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TOM SWIFT AND HIS AERIAL WARSHIP or The Naval Terror of the Seas

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The Naval Terror of the Seas







"What's the matter, Tom? You look rather blue!"

"Blue! Say, Ned, I'd turn red, green, yellow, or any other
color of the rainbow, if I thought it would help matters any."


Ned Newton, the chum and companion of Tom Swift, gave vent to a
whistle of surprise, as he gazed at the young fellow sitting
opposite him, near a bench covered with strange-looking tools and
machinery, while blueprints and drawings were scattered about.

Ranged on the sides of the room were models of many queer
craft, most of them flying machines of one sort or another, while
through the open door that led into a large shed could be seen
the outlines of a speedy monoplane.

"As bad as that, eh, Tom?" went on Ned. "I thought something
was up when I first came in, but, if you'll excuse a second
mention of the color scheme, I should say it was blue--decidedly
blue. You look as though you had lost your last friend, and I
want to assure you that if you do feel that way, it's dead wrong.
There's myself, for one, and I'm sure Mr. Damon--"

"Bless my gasoline tank!" exclaimed Tom, with a laugh, in
imitation of the gentleman Ned Newton had mentioned, "I know
that! I'm not worrying over the loss of any friends."

"And there are Eradicate, and Koku, the giant, just to mention
a couple of others," went on Ned, with a smile.

"That's enough!" exclaimed Tom. "It isn't that, I tell you."

"Well, what is it then? Here I go and get a half-holiday off
from the bank, and just at the busiest time, too, to come and see
you, and I find you in a brown study, looking as blue as indigo,
and maybe you're all yellow inside from a bilious attack, for all
I know."

"Quite a combination of colors," admitted Tom. "But it isn't
what you think. It's just that I'm puzzled, Ned."

"Puzzled?" and Ned raised his eyebrows to indicate how
surprised he was that anything should puzzle his friend.

"Yes, genuinely puzzled."

"Has anything gone wrong?" Ned asked. "No one is trying to take
any of your pet inventions away from you, is there?"

"No, not exactly that, though it is about one of my inventions
I am puzzled. I guess I haven't shown you my very latest; have I, Ned?"

"Well, I don't know, Tom. Time was when I could keep track of
you and your inventions, but that was in your early days, when
you started with a motorcycle and were glad enough to have a
motorboat. But, since you've taken to aerial navigation and
submarine work, not to mention one or two other lines of activity,
I give up. I don't know where to look next, Tom, for something new."

"Well, this isn't so very new," went on the young inventor, for
Tom Swift had designed and patented many new machines of the air,
earth and water. "I'm just trying to work out some new problems
in aerial navigation, Ned," he went on.

"I thought there weren't any more," spoke Ned, soberly enough.

"Come, now, none of that!" exclaimed Tom, with a laugh. "Why,
the surface of aerial navigation has only been scratched. The
science is far from being understood, or even made safe, not to
say perfected, as water and land travel have been. There's lots
of chance yet."

"And you're working on something new?" asked Ned, as he looked
around the shop where he and Tom were sitting. As the young bank
employee had said, he had come away from the institution that
afternoon to have a little holiday with his chum, but Tom, seated
in the midst of his inventions, seemed little inclined to jollity.

Through the open windows came the hum of distant machinery, for
Tom Swift and his father were the heads of a company founded to
manufacture and market their many inventions, and about their
home were grouped several buildings. From a small plant the
business had grown to be a great tree, under the direction of Tom
and his father.

"Yes, I'm working on something new," admitted Tom, after a
moment of silence.

"And, Ned," he went on, "there's no reason why you shouldn't
see it. I've been keeping it a bit secret, until I had it a
little further advanced, but I've got to a point now where I'm
stuck, and perhaps it will do me good to talk to someone about

"Not to talk to me, though, I'm afraid. What I don't know about
machinery, Tom, would fill a great many books. I don't see how I
can help you," and Ned laughed.

"Well, perhaps you can, just the same, though you may not know
a lot of technical things about machines. It sometimes helps me
just to tell my troubles to a disinterested person, and hear him
ask questions. I've got dad half distracted trying to solve the
problem, so I've had to let up on him for a while. Come on out
and see what you make of it."

"Sure, Tom, anything to oblige. If you want me to sit in front
of your photo-telephone, and have my picture taken, I'm
agreeable, even if you shoot off a flashlight at my ear. Or, if
you want me to see how long I can stay under water without
breathing I'll try that, too, provided you don't leave me under
too long, lead the way--I'm agreeable as far as I'm able, old

"Oh, it isn't anything like that," Tom answered with a laugh.
"I might as well give you a few hints, so you'll know what I'm
driving at. Then I'll take you out and show it to you."

"What is it--air, earth or water?" asked Ned Newton, for he
knew his chum's activities led along all three lines.

"This happens to be air."

"A new balloon?"

"Something like that. I call it my aerial warship, though."

"Aerial warship, Tom! That sounds rather dangerous!"

"It will be dangerous, too, if I can get it to work. That's
what it's intended for."

"But a warship of the air!" cried Ned. "You can't mean it. A
warship carries guns, mortars, bombs, and--"

"Yes, I know," interrupted Tom, "and I appreciate all that when
I called my newest craft an aerial warship."

"But," objected Ned, "an aircraft that will carry big guns will
be so large that--"

"Oh, mine is large enough," Tom broke in.

"Then it's finished!" cried Ned eagerly, for he was much
interested in his chum's inventions.

"Well, not exactly," Tom said. "But what I was going to tell
you was that all guns are not necessarily large. You can get big
results with small guns and projectiles now, for high-powered
explosives come in small packages. So it isn't altogether a
question of carrying a certain amount of weight. Of course, an
aerial warship will have to be big, for it will have to carry
extra machinery to give it extra speed, and it will have to carry
a certain armament, and a large crew will be needed. So, as I said,
it will need to be large. But that problem isn't worrying me."

"Well, what is it, then?" asked Ned.

"It's the recoil," said Tom, with a gesture of despair.

"The recoil?" questioned Ned, wonderingly.

"Yes, from the guns, you know. I haven't been able to overcome that,
and, until I do, I'm afraid my latest invention will be a failure."

Ned shook his head.

"I'm afraid I can't help you any," he said. "The only thing I
know about recoils is connected with an old shotgun my father
used to own.

"I took that once, when he didn't know it," Ned proceeded. "It
was pretty heavily loaded, for the crows had been having fun in
our cornfield, and dad had been shooting at them. This time I
thought I'd take a chance.

"Well, I fired the gun. But it must have had a double charge in
it and been rusted at that. All I know is that after I pulled the
trigger I thought the end of the world had come. I heard a clap of
thunder, and then I went flying over backward into a blackberry patch."

"That was the recoil," said Tom.

"The what?" asked Ned.

"The recoil. The recoil of the gun knocked you over.

"Oh, yes," observed Ned, rubbing his shoulder in a reflective
sort of way. "I always thought it was something like that. But,
at the time I put it down to an explosion, and let it go at that."

"No, it wasn't an explosion, properly speaking," said Tom. "You
see, when powder explodes, in a gun, or otherwise, its force is
exerted in all directions, up, down and every way.

"This went mostly backward--in my direction," said Ned ruefully.

"You only thought so," returned Tom. "Most of the power went
out in front, to force out the shot. Part of it, of course, was
exerted on the barrel of the gun--that was sideways--but the
strength of the steel held it in. And part of the force went
backward against your shoulder. That part was the recoil, and it
is the recoil of the guns I figure on putting aboard my aerial
warship that is giving me such trouble."

"Is that what makes you look so blue?" asked Ned.

"That's it. I can't seem to find a way by which to take up the
recoil, and the force of it, from all the guns I want to carry,
will just about tear my ship to pieces, I figure."

"Then you haven't actually tried it out yet?" asked Ned.

"Not the guns, no. I have the warship of the air nearly done,
but I've worked out on paper the problem of the guns far enough
so that I know I'm up against it. It can't be done, and an aerial
warship without guns wouldn't be worth much, I'm afraid."

"I suppose not," agreed Ned. "And is it only the recoil that is
bothering you?"

"Mostly. But come, take a look at my latest pet," and Tom arose
to lead the way to another shed, a large one in the distance,
toward which he waved his hand to indicate to his chum that there
was housed the wonderful invention.

The two chums crossed the yard, threading their way through the
various buildings, until they stood in front of the structure to
which Tom had called attention.

"It's in here," he said. "I don't mind admitting that I'm quite
proud of it, Ned; that is, proud as far as I've gone. But the gun
business sure has me worried. I'm going to talk it off on you.
Hello!" cried Tom suddenly, as he put a key in the complicated
lock on the door, "someone has been in here. I wonder who it is?"

