TOM SWIFT AND HIS AIR SCOUT OR Uncle Sam's Mastery of the Sky

Part 2 out of 4

power into the motor, and the muffler didn't give any chance for
the accumulated exhaust gases to expand and escape. I didn't
allow for that, and they simply backed up, compressed and
exploded. I guess that's the whole explanation."

"I'm inclined to agree with you, Son," said Mr. Swift dryly.
"Don't try to get rid of all the noise at once. Eliminate it by
degrees and it will be safer."

"I guess so," agreed Tom.

By this time a score of workmen from the other shops had
congregated around the one though the roof of which the motor had
been blown. Tom opened the door to assure Jackson and the others
that no one was hurt, and then the young inventor saw the
exploded motor had buried in the dirt a short distance away from
the experiment building.

"Lucky none of us were standing over it when it went up," said
Tom, as he made an inspection of the broken machine. "We'd have
gone through the roof with it."

"She certainly went sailing!" commented Ned. "Must have been a
lot of power there, Tom."

And this was evidenced by the bent and twisted rods that had
held the motor to the testing block, and by the cylinders, some
of which were torn apart as though made of paper instead of heavy
steel. But for the fact that all the force of the explosion was
directly upward, instead of at the sides, none might have been
left alive in the shop. All had escaped most fortunately, and
they realized this.

"Well," queried Ned, as Tom gave orders to have the damaged
machine removed and the roof repaired, "does this end the
wonderful silent motor, Tom?"

"End it! What do you mean--"

"I mean are you going to experiment any further?"

"Why, of course! Just because I've had one failure doesn't mean
that I'm going to give up. Especially when I know what the matter
was--not leaving any vent for the escaping gases. Why this isn't
anything. When I was perfecting my giant cannon I was nearly
blown up more than once, and you remember how we got stuck in the

"I should say I did!" exclaimed Ned with a shudder. "I don't
want any more of that. But as between being blown through a roof
and held at the bottom of the sea, I don't know that there's much

"Well, perhaps not," agreed Tom. "But as for ending my
experiments, I wouldn't dream of such a thing! Why, I've only
just begun! I'll have a silent motor yet!"

"And a non-explosive one, I hope," added Mr. Damon dryly.
"Bless my shoe buttons, Tom, but if my wife knew what danger I'd
been in she'd never let me come over to see you any more."

"Well, the next time I invite you to a test I'll be more
careful," promised the young inventor.

"There isn't going to be any next time as far as I'm
concerned!" laughed Ned. "I think it's safer to sell Liberty

And, though they joked about it, they all realized the narrow
escape they had had. As for Eradicate, once he knew he had not
been the one who caused the damage, he felt rather proud of the
part he had taken in the mishap, and for many days he boasted
about it to Koku.

True to his determination, Tom Swift did not give up his
experimental work on the silent motor. The machine that had been
blown through the roof was useless now, and it was sent to the
scrap heap, after as much of it as possible had been salvaged.
Then Tom got another piece of apparatus out of his store room and
began all over again.

He worked along the same lines as at first--providing a chamber
for the escaping gases of the exhaust to expend their noise and
energy in, at the same time laboring to cut down the concussion
of the explosions in the cylinder without reducing their force
any. And that it was no easy problem to do either of these, Tom
had to admit as he progressed. All previous types of mufflers or
silencers had to be discarded and a new one evolved.

"Jackson, I need some one to help me," said Tom to his chief
mechanician one day. "Haven't you a good man who is used to
experimental work that you can let me take from the works?"

"Why, yes," was the answer. "Let me see. Roberts is busy on the
new bomb you got up, but I could take him off that--"

"No, don't!" interposed Tom. "I want that work to go on. Isn't
there some one else you can let me have?"

"Well, there's a new man who came to me well recommended. I
took him on last week, and he's a wonderful mechanic. Knows a lot
about gas engines. I could let you have him--Bower his name is.
The only thing about it, though, is that I don't like to give you
a man of whom I am not dead certain, when you're working on a new

"Oh, that will be all right," said Tom. "There won't be any
secrets he can get, if you mean you think he might be up to spy

"That's what I did mean, Tom. You never can tell, you know, and
you have some bitter enemies."

