Bless my shovel and hoe!" cried Mr. Damon.

 

"If we can turn enough of the water into the other valley,

where no one lives, and where it can escape into the big river

there, the amount that will flow down this valley will be so

small that only a little damage will be done."

 

"That's right!" declared the steel foreman, as he caught Tom's

idea. "It's the only way it could be done, too, for there won't

be time to make the necessary excavation any other way. Is the

gun swung around far enough, Mr. Swift?"

 

"No, a little more toward me," answered Tom, as he peered

through the telescope sights. "There, that will do. Now to get

the proper elevation," and he began to work the other apparatus,

having estimated the range as well as he could.

 

In a few seconds the giant cannon was properly trained on the

white rock. Meanwhile the horseman, with his red flag, had

continued on down the valley. In spite of his warning of the

night before, it developed that a number had disregarded it, and

had remained in their homes. Most of the inhabitants, however,

had fled to the hills, to stay in tents, or with such neighbors

as could accommodate them. Some lingered to move their household

goods, while others fled with what they could carry.

 

It was to see that the town was deserted by these late-stayers

that the messenger rode, crying his warning as did the messenger

at the bursting of the Johnstown dam twenty-odd years ago.

 

"The projectile!" cried Tom, as he saw that all was in

readiness. "Lively now! I can see the top of the dam beginning to

crumble," and he laid aside the telescope he had been using.

 

The projectile, with a heavy charge of bursting powder, was

slung into the breech of the gun.

 

"Now the powder, Koku!" called Tom. "Be quick; but not so fast

that you drop any of it."

 

"Me fetch," responded the giant, as he hastened toward the

small cave where the explosive was kept. As the big man brought

the first lot, and Ned was about to insert it in the breech of

the gun, behind the projectile, Tom exclaimed:

 

"Just let me have a look at that. It's some that I first made,

and I want to be sure it hasn't gone stale."

 

Critically he looked at the powerful explosive. As he did so a

change came over his face.

 

"Here, Koku!" the young inventor said. "Where did you get

this?"

 

"In cave, Master."

 

"Is there any more left?"

 

"Only enough for this one shoot."

 

"By Jove!" muttered Tom. "There's been some trick played here!"

and he set off on a run toward the bomb-proof.

 

"What's the matter?" cried Ned, as he noticed the agitation of

his chum.

 

"The powder has been doped!" yelled Tom. "Something has been

put in it to make it nonexplosive. It's no good. It wouldn't send

that shell a thousand yards, and it's got to go five miles to do

any good. My plan won't work."

 

"Doped the powder?" gasped Ned. "Who could have done it?"

 

"I don't know. There must have been some spy at work. Quick,

run and ask the foreman if any of his men are missing. I'll see

if there's enough of the good powder left to break down the

barrier!"

 

Ned was away like a shot, while the others, not knowing what to

make of the strange conduct of the two lads, looked on in wonder.

Tom raced toward the cave where the powder was stored, Koku

following him.

 

"Bless my shoe laces!" cried Mr. Damon. "Look at the dam now

 

They gazed to where he pointed. In several places the concrete

spillway had crumbled down to a ragged edge, showing that the

solid wall was giving way. The amount of water flowing over the

dam was greater now. The creek was steadily rising. Down the

valley the horseman with the red flag was but a speck in the

distance.

 

"What can I do? What can I do?" murmured Tom. "If all the

powder there is left has been doped, I can't save the town! What

can I do? What can I do?"

 

Ned had reached the foreman, who, with his helpers, was

standing about the big gun.

 

"Have any of your men left recently?" yelled Ned.

 

"Any of my men left? What do you mean?

 

"Schlichter went yesterday," said the timekeeper. "I thought he

was in quite a hurry to get his money, too."

 

"Schlichter gone!" exclaimed the foreman. "He was no good

anyhow. I think he was a sort of Anarchist; always against the

government, the way he talked. So he has left; eh? But what's the

matter, Ned?"

 

"Something wrong with the powder. Tom can't shoot the cannon

and turn aside the water to save the town. Some of his enemies

have been at work. Schlichter leaving at this time, and in such

hurry, makes it look suspicious."

 

"It sure does! And, now I recall it, I saw him yesterday near

your powder magazine. I called him down for it, for I knew Tom

Swift had given orders that only his own party was to go near it.

So the powder is doped; eh?"

 

"Yes! It's all off now."

 

He turned to see Tom approaching on the run.

 

"Any good powder left?" asked Ned.

 

"Not a pound. Did you hear anything?"

 

"Yes, one man has disappeared. Oh, Tom, we've got to fail after

all! We can't save the town!"

 

"Yes, we can, Ned. If that dam will only hold for half an hour

more."

 

"What do you mean

 

"I mean that I have another supply of good powder in the

village. I secreted some there, you remember I told you. If I can

go get that, and get back here in time, I can break down the

barrier with one shot, and save Preston."

 

"But you never can make the trip there and back in time, with

the powder, Tom. It's impossible. The dam may hold half an hour,

or it may not. But, if it does, you can't do anything!"

 

"I can't? Well, I'm going to make a big try, Ned. You stay on

the job here. Have everything ready so that when I get back with

the new explosive, which I hope hasn't been tampered with, I can

shove it into the breech, and set it off. Have the wires, primers

and button all ready for me."

 

Then Tom set off on the run.

 

"Where are you going?" gasped his chum. "You can never run to

Preston and back in time."

 

"I don't intend to. I'm going in my airship. Koku, never mind

bringing the rest of the powder from the cave. It's no good. Run

out the Humming Bird. I'm going to drive her to the limit. I've

just got to get that powder here on time!"

 

"Bless my timetable!" gasped Mr. Damon. "That's the only way it

can be done. Lucky Tom brought the airship along!"

 

The young inventor, pausing only to get some cans for the

explosive, and some straps with which to fasten them in the

monoplane, leaped into the speedy craft.

 

The motor was adjusted; Koku whirled the propeller blades.

There was a staccato succession of explosions, a rushing, roaring

sound, and then the craft rose like a bird, and Tom circled

about, making a straight course for the distant town, while below

him the creek rose higher and higher as the dam continued to

crumble away.

 

 

 

CHAPTER XIX

 

BLOWING DOWN THE BARRIER

 

 

"Can you see anything of him, Ned?"

 

"Not a thing, Mr. Damon. Wait--hold on--no! It's only a bird,"

and the lad lowered the glasses with which he had been sweeping

the sky. looking for his chum returning in his airship with the

powder.

 

"He'd better hurry," murmured the foreman. "That dam can't last

much longer. The water is rising fast. When it does go out it

will go with a rush. Then good-bye to the village of Preston."

 

"Bless my insurance policy!" cried Mr. Damon. "Don't say such

things, my friend."

 

"But they're true!" insisted the man. "You can see for yourself

that the cracks in the dam are getting larger. It will be a big

flood when it does come. And I'm not altogether sure that we're

safe up here," he added, as he looked down the sides of the hill

to where the creek was now rapidly becoming a raging torrent.

 

"Bless my hat-band!" gasped Mr. Damon. "You--you are getting on

my nerves

 

"I don't want to be a calamity howler," went on the foreman;

"but we've got to face this thing. We'd better get ready to

vamoose if Tom Swift doesn't reach here in time to fire that

shot--and he doesn't seem to be in sight."

 

Once more Ned swept the sky with his glasses. The roar of the

water below them could be plainly heard now.

 

"I wish I could get hold of that rascally German," muttered the

foreman. "I'd give him more than a piece of my mind. It will be

his fault if the town is destroyed, for Tom's plan would have

saved it. I wonder who he can be, anyhow?"

 

"Some spy," declared Ned. "We've been having trouble right

along, you know, and this is part of the game. I have some

suspicions, but Tom doesn't agree with me. Certainly the fellow,

whatever his object, has made trouble enough this time."

 

"I should say so," agreed the foreman.