Ned was a little startled at the look on Tom s face and the
sound of alarm in his chum's voice.


Tom Swift quickly opened the door of the big shed. It was built
to house a dirigible balloon, or airship of some sort. Ned could
easily tell that from his knowledge of Tom's previous inventions.

"Something wrong?" asked the young bank clerk.

"I don't know," returned Tom, and then as he looked inside the
place, he breathed a sigh of relief.

"Oh, it's you, is it, Koku?" he asked, as a veritable giant of
a man came forward.

"Yes, master, it is only Koku and your father," spoke the big
chap, with rather a strange accent.

"Oh, is my father here?" asked Tom. "I was wondering who had
opened the door of this shed."

"Yes, Tom," responded the elder Swift, coming up to them, "I
had a new idea in regard to some of those side guy wires, and I
wanted to try it out. I brought Koku with me to use his strength
on some of them."

"That's all right, Dad. Ned and I came out to wrestle with that
recoil problem again. I want to try some guns on the craft soon,

"You'd better not, Tom," warned his father. "It will never
work, I tell you. You can't expect to take up quick-firing guns
and bombs in an airship, and have them work properly. Better give
it up."

"I never will. I'll make it work, Dad!"

"I don't believe you will, Tom. This time you have bitten off
more than you can chew, to use a homely but expressive

"Well, Dad, we'll see," began Tom easily. "There she is, Ned,"
he went on. "Now, if you'll come around here

But Tom never finished that sentence, for at that moment there
came running into the airship shed an elderly, short, stout,
fussy gentleman, followed by an aged colored man. Both of them
seemed very much excited.

"Bless my socks, Tom!" cried the short, stout man. "There sure
is trouble!"

"I should say So, Massa Tom!" added the colored man. "I done
did prognosticate dat some day de combustible material of which
dat shed am composed would conflaggrate--"

"What's the matter?" interrupted Tom, jumping forward. "Speak
out! Eradicate! Mr. Damon, what is it?"

"The red shed!" cried the short little man. "The red shed, Tom

"It's on fire!" yelled the colored man.

"Great thunderclaps!" cried Tom. "Come on --everybody on the
job!" he yelled. "Koku, pull the alarm! If that red shed goes--"

Instantly the place was in confusion. Tom and Ned, looking from
a window of the hangar, saw a billow of black smoke roll across
the yard. But already the private fire bell was clanging out its
warning. And, while the work of fighting the flames is under way,
I will halt the progress of this story long enough to give my new
readers a little idea of who Tom Swift is, so they may read this
book more intelligently. Those of you who have perused the
previous volumes may skip this part.

Tom Swift, though rather young in years, was an inventor of
note. His tastes and talents were developed along the line of
machinery and locomotion. Motorcycles, automobiles, motorboats,
submarine craft, and, latest of all, craft of the air, had occupied
the attention of Tom Swift and his father for some years.

Mr. Swift was a widower, and lived with Tom, his only son, in
the village of Shopton, New York State. Mrs. Baggert kept house
for them, and an aged colored man, Eradicate Sampson, with his
mule, Boomerang, did "odd jobs" about the Shopton home and

Among Tom's friends was a Mr. Wakefield Damon, from a nearby
village. Mr. Damon was always blessing something, from his hat to
his shoes, a harmless sort of habit that seemed to afford him
much comfort. Then there was Ned Newton, a boyhood chum of Tom's,
who worked in the Shopton bank. I will just mention Mary Nestor,
a young lady of Shopton, in whom Tom was more than ordinarily
interested. I have spoken of Koku, the giant. He really was a
giant of a man, of enormous strength, and was one of two whom Tom
had brought with him from a strange land where Tom was held
captive for a time. You may read about it in a book devoted to
those adventures.

Tom took Koku into his service, somewhat to the dismay of
Eradicate, who was desperately jealous. But poor Eradicate was
getting old, and could not do as much as he thought he could. So,
in a great measure, Koku replaced him, and Tom found much use for
the giant's strength.

Tom had begun his inventive work when, some years before this
story opens, he had bargained for Mr. Damon's motorcycle, after
that machine had shot its owner into a tree. Mr. Damon was,
naturally, perhaps, much disgusted, and sold the affair cheap.
Tom repaired it, made some improvements, and, in the first
volume of this series, entitled "Tom Swift and His Motorcycles,"
you may read of his rather thrilling adventures on his speedy

From then on Tom had passed a busy life, making many machines
and having some thrilling times with them. Just previous to the
opening of this story Tom had made a peculiar instrument,
described in the volume entitled "Tom Swift and His Photo-
Telephone." With that a person talking could not only see the
features of the person with whom he was conversing, but, by means
of a selenium plate and a sort of camera, a permanent picture
could be taken of the person at either end of the wire.

By means of this invention Tom had been able to make a picture
that had saved a fortune. But Tom did not stop there. With him to
invent was as natural and necessary as breathing. He simply could
not stop it. And so we find him now about to show to his chum,
Ned Newton, his latest patent, an aerial warship, which, however,
was not the success Tom had hoped for.

But just at present other matters than the warship were in
Tom's mind. The red shed was on fire.

That mere statement might not mean anything special to the
ordinary person, but to Tom, his father, and those who knew about
his shops, it meant much.

"The red shed!" Tom cried. "We mustn't let that get the best of
us! Everybody at work! Father, not you, though. You mustn't
excite yourself!"

Even in the midst of the alarm Tom thought of his father, for
the aged man had a weak heart, and had on one occasion nearly
expired, being saved just in time by the arrival of a doctor,
whom Tom brought to the scene after a wonderful race through the

"But, Tom, I can help," objected the aged inventor.

"Now, you just take care of yourself, Father!" Tom cried.
"There are enough of us to look after this fire, I think."

"But, Tom, it--it's the red shed!" gasped Mr. Swift.

"I realize that, Dad. But it can't have much of a start yet. Is
the alarm ringing, Koku?"

"Yes, Master," replied the giant, in correct but stilted
English. "I have set the indicator to signal the alarm in every
shop on the premises."

"That's right." Tom sprang toward the door. "Eradicate!" he

"Yais, sah! Heah I is!" answered the colored man. "I'll go git
mah mule, Boomerang, right away, an' he--"

"Don't you bring Boomerang on the scene!" Tom yelled. "When I
want that shed kicked apart I can do it better than by using a
mule's heels. And you know you can't do a thing with Boomerang
when he sees fire."

"Now dat's so, Massa Tom. But I could put blinkers on him,

"No, you let Boomerang stay where he is. Come on, Ned. We'll
see what we can do. Mr. Damon--"

"Yes, Tom, I'm right here," answered the peculiar man, for he
had come over from his home in Waterford to pay a visit to his
friends, Tom and Mr. Swift. "I'll do anything I can to help you,
Tom, bless my necktie!" he went on. "Only say the word!"

"We've got to get some of the stuff out of the place!" Tom
cried. "We may be able to save it, but I can't take a chance on
putting out the fire and letting some of the things in there go
up in smoke. Come on!"

Those in the shed where was housed what Tom hoped would prove
to be a successful aerial warship rushed to the open. From the
other shops and buildings nearby were pouring men and boys, for
the Swift plant employed a number of hands now.

Above the shouts and yells, above the crackle of flames, could
be heard the clanging of the alarm bell, set ringing by Koku, who
had pulled the signal in the airship shed. From there it had gone
to every building in the plant, being relayed by the telephone
operator, whose duty it was to look after that.

"My, you've got a big enough fire-fighting force, Tom!" cried
Ned in his chum's ear.

"Yes, I guess we can master it, if it hasn't gotten the best of
us. Say, it's going some, though!"

Tom pointed to where a shed, painted red--a sign of danger--
could be seen partly enveloped in smoke, amid the black clouds of
which shot out red tongues of flame.

"What have you got it painted red for?" Ned asked pantingly, as
they ran on.

"Because--" Tom began, but the rest of the sentence was lost in
a yell.

Tom had caught sight of Eradicate and the giant, Koku,
unreeling from a central standpipe a long line of hose.

"Don't take that!" Tom cried. "Don't use that hose! Drop it!"

"What's the matter? Is it rotten?" Ned wanted to know.

"No, but if they pull it out the water will be turned on

"Well, isn't that what you want at a fire--water?" Ned

"Not at this fire," was Tom's answer. "There's a lot of calcium
carbide in that red shed--that's why it's red--to warn the men of
danger. You know what happens when water gets on carbide--there's
an explosion, and there's enough carbide in that shed to send the
whole works sky high.

"Drop that hose!" yelled Tom in louder tones. "Drop it, Rad--
Koku! Do you want to kill us all!"