"Yes, but I'll take care this man doesn't see the plans, or any
of my drawings. I only want some one to do the heavy assembling
work on the experimental muffler I'm getting up. We can let him
think it's for a new kind of automobile."

"Oh, then I guess it will be all right. I'll send Bower to

Tom rather liked the new workman, who seemed quiet and
efficient. He did not ask questions, either, about the machine on
which he was engaged, but did as he was told. As Tom had said, he
kept his plans and drawing under lock and key--in a safe to be
exact--and he did not think they were in any danger from his new

But Tom Swift held into altogether too slight regard the powers
of those who were opposed to him. He did not appreciate the
depths to which they would stoop to gain their ends.

He had been working hard on his new device, and had reached a
point further along than when the other motor had exploded. He
began to see success ahead of him, and he was jubilant. Whether
this made him careless does not matter, but the fact was that he
left Bower more to himself, and alone in the experimental shop
several times.

And it was on one of these occasions, when Tom had been for
some time in one of the other shops, where he and Jackson were in
consultation over a new machine, that as he came back to the test
room unexpectedly, he saw Bower move hastily away from in front
of the safe. Moreover, Tom was almost certain he had heard the
steel door clang shut as he approached the building.

And then, before he could ask his helper a question, Tom looked
from a window and saw a stranger running hastily along the side
of the building where his trial motor was being set up.

"Who's that? Who is that man? Did he come in here? Was he
tampering with my safe?" cried Tom. He saw Bower hesitate and
change color, and Tom knew it was time to act.

The window was open, and with one bound the young inventor was
out and running after the stranger he had seen departing in such
a hurry. The man was but a short distance ahead of him, and Tom
saw he was stuffing some papers into his pocket.

"Here! Come back! Stop!" ordered Tom, but the man ran on the

"That's a spy as sure as guns!" reflected Tom Swift. "And Bower
is in with him!" he added. "I've got to catch that fellow!" and
he speeded his pace as he ran after the fellow.


There was no question in the mind of Tom Swift but that the man
he was running after was guilty of some wrong-doing. In the first
place he was a stranger, and had no right inside the big fence
that surrounded the Swift machine plant. Then, too, the very fact
that he ran away was suspicious.

And this, coupled with the confusion on the part of Bower, and
his proximity to the safe, made Tom fear that some of his plans
had been stolen. These he was very anxious to recover if this
strange man had them, and so he raced after him with all speed.

"Stop! Stop!" called Tom, but the on-racing stranger did not

The cries of the young inventor soon attracted the attention of
his men, and Jackson and some of the others came running from
their various shops to give whatever aid was needed. But they
were all too far away to give effective chase.

"Bower might have come with me if he had wanted to help,"
thought Tom. But a backward glance over his shoulder did not show
that the new helper was engaging in the pursuit, and he could
have started almost on the same terms as Tom himself.

The runaway, looking back to see how near the young inventor
was to him, suddenly changed his course, and, noting this, Tom
Swift thought:

"I've got him now! He'll be bogged if he runs that way," for
the way led to a piece of swampy land that, after the recent
rains, was a veritable bog which was dangerous for cattle at
least; and more than one man had been caught there.

"He can't run across the swamp, that's sure," reflected Tom
with some satisfaction. "I'll get him all right!"

But he wanted to capture the man, if possible, before he
reached the bog, and, to this end, Tom increased his speed to
such good end that presently, on the firm ground that bordered
the swamp, Tom was almost within reaching distance of the

But the latter kept up running, and dodged and turned so that
Tom could not lay hands on him. Suddenly, turning around a clump
of trees the fleeing man headed straight for a veritable mud hole
that lay directly in his path. It was part of the swamp--the most
liquid part of the bog and a home of frogs and lizards.

Too late, the man, who was evidently unaware of the proximity
of the swamp, saw his danger. His further flight was cut off by
the mud hole, but it was too late to turn back. Tom Swift was at
his heels now, and seeing that it was impossible to grab the man,
Tom did the next best thing. He stuck out his foot and tripped
him, and tripped him right on the edge of the mud hole, so that
the man fell in with a big splash, the muddy water flying all
around, some even over the young inventor.