 

"Look, Ned!" cried Mr. Damon. "Is that a

bird; or is it Tom?" and he pointed to a speck in

the sky. Ned quickly focused his glasses on it.

 

"It's Tom!" he cried a second later. "It's Tom in the Humming

Bird!"

 

"Thank Heaven for that!" exclaimed Mr. Damon, fervently,

forgetting to bless anything on this occasion. "If only he can

get here in time!"

 

"He's driving her to the limit!" cried Ned, still watching his

chum through the glass. "He's coming!"

 

"He'll need to," murmured the foreman, grimly. "That dam can't

last ten minutes more. Look at the people fleeing from the

valley!"

 

He pointed to the north, and a confused mass of small black

objects--men, women and children, doubtless, who had lingered in

spite of the other warning--could be seen clambering up the sides

of the valley.

 

"Is everything ready at the gun?" asked Mr. Damon.

 

"Everything," answered Ned, whom Tom had instructed in all the

essentials. "As soon as he lands we'll jam in the powder, and

fire the shot."

 

"I hope he doesn't land too hard, with all that explosive on

board," murmured the foreman.

 

"Bless my checkerboard!" cried Mr. Damon. "Don't suggest such a

thing."

 

"I guess we can trust Tom," spoke Ned.

 

They looked up. The distant throb of the monoplane's motor

could now be heard above the roar of the swollen waters. Tom

could be seen in his seat, and beside him, in the other, was a

large package.

 

Nearer and nearer came the monoplane. It began to descend, very

gently, for well Tom Swift knew the danger of hitting the ground

too hard with the cargo he carried.

 

He described a circle in the air to check his speed. Then,

gently as a bird, he made a landing not far from the gun, the

craft running easily over one of the few level places on the side

of the hill. Tom yanked on the brake, and the iron-shod pieces of

wood dug into the ground, checking the progress of the monoplane

on its bicycle wheels.

 

"Have you got it, Tom?" yelled Ned.

 

"I have," was the answer of the young inventor as he leaped

from his seat.

 

"Is it good powder?" asked the foreman, anxiously.

 

"I don't know," spoke Tom. "I didn't have time to look. I just

rushed up to where I had stored it, got some out and came back

with the motor at full speed. Ran into an airpocket, too, and I

thought it was all up with me when I began to fall. But I managed

to get out of it. Say, we're going to have it nip and tuck here

to save the village."

 

"That's what!" agreed the foreman, as he helped Koku take the

cans of explosive.

 

"Wait until I look at it," suggested Tom, as he opened one. His

trained eye and touch soon told him that this explosive had not

been tampered with.

 

"It's all right!" he shouted. "Into the gun with it, and we'll

see what happens."

 

It was the work of only a few moments to put in the charge.

Then, once more, the breech-block was slotted home, and the

trailing electric wires unreeled to lead to the bomb-proof.

 

Tom Swift took one last look through the telescope sights of

his giant cannon. He changed the range slightly by means of the

hand and worm-screw gear, and then, with the others, ran to the

shelter of the cave. For, though the gun had stood the previous

tests well, Tom had used a heavier charge this time, both in the

firing chamber and in the projectile, and he wanted to take no

chances.

 

"All ready?" asked the young inventor, as he looked around at

his friends gathered in the cave.

 

"I--I guess so," answered Ned, somewhat doubtfully.

 

Tom hesitated a moment, then, as his fingers stiffened to press

the electric button there sounded to the ears of all a dull,

booming sound.

 

"The dam! It has given way!" cried Ned.

 

"That's it!" shouted the foreman. "Fire!"

 

Tom pressed the button. Once again was that awful tremor of the

earth--the racking shake--the terrific explosion and a shock that

knocked a couple of the men down.

 

"All right!" shouted Tom. "The gun held together. It's safe to

go out. We'll see what happened!"

 

They all rushed from the shelter of the cave. Before them was

an awe-inspiring sight. A great wall of water was coming down the

valley, from a large opening in the centre of the dam. It seemed

to leap forward like a race horse.

 

Tom declared afterward that he saw his projectile strike the

barrier that separated one valley from the other, but none of the

others had eyes-sight as keen as this--and perhaps Tom was in

error.

 

But there was no doubt that they all saw what followed. They

heard a distant report as the great projectile burst. Then a wall

of earth seemed to rise up in front of the advancing wall of

water. High into the air great stones and masses of dirt were

thrown.

 

"A good shot!" cried the foreman. "Just in the right place,

Tom Swift!"

 

For a moment it was as though that wall of water hesitated, not

deciding whether to continue on down the populated valley, or to

swing over into the other gash where it could do comparatively

little harm. It was a moment of suspense.

 

Then, as Tom's great shot had, by means of the exploding

projectile, torn down the barrier, the water chose the more

direct and shorter path. With a mighty roar, like a distant

Niagara, it swept into the new channel the young inventor had

made. Into the transverse valley it tumbled and tossed in muddy

billows of foam, and only a small portion of the flood added

itself to the already swollen creek.

 

The village of Preston had been saved by the

shot from Tom's giant cannon.

 

 

 

CHAPTER XX

 

THE GOVERNMENT ACCEPTS

 

 

"Whew! Let me sit down somewhere and get my breath!" gasped

Tom, when it was all over.

 

"I should think you would want a bit of quiet," replied Ned.

"You've been on the jump since early morning."

 

"Bless my dining-room table!" cried Mr. Damon. "I should say

so! I'll go tell the cook to get us all a good meal--we need it,"

for a competent cook had been installed in the old farmhouse

where Tom and his party had their headquarters.

 

"But you did the trick, Tom, old man!" exclaimed Ned,

fervently, as he looked down the valley and saw the receding

water. For, with the opening of the channel into the other valley

the flood, at no time particularly dangerous near Preston, was

subsiding rapidly.

 

"He sure did," declared the foreman. "No one else could have

done it, either."

 

"Oh, I don't know," spoke Tom, modestly. "It just happened so.

There was one minute, though, after I got to the place in Preston

where I had stored the powder, that I didn't know whether I would

succeed or not."

 

"How was that?" asked Mr. Damon.

 

"Why, in my hurry and excitement I forgot the key to the

underground storeroom where I had put the explosive. I knew there

was no time to get another, so I took a chance and burst in the

door with an axe I found in the freight depot."

 

"I should say you did take a chance!" declared Ned, who knew

how "freaky" the high explosive was, and how likely it was, at

times, to be set off by the least concussion.

 

"But it came out all right," went on Tom. "I bundled it into

the other seat of my Humming Bird, and started back."

 

"Had most of the folks left town?" asked the foreman.

 

"Nearly all," replied Tom. "The last of them were hurrying away

as I left. And it shows how scared they were, they didn't pay any

attention to me and my flying machine, though I'll wager some of

them never saw one before."

 

"Well, they don't need to be scared any more," put in Mr. Damon

"You saved their homes for them, Tom."

 

"I'd like to get hold of the fellow who doped my powder; that's

what I'd like to do," murmured the young inventor. "Ned, we'll

have to be doubly watchful from now on. But I must take a look at

my gun. That last charge may have strained it."

 

But the giant cannon was as perfect as the day it was turned

out of the shop. Not even the extra charge of the powerful

explosive had injured it.

 

"That's fine!" cried Tom, as he looked at every part. "As soon

as this flood is over we'll try some more practice shots. But

we're all entitled to a rest now"

 

The great gun was covered with tarpaulins to protect it from

the weather, and then all retired to the house for a bountiful

meal. Late that afternoon nearly all signs of the flood had

disappeared, save that along the edges of the creek was much

driftwood, showing the height to which the creek had risen. But

it would have gone much higher had it not been for Tom's timely

shot.

 

The water from the impounded lake continued to pour down into

the cross valley, and did some damage, but nothing like what

would have followed its advent into Preston. The few inhabitants

of the gulch into which the young inventor had directed the flood

had had warning, and had fled in time. In Preston, some few

houses nearest the banks of the rising creek were flooded, but

were not carried away.