Tom's tones and voice were so insistent that the giant and the
colored man had no choice but to obey. They dropped the hose
which, half unreeled, lay like some twisted snake in the grass.
Had it been pulled out all the way the water would have spurted
from the nozzle, for it was of the automatic variety, with which
Tom had equipped all his plant.

"But what are you going to do, Tom, if you don't use water?"
asked Ned, wonderingly.

"I don't know--yet, but I know water is the worst thing you can
put on carbide," returned Tom. For all he spoke Slowly his brain
was working fast. Already, even now, he was planning how best to
give battle to the flames.

It needed but an instant's thought on the part of Ned to make
him understand that Tom was right. It would be well-nigh fatal to
use water on carbide. Those of you who have bicycle lanterns, in
which that not very pleasant-smelling chemical is used, know that
if a few drops of water are allowed to drip slowly on the gray
crystals acetylene gas is generated, which makes a brilliant
light. But, if the water drips too fast, the gas is generated too
quickly, and an explosion results. In lamps, of course, and in
lighting plants where carbide is used, there are automatic
arrangements to prevent the water flowing too freely to the
chemical. But Tom knew if the hose were turned on the fire in the
red shed a great explosion would result, for some of the tins of
carbide would be melted by the heat.

Yet the fire needed to be coped with. Already the flames were
coming through the roof, and the windows and door were spouting
red fire and volumes of smoke.

Several other employees of Tom's plant had made ready to unreel
more hose, but the warning of the young inventor, shouted to
Eradicate and Koku, had had its effect. Every man dropped the
line he had begun to unreel.

"Ha! Massa Tom say drop de hose, but how yo' gwine t' squirt
watah on a fire wifout a hose; answer me dat?" and Eradicate
looked at Koku.

"Me no know," was the slow answer. "I guess Koku go pull shed
down and stamp out fire."

"Huh! Maybe yo' could do dat in cannibal land, where yo' all
come from," spoke Eradicate, "but yo' can't do dat heah! 'Sides,
de red shed will blow up soon. Dere's suffin' else in dere except
carbide, an' dat's gwine t' go up soon, dat's suah!"

"Maybe you get your strong man-mule, Boomerang," suggested
Koku. "Nothing ever hurt him--explosion or nothing. He can kick
shed all to pieces, and put out fire."

"Dat's what I wanted t' do, but Massa Tom say I cain't,"
explained the colored man. "Golly! Look at dat fire!"

Indeed the blaze was now assuming alarming proportions. The red
shed, which was not a small structure, was blazing on all sides.
About it stood the men from the various shops.

"Tom, you must do something," said Mr. Swift. "If the flames
once reach that helmanite--"

"I know, Father. But that explosive is in double vacuum
containers, and it will be safe for some time yet. Besides, it's
in the cellar. It's the carbide I'm most worried about. We
daren't use water."

"But something will have to be done!" exclaimed Mr. Damon.
"Bless my red necktie, if we don't--"

"Better get back a way," suggested Tom. "Something may go off!"

His words of warning had their effect, and the whole circle
moved back several paces.

"Is there anything of value in the shed?" asked Ned.

"I should say there was!" Tom answered. "I hoped we could get
some of them out, but we can't now--until the fire dies down a
bit, at any rate."

"Look, Tom! The pattern shop roof is catching!" shouted Mr.
Swift, pointing to where a little spurt of flame showed on the
roof of a distant building.

"It's from sparks!" Tom said.

"Any danger of using water there?" Ned wanted to know.

"No, use all you like! That's the only thing to do. Come on,
you with the hose!" Tom yelled. "Save the other buildings!"

"But are you going to let the red shed burn?" asked Mr. Swift.
"You know what it means, Tom."

"Yes, Father, I know. And I'm going to fight that fire in a new
way. But we must save the other buildings, too. Play water on all
the other sheds and structures!" ordered the young inventor.
"I'll tackle this one myself. Oh, Ned!" he called.

"Yes," answered his chum. "What is it?"

"You take charge of protecting the place where the new aerial
warship is stored. Will you? I can't afford to lose that."

"I'll look after it, Tom. No harm in using water there, though;
is there?"

"Not if you don't use too much. Some of the woodwork isn't
varnished yet, and I wouldn't want it to be wet. But do the best
you can. Take Koku and Eradicate with you. They can't do any good

"Do you mean to say you're going to give up and let this burn?"

"Not a bit of it, Ned. But I have another plan I want to try.
Lively now! The wind's changing, and it's blowing over toward my
aerial warship shed. If that catches--"

Tom shook his head protestingly, and Ned set off on the run,
calling to the colored man and the giant to get out another line
of hose.

"I wonder what Tom is going to do?" mused Ned, as he neared the
big shed he and the others had left on the alarm of fire.

Tom, himself, seemed in no doubt as to his procedure With one
look at the blazing red shed, as if to form an opinion as to how
much longer it could burn without getting entirely beyond
control, Tom set off on a run toward another large structure.
Ned, glancing toward his chum, observed:

"The dirigible shed! I wonder what his game is? Surely that
can't be in danger--it's too far off!"

Ned was right as to the last statement. The shed, where was
housed a great dirigible balloon Tom had made, but which he
seldom used of late, was sufficiently removed from the zone of
fire to be out of danger.

Meanwhile several members of the fire-fighting force that had
been summoned from the various shops by the alarm, had made an
effort to save from the red shed some of the more valuable of the
contents. There were some machines in there, as well as
explosives and chemicals, in addition to the store of carbide.

But the fire was now too hot to enable much to be done in the
way of salvage. One or two small things were carried out from a
little addition to the main structure, and then the rescuers were
driven back by the heat of the flames, as well as by the rolling
clouds of black smoke.

"Keep away!" warned Mr. Swift. "It will explode soon. Keep

"That's right!" added Mr. Damon. "Bless my powder-horn! We may
all be going sky-high soon, and without aid from any of Tom
Swift's aeroplanes, either."

Warned by the aged inventor, the throng of men began slowly
moving away from the immediate neighborhood of the blazing shed.
Though it may seem to the reader that some time has elapsed since
the first sounding of the alarm, all that I have set down took
place in a very short period--hardly three minutes elapsing since
Tom and the others came rushing out of the aerial warship

Suddenly a cry arose from the crowd of men near the red shed.
Ned, who stood ready with several lines of hose, in charge of
Koku, Eradicate and others, to turn them on the airship shed, in
case of need, looked in the direction of the excited throng.

The young bank clerk saw a strange sight. From the top of the
dirigible balloon shed a long, black, cigar-shaped body arose,
floating gradually upward. The very roof of the shed slid back
out of the way, as Tom pressed the operating lever, and the
dirigible was free to rise--as free as though it had been in an
open field.

"He's going up!" cried Ned in surprise. "Making an ascent at a
time like this, when he ought to stay here to fight the fire!
What's gotten into Tom, I'd like to know? I wonder if he can

Ned did not finish his half-formed sentence. A dreadful thought
came into his mind. What if the sudden fire, and the threatened
danger, as well as the prospective loss that confronted Tom, had
affected his mind?

"It certainly looks so," mused Ned, as he saw the big balloon
float free from the shed. There was no doubt but that Tom was in
it. He could be seen standing within the pilot-house, operating
the various wheels and levers that controlled the ship of the

"What can he be up to?" marveled Tom. "Is he going to run away
from the fire?"

Koku, Eradicate and several others were attracted by the sight
of the great dirigible, now a considerable distance up in the
air. Certainly it looked as though Tom Swift were running away.
Yet Ned knew his chum better than that.

Then, as they watched, Ned and the others saw the direction of
the balloon change. She turned around in response to the
influence of the rudders and propellers, and was headed straight
for the blazing shed, but some distance above it.

"What can he be planning?" wondered Ned.

He did not have long to wait to find out.

An instant later Tom's plan was made clear to his chum. He saw
Tom circling over the burning red shed, and then the bank clerk
saw what looked like fine rain dropping from the lower part of
the balloon straight into the flames.

"He can't be dousing water on from up above there," reasoned
Ned. "Pouring water on carbide from a height is just as bad as
spurting it on from a hose, though perhaps not so dangerous to
the persons doing it. But it can't be--"

"By Jove!" suddenly exclaimed Ned, as he had a better view of
what was going on. "It's sand, that's what it is! Tom is giving
battle to the flames with sand from the ballast bags of the
dirigible! Hurray? That's the ticket! Sand! The only thing safe
to use in case of an explosive chemical fire.

"Fine for you. Tom Swift! Fine!"