For a moment the man disappeared completely beneath the
surface, for the mud hole was rather deep just where Tom had
thrown him. Then there was another violent agitation of the
surface, and a very woebegone and muddy face was raised from the
slough, followed by the rest of the figure of the man. Slowly he
got to his feet, mud and water dripping from him. He cleared his
face by rubbing his hands over it, not that it made his
countenance clean, but it removed masses of mud from his eyes,
nose, and mouth, so that he could see and speak, though his first
operation was to gasp for breath.

"What--what are you doin'?" he demanded of Tom, and as the man
opened his mouth to speak Tom was aware of a glitter, which
disclosed the 'fact that the man had a large front tooth of gold.

"What am I doing?" repeated Tom. "I think it's up to you to
answer that question, not me. What are you doing?"

"You--you tripped me into this mud hole!" declared the man.

"I did, yes; because you were trespassing on my property, and
ran away instead of stopping when I told you to," went on Tom.
"Who are you and what are you doing? What were you doing with
Bower at my shop?"

"Nothin'! I wasn't doin' nothin'!"

"Well, we'll inquire into that. I want to see what you have in
your pockets before I believe you. Come on out!"

"You haven't any right to go through my pockets!" blustered the

"Oh, haven't I? Well, I'm going to take the right. Jackson--
Koku--just see that he doesn't get away. We'll take him back and
search him," and Tom motioned to his chief machinist and the
giant, who had reached the scene, to take charge of the man. But
Koku was sufficient for this purpose, and the mud-bespattered
stranger seemed to shrink as he saw the big creature approach
him. There was no question of running away after that.

"Bring him along," ordered Tom, and Koku, taking a tight grip
on the man by the slack of his garments behind, walked him along
toward the office, the mud and water splashing and oozing from
his shoes at every step.

"Now you look here!" the gold-toothed man cried, as he was
forced along, "you ain't got any right to detain me. I ain't done
nothin'!" And each time he spoke the bright tooth in his mouth
glittered in the sun.

"I don't know whether you've done anything or not," said Tom.
"I'm going to take you back and see what you and Bower have to
say. He may know something about this."

"If he does I don't believe he'll tell," said Jackson.

"Why not?" asked Tom, quickly.

"Because he's gone."

"Gone! Bower gone?"

"Yes," answered Jackson. "I saw him running out of the
experiment shop as we raced along to help you. I didn't think, at
the time, that he was doing more than go for aid, perhaps. But I
see the game now."

"Oh, you mean--him?" and Tom pointed to the dripping figure.

"Yes," said Jackson in a low voice, as Koku went on ahead with
his prisoner. "If, as you say, this man was in league with Bower,
the latter has smelled a rat and skipped. He has run away, and I
only hope he hasn't done any damage or got hold of any of your

"We'll soon know about that," said Tom. "I wonder who is at the
bottom of this?"

"Maybe those men you wouldn't work for," suggested the

"You mean Gale and Ware of the Universal Flying Machine


"Oh, I don't believe they'd stoop to any such measures as this-
-sending spies around," replied Tom. "But I can't be too careful.
We'll investigate."

The first result of the investigation was to disclose the fact
that Bower was gone. He had taken his few possessions and left
the Swift plant while Tom was racing after the stranger. A hasty
examination of the safe did not reveal anything missing, as Tom's
plans and papers were intact. But they showed evidences of having
been looked over, for they were out of the regular order in which
the young inventor kept them.

"I begin to see it," said Tom, musingly. "Bower must have
managed to open the safe while I was gone, and he must have made
a hasty copy of some of the drawings of the silent motor, and
passed them out of the window to this gold-tooth man, who tried
to make off with them. Did you find anything on him?" he asked,
as one of the men who had been instructed to search the stranger
came into the office just then.

"Not a thing, Mr. Swift! Not a thing!" was the answer. "We took
off every bit of his clothes and wrapped him in a blanket. He's
in the engine room getting dry now. But there isn't a thing in
any of his pockets."

"But I saw him stuffing some papers in as he ran away from me,"
said Tom. "We must be sure about this. And don't let the fellow
get away until I question him."

"Oh, he's safe enough," answered the man. "Koku is guarding
him. He won't get away."