 

The following day some of the officers of the water company

paid a visit to Tom, to thank him for what he had done. But for

him they would have been responsible for great property damage,

and loss of life might have followed.

 

They intended to rebuild the dam, they said, on a new

principle, making it much stronger.

 

"And," said the president, "we will have an emergency outlet

gate into that valley you so providentially opened for us, Mr.

Swift. Then, in time of great rain, we can let the water out

slowly as we need to."

 

Tom's chief anxiety, now, was to bring his perfected gun to the

notice of the United States Government officials. To have them

accept it, he knew he must give it a test before the ordnance

board, and before the officers of the army and navy. Accordingly

he prepared for this.

 

He ordered several new projectiles, some of a different type

from those heretofore used, and leaving Koku and Ned in charge of

the gun, went back to Shopton to superintend the manufacture of

an additional supply of his explosive. He took care, too, that no

spies gained access to it.

 

Then, with a plentiful supply of ammunition and projectiles,

Tom resumed his practice in the lonely valley. He had, in the

meanwhile, sent requests to the proper government officials to

come and witness the tests.

 

At first he met with no success, and he learned, incidentally,

that General Waller had built a new gun, the merits of which he

was also anxious to show.

 

"It's a sort of rivalry between us," said Tom to Ned.

 

But, in a way, fortune favored our hero. For when General

Waller tested his new gun, though it did not burst, it did not

come up to expectations, and its range was not as great as some

of the weapons already in use.

 

Then, too, Captain Badger acted as Tom's friend at court. He

"pulled wires" to good advantage, and at last the government sent

word that one of the ordnance officers would be present on a

certain day to witness the tests.

 

"I wish the whole board had come," said Tom. "Probably they

have only sent a young fellow, just out of West Point, who will

turn me down.

 

"But I'm going to give him the surprise of his life; and if he

doesn't report favorably, and insist on the whole board coming

out here, I'll be much disappointed."

 

Tom made his preparations carefully, and certainly Captain

Waydell, the young officer who came to represent Uncle Sam, was

impressed. Tom sent shell after shell, heavily charged, against

the side of the mountain. Great holes and gashes were torn in the

earth. The gun even exceeded the range of thirty miles. And the

heaviest armor plate that could be procured was to the

projectiles of the giant cannon like cheese to a revolver bullet.

 

"It's great, Mr. Swift! Great!" declared the young captain. "I

shall strongly recommend that the entire board see this test."

And when Tom let him fire the gun himself the young man was more

than delighted.

 

He was as good as his word, and a week later the entire

ordnance board, from the youngest member to the grave and

grizzled veterans, were present to witness the test of Tom's

giant cannon.

 

It is needless to say that it was successful. Tom and Ned, not

to mention Mr. Damon, Koku and every loyal member of the steel

working gang, saw to it that there was no hitch. The solid shots

were regarded with wonder, and when the explosive one was sent

against the hillside, making a geyser of earth, the enthusiasm

was unbounded.

 

"We shall certainly recommend your gun, Mr. Swift," declared

the Chief of Staff. "It does just what we want it to do, and we

have no doubt that Congress will appropriate the money for

several with which to fortify the Panama Canal."

 

"The gun is most wonderful," spoke a voice with a German

accent. "It is surprising!"

 

Tom and Ned both started. They saw an officer, evidently a

foreigner, resplendent in gold trimmings, and with many medals,

standing near the secretary of the ordnance board.

 

"Yes, General von Brunderger," agreed the chief, "it is a most

timely invention. Mr. Swift, allow me to present you to General

von Brunderger, of the German army, who is here learning how

Uncle Sam does things."

 

Tom bowed and shook hands. He glanced sharply at the German,

but was sure he had never seen him before. Then all the board,

and General von Brunderger, who, it appeared, was present as an

invited guest, examined the big cannon critically, while Tom

explained the various details.

 

When the board members left, the chief promised to let Tom know

the result of the formal report as soon as possible.

 

The young inventor did not have long to wait. In about two

weeks, during which time he and Ned perfected several little

matters about the cannon, there came an official-looking

document.

 

"Well, we'll soon know the verdict," spoke Tom, somewhat

nervously, as he opened the envelope. Quickly he read the

enclosure.

 

"What is it!" cried Ned.

 

"The government accepts my gun!" exclaimed the young inventor.

"It will purchase a number as soon as they can be made. We are to

take one to Panama, where it will be set up. Hurray, Ned, my boy!

Now for Panama!"

 

 

 

CHAPTER XXI

 

OFF FOR PANAMA

 

 

"WELL," Tom, it doesn't seem possible; does it, old man?"

 

"You're right, Ned--in a way. And yet, after all the hard work

we've done, almost anything is possible."

 

"Hard work! We? Oh, pshaw! You've done most of it, Tom. I only

helped here and there."

 

"Indeed, and you did more than that. If it hadn't been for you,

Mr. Damon and Koku we'd never have gotten off as soon as we did.

The government is the limit for doing things, sometimes."

 

"Bless my timetable! but I agree with you," put in Mr. Damon.

"But at last we are on the way, in spite of delays."

 

This conversation took place on board one of Uncle Sam's

warships, which the President had designated to take Tom's giant

cannon to the Panama Canal.

 

The big gun had been lashed to the deck of the vessel, and was

well protected from the weather. In the hold the parts of the

disappearing carriage, which Tom had at last succeeded in having

made, were securely stowed. In another part of the warship were

the big projectiles, some arranged to be fired as solid shots,

and others with a bursting charge. There was also a good supply

of the powerful explosive, and Tom had taken extraordinary

precautions so that it could not be tampered with. Koku had been

detailed as a sort of guard over it, and to relieve him was a

trustworthy sergeant of marines.

 

"If anyone tries to dope that powder now, and spoil my test at

Panama," declared Tom, "he'll wish he'd never tried it."

 

"Especially if Koku gets hold of him," added Ned, grimly.

 

"But I don't believe there is any danger," went on the young

inventor. "I spoke about what had happened, and the ordnance

board took extra precautions to see that none but men and

officers who could be implicitly trusted had anything to do with

this expedition."

 

"You don't really believe anything like treachery would be

attempted; do you, Tom?"

 

"I don't know what to say. Certainly I can't see why anyone

connected with Uncle Sam would want to throw cold water on a plan

to fortify the canal, even if an outsider has invented the gun--I

mean someone like myself, not connected with the army or navy."

 

"If it's anything it's jealousy," declared Ned, "That General

Waller--"

 

"There you go again, Ned. Let's not talk about it. Come on

forward and see what progress we are making."

 

It must not be supposed that to get the big gun aboard the

vessel, arrange for a new supply of the explosive, and for many

of the great projectiles, had been easy work. It was a task that

taxed the skill and strength of Tom and his friends to the

utmost.

 

There had been wearying delays, especially in the matter of

making the disappearing carriage. At times it seemed as if the

required projectiles would never be finished. The powder, too,

gave trouble, for sometimes batches would be turned out that were

utterly worthless.

 

But Tom never gave up, even when it seemed that some of the

failures were purposely made. Ned declared that there was a

conspiracy against his chum, but Tom could not see it that way.

It was due to a combination of circumstances, he insisted.

 

But finally the gun had been put aboard the ship, having been

transported from the proving ground in the valley, and they were

now en route to Panama. There the giant cannon was to be set up,

and tried again. If it came up to expectations it was to be

finally adopted as the official gun for the protection of the big

canal, and Tom would receive a substantial reward.

 

"And I'm confident that it will make good," said the young

inventor to his chum, as they paced the deck of the vessel. "In

fact, I'm so sure I have practically engaged the Universal Steel

Company to hold itself in readiness to make several more of the

guns."

 

"But suppose Uncle Sam decides against the cannon on this

second test?"

 

"Well, then I've lost out, that's all," declared Tom,

philosophically. "But I don't believe they will."