High up aloft, over the blazing red shed, with its dangerous
contents that any moment might explode, Tom Swift continued to
hold his big dirigible balloon as near the flames as possible.
And as he stood outside on the small deck in front of the
pilot-house, where were located the various controls, the young
inventor pulled the levers that emptied bag after bag of fine
sand on the spouting flames that, already, were beginning to die
down as a result of this effectual quenching.

"Tom's done the trick!" yelled Ned, paying little attention now
to the big airship shed, since he saw that the danger was about

"Dhat's what he suah hab done!" agreed Eradicate. "Mah ole mule
Boomerang couldn't 'a' done any better."

"Huh! Your mule afraid of fire," remarked Koku.

"What's dat? Mah mule afraid ob fire?" cried the colored man.
"Look heah, yo' great, big, overgrowed specimen ob an equilateral
quadruped, I'll hab yo' all understand dat when yo' all speaks
dat way about a friend ob mine dat yo'--"

"That'll do, Rad!" broke in Ned, with a laugh. He knew that
when Tom's helper grew excited on the subject of his mule there
was no Stopping him, and Boomerang was a point on which Eradicate
and Koku were always arguing. "The fire is under control now."

"Yes, it seems to have gone visiting," observed Koku.

"Visiting?" queried Ned, in some surprise.

"Yes, that is, it is going out," went on Koku.

"Oh, I understand!" laughed Ned. "Yes, and I hope it doesn't
pay us another visit soon. Oh, look at Tom, would you!" he cried,
for the young aviator had swung his ship about over the flames,
to bring another row of sand bags directly above a place where
the fire was hottest.

Down showered more sand from the bags which Tom opened. No fire
could long continue to blaze under that treatment. The supply of
air was cut off, and without that no fire can exist. Water would
have been worse than useless, because of the carbide, but the
sand covered it up so that it was made perfectly harmless.

Moving slowly, the airship hovered over every part of the now
slowly expiring flames, the burned opening in the roof of the
shed making it possible for the sand to reach the spots where it
was most needed. The flames died out in section after section,
until no more could be seen--only clouds of black smoke.

"How is it now?" came Tom's voice, as he spoke from the deck of
the balloon through a megaphone.

"Almost out," answered Mr. Damon. "A little more sand, Tom."

The eccentric man had caught up a piece of paper and, rolling
it into a cone, made an improvised megaphone of that.

"Haven't much more sand left," was Tom's comment, as he sent
down a last shower. "That will have to do. Hustle that carbide
and other explosive stuff out of there now, while you have a

"That's it!" cried Ned, who caught his chums meaning. "Come on,
Koku. There's work for you."

"Me like work," answered the giant, stretching out his great

The last of the sand had completely smothered the fire, and
Tom, observing from aloft that his work was well done, moved away
in the dirigible, sending it to a landing space some little
distance away from the shed whence it had arisen. It was
impossible to drop it back again through the roof of the hangar,
as the balloon was of such bulk that even a little breeze would
deflect it so that it could not be accurately anchored. But Tom
had it under very good control, and soon it was being held down
on the ground by some of his helpers.

As all the sand ballast had been allowed to run out Tom was
obliged to open the gas-valves and let some of the lifting vapor
escape, or he could not have descended.

"Come on, now!" cried the inventor, as he leaped from the deck
of his sky craft. "Let's clean out the red shed. That fire is
only smothered, and there may be sparks smoldering under that
sand, which will burst into flame, if we're not careful. Let's
get the explosives out of the way.

"Bless my insurance policy, yes," exclaimed Mr. Damon. "That
was a fine move of yours."

"It was the only way I could think of to put out the fire," Tom
replied. "I knew water was out of the question, and sand was the
next thing."

"But I didn't know where to get any until I happened to think
of the ballast bags of my dirigible. Then I knew, if I could get
above the fire, I could do the trick. I had to fly pretty high,
though, as the fire was hot, and I was afraid it might explode
the gas bag and wreck me."

"You were taking a chance," remarked Ned.

"Oh, well, you have to take chances in this business," observed
Tom, with a smile. "Now, then, let's finish this work."

The sand, falling from the ballast bags of the dirigible, had
so effectually quenched the fire that it was soon cool enough to
permit close approach. Koku, Tom and some of the men who best
knew how to handle the explosives, were soon engaged in the work
of salvage.

"I wish I could help you, Tom," said his aged father. "I don't
seem able to do anything but stand here and look on," and he
gazed about him rather sadly.

"Never you mind, Dad!" Tom exclaimed. "We'll get along all
right now. You'd better go up to the house. Mr. Damon will go
with you.

"Yes, of course!" exclaimed the odd man, catching a wink from
Tom, who wanted his father not to get too excited on account of
his weak heart. "Come along, Professor Swift. The danger is all

"All right," assented the aged inventor, with a look at the
still smoking shed.

"And, Dad, when you haven't anything else to do," went on Tom,
rather whimsically, "you might be thinking up some plan to take
up the recoil of those guns on my aerial warship. I confess I'm
clean stumped on that point."

"Your aerial warship will never be a success," declared Mr.
Swift. "You might as well give that up, Tom."

"Don't you believe it, Dad!" cried Tom, with more of a jolly
air of one chum toward another than as though the talk was
between father and son. "You solve the recoil problem for me, and
I'll take care of the rest, and make the air warship sail. But
we've got something else to do just now. Lively, boys."

While Mr. Swift, taking Mr. Damon's arm, walked toward the
house, Tom, Ned, Koku, and some of the workmen began carrying out
the explosives which had so narrowly escaped the fire. With long
hooks the men pulled the shed apart, where the side walls had
partly been burned through. Tom maintained an efficient
firefighting force at his works, and the men had the proper tools
with which to work.

Soon large openings were made on three sides of the red shed,
or rather, what was left of it, and through these the dangerous
chemicals and carbide, in sheet-iron cans, were carried out to a
place of safety. In a little while nothing remained but a heap of
hot sand, some charred embers and certain material that had been

"Much loss, Tom?" asked Ned, as they surveyed the ruins. They
were both black and grimy, tired and dirty, but there was a great
sense of satisfaction.

"Well, yes, there's more lost than I like to think of,"
answered Tom slowly, "but it would have been a heap sight worse
if the stuff had gone up. Still, I can replace what I've lost,
except a few models I kept in this place. I really oughtn't to
have stored them here, but since I've been working on my new
aerial warship I have sort of let other matters slide. I intended
to make the red shed nothing but a storehouse for explosive
chemicals, but I still had some of my plans and models in it when
it caught."

"Only for the sand the whole place might have gone," said Ned
in a low voice.

"Yes. It's lucky I had plenty of ballast aboard the dirigible.
You see, I've been running it alone lately, and I had to take on
plenty of sand to make up for the weight of the several
passengers I usually carry. So I had plenty of stuff to shower
down on the fire. I wonder how it started, anyhow? I must
investigate this."

"Mr. Damon and Eradicate seem to have seen it first," remarked

"Yes. At least they gave the alarm. Guess I'll ask Eradicate
how he happened to notice. Oh, I say, Rad!" Tom called to the
colored man.

"Yais, sah, Massa Tom! I'se comin'!" the darky cried, as he
finished piling up, at a safe distance from the fire, a number of
cans of carbide.

"How'd you happen to see the red shed ablaze?" Tom asked.

"Why, it was jest dish yeah way, Massa Tom," began the colored
man. "I had jest been feedin' mah mule, Boomerang. He were
pow'ful hungry, Boomerang were, an', when I give him some oats,
wif a carrot sliced up in 'em--no, hole on--did I gib him a
carrot t'day, or was it yist'day?--I done fo'got. No, it were
yist'day I done gib him de carrot, I 'member now, 'case--"

"Oh, never mind the carrot, or Boomerang, either, Rad!" broke
in Tom, "I'm asking you about the fire."

"An' I'se tellin' yo', Massa Tom," declared Eradicate, with a
rather reproachful look at his master. "But I wanted t' do it
right an' proper. I were comin' from Boomerang's stable, an' I
see suffin' red spoutin' up at one corner ob de red shed. I
knowed it were fire right away, an' I yelled."

"Yes, I heard you yell," Tom said. "But what I wanted to know
is, did you see anyone near the red shed at the time?"

"No, Massa Tom, I done didn't."

"I wonder if Mr. Damon did? I must ask him," went on the young
inventor. "Come, on, Ned, we'll go up to the house. Everything is
all right here, I think. Whew! But that was some excitement. And
I didn't show you my aerial warship after all! Nor have you
settled that recoil problem for me."

"Time enough, I guess," responded Ned. "You sure did have a
lucky escape, Tom."

"That's right. Well, Koku, what is it?" for the giant had
approached, holding out something in his hand.

