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

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"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,

"I'll tell you in a minute. I want to do a little figuring

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

"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

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

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

Followed by the others, the young inventor started toward the
small square "cannon." Tom wanted to read the records made by the

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

"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.



"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

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

"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

"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,

"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-

"General Waller!" exclaimed Tom. "What can he want out here?"

"And on a motor-cycle, too!" added Ned. "Tom, what's going on,

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.



"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

"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

"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

"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,

"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.

"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

"All right, General," answered Tom, genially. "May the best gun

"Bless my powder box!" cried Mr. Damon. "That's the way to

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.

"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

"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

"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

"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.



"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

Only for the prompt action of Koku, Tom might have been
seriously injured. As it was he lost some valuable patterns and

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

"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

"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.



"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

"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

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

"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

"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

"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

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

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

"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

"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

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

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

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.



"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

"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

"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

"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!"



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

"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--

"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

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?"


"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

"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

The great piece of hollow steel tubing was lifted to the boring
lathe. Then Tom and the manager examined it for superficial

"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

"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."



"Whew, how it rains!" exclaimed Ned, as he looked out of the

"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

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

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

"But it would take considerable digging to open a way through
that side of the mountain, into the other valley," went on the

"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

"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!"



"Bless my fountain pen!" exclaimed Mr. Damon. "You don't mean

"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

"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

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

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.

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