"Then I'll have a look at his clothes," decided Tom. "He may
have a secret pocket."

But nothing like this was disclosed, and the most careful
search did not reveal anything incriminating in the man's

"He might have thrown away any papers Bower gave him," said
Tom. "Maybe they're at the bottom of the mud hole! If they're
there they're safe enough. But have a search made of the ground
where this man ran."

This was done, but without result. Some of the workmen even
dragged the mud hole without finding anything. Then Tom and his
father had a talk with the stranger, who refused to give his
name. The man was sullen and angry. He talked loudly about his
innocence and of "having the law on" Tom for having tripped him
into the mud.

"All right, if you want to make a complaint, go ahead," said
the young inventor. "I'll make one against you for trespass. Why
did you come on my grounds?"

"I was going to ask for work. I'm a. good machinist and I
wanted a job."

"How did you get in? Who admitted you at the gate?"

"I--I jest walked in," said the man, but Tom knew this could
not be true, as no strangers were admitted without a permit and
none had been issued. The man denied knowing anything about
Bower, but the latter's flight was evidence enough that something
was wrong.

Not wishing to go to the trouble of having the man arrested
merely as a trespasser, Tom let him go after his clothes had been
dried on a boiler in one of the shops.

"Take him to the gate, and tell him if he comes back he'll get
another dose of the same kind of medicine," ordered Tom to one of
the guards at the plant, and when the latter had reported that
this had been done, he added in an earnest tone:

"He went off talking to himself and saying he'd get even with
you, Mr. Swift."

"All right," said Tom easily. "I'll be on the watch."

The young inventor made a thorough examination of his
experiment shop and the test motor. No damage seemed to have been
done, and Tom began to think he had been too quick for the
conspirators, if such they were. His plans and drawings were
intact, and though Bower might have given a copy to the stranger
with the gold tooth, the latter did not take any away with him.
That he had some papers he wished to conceal and escape with,
seemed certain, but the splash into the mud hole had ended this.

No trace was found of Bower, and an effort Tom made to
ascertain if the man was a spy in the employ of Gale and Ware
came to naught. The machinist had come well recommended, and the
firm where he was last employed had nothing but good to say of

"Well, it's a mystery," decided Tom. "However, I got out of it
pretty well. Only if that gold-tooth individual shows up again he
won't get off so easily.


Taking a lesson from what had happened, Tom was very much more
careful in the following experiments on his new, silent motor. He
made some changes in his shop, and took Jackson in to help on the
new machine, thus insuring perfect secrecy as the apparatus

Tom also changed the safe in which he kept his plans, for the
one he had used previous to the episode in which Bower and the
stranger who took the mud bath figured, was one the combination
of which could easily be ascertained by an expert. The new safe
was more complicated, and Tom felt that his plans,
specifications, and formulae which he had worked out were in less

"I can just about figure out what happened," said Ned Newton to
Tom, when told of the circumstances. "These Universal people were
provoked because you wouldn't give them the benefit of your
experience on their flying machines, and so they sent a spy to
get work with you. They, perhaps, hoped to secure some of your
ideas for their own, or they may have had a deeper motive."

"What deeper motive could they have, Ned?" "They might have
hoped to disable you, or some of your machines, so that you
couldn't compete with them. They're unscrupulous, I hear, and
will do anything to succeed and make money. So be on your guard
against them."

"I will," Tom promised. "But I don't believe there's any more
danger now. Anyhow, I have to take some chances."

"Yes, but be as careful as you can. How is the silent motor
coming on?"

"Pretty good. I've had a lot of failures, and the thing isn't
so easy as I at first imagined it would be. Noise is a funny
thing, and I'm just beginning to understand some of the laws of
acoustics we learned at high school. But I think I'm on the right
track with the muffler and the cutting down of the noise of the
explosions in the cylinders. I'm working both ends, you see--
making a motor that doesn't cause as much racket as those now in
use, and also providing means to take care of the noise that is
made. It isn't possible to make a completely silent motor of an
explosive gas type. The only thing that can be done is to kill
the noise after it is made."

"What about the propeller blades?"