"Koku found this in red shed," went on the giant, holding out a
round, blackened object. "Maybe him powder; go bang-bang!"

"Oh, you think it's something explosive, eh?" asked Tom, as he
took the object from the giant.

"Koku no think much," was the answer. "Him look funny."

Tom did not speak for a moment. Then he cried:

"Look funny! I should say it did! See here, Ned, if this isn't
suspicious I'll eat my hat!" and Tom beckoned excitedly to his
chum, who had walked on a little in advance.


What Tom Swift held in his hand looked like a small cannon
ball, but it could not have been solid or the young aviator would
not so easily have held it out at arm's length for his friend Ned
Newton to look at.

"This puts a different face on it, Ned," Tom went on, as he
turned the object over.

"Is that likely to go off?" the bank clerk asked, as he came to
a halt a little distance from his friend.

"Go off? No, it's done all the damage it could, I guess."

"Damage? It looks to me as though it had suffered the most
damage itself. What is it, one of your models? Looks like a bomb
to me."

"And that's what it is, Ned."

"Not one of those you're going to use on your aerial warship,
is it, Tom?"

"Not exactly. I never saw this before, but it's what started
the fire in the red shed all right; I'm sure of that."

"Do you really mean it?" cried Ned.

"I sure do."

"Well, if that's the case, I wouldn't leave such dangerous
things around where there are explosives, Tom."

"I didn't, Ned. I wouldn't have had this within a hundred miles
of my shed, if I could have had my way. It's a fire bomb, and it
was set to go off at a certain time. Only I think something went
wrong, and the bomb started a fire ahead of time.

"If it had worked at night, when we were all asleep, we might
not have put the fire out so easily. This sure is suspicious! I'm
glad you found this, Koku."

Tom was carefully examining the bomb, as Ned had correctly
named it. The bank clerk, now that he was assured by his chum
that the, object had done all the harm it could, approached

What he saw was merely a hollow shell of iron, with a small
opening in it, as though intended for a place through which to
put a charge of explosives and a fuse.

"But there was no explosion, Tom," explained Ned.

"I know it," said Tom quietly. "It wasn't an explosive bomb.
Smell that!"

He held the object under Ned's nose so suddenly that the young
bank clerk jumped back.

"Oh, don't get nervous," laughed Tom. "It can't hurt you now.
But what does that smell like?"

Ned sniffed, sniffed again, thought for a moment, and then
sniffed a third time.

"Why," he said slowly, "I don't just know the name of it, but
it's that funny stuff you mix up sometimes to put in the oxygen
tanks when we go up in the rarefied atmosphere in the balloon or

"Manganese and potash," spoke Tom. "That and two or three other
things that form a chemical combination which goes off by itself
of spontaneous combustion after a certain time. Only the person
who put this bomb together didn't get the chemical mixture just
right, and it went off ahead of time; for which we have to be
duly thankful."

"Do you really think that, Tom?" cried Ned.

"I'm positive of it," was the quiet answer.

"Why--why--that would mean some one tried to set fire to the
red shed, Tom!"

"They not only tried it, but did it," responded Tom, more
coolly than seemed natural under the circumstances. "Only for the
fact that the mixture went off before it was intended to, and
found us all alert and ready--well, I don't like to think what
might have happened," and Tom cast a look about at his group of
buildings with their valuable contents.

"You mean some one purposely put that bomb in the red shed,

"That's exactly what I mean. Some enemy, who wanted to do me an
injury, planned this thing deliberately. He filled this steel
shell with chemicals which, of themselves, after a certain time,
would send out a hot tongue of flame through this hole," and Tom
pointed to the opening in the round steel shell.

"He knew the fire would be practically unquenchable by ordinary
means, and he counted on its soon eating its way into the carbide
and other explosives. Only it didn't."

"Why, Tom!" cried Ned. "It was just like one of those alarm-
clock dynamite bombs--set to go off at a certain time."

"Exactly," Tom said, "only this was more delicate, and, if it
had worked properly, there wouldn't have been a vestige left to
give us a clue. But the fire, thanks to the ballast sand in the
dirigible, was put out in time. The fuse burned itself out, but I
can tell by the smell that chemicals were in it. That's all,
Koku," he went on to the giant who had stood waiting, not
understanding all the talk between Tom and Ned. "I'll take care
of this now."

"Bad man put it there?" asked the giant, who at least
comprehended that something was wrong.

"Well, yes, I guess you could say it was a bad man," replied

"Ha! If Koku find bad man--bad for that man!" muttered the
giant, as he clasped his two enormous hands together, as though
they were already on the fellow who had tried to do Tom Swift
such an injury.

"I wouldn't like to be that man, if Koku catches him," observed
Ned. "Have you any idea who it could be, Tom?"

"Not the least. Of course I know I have enemies, Ned. Every
successful inventor has persons who imagine he has stolen their
ideas, whether he has ever seen them or not. It may have been one
of those persons, or some half-mad crank, who was jealous. It
would be impossible to say, Ned."

"It wouldn't be Andy Foger, would it?"

"No; I don't believe Andy has been in this neighborhood for
some time. The last lesson we gave him sickened him, I guess."

"How about those diamond-makers, whose secret you discovered?
They wouldn't be trying to get back at you, would they?"

Well, it's possible, Ned. But I don't imagine so. They seem to
have been pretty well broken up. No, I don't believe it was the
diamond-makers who put this fire bomb in the red shed. Their line
of activities didn't include this branch. It takes a chemist to
know just how to blend the things contained in the bomb, and even
a good chemist is likely to fail--as this one did, as far as time

"What are you going to do about it?" Ned asked.

"I don't know," and Tom spoke slowly, "I hoped I was done with
all that sort of thing," he went on; "fighting enemies whom I
have never knowingly injured. But it seems they are still after
me. Well, Ned, this gives us something to do, at all events."

"You mean trying to find out who these fellows are?"

"Yes; that is, if you are willing to help."

"Well, I guess I am!" cried the bank clerk with sparkling eyes.
"I wouldn't ask anything better. We've been in things like this
before, Tom, and we'll go in again--and win! I'll help you all I
can. Now, let's see if we can pick up any other clues. This is
like old times!" and Ned laughed, for he, like Tom, enjoyed a
good "fight," and one in which the odds were against them.

"We sure will have our hands full," declared the young
inventor. "Trying to solve the problem of carrying guns on an
aerial warship, and finding out who set this fire."

"Then you're not going to give up your aerial warship idea?"

"No, indeed!" Tom cried. "What made you think that?"

"Well, the way your father spoke--"

"Oh, dear old dad!" exclaimed Tom affectionately. "I don't want
to argue with him, but he's dead wrong!"

"Then you are going to make a go of it?"

"I sure am, Ned! All I have to solve is the recoil proposition,
and, as soon as we get straightened out from this fire, we'll
tackle that problem again--you and I. But I sure would like to
know who put this in my red shed," and Tom looked in a puzzled
manner at the empty fire bomb he still held.

Tom paused, on his way to the house, to put the bomb in one of
his offices.

"No use letting dad know about this," he went on. It would only
be something else for him to worry about."

"That's right," agreed Ned.

By this time nearly all evidences of the fire, except for the
blackened ruins of the shed, had been cleared away. High in the
air hung a cloud of black smoke, caused by some chemicals that
had burned harmlessly save for that pall. Tom Swift had indeed
had a lucky escape.

The young inventor, finding his father quieted down and
conversing easily with Mr. Damon, who was blessing everything he
could think of, motioned to Ned to follow him out of the house

"We'll leave dad here," said Tom, "and do a little
investigating on our own account. We'll look for clues while
they're fresh."

But, it must be confessed, after Tom and Ned had spent the rest
of that day in and about the burned shed, they were little wiser
than when they started. They found the place where the fire bomb
had evidently been placed, right inside the main entrance to the
shed. Tom knew it had been there because there were peculiar
marks on the charred wood, and a certain queer smell of chemicals
that confirmed his belief.

"They put the bomb there to prevent anyone going in at the
first alarm and saving anything," Tom said. "They didn't count on
the roof burning through first, giving me a chance to use the
sand. I made the roof of the red shed flimsy just on that
account, so the force of the explosion if one ever came, would be
mostly upward. You know the expanding gases, caused by an
explosion or by rapid combustion, always do just as electricity
does, seek the shortest and easiest route. In this case I made
the roof the easiest route."

"A lucky provision," observed Ned.

That night Tom had to confess himself beaten, as far as finding
clues was concerned. The empty fire bomb was the only one, and
that seemed valueless.

Close questioning of the workmen failed to disclose anything.
Tom was particularly anxious to discover if any mysterious
strangers had been seen about the works. There was a strict rule
about admitting them to the plant, however, and it could not be
learned that this had been violated.