 

"It certainly is a giant cannon," remarked Ned, as he paused to

look at the prostrate monster, lashed to the deck, with its

wrappings of tarpaulins. "It looks bigger here than it did when

you fired the shot that saved the town, Tom."

 

"Yes, I suppose it does, by contrast. But let's go down and see

how the powder and shells are standing the trip. I told the

captain to have them securely lashed, so if we struck rough

weather, and the vessel rolled, they wouldn't carry away."

 

"Especially the powder," put in Ned. "If that starts to banging

around--well, I'd rather be somewhere else."

 

"Bless my rain gauge!" cried Mr. Damon. "Please don't say such

things. You make me nervous. You're as bad as that steel

foreman."

 

"All right, I'll be better," promised Ned, with a laugh.

 

The two chums found that every precaution had been taken in

regard to the projectiles and powder. Koku was on guard, the

giant regarding the boxes of explosive with a calm but determined

eye. It would not be well for any unauthorized hand to tamper

with them.

 

"Am dere anyt'ing I kin do fo' yo'-all, Massa Tom?" inquired

Eradicate, as the young inventor and Ned prepared to go on deck

again. The aged colored man had insisted on coming as a sort of

personal bodyguard to Tom, and the latter had not the heart to

refuse him. Eradicate was desperately jealous of the giant.

 

"Huh!" Eradicate had said, "anybody kin sit an' look at a lot

ob dem powder boxes; but 'tain't everybody what kin wait on Massa

Tom. I kin, an' I'se gwine t' do it." And so he had.

 

It was planned to proceed directly to Colon, the eastern

terminus of the canal, from New York, stopping at Santiago to

transact some government business there. The big gun was to be

mounted on a barbette near the Gatun locks, pointing out to sea,

and the trial shots would be fired over the water.

 

Eventually the gun would be so mounted as to swing in a

circle,, so as to command the land as well as the water; and, in

fact, if the government decided to adopt Tom's giant cannon as

the official protective arm of the canal, they would all be so

mounted. For, of course, it might be possible for land as well as

sea forces to attack and try to capture the big ditch.

 

The first few days of the voyage were pleasant enough. The

weather was fine, and Tom was kept busy explaining to many of the

officers aboard the ship the principles of his gun, powder and

projectiles. Members of the ordnance board, who had been detailed

to witness the test, were also much interested as Tom modestly

described his work on the giant cannon.

 

At Santiago de Cuba, when Tom and Ned were standing near the

gangway, watching the officers returning from shore leave, for

the ship was to proceed soon, after a two days' stay, the young

inventor started as he noticed a military man walking aboard.

 

"Look, Ned!" he exclaimed, in a low voice.

 

"Where?"

 

"At that man--an officer in civilian dress, I should judge--

haven't you seen him before?"

 

"I have, Tom. Now, where was it? I seem to remember his face;

and yet he wasn't dressed like this the last time I saw him."

 

"I guess not, Ned. He had on a uniform then."

 

"By jinks! I have it. That German officer--von Brunderger!

That's he!"

 

"You're right, Ned. And he's got his servant with him, I

guess," and Tom nodded toward a stolid German who was carrying

the other's suitcase.

 

"I wonder what he's doing aboard here?" went on our hero's

chum.

 

"We'll soon know," spoke Tom. "He's seen us and is nodding. We

might as well go meet him."

 

"Ah, my good friend, Tom Swift!" exclaimed General von

Brunderger, genially, as he grasped the hands of Tom and Ned. "I

am glad to see you both again." He seemed to mean it, though he

had not been especially cordial to them at the first gun test.

"Take my grip below," he said in German to the man, "and,

Rudolph, find Lieutenant Blake and inform him that I am on board.

I have been invited to go to Panama by Lieutenant Blake," he

added to Tom. "I have never seen the big ditch that you wonderful

Americans have so nearly finished."

 

"It is going to be a big thing," spoke Tom. "I am proud that my

gun is going to help protect it."

 

"Ah, so you were successful, then?" and his voice expressed

surprise. "I had not heard. And the big gun; is he here?" Though

speaking very good English, von Brunderger occasionally lapsed

into the idioms of his Fatherland.

 

"Yes, it's on board," said Tom. "Are you going to Panama for

any special purpose?"

 

Ned declared afterward that the German started as Tom asked

this question, but if he did the young inventor scarcely noticed

it. In an instant, however, von Brunderger was composed again.

 

"I go but to see the big ditch before the water is let in," he

replied. "And since your gun is to have a test I shall be glad to

witness that. You see, I am commissioned by my Kaiser to learn

all that you Americans will allow me to in reference to your ways

of doing things--in the army, the navy and in the pursuit of

peace. After all, preparation for war is the best means of

securing peace. Your officers have been more than kind and I have

taken advantage of the offer to go to Panama. Lieutenant Blake

said the ship would stop here, and, as I had business in Cuba, I

came and waited. I am delighted to see you both again."

 

He went below, leaving Tom and Ned staring at one another.

 

"Well, what do you think of it?" asked Ned.

 

"I don't see anything to be worried about," declared Tom. "It's

true that a German once tried to make trouble for me, but this

von Brunderger is all right, as far as I can learn. He has the

highest references, and is an accredited representative of the

Kaiser. You are too suspicious, Ned, just as you were in the case

of General Waller."

 

"Maybe so."

 

From Santiago, swinging around the island of Jamaica, the

warship took her way, with the big gun, to Colon. When half way

across the Caribbean Sea they encountered rough weather.

 

The storm broke without any unusual preliminaries, but quickly

increased to a hurricane, and when night fell it saw the big ship

rolling and tossing in a tempestuous sea. Torn was anxious about

his big gun, but the captain assured him that double lashings

would make it perfectly safe.

 

Tom and Ned had seen little of the German officer that day,

nor, in fact, since he came aboard. He kept much in the quarters

of the other officers, and the report was current that he was a

"jolly good fellow."

 

Rather anxious as to the outcome of the storm, Tom turned in

late that night, not expecting to sleep much, for there were many

unusual noises. But he did drop off into a doze, only to be

awakened about an hour later by a commotion on deck.

 

"What's up, Ned?" he called to his chum, who had an adjoining

stateroom.

 

"I don't know, Tom. Something is going on, though. Hear that

thumping and pounding!"

 

As Ned spoke there came a tremendous noise from the deck.

 

"By Jove!" yelled Tom, jumping from his berth. "It's my big

gun! It has torn loose from the lashings and may roll overboard!"

 

 

 

CHAPTER XXII

 

AT GATUN LOCKS

 

 

"Steady there now, men! Pass forward those lashings! Careful!

Look out, or you'll be caught by it when she rolls! Another turn

around the bitts!"

 

It was the officer of the deck giving orders to a number of

marines and sailors as Tom hastily clad, leaped on deck, followed

by his chum. The warship was pitching and tossing worse than ever

in the heaving billows, and the men were engaged in making fast

the giant cannon, which, as Tom had surmised, had torn loose from

the steel cables holding it down on deck.

 

"Come on, Ned!" cried Tom. "We've got to help here!"

 

"That's right. Look at her swing, would you? If she hits

anything it's a goner!"

 

The breech of the gun appeared to be the end that had come

loose, while the muzzle still held fast. And this immense mass of

steel was swinging about, eluding the efforts of the ship's

officers and crew to capture it. And it seemed only a question of

time when the muzzle would tear loose, too. Then, free on deck,

the giant cannon would roll through the frail bulwarks, and

plunge. into the depths of the sea.

 

"Look out for yourselves, boys!" cried the officer, as he saw

Tom and Ned. "This is no plaything!"

 

"I know it!" gasped Tom. "But we've got to fasten it down."

 

"That's what we're trying to do," answered the other. "We did

get the bight of a cable over the breech, but the men could not

hold it, even though they took a couple of turns around the

bitts."

 

"Ned, go call Koku!" cried Tom. "We need him up here."

 

"That's right!" declared his chum. "If anyone can hold the

cable with the weight of the big gun straining on it, the giant

can. I'll get him!"

