Tom Swift And His Giant Cannon or The Longest Shots on Record

Part 1 out of 3








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."


 


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