"Well, we'll just have to lay that aside for a while," Tom said
the next day, when Ned again came to pay a visit. "Now, what do
you say to tackling, with me, that recoil problem on the aerial

"I'm ready, if you are," Ned agreed, "though I know about as
much of those things as a snake does about dancing. But I'm

The two friends walked out toward the shed where Tom's new
craft was housed. As yet Ned had not seen it. On the way they saw
Eradicate walking along, talking to himself, as he often did.

"I wonder what he has on his mind," remarked Ned musingly.

"Something does seem to be worrying him," agreed Tom.

As they neared the colored man, they could hear him saying:

"He suah did hab nerve, dat's what he did! De idea ob askin' me
all dem questions, an' den wantin' t' know if I'd sell him!"

"What's that, Eradicate?" asked Tom.

"Oh, it's a man I met when I were comin' back from de ash
dump," Eradicate explained. One of the colored man's duties was
to cart ashes away from Tom's various shops, and dump them in a
certain swampy lot. With an old ramshackle cart, and his mule,
Boomerang, Eradicate did this task to perfection.

"A man--what sort of a man?" asked Tom, always ready to be
suspicious of anything unusual.

"He were a queer man," went on the aged colored helper. "First
he stopped me an' asted me fo' a ride. He was a dressed-up
gen'man, too, an' I were suah s'prised at him wantin' t" set in
mah ole ash cart," said Eradicate. "But I done was polite t' him,
an' fixed a blanket so's he wouldn't git too dirty. Den he asted
me ef I didn't wuk fo' yo', Massa Tom, an' of course I says as
how I did. Den he asted me about de fire, an' how much damage it
done, an' how we put it out. An' he end up by sayin' he'd laik t'
buy mah mule, Boomerang, an' he wants t' come heah dis arternoon
an' talk t' me about it."

"He does, eh?" cried Tom. "What sort of a man was he, Rad?"

"Well, a gen'man sort ob man, Massa Tom. Stranger t' me. I
nebber seed him afo'. He suah was monstrous polite t' ole black
Eradicate, an' he gib me a half-dollar, too, jest fo' a little
ride. But I aint' gwine t' sell Boomerang, no indeedy, I ain't!"
and Eradicate shook his gray, kinky head decidedly.

"Ned, there may be something in this!" said Tom, in an excited
whisper to his chum. "I don't like the idea of a mysterious
stranger questioning Eradicate!"


Ned Newton looked at Tom questioningly. Then he glanced at the
unsuspicious colored man, who was industriously polishing the
half-dollar the mysterious stranger had given him.

"Rad, just exactly what sort of a man was this one you speak
of?" asked Tom.

"Why, he were a gen'man--"

"Yes, I know that much. You've said it before. But was he an
Englishman, an American--or--"

Tom paused and waited for an answer.

"I think he were a Frenchman," spoke Eradicate. "I done didn't
see him eat no frogs' laigs, but he smoked a cigarette dat had a
funny smell, and he suah was monstrous polite. He suah was a
Frenchman. I think."

Tom and Ned laughed at Eradicate's description of the man, but
Tom's face was soon grave again.

"Tell us more about him, Rad," he suggested. "Did he seem
especially interested in the fire?"

"No, sah, Massa Tom, he seemed laik he was more special
interested in mah mule, Boomerang. He done asted how long I had
him, an' how much I wanted fo' him, an' how old he was."

"But every once in a while he put in some question about the
fire, or about our shops, didn't he, Rad?" Tom wanted to know.

The colored man scratched his kinky head, and glanced with a
queer look at Tom.

"How yo' all done guess dat?" he asked.

"Answer my question," insisted Tom.

"Yes, sah, he done did ask about yo', and de wuks, ebery now
and den," Rad confessed. "But how yo' all knowed dat, Massa Tom,
when I were a-tellin' yo' all about him astin' fo' mah mule, done
gets me--dat's what it suah does."

"Never mind, Rad. He asked questions about the plant, that's
all I want to know. But you didn't tell him much, did you?"

Eradicate looked reproachfully at his master.

"Yo' all done knows me bettah dan dat, Massa Tom," the old
colored man said. "Yo' all know yo' done gib orders fo' nobody t'
talk about yo' projections."

"Yes, I know I gave those orders," Tom said, with a smile, "but
I want to make sure that they have been followed."

"Well, I done follered 'em, Massa Tom."

"Then you didn't tell this queer stranger, Frenchman, or
whatever he is, much about my place?"

"I didn't tell him nuffin', sah. I done frowed dust in his

Ned uttered an exclamation of surprise.

"Eradicate is speaking figuratively," Tom said, with a laugh.

"Dat's what I means," the colored man went on. "I done fooled
him. When he asted me about de fire I said it didn't do no damage
at all--in fack dat we'd rather hab de fire dan not hab it,
'case it done gib us a chance t' practice our hose drill."

"That's good," laughed Tom. "What else?"

"Well, he done sort ob hinted t' me ef we all knowed how de
fire done start. I says as how we did, dat we done start it
ourse'ves fo' practice, an dat we done expected it all along, an'
were ready fo' it. Course I knows dat were a sort of fairy story,
Massa Tom, but den dat cigarette-smokin' Frenchman didn't hab no
right t' asted me so many questions, did he?"

"No, indeed, Rad. And I'm glad you didn't give him straight
answers. So he's coming here later on, is he?"

"T' see ef I wants t' sell mah mule, Boomerang, yais, sah. I
sort ob thought maybe you'd want t' hab a look at dat man, so I
tole him t' come on. Course I doan't want t' sell Boomerang, but
ef he was t' offer me a big lot ob money fo' him I'd take it."

"Of course," Tom answered. "Very well, Rad. You may go on now,
and don't say anything to anyone about what you have told me."

"I won't, Massa Tom," promised the colored man, as he went off
muttering to himself.

"Well, what do you make of it, Tom?" asked Ned of his chum, as
they walked on toward the shed of the new, big aerial warship.

"I don't know just what to think, Ned. Of course things like
this have happened before--persons trying to worm secrets out of
Eradicate, or some of the other men."

"They never succeeded in getting much, I'm glad to say, but it
always keeps me worried for fear something will happen," Tom

"But about this Frenchman?"

"Well, he must be a new one. And, now I come to think of it, I
did hear some of the men speaking about a foreigner--a stranger--
being around town last week. It was just a casual reference, and
I paid little attention to it. Now it looks as though there might
be something in it."

"Do you think he'll come to bargain with Eradicate about the
mule?" Ned asked.

"Hardly. That was only talk to make Eradicate unsuspicious. The
stranger, whoever he was, sized Rad up partly right. I surmised,
when Rad said he asked a lot of questions about the mule, that
was only to divert suspicion. and that he'd come back to the
subject of the fire every chance he got."

"And you were right."

"Yes, so it seems. But I don't believe the fellow will come
around here. It would be too risky. All the same, we'll be
prepared for him. I'll just rig up one of my photo-telephone
machines, so that, if he does come to have a talk with Rad, we
can both see and hear him."

"That's great, Tom! But do you think this fellow had anything
to do with the fire?"

"I don't know. He knew about it, of course. This isn't the
first fire we've had in the works, and, though we always fight
them ourselves, still news of it will leak out to the town. So he
could easily have known about it. And he might be in with those
who set it, for I firmly believe the fire was set by someone who
has an object in injuring me."

"It's too bad!" declared Ned. "Seems as though they might let
you alone, if they haven't gumption enough to invent things for

"Well, don't worry. Maybe it will come out all right," returned
Tom. "Now, let's go and have a look at my aerial warship. I
haven't shown it to you yet. Then we'll get ready for that
mysterious Frenchman, if he comes--but I don't believe he will."

The young inventor unlocked the door of the shed where he kept
his latest "pet," and at the sight which met his eyes Ned Newton
uttered an exclamation of surprise.

"Tom, what is it?" he cried in an awed voice.

"My aerial warship!" was the quiet answer.

Ned Newton gave vent to a long whistle, and then began a
detailed examination of the wonderful craft he saw before him.
That is, he made as detailed an examination as was possible under
the circumstances, for it was a long time before the young bank
clerk fully appreciated all Tom Swift had accomplished in
building the Mars, which was the warlike name painted in red
letters on the big gas container that tugged and swayed overhead.

"Tom, however did you do it?" gasped Ned at length.

"By hard work," was the modest reply. "I've been at this for a
longer time than you'd suppose, working on it at odd moments. I
had a lot of help, too, or I never could have done it. And now it
is nearly all finished, as far as the ship itself is concerned.
The only thing that bothers me is to provide for the recoil of
the guns I want to carry. Maybe you can help me with that. Come
on, now, I'll explain how the affair works, and what I hope to
accomplish with it."