"Oh, they aren't giving me any trouble. The noise they make
can't be heard a hundred feet in the air, but I am also working
on improvements to the blades. Take it altogether, I'll have an
almost silent aeroplane if my plans come out all right."

"Have you said anything to the government yet?"

"No; I want to have it pretty well perfected before I do.
Besides, I don't want any publicity about it until I'm ready. If
these Universal people are after me I'll fool 'em."

"That's right, Tom! Well, I must go. Another week of this
Liberty Bond campaign!"

"I suppose you'll be glad when it's over."

"Well, I don't know," said Ned slowly. "It's part of my small
contribution to Uncle Sam. I'm not like you--I can't invent

"But you have an awful smooth line of talk, Ned!" laughed his
chum. "I believe you could sell chloride of sodium to some of the
fishes in the Great Salt Lake--that is if it has fishes."

"I don't know that it has, Tom. And, anyhow, I'm not posing as
a salt salesman," and Ned grinned. "But I must really go. Our
bank hasn't reached its quota in the sale of Liberty Bonds yet,
and it's up to me to see that it doesn't fall down."

"Go to it, Ned! And I'll get busy on my silent motor."

"Getting busy" was Tom Swift's favorite occupation, and when he
was working on a new idea, as was the case now, he was seldom
idle, night or day.

"I have hardly seen you for two weeks," Mary Nestor wrote him
one day. "Aren't you ever coming to see me any more, or take me
for a ride?"

"Yes," Tom wrote back. "I'll be over soon. And perhaps on the
next ride we take I won't have to shout at you through a speaking
tube because the motor makes so much noise."

From this it may be gathered that Tom was on the verge of
success. While not altogether satisfied with his progress, the
young inventor felt that he was on the right track. There were
certain changes that needed to be made in the apparatus he was
building--certain refinements that must be added, and when this
should be done Tom was pretty certain that he would have what
would prove to be a very quiet aeroplane, if not an absolutely
silent one.

The young inventor was engaged one day with some of the last
details of the experiment. The new motor, with the silencer and
the changed cylinders, had been attached to one of Tom's speedy
aeroplanes, and he was making some intricate calculations in
relation to a new cylinder block, to be used when he started to
make a completely new machine of the improved type.

Tom had set down on paper some computations regarding the
cross-section of one of the cylinders, and was working out the
amount of stress to which he could subject a shoulder strut, when
a shadow was cast across the drawing board he had propped up in
his lap.

In an instant Tom pulled a blank sheet over his mass of figures
and looked up, a sudden fear coming over him that another spy was
at hand. But a hearty voice reassured him.

"Bless my rice pudding!" cried Mr. Damon, "you shut yourself up
here, Tom, like a hermit in the mountains. Why don't you come out
and enjoy life?"

"Hello! Glad to see you!" cried Tom, joyfully. "You're just in

"Time for what--dinner?" asked the eccentric man, with a
chuckle. "If so, my reference to rice pudding was very proper."

"Why, yes, I imagine there must be a dinner in prospect
somewhere, Mr. Damon," said Tom with a smile. "We'll have to see
Mrs. Baggert about that. But what I meant was that you're just in
time to have a ride with me, if you want to go."

"Go where?"

"Oh, up in cloudland. I have just finished my first sample of a
silent motor, and I'm going to try it this evening. Would you
like to come along?"

"I would!" exclaimed Mr. Damon. "Bless my onion soup, Tom, but
I would! But why fly at night? Isn't it safer by daylight?"

"Oh, that doesn't make much difference. It's safe enough at any
time. The reason I'm going to make my first flight after dark is
that I don't want any spies about."

"Oh, I see! Are they camping on your trail?"

"Not exactly. But I can't tell where they may be. If I should
start out in daylight and be forced to make a landing-- Well, you
know what a crowd always collects to see a stranded airship."

"That's right, Tom."

"That decided me to start off after dark. Then if we have to
come down because of some sort of engine trouble or because my
new attachment doesn't work right, we sha'n't have any prying

"I see! Well, Tom, I'll go with you. Fortunately I didn't tell
my wife where I was going when I started out this afternoon, so
she won't worry until after it's over, and then it won't hurt
her. I'm ready any time you are."

"Good! Stay to dinner and I'll show you what I've made. Then
we'll take a flight after dark."