 

"On deck, Koku, quick!" gasped Ned. "Master's cannon may fall

into the sea."

 

"But the powder!" asked the big man, simply. "Master told me to

guard the powder. I stay here."

 

"No, I'll stay!" insisted Ned. "You are needed on deck, I'll

take your place here."

 

Koku stared uncomprehendingly for a moment, while the loosened

gun continued to thump and pound on the deck as though it would

burst through. Then it filtered through the dull brain of honest

Koku what was wanted.

 

"I go," he said, and he hurried up the companionway, while Ned,

eager to be with Tom, took up the less exciting work of guarding

the powder.

 

Once more, with the giant strength of Koku to aid in the work,

the task of lashing the gun again to the deck was undertaken. A

bight of steel cable was gotten around the breech, and then

passed to a big bitt, or stanchion, bolted to the deck. Koku,

working on the heaving deck, amid the hurricane, took a turn

around the brace.

 

There came a roll of the ship that threatened to send the gun

sliding against the stanchion, but Koku braced himself. His arms,

great bunches of muscles, strained and fairly cracked with the

strain. The wire rope seemed to give. Then, as the ship rolled

the other way, the strain eased. Koku, aided by the cable, and by

the leverage given by the several turns about the bitts, had held

the big gun.

 

"Quick!" cried Tom. "Now another rope so it can't roll the

opposite way, and we'll have her."

 

For a moment the ship was on a level keel, and taking advantage

of this, when the weight of the gun would be neutral, another

cable was passed around it. Then it was a comparatively easy

matter to put on more lashings until the giant cannon was once

more fast.

 

"Whew! But that was tough work!" exclaimed Tom, as he once more

entered the stateroom with Ned.

 

"It must have been," agreed his chum, who had been relieved at

the powder station by the giant.

 

"I thought it would surely go overboard," went on Tom. "Only

for Koku it would have. Those fellows couldn't hold it when the

ship rolled."

 

"How did it happen to get loose?" asked Ned.

 

"Oh, the cables frayed, I suppose. I'll take a look in the

morning. Say, but this is some storm!"

 

"Is the gun all right now?"

 

"Yes, it's fastened down like a mummy. It can't get loose

unless the whole deck comes with it. We can sleep in peace."

 

"Not much sleep in this blow, I guess," responded Ned.

 

But they did manage to get some rest by morning, at which time

the hurricane seemed to have blown itself out. The day saw the

sea gradually calm down, and the big cannon was made additionally

secure against a possible recurrence of the accident. But a few

days more and it would be safe at Colon.

 

Tom and Ned had gone on deck soon after breakfast to look at

the cannon. All about were pieces of the broken cables, that had

been cast aside when the new lashings were put on. Ned picked up

one end, remarking:

 

"These seem mighty strong. It's queer how they broke."

 

"Well, there was quite a weight upon them," spoke Tom.

 

Ned did not reply for a moment. Then, as he looked at another

piece of a severed cable, he exclaimed:

 

"Tom, the weight of your gun never broke these."

 

"What do you mean, Ned?"

 

"I mean that they were partly filed, or cut through--then the

storm and the pressure of the gun did the rest. Look!"

 

He held out the piece of wire rope. There, on the end, could be

seen several strands cleanly severed, as though a file or a hack-

saw had been used.

 

"By Jove!" murmured Tom. He looked about the deck. There was no

one near the big gun. "Ned," whispered his chum, "there's

something wrong here. It's more of that conspiracy to defeat my

aims. Don't say anything about this, and we'll keep our eyes

open. We'll do a bit of detective work."

 

"The scoundrels!" exclaimed Ned. "I wish we knew who they were.

General Waller isn't aboard, and what other of the officers has a

gun of his own that he would rather see accepted by the

government than yours?"

 

"None that I know of," replied Tom.

 

"General Waller might have hired someone to--"

 

"Don't go making any unwarranted charges," warned the young

inventor.

 

"Or perhaps that German, Tom, might--"

 

"Hush!" cautioned Tom. "Here he comes now," and, as he spoke,

General von Brunderger came strolling along the deck.

 

"I am glad to see that the accident of last night had no

serious effects," he said, smiling.

 

"It was no accident!" burst out Ned.

 

"No accident? You surprise me. I thought--"

 

"Oh, Ned means that some of the cables look as though they had

been cut," hastily put in Tom, nudging his chum in the ribs as a

signal for him to keep quiet.

 

"The cables cut!" exclaimed the German, and his voice indicated

anxious solicitude.

 

"Or else filed," went on Tom easily, with a warning glance at

Ned. "But I dare say they were old cables, that had been used on

other work, and may have become frayed. Everything is safe now,

though. New cables were lashed on this morning."

 

"I am glad to hear it. It would be a--er--ah, a national

calamity to lose so valuable a gun, and the opening of the canal

so near at hand. I am glad that your invention is safe, Herr

Swift," and he smiled genially at Tom and Ned.

 

"What did you shut me off for?" asked Ned, when he and his chum

were alone in their stateroom again.

 

"Because I didn't want you to make any breaks before him,"

answered Tom.

 

"Then you suspect--"

 

"I suspect many things, Ned, but I'm not going to show my hand

until I'm ready. I'm going to watch and listen."

 

"And I'll be with you."

 

But no further accidents occurred. There were no more storms,

no attempt was made to meddle with Tom's powder, and in due

season the ship arrived at Colon, and after much labor the great

gun, its carriage, the shells and the powder were taken to the

barbette at the Gatun locks, designed to admit vessels from the

Caribbean Sea into Gatun Lake.

 

"And now for some more hard work," remarked Tom, as all the

needful stores were landed.

 

 

 

CHAPTER XXIII

 

NEWS OF THE MINE

 

 

"Just a little farther over this way, Ned. That's better. Now

mark it there, and we'll have it clamped down."

 

"But can you get enough elevation here, Tom?"

 

"Oh, yes, I think so. Besides, I've added a few more inches to

the lift of the disappearing carriage, and it will send the gun

so much farther in the air. I think this will do. Where is Koku?"

 

"Here I be, Master."

 

"Just get hold of that small derrick, Koku, and lift up one of

the projectiles. I want to see if they come in the right place

for the breech before I set the hoisting apparatus permanently."

 

The giant was soon engaged in winding up the rope of an

improvised hoist that stood about in the position the permanent

one was to go. From the interior of the barbette, which was, in

effect, a bomb-proof structure, there was lifted one of the big

projectiles destined to be hurled from Tom Swift's giant cannon.

 

"Yes, I think that will do," decided the young inventor, as he

watched Koku. "Now, Mr. Damon, if you will kindly oversee this

part of the work, I'll see if we can't get that motor in better

shape. It didn't work worth a cent this morning."

 

"Bless my rubber coat, Tom, I'll do all I can to help you!"

declared the odd man.

 

"Massa Tom! Massa Tom!" called Eradicate.

 

"Yes, Rad. What is it?"

 

"Heah am dem chicken sandwiches, an' some hot coffee fo' yo'

all. I done knowed yo' alt wouldn't hab no time t' stop fo'

dinnah, so I done made yo' all up a snack."

 

"That's mighty good of you, Rad," spoke Tom, with a laugh. "I

was getting pretty hungry; but I didn't want to stop until I had

things moving in better shape. Come on, Ned, let's knock off for

a few minutes and take a bite. You, too, Mr. Damon."

 

As they sat about the place where the gun was being mounted,

munching sandwiches and drinking the coffee which the aged

colored man had so thoughtfully provided, Eradicate said, with a

chuckle:

 

"By gar! Dey can't git erlong wifout dish yeah coon, arter all!

Ha! ha! Dat cocoanut giant he mighty good when it comes t'

fastening big guns down so dey won't blow away, but when it comes

t' eatin' dey has t' depend on ole Eradicate! Ha! ha! I'se got

dat cocoanut giant beat all right!"