In brief Tom's aerial warship was a sort of German Zeppelin
type of dirigible balloon, rising in the air by means of a gas
container, or, rather, several of them, for the section for
holding the lifting gas element was divided by bulkheads.

The chief difference between dirigible balloons and ordinary
aeroplanes, as you all know, is that the former are lifted from
the earth by a gas, such as hydrogen, which is lighter than air,
while the aeroplane lifts itself by getting into motion, when
broad, flat planes, or surfaces, hold it up, just as a flat stone
is held up when you sail it through the air. The moment the
stone, or aeroplane, loses its forward motion, it begins to fall.

This is not so with a dirigible balloon. It is held in the air
by means of the lifting gas, and once so in the air can be sent
in any direction by means of propellers and rudders.

Tom's aerial warship contained many new features. While it was
as large as some of the war-type Zeppelins, it differed from them
materially. But the details would be of more interest to a
scientific builder of such things than to the ordinary reader, so
I will not weary you with them.

Sufficient to say that Tom's craft consisted first of a great
semi-rigid bag, or envelope, made of specially prepared oiled
silk and aluminum, to hold the gas, which was manufactured on
board. There were a number of gas-tight compartments, so that if
one, or even if a number of them burst, or were shot by an enemy,
the craft would still remain afloat.

Below the big gas bag was the ship proper, a light but strong
and rigid framework about which were built enclosed cabins. These
cabins, or compartments, housed the driving machinery, the
gas-generating plant, living, sleeping and dining quarters, and a
pilot-house, whence the ship could be controlled.

But this was not all.

Ned, making a tour of the Mars, as she swayed gently in the big
shed, saw where several aluminum pedestals were mounted, fore and
aft and on either beam of the ship.

"They look just like places where you intend to mount guns,"
said Ned to Tom.

"And that's exactly what they are," the young inventor replied.
"I have the guns nearly ready for mounting, but I can't seem to
think of a way of providing for the recoil. And if I don't take
care of that, I'm likely to find my ship coming apart under me,
after we bombard the enemy with a broadside or two."

"Then you intend to fight with this ship?" asked Ned.

"Well, no; not exactly personally. I was thinking of offering
it to the United States Government. Foreign nations are getting
ready large fleets of aerial warships, so why shouldn't we?
Matters in Europe are mighty uncertain. There may be a great war
there in which aerial craft will play a big part. I am conceited
enough to think I can build one that will measure up to the
foreign ones, and I'll soon be in a position to know."

"What do you mean?"

"I mean I have already communicated with our government
experts, and they are soon to come and inspect this craft. I have
sent them word that it is about finished. There is only the
matter of the guns, and some of the ordnance officers may be able
to help me out with a suggestion, for I admit I am stuck!"
exclaimed Tom.

"Then you're going to do the same with this aerial warship as
you did with your big lantern and that immense gun you
perfected?" asked Ned.

"That's right," confirmed Tom. My former readers will know to
what Ned Newton referred, and those of you who do not may learn
the details of how Tom helped Uncle Sam, by reading the previous
volumes, "Tom Swift and His Great Searchlight," and "Tom Swift
and His Giant Cannon."

"When do you expect the government experts?," Ned asked.

"Within a few days, now. But I'll have to hustle to get ready
for them, as this fire has put me back. There are quite a number
of details I need to change. Well, now, let me explain about that
gun recoil business. Maybe you can help me."

"Fire away," laughed Ned. "I'll do the best I can."

Tom led the way from the main shed, where the aerial warship
was housed, to a small private office. As Ned entered, the door,
pulled by a strong spring, swung after him. He held back his hand
to prevent it from slamming, but there was no need, for a patent
arrangement took up all the force, and the door closed gently.
Ned looked around, not much surprised, for the same sort of
door-check was in use at his bank. But a sudden idea came to him.

"There you are, Tom!" he cried. "Why not take up the recoil of
the guns on your aerial warship by some such device as that?" and
Ned pointed to the door-check.


For a moment or two Tom Swift did not seem to comprehend what
Ned had said. He remained staring, first at his chum, who stood
pointing, and from him Tom's gaze wandered to the top of the
door. It may have been, and probably was, that Tom was thinking
of other matters at that instant. But Ned said again:

"Wouldn't that do, Tom? Check the recoil of the gun with
whatever stuff is in that arrangement!"

A sudden change came over Tom's face. It was lighted up with a
gleam of understanding.

"By Jove, Ned, old man!" he cried. "I believe you've struck it!
And to think that has been under my nose, or, rather, over my
head, all this while, and I never thought of it. Hurray! That
will solve the problem!"

"Do you think it will?" asked Ned, glad that he had contributed
something, if only an idea, to Tom's aerial warship.

"I'm almost sure it will. I'll give it a trial right away."

"What's in that door-check?" Ned asked. "I never stopped before
to think what useful things they are, though at the bank, with
the big, heavy doors, they are mighty useful."

"They are a combination of springs and hydrostatic valves,"
began Tom.

"Good-night!" laughed Ned. "Excuse the slang, Tom, but what in
the world is a hydrostatic valve?"

"A valve through which liquids pass. In this door-check there
may be a mixture of water, alcohol and glycerine, the alcohol to
prevent freezing in cold weather, and the glycerine to give body
to the mixture so it will not flow through the valves too

"And do you think you can put something like that on your guns,
so the recoil will be taken up?" Ned wanted to know.

"I think so," spoke Tom. "I'm going to work on it right away,
and we'll soon see how it will turn out It's mighty lucky you
thought of that, for I sure was up against it, as the boys say."

"It just seemed to come to me," spoke Ned, "seeing how easily
the door closed."

"If the thing works I'll give you due credit for it," promised
Tom. "Now, I've got to figure out how much force a modified
hydrostatic valve check like that will take up, and how much
recoil my biggest gun will have."

"Then you're going to put several guns on the Mars?" asked Ned.

"Yes, four quick-firers, at least, two on each side, and
heavier guns at the bow and stern, to throw explosive shells in a
horizontal or upward direction. For a downward direction we won't
need any guns, we can simply drop the bombs, or shells, from a
release clutch."

"Drop them on other air craft?" Ned wanted to know.

"Well, if it's necessary, yes. Though I guess there won't be
much chance of doing that to a rival aeroplane or dirigible. But
in flying over cities or forts, explosive bombs can be dropped
very nicely. For use in attacking other air craft I am going to
depend on my lateral fire, from the guns mounted on either beam,
and in the bow and stern."

"You speak as though you, yourself, were going into a battle of
the air," said Ned.

"No, I don't believe I'll go that far," Tom replied. "Though,
if the government wants my craft, I may have to go aloft and fire
shots at targets for them to show them how things work.

"Please don't think that I am in favor of war, Ned," went on
Tom earnestly. "I hate it, and I wish the time would come when
all nations would disarm. But if the other countries are laying
themselves out to have aerial battleships, it is time the United
States did also. We must not be left behind, especially in view
of what is taking place in Europe."

"I suppose that's right," agreed Ned. "Have you any of your
guns ready?"

"Yes, all but the mounting of them on the supports aboard the
Mars. I haven't dared do that yet, and fire them, until I
provided some means of taking up the recoil. Now I'm going to get
right to work on that problem."

There was considerable detailed figuring and computation work
ahead of Tom Swift, and I will not weary you by going into the
details of higher mathematics. Even Ned lost interest after the
start of the problem, though he was interested when Tom took down
the door-check and began measuring the amount of force it would
take up, computing it on scales and spring balances.

Once this had been done, and Tom had figured just how much
force could be expected to be taken up by a larger check, with
stronger hydrostatic valves, the young inventor explained:

"And now to see how much recoil force my guns develop!"

"Are you really going to fire the guns?" asked Ned.

"Surely," answered Tom. "That's the only way to get at real
results. I'll have the guns taken out and mounted in a big field.
Then we'll fire them, and measure the recoil."

"Well, that may be some fun," spoke Ned, with a grin. "More fun
than all these figures," and he looked at the mass of details on
Tom's desk.

This was the second or third day after the fire in the red
shed, and in the interim Tom had been busy making computations.
These were about finished. Meanwhile further investigation bad
been made of clues leading to the origin of the blaze in the
shed, but nothing had been learned.

A photo-telephone had been installed near Eradicate's quarters,
in the hope that the mysterious stranger might keep his promise,
and come to see about the mule. In that case something would have
been learned about him. But, as Tom feared, the man did not

Ned was much interested in the guns, and, a little later, he
helped Tom and Koku mount them in a vacant lot. The giant's
strength came in handy in handling the big parts.