This suited the eccentric man, and a little later, after he had
eaten one of Mrs. Baggert's best meals, including rice pudding,
of which he was very fond, Mr. Damon accompanied Tom to one of
the big hangars where the new aeroplane had been set up.

"So that's the Air Scout, is it, Tom?" asked Mr. Damon, as he
viewed the machine.

"Yes, that's the girl. 'Air Scout' is as good a name as any,
until I see what she'll do."

"It doesn't look different from one of your regular craft of
the skies, Tom."

"No, she isn't. The main difference is here," and Tom showed
his friend where a peculiar apparatus had been attached to the
motor. This was the silencer--the whole secret of the invention,
so to speak.

To Mr. Damon it seemed to consist of an amazing collection of
pipes, valves, baffle-plates, chambers, cylinders and reducers,
which took the hot exhaust gases as they came from the motor and
"ate them up," as he expressed it.

"The cylinders, too, and the spark plugs are differently
arranged in the motor itself, if you could see them," said Tom to
his friend. "But the main work of cutting down the noise is done
right here," and he put his hand on the steel case attached to
the motor, the case containing the apparatus already briefly

"Well, I'm ready when you are, Tom," said Mr. Damon.

"We'll go as soon as it's dark," was the reply. "But first I'll
give you a demonstration. Start the motor, Jackson!" Tom called
to his chief helper.

Mr. Damon had ridden in aeroplanes before, and had stood near
when Tom started them; so he was prepared for a great rush of air
as the propellers whirled about, and for deafening explosions
from the engine.

The big blades, of new construction, were turned until the gas
in the cylinders was sufficiently compressed. Then Jackson
stepped back out of danger while Tom threw over the switch.

"Contact!" cried the young inventor.

Jackson gave the blades a quarter pull, and, a moment later, as
he leaped back out of the way, they began to revolve with the
swiftness of light. There was the familiar rush of air as the
wooden wings cut through the atmosphere, but there was scarcely
any noise. Mr. Damon could hardly believe his ears.

"I'm not running her at full speed," said Tom. "If I did she'd
tear loose from the holding blocks. But you can see what little
racket she makes."

"Bless my fountain pen!" cried Mr. Damon. "You are right, Tom
Swift! Why, I can hear you talk almost as easily as if no engine
were going. And I don't have to shout my head off, either."

This was perfectly true. Tom could converse with Mr. Damon in
almost ordinary tones. The exhaust from the motor was nearly
completely muffled.

"Out in the air it will seem even more quiet," said Tom. "I'll
soon give you a chance to verify that statement."

He ran the engine a little longer, the aeroplane quivering with
the vibrations, but remaining almost silent.

"I'm anxious to see what she'll do when in motion," said Tom,
as he shut off the gas and spark.

Soon after supper, when the shades of evening were falling, he
and Mr. Damon took their places in the first of the Air Scouts,
to give it the preliminary test in actual flying.

Would Tom's hopes be justified or would he be disappointed?


"All ready, Mr. Damon?" asked Tom, as he looked to see that all
the levers, wheels, valves, and other controls were in working
order on his Air Scout.

"As ready as I ever shall be, Tom," was the answer. "I don't
know why it is, but somehow I feel that something is going to
happen on this trip."

"Nonsense!" laughed Tom. "You're nervous; that's all."

"I suppose so. Don't think I'm going to back out, or anything
like that, but I wish it were successfully over with, Tom Swift,
I most certainly do."

"It will be in a little while," returned Tom, as he settled
himself comfortably in his seat and pulled the safety strap
tight. "You've gone up in this same plane before, when it didn't
have the silent motor aboard."

"Yes, I know I have. Oh, I dare say it will be all right, Tom.
And yet, somehow, I can't help feeling--"

But Tom Swift felt that the best way to set Mr. Damon's
premonitions to rest was to start the motor, and this he gave
orders to have done, Jackson and some others of the men from the
shops congregating about the craft to see the beginning of the
night flight. Mr. Swift was there also, and Eradicate. Mary
Nestor had been invited, but her Red Cross work engaged her that
evening, she said. Ned Newton was away from town on Liberty Bond
business, and he could not be present at the test.