 

"He sure is jealous of Koku," remarked Ned, as Tom and Mr.

Damon smiled at the colored man.

 

"He certainly hit me in the right spot," declared Tom, as he

reached for another sandwich.

 

They had landed from the warship several days before, and from

then on there had been hard work and plenty of it. Tom was here,

there and everywhere, directing matters so that his gun would be

favorably placed.

 

Some preliminary work had been done before they arrived in the

way of preparing a place to mount the gun, and this work was now

proceeding. The officers of the ordnance department were in

actual charge, but they always deferred to Tom, since he had most

at stake.

 

"It will be some days before you can actually fire your gun;

will it not?" asked Ned of his chum, as they finished the lunch,

and prepared to resume work.

 

"Yes--a week at least, I expect. It is taking longer to set up

the carriage than I thought. But it will be an improvement over

the solid one we formerly used. That was fine, Rad," he concluded

as the colored man went back to the shack of which he had taken

possession for himself and his cooking operations. It adjoined

the quarters to which Tom, Ned, Mr. Damon and Koku had been

assigned.

 

"Golly! I ain't so old yit but what I knows de stuff Massa Tom

laiks!" exclaimed the colored man, moving off with a chuckle.

 

Tom, though he had many suspicions about the cut cables that

had nearly been the cause of his gun sliding into the sea, had

learned nothing definite--nor had Ned.

 

The German officer, with his body servant, who seldom spoke,

had landed at Colon, and was proceeding to make himself at home

with the officers and men who were building the canal.

Occasionally he paid a visit to Tom and Ned, where they were

engaged about the big gun. He always seemed pleasant, and

interested in their labors, asking many question, but that was

all, and our hero began to feel that perhaps he was wrong in his

suspicions.

 

As for Ned, he veered uncertainly from one suspicion to

another. At one time he declared that von Brunderger and General

Waller were in a conspiracy to upset Tom's plans. Again he would

accuse the German alone, until Tom laughingly bade him attend

more to work and less to theories.

 

Slowly the work progressed. The gun was mounted after much

labor, and then arrangements began to be made for the test. A

series of shots were to be fired out to sea, and the proper

precautions were to be taken to prevent any ships from being

struck.

 

"Though if you intend to send a projectile thirty miles," said

one of the officers, "I'm afraid there may be some danger, after

all. Are you sure you have a range of thirty miles, Mr. Swift?"

 

"I have," answered Tom, calmly, "and with the increased

elevation that I am able to get here, it may exceed that."

 

The officer said nothing, but he looked at Tom in what our hero

thought was a peculiar manner.

 

A few days before the date set for the test one of the

sentinels, who had been detailed to keep curiosity-seekers away

from the giant cannon, approached Tom and said:

 

"There is a gentleman asking to see you, Mr. Swift."

 

"Who is it?" asked Tom, laying aside a pressure gauge he

intended attaching to the gun.

 

"He says his name is Peterson--Alec Peterson. Do you want to

see him?"

 

"Yes, let him come up," directed the young inventor. "Do you

hear that, Ned?" he called. "Our fortune-hunting friend is here."

 

"Maybe he's found that lost opal mine," suggested Ned.

 

"I hope he has, for dad's sake," went on Tom. "Hello, Mr.

Peterson!" he called, as he noticed the old prospector coming

along. "Have you had any luck?"

 

"I heard you were down here," said the many not answering the

question directly, "and as I had to run over from my island for

some supplies I thought I'd stop and see you. How are you?" and

he shook hands.

 

"Fine!" answered Tom. "Have you found the lost mine yet?"

 

Alec Peterson paused a moment. Then he said slowly:

 

"No, Tom, I haven't succeeded in locating the mine yet. But I--

I expect to any day now!" he added, hastily.

 

 

 

CHAPTER XXIV

 

THE LONGEST SHOT

 

 

"Well, Mr. Peterson," remarked Tom, after a pause, "I'm sure I

hope you will succeed in your quest. You must have met

disappointment so far."

 

"I have, Tom. But I'm not going to give up. Can't you come over

and see me before you go back North?"

 

"I'll try. Just where is your island?"

 

"Off in that direction," responded the fortune-hunter, pointing

to the northeast. "It's a little farther from here than I thought

it was at first--about thirty miles. But I have a little second-

hand steam launch that my pardners and I use. I'll come for you,

take you over and bring you back any time you say."

 

"After my gun has been tested," said Tom, with a smile. "Better

stay and see it."

 

"No, I must get back to the island. I have some new information

that I am sure will enable me to locate the lost mine."

 

"Well, good-bye, and good luck to you," called Tom, as the

fortune-hunter started away.

 

"Do you think he'll ever find the opals, Tom?" asked Ned.

 

His chum shook his head.

 

"I don't believe so," he answered. "Alec has always been that

way--always visionary--always just about to be successful; but

never quite getting there."

 

"Then your father's ten thousand dollars will be lost?"

 

"Yes, I suppose so; but, in a way, dad can stand it. And if I

make good on this gun test, ten thousand dollars won't look very

big to me. I guess dad gave it to Alec from a sort of sentimental

feeling, anyhow."

 

"You mean because he saved you from the live wire?"

 

"That's it, Ned. It was a sort of reward, in a way, and I guess

dad won't be broken-hearted if Alec doesn't succeed. Only, of

course, he'll feel badly for Alec himself. Poor old man! he won't

be able to do much more prospecting. Well, Ned, let's get to work

on that ammunition hoist. It still jams a little on the ways, and

I want it to work smoothly. There's no use having a hitch--even a

small one--when the big bugs assemble to see how my cannon

shoots."

 

"That's right, Tom. Well, start off, I'm with you."

 

The two youths labored for some time, being helped, of course,

by the workmen provided by the government, and some from the

steel concern.

 

There were many little details to look after, not the least of

which was the patrolling of the stretch of ocean over which the

great projectiles would soar in reaching the far-off targets at

which Tom had planned to shoot. No ships were to be allowed to

cross the thirty-mile mark while the firing was in progress. So,

also, the zone where the shots were expected to fall was to be

cleared.

 

But at last all seemed in readiness. The gun had been tried

again and again on its carriage. The projectiles were all in

readiness, and the terribly powerful ammunition had been stored

below the gun in a bomb-proof chamber, ready to be hoisted out as

needed.

 

Because the gun had been fired so many times with a charge of

powder heavier than was ordinarily called for, and had stood the

strain well, Tom had no fear of standing reasonably close to it

to press the button of the battery. There would be no retreating

to the bombproof this time.

 

The German officer was occasionally seen about the place where

the gun was mounted, but he appeared to take only an ordinary

interest in it. Tom began to feel more than ever that perhaps his

suspicions were unfounded.

 

Some officials high in government affairs had arrived at Colon

in anticipation of the test, which, to Tom's delight, had

attracted more attention than he anticipated. At the same time he

was a bit nervous.

 

"Suppose it fails, Ned?" he said.

 

"Oh, it can't!" cried his chum. "Don't think about such a

thing.''

 

Plans had been made for a ship to be stationed near the zone of

fire, to report by wireless the character of each shot, the

distance it traveled, and how near it came to the target. The

messages would be received at a station near the barbette, and at

once reported to Tom, so that he would know how the test was

progressing.

 

"Well, today tells the tale!" exclaimed the young inventor, as

he got up one morning. "How's the weather, Ned?"

 

"Couldn't be better--clear as a bell, Tom."

 

"That's good. Well, let's have grub, and then go out and see

how my pet is."

 

"Oh, I guess nothing could happen, with Koku on guard."

 

"No, hardly. I'm going to keep him in the ammunition room until

after the test, too. I'm going to take no chances."

 

"That's the ticket!"

 

The gun was found all right, in its great tarpaulin cover, and

Tom had the latter taken off that he might go over every bit of

mechanism. He made a few slight changes, and then got ready for

the final trials.