Mr. Swift strolled past, as the guns were being mounted for the
preliminary test, and inquired what his son was doing

"It will never work, Tom, never!" declared the aged inventor,
when informed. "You can't take up those guns in your air craft,
and fire them with any degree of safety."

"You wait, Dad," laughed Tom. "You haven't yet seen how the
Newton hydrostatic recoil operates."

Ned smiled with pleasure at this.

It took nearly a week to get all the guns mounted, for some of
them required considerable work, and it was also necessary to
attach gauges to them to register the recoil and pressure. In the
meanwhile Tom had been in further communication with government
experts who were soon to call on him to inspect the aerial
warship, with a view to purchase.

"When are they coming?" asked Ned, as he and Tom went out one
morning to make the first test of the guns.

"They will be here any day, now. They didn't set any definite
date. I suppose they want to take us unawares, to see that I
don't 'frame-up' any game on them. Well, I'll be ready any time
they come. Now, Koku, bring along those shells, and don't drop
any of them, for that new powder is freakish stuff."

"Me no drop any, Master," spoke the giant, as he lifted the
boxes of explosives in his strong arms.

The largest gun was loaded and aimed at a distant hill, for Tom
knew that if the recoil apparatus would take care of the excess
force of his largest gun, the problem of the smaller ones would
be easy to solve.

"Here, Rad, where are you going?" Tom asked, as he noticed the
colored man walking away, after having completed a task assigned
to him.

"Where's I gwine, Massa Tom?"

"Yes, Rad, that's what I asked you."

"I--I'se gwine t' feed mah mule, Boomerang," said the colored
man slowly. "It's his eatin' time. jest now, Massa Tom."

"Nonsense! It isn't anywhere near noon yet."

"Yais, sab, Massa Tom, I knows dat," said Eradicate, as he
carefully edged away from the big gun, "but I'se done changed de
eatin' hours ob dat mule. He had a little touch ob indigestion de
udder day, an' I'se feedin' him diff'rent now. So I guess as how
yo'll hab t' 'scuse me now, Massa Tom."

"Oh, well, trot along," laughed the young inventor. "I guess we
won't need you. Is everything all right there, Koku?"

"All right, Master."

"Now, Ned, if you'll stand here," went on Tom, "and note the
extreme point to which the hand on the pressure gauge goes, I'll
be obliged to you. Just jot it down on this pad."

"Here comes someone," remarked the bank clerk, as he saw that
his pencil was sharpened. He pointed to the field back of them.

"It's Mr. Damon," observed Tom. "We'll wait until he arrives.
He'll be interested in this."

"Bless my collar button, Tom! What's going on?" asked the
eccentric man, as he came up. "Has war been declared?"

"Just practicing," replied the young inventor. "Getting ready
to put the armament on my aerial warship."

"Well, as long as I'm behind the guns I'm all right, I

"Perfectly," Tom replied. "Now then, Ned, I think we'll fire."

There was a moment of inspection, to see that nothing had been
forgotten, and then the big gun was discharged. There was a loud
report, not as heavy, though, as Ned had expected, but there was
no puff of smoke, for Tom was using smokeless powder. Only a
little flash of flame was observed.

"Catch the figure, Ned!" Tom cried.

"I have it!" was the answer. "Eighty thousand!"

"Good! And I can build a recoil check that will take up to one
hundred and twenty thousand pounds pressure. That ought to be
margin of safety enough. Now we'll try another shot."

The echoes of the first had hardly died away before the second
gun was ready for the test. That, too, was satisfactory, and then
the smaller ones were operated. These were not quite so
satisfactory, as the recoil developed was larger, in proportion
to their size, than Tom had figured.

"But I can easily put a larger hydrostatic check on them," he
said. "Now, we'll fire by batteries, and see what the total is."

Then began a perfect bombardment of the distant hillside,
service charges being used v, and explosive shells sent out so that
dirt, stones and gravel flew in all directions. Danger signs and
flags had been posted, and a cordon of Tom's men kept spectators
away from the hill, so no one would be in the danger zone.

The young inventor was busy making some calculations after the
last of the firing had been completed. Koku was packing up the
unfired shells, and Mr. Damon was blessing his ear-drums, and the
pieces of cotton he had stuffed in to protect them, when a tall,
erect man was observed strolling over the fields in the direction
of the guns.

"Somebody's coming, Tom," warned Ned.

"Yes, and a stranger, too," observed Tom. "I wonder if that can
be Eradicate's Frenchman?"

But a look at the stranger's face disproved that surmise. He
had a frank and pleasant countenance, obviously American.

"I beg your pardon," he began, addressing everyone in general,
"but I am looking for Tom Swift. I was told he was here."

"I am Tom Swift," replied our hero.

"Ah! Well, I am Lieutenant Marbury, with whom you had some
correspondence recently about--"

"Oh, yes, Lieutenant Marbury, of the United States Navy,"
interrupted Tom. "I'm glad to see you," he went on, holding out
his hand. "We are just completing some tests with the guns. You
called, I presume, in reference to my aerial warship?"

"That is it--yes. Have you it ready for a trial flight?"

"Well, almost. It can be made ready in a few hours. You see, I
have been delayed. There was a fire in the plant

"A fire!" exclaimed the officer in surprise. "How was that? We
heard nothing of it in Washington."

"No, I kept it rather quiet," Tom explained. "We had reason to
suspect that it was a fire purposely set, in a shed where I kept
a quantity of explosives."

"Ha!" exclaimed Lieutenant Marbury. "This fits in with what I
have heard. And did you not receive warning?" he asked Tom.

"Warning? No. Of what?"

"Of foreign spies!" was the unexpected answer. "I am sorry.
Some of our Secret Service men unearthed something of a plot
against you, and I presumed you had been told to watch out. If
you had, the fire might not have occurred. There must have been
some error in Washington. But let me tell you now, Tom Swift--be
on your guard!"


The officer's words were so filled with meaning that Tom
started. Ned Newton, too, showed the effect he felt.

"Do you really mean that?" asked the young inventor, looking
around to make sure his father was not present. On account of
Professor Swift's weak heart, Tom wished to spare him all
possible worry.

"I certainly do mean it," insisted Lieutenant Marbury. "And,
while I am rather amazed at the news of the fire, for I did not
think the plotters would be so bold as that, it is in line with
what I expected, and what we suspected in Washington."

"And that was--what?" asked Tom.

"The existence of a well-laid plot, not only against our
government, but against you!"

"And why have they singled me out?" Tom demanded.

"I might as well tell it from the beginning," the officer went
on. "As long as you have not received any official warning from
Washington you had better hear the whole story. But are you sure
you had no word?"

"Well, now, I won't be so sure," Tom confessed. "I have been
working very hard, the last two days, making some intricate
calculations. I have rather neglected my mail, to tell you the

"And, come to think of it, there were several letters received
with the Washington postmark. But, I supposed they had to do with
some of my patents, and I only casually glanced over them. There
was one letter, though, that I couldn't make head or tail of."

"Ha! That was it!" cried the lieutenant. "It was the warning in
cipher or code. I didn't think they would neglect to send it to

"But what good would it do me if I couldn't read it?" asked

"You must also have received a method of deciphering the
message," the officer said. "Probably you overlooked that. The
Secret Service men sent you the warning in code, so it would not
be found out by the plotters, and, to make sure you could
understand it, a method of translating the cipher was sent in a
separate envelope. It is too bad you missed it."

"Yes, for I might have been on my guard," agreed Tom. "The red
shed might not have burned, but, as it was, only slight damage
was done."

"Owing to the fact that Tom put the fire out with sand ballast
from his dirigible!" cried Ned. "You should have seen it!"

"I should have liked to be here," the lieutenant spoke. "But,
if I were you, Tom Swift, I would take means to prevent a
repetition of such things."

"I shall," Tom decided. "But, if we want to talk, we had better
go to my office, where we can be more private. I don't want the
workmen to hear too much."

Now that the firing was over, a number of Tom's men from the
shops had assembled around the cannon. Most of them, the young
inventor felt, could be trusted, but in so large a gathering one
could never be sure.

"Did you come on from Washington yesterday?" asked Tom, as he,
Ned and the officer strolled toward the shed where was housed the
aerial warship.

"Yes, and I spent the night in New York. I arrived in town a
short time ago, and came right on out here. At your house I was
told you were over in the fields conducting experiments, so I
came on here."

"Glad you did," Tom said. "I'll soon have something to show
you, I hope. But I am interested in hearing the details of this
suspected plot. Are you sure one exists?"

"Perfectly sure," was the answer. "We don't know all the
details yet, nor who are concerned in it, but we are working on

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