However, as Tom expected to have other trials when his motor
was in even better shape, he was not exactly sorry for the
absence of his friends.

"Contact!" called the young inventor, when Jackson had stepped
back, indicating it was time to throw over the switch.

"Let her go!" cried Tom, and the next moment the motor was in
operation, but so silently that his voice and that of Mr. Damon's
could easily be heard above the machinery.

"Good, Tom! That's good!" cried Mr. Swift, and Tom easily heard
his father's voice, though under other, and ordinary,
circumstances this would have been impossible.

True, the hearing of Tom and Mr. Damon was muffled to a certain
extent by the heavy leather and fur-lined caps they wore. But Tom
had several small eyelet holes set into the flaps just over the
opening of the ears, and these holes were sufficient to admit
sounds, while keeping out most of the cold that obtains in the
upper regions.

The aeroplane moved swiftly along the level starting ground,
and away from the lighted hangars. Faster and faster it swung
along as Tom headed it into the wind, and then, as the speed of
the motor increased, the Air Scout suddenly left the earth and
went soaring aloft as she had done before.

But there was this difference. She moved almost as silently as
a great owl which swoops down out of the darkness--a bit of the
velvety blackness itself. Up and up, and onward and onward, went
the Air Scout. Tom Swift's improved, silent motor urged it
onward, and as the young inventor listened to catch the noise of
the machinery, his heart gave a bound of hope. For he could
detect only very slight sounds.

"She's a success!" exulted Tom to himself. "She's a success,
but she isn't perfect yet," he added. "I've got to make the
muffler bigger and put in more baffle-plates. Then I think I can
turn the trick."

He swung the machine out over the open country, and then, when
they were up at a height and sailing along easily, he called back
to Mr. Damon in the seat behind him:

"How do you like it?"

"Great!" exclaimed the eccentric man. "Bless my postage stamp,
but it's great! Why, there's hardly a sound, Tom, and I can hear
you quite easily."

"And I can hear you," added Tom. "I don't believe, down below
there," and he nodded toward the earth, though Mr. Damon could
not see this, as the airship, save for a tiny light over the
instrument board, was in darkness, "they know that we're flying
over their heads."

"I agree with you," was the answer. "Tom, my boy, I believe
you've solved the trick! You have produced a silent aeroplane,
and now it's up to the government to make use of it."

"I'm not quite ready for that yet," replied the young inventor.
"I have several improvements to make. But, when they are
finished, I'll let Uncle Sam know what I have. Then it's up to

"And you must be careful, Tom, that some of your rivals don't
hear of your success and get it away from you," warned Mr. Damon,
as Tom guided the Air Scout along the aerial way--an unlighted
and limitless path in the silent darkness.

"Oh, they'll have to get up pretty early in the morning to do
that!" boasted Tom, and afterward he was to recall those words
with a bit of chagrin.

On and on they sailed, and as Tom increased the speed of the
motor, and noted how silently it ran, he began to have high hopes
that he had builded better than he knew. For even with the motor
running at almost full speed there was not noise enough to hinder
talk between himself and Mr. Damon.

Of course there was some little sound. Even the most perfect
electric motor has a sort of hum which can be detected when one
is close to it. But at a little distance a great dynamo in
operation appears to be silence itself.

"I can go this one better, though," said Tom as he sailed along
in the night. "I see where I've made a few mistakes in the baffle
plate of the silencer. I'll correct that and--"

As he spoke the machine gave a lurch, and the motor, instead of
remaining silent, began to cough and splutter as in the former

"Bless my rubber boots, Tom! what's the matter?" cried Mr.

"Something's gone wrong," Tom answered, barely able to hear and
make himself heard above the sudden noise. "I'll have to shut off
the power and glide down. We can make a landing in this big
field," for just then the moon came out from behind a cloud, and
Tom saw, below them, a great meadow, not far from the home of
Mary Nestor. He had often landed in this same place.

"Something has broken in the muffler, I think, letting out some
of the exhaust," he said to Mr. Damon, for, now that the motor
was shut off, Tom could speak in his ordinary tones. "I'll soon
have it fixed, or, if I can't, we can go back in the old style--
with the machine making as much racket as it pleases."