 

On an improvised platform, not too near the giant cannon, had

gathered the ordnance board, the specially invited guests, a

number of officers and workers in the canal zone, and one or two

representatives of foreign governments. Von Brunderger was there,

but his "familiar," as Ned had come to call the stolid German

servant, was not present.

 

Tom took some little time to explain, modestly enough, the

working of his gun. A number of questions were asked, and then it

was announced that the first shot, with only a practice charge of

powder, would be fired.

 

"Careful with that projectile now. That's it, slip it in

carefully. A little farther forward. That's better. Now the

powder--Koku, are you down there?" and Tom called down the tube

into the ammunition chamber.

 

"Me here, Master," was the reply.

 

"All right, send up a practice load."

 

Slowly the powerful explosive came up on the electric hoist. It

was placed in the firing chamber and the breech dosed.

 

"Now, gentlemen," said Tom, "this is not a shot for distance.

It is merely to try the gun and get it warmed up, so to speak,

for the real tests that will follow. All ready?"

 

"All ready!" answered Ned, who was acting as chief assistant.

 

"Here she goes!" cried Tom, and he pressed the button.

 

Many were astonished by the great report, but Tom and the

others, who were used to the service charges, hardly noticed this

one. Yet when the wireless report came in, giving the range as

over fourteen thousand yards, there was a gasp of surprise.

 

"Over eight miles!" declared one grizzled officer; "and that

with only a practice charge. What will happen when he puts in a

full one?'

 

"I don't know," answered a friend.

 

Tom soon showed them. Quickly he called for another projectile,

and it was inserted in the gun. Then the powder began to come up

the hoist. Meanwhile the young inventor had assured himself that

the gun was all right. Not a part had been strained.

 

This time, when Tom pressed the button there was such a

tremendous concussion that several, who were not prepared for it,

were knocked back against their neighbors or sent toppling off

their chairs or benches. And as for the report, it was so

deafening that for a long time after it many could not hear well.

 

But Tom, and those who knew the awful power of the big cannon,

wore specially prepared eardrum protectors, that served to reduce

the shock.

 

"What is it?" called Tom to the wireless operator, who was

receiving the range distance from the marking ship.

 

"A little less than twenty-nine miles."

 

"We must do better than that," said Tom. "I'll use more powder,

and try one of the newer shells. I'll elevate the gun a trifle,

too."

 

Again came that terrific report, that trembling of the ground,

that concussion, that blast of air as it rushed in to fill the

vacuum caused, and then the vibrating echoes.

 

"I think you must have gone the limit this time, Tom!" yelled

Ned, as he turned on the compressed air to blow the powder fumes

and unconsumed bits of explosive from the gun tube.

 

"Possibly," admitted Tom. "Here comes the report." The wireless

operator waved a slip of paper.

 

"Thirty-one miles!" he announced.

 

"Hurray!" cried Mr. Damon. "Bless my telescope! The longest

shot on record!"

 

"I believe it is," admitted the chief of the ordnance

department. "I congratulate you, Mr. Swift."

 

"I think I can do better than that," declared Tom, after

looking at the various recording gauges, and noting the elevation

of the gun. "I think I can get a little flatter trajectory, and

that will give a greater distance. I'm going to try."

 

"Does that mean more powder, Tom?" asked Ned.

 

"Yes, and the heaviest shell we have--the one with the bursting

charge. I'll fire that, and see what happens. Tell the zone-ship

to be on the lookout," he said to the wireless operator, giving a

brief statement of what he was about to attempt.

 

"Isn't it a risk, Tom?" his chum asked.

 

"Well, not so much. I'm sure my cannon will stand it. Come on

now, help me depress the muzzle just a trifle," and by means of

the electric current the big gun was raised at the breech a few

inches.

 

As is well known, cannon shots do not go in straight lines.

They leave the muzzle, curve upward and come down on another

curve. It is this curve described by the projectile that is

called the trajectory. The upward curve, as you all know, is

caused by the force of the powder, and the downward by the force

of gravitation acting on the shot as soon as it reaches its

zenith. Were it not for this force the projectiles could be fired

in straight lines. But, as it is, the cannon has to be elevated

to send the shot up a bit, or it would fall short of its mark.

 

Consequently, the flatter the trajectory the farther it will

go. Tom's object, then, was to flatten the trajectory, by

lowering the muzzle of the gun, in order to attain greater

distance.

 

"If this doesn't do the trick, we'll try it with the muzzle a

bit lower, and with a trifle more powder," he said to Ned, as he

was about to fire.

 

The young inventor was not a little nervous as he prepared to

press the button this time. It was a heavier charge than any used

that day, though the same quantity had been fired on other

occasions with safety. But he was not going to hesitate.

 

Coincident with the pressure of Tom's fingers there seemed to

be a veritable earthquake. The ground swayed and rocked, and a

number of the spectators staggered back. It was like the blast of

a hundred thunderbolts. The gun shook as it recoiled from the

shock, but the wonderful disappearing carriage, fitted with

coiled, pneumatic and hydrostatic buffers, stood the strain.

 

Following the awful report, the terrific recoil and the howl of

the wind as it rushed into the vacuum created, there was an

intense silence. The projectile had been seen by some as a dark

speck, rushing through the air like a meteor. Then the wireless

operator could be seen writing down a message, the telephone-like

receivers clamped over his ears.

 

"Something happened, all right!" he called aloud. "That shot

hit something."

 

"Not one of the ships!" cried Tom, aghast.

 

"I don't know. There seems to be some difficulty in

transmitting. Wait--I'm getting it: now."

 

As he ceased speaking there came from underneath the great gun

the sound of confused shouts. Tom and Ned recognized Koku's voice

protesting:

 

"No--no--you can't come in here! Master said no one was to come

in."

 

"What is it, Koku?" yelled Tom, springing to the speaking tube

connecting with the powder magazine, at the same time keeping an

eye on the wireless operator. Tom was torn between two anxieties.

 

"Someone here, Master!" cried the giant. "Him try to fix

powder. Ah, I fix you!" and with a savage snarl the giant, in the

concrete chamber below, could be heard to attack someone who

cried out gutturally in German:

 

"Help! Help! Help!"

 

"Come on, Ned!" cried Tom, making a dash for the stairs that

led into the magazine. There was confusion all about, but through

it all the wireless operator continued to write down the message

coming to him through space.

 

"What is it, Koku? What is it?" cried Tom, plunging down into

the little chamber.

 

As he reached it, a door leading to the outer air flew open,

and out rushed a man, badly torn as to his clothes, and scratched

and bleeding as to his face. On he ran, across the space back of

the barbette, toward the lower tier of seats that had been

erected for the spectators.

 

"It's von Brunderger's servant!" gasped Ned, recognizing the

fellow.

 

"What did he do, Koku?" demanded the young inventor.

 

"Him sneak in here--have some of that stuff you call 'dope.' I

sent up powder, and I come back here to see him try to put some

dope in Master's ammunition."

 

"The scoundrel!" cried Tom. "They're trying to break me, even

at the last minute! Come on, Ned."

 

They raced outside to behold a curious sight. Straight toward

von Brunderger rushed the man as if in a frenzy of fear. He

called out something in German to his master, and the latter's

face went first red, then white. He was observed to look about

quickly, as though in alarm, and then, with a shout at his

servant, the German officer rushed from the stand, and the two

disappeared in the direction of the barracks.

 

"What does it mean?" cried Ned.

 

"Give it up," answered Tom, "except that Koku spoiled their

trick, whatever it was. It looks as if this was the end of it,

and that the mystery has been cleared up."

 

"Mr. Swift! Where's Mr. Swift?" shouted the wireless operator.

"Where are you?"

 

"Yes; what is it?" demanded Tom, so excited that he hardly knew

what he was doing.

 

"The longest shot on record!" cried the man. "Thirty-three

miles, and it struck, exploded, and blew the top off a mountain

on an island out there!" and he pointed across the sun-lit sea.

 

 

 

CHAPTER XXV

 

THE LONG-LOST MINE

 

 

There was a silence after the inspiring words of the operator,

and then it seemed that everyone began to talk at once. The

record-breaking shot, the effect of it and the struggle that had

taken place in the powder room, together with the flight of von

Brunderger and his servant, gave many subjects for excited

conversation.

 

"I've got to get at the bottom of this!" cried Tom, making his

way through the press of officials to where the wireless operator

stood. "Just repeat that," requested Tom, and they all gave place

for him, waiting for the answer.

 

The operator read the message again.

 

"Thirty-three miles!" murmured Tom. "That is better than I

dared to hope. But what's that about blowing the top off an

island?"

 

"That's what you did, with that explosive shell, Mr. Swift. The

operator on the firing-zone ship saw the top fly off when the

shell struck. The ship was about half a mile away, and when they

heard that shell coming the officers thought it was all up with

them. But, instead, it passed over them and demolished the top of

the mountain.

 

"Anybody hurt?" asked Tom, anxiously.

 

"No, it was an uninhabited island. But you have made the record

shot, all right. It went farther than any of the others."

 

"Then I suppose I ought to be satisfied," remarked Tom, with a

smile.

 

"What was that disturbance, Mr. Swift?" asked the chief

ordnance officer, coming forward.

 

"I don't understand it myself," replied the young inventor. "It

appeared that someone went into the ammunition room, and Koku, my

giant servant, attacked him."

 

"As he had a right to do. But who was the intruder?"

 

"Herr von Brunderger's man."

 

"Ha! That German officer's! Where is he, he must explain this."

 

But Herr von Brunderger was not to be found, nor was his man in

evidence. They had fled, and when a search was made of their

rooms, damaging evidence was found. Before a board of

investigating officers Koku told his story, after the gun tests

had been declared off for the day, they having been most

satisfactory.

 

The German officer's servant, it appeared, had managed to gain

entrance to the ammunition chamber by means of a false key to the

outer door. There were two entrances, the other being from the

top of the platform where the cannon rested. Koku had seen him

about to throw something into one of the ammunition cases, and

had grappled with him. There was a fight, and, in spite of the

giant's strength, the man had slipped away, leaving part of his

garments in the grasp of Koku.

 

An investigation of some of the powder showed that it had been

covered with a chemical that would have made it explode

prematurely when placed in the gun. It would probably have

wrecked the cannon by blowing out the breech block, and might

have done serious damage to life as well as property.

 

"But what was the object?" asked Ned.

 

"To destroy Tom's gun," declared Mr. Damon.

 

"Why should von Brunderger want to do that?"

 

They found the answer among his papers. He had been a German

officer of high rank, but had been dismissed from the secret

service of his country for bad conduct. Then, it appeared, he

thought of the plan of doing some damage to a foreign country in

order to get back in the good graces of his Fatherland.

 

He forged documents of introduction and authority, and was

received with courtesy by the United States officials. In some

way he heard of Tom's gun, and that it was likely to be so

successful that it would be adopted by the United States

government. This he wanted to prevent, and he went to great

lengths to accomplish this. It was he, or an agent of his, who

forged the letter of invitation to General Waller, and who first

tried to spoil Tom's test by doping the powder through Koku.

 

Later he tried other means, sending a midnight visitor to Tom's

house and even going to the length of filing the cables in the

storm, so the gun would roll off the warship into the sea. All

this was found set down in his papers, for he kept a record of

what he had done in order to prove his case to his own

government. It was his servant who tried to get near the gun

while it was being cast.

 

That he would be restored to favor had he succeeded, was an

open question, though with Germany's friendliness toward the

United States it is probable that his acts would have been

repudiated. But he was desperate.

 

Failing in many attempts he resolved on a last one. He sent his

servant to the ammunition room to "dope" the powder, hoping that,

at the next shot, the gun would be mined. Perhaps he hoped to

disable Tom. But the plot failed, and the conspirators escaped.

They were never heard of again, probably leaving Panama under

assumed names and in disguise.

 

"Well, that explains the mystery," said Tom to Ned a few days

later. "I guess we won't have to worry any more."

 

"No, and I'm sorry I suspected General Waller."

 

"Oh, well, he'll never know it, so no harm is done. Oh, but I'm

glad this is over. It has gotten on my nerves."

 

"I should say so," agreed Ned.

 

"Bless my pillow sham!" cried Mr. Damon. "I think I can get a

good night's sleep now. So they have formally accepted your giant

cannon, Tom?"

 

"Yes. The last tests I gave them, showing how easily it could

be manipulated, convinced them. It will be one of the official

defense guns of the Panama Canal."

 

"Good! I congratulate you, my boy!" cried the odd man. "And

now, bless my postage stamp, let's get back to the United

States."

 

"Before we go," suggested Ned, "let's go take a look at that

island from which Tom blew the top. It must be quite a sight--and

thirty-three miles away! We can get a launch and go out."

 

But there was no need. That same day Alec Peterson came to

Colon inquiring for Tom. His face showed a new delight.

 

"Why," cried Tom, "you look as though you had found your opal

mine."

 

"I have!" exclaimed the fortune-hunter. "Or, rather, Tom, I

think I have you to thank for finding it for me."

 

"Me find it?"

 

"Yes. Did you hear about the top of the island-mountain you

blew to pieces?"

 

"We did, but--"

 

"That was my island!" exclaimed Mr. Peterson. "The mine was in

that mountain, but an earthquake had covered it. I should never

have found it but for you. That shot you accidentally fired

ripped the mountain apart. My men and I were fortunately at the

base of it then, but we sure thought our time had come when that

shell struck. It went right over our heads. But it did the

business, all right, and opened up the old mine. Tom, your father

won't lose his money, we'll all be rich. Oh, that was a lucky

shot! I knew it was your cannon that did it."

 

"I'm glad of it!" answered the young inventor, heartily. "Glad

for your sake, Mr. Peterson."

 

"You must come and see the mine--your mine, Tom, for it never

would have been rediscovered had it not been for your giant

cannon, that made the longest shot on record, so I'm told."

 

"We will come, Mr. Peterson, just as soon as I close up matters

here."

 

It did not take Tom long to do this. His type of cannon was

formally accepted as a defense for the Panama Canal, and he

received a fine contract to allow that type to be used by the

government. His powder and projectiles, too, were adopted.

 

Then, one day, he and Ned, with Koku and Mr. Damon, visited the

scene of the great shot. As Mr. Peterson had said, the whole top

of the mountain had been blown off by the explosive shell,

opening up the old mine. While it was not quite as rich as Mr.

Peterson had glowingly painted, still there was a fortune in it,

and Mr. Swift got back a substantial sum for his investment.

 

"And now for the good old U. S. A.!" cried Tom, as they got

ready to go back home. "I'm going to take a long rest, and the

only thing I'm going to invent for the next six months is a new

potato slicer." But whether Tom kept his words can be learned by

reading the next volume of this series.

 

"Bless my hand towel!" cried Mr. Damon. "I think you are

entitled to a rest, Tom."

 

"That's what I say," agreed Ned.

 

"I'll take care ob him--I'll take care ob Massa Tom," put in

Eradicate, as he cast a quick look at Koku. "Giants am all right

fo' cannon wuk, but when it comes t' comforts Massa Tom gwine t'

'pend on ole 'Radicate; ain't yo' all, Massa Tom?"

 

"I guess so, Rad!" exclaimed the young inventor, with a laugh.

"Is dinner ready?"

 

"It suah am, Massa Tom, an' I 'specially made some oh dat

fricasseed chicken yo' all does admire so much. Plenty of it,

too, Massa Tom."

 

"That's good, Rad," put in Ned. "For we'll all be hungry after

that trip to the island. That sure was a great shot Tom--thirty-

three miles!"

 

"Yes, it went farther than I thought it would," replied Tom.

And now, as they are taking a closing meal at Panama, ready to

return to the United States, we will take leave of Tom Swift and

his friends.

 

 

 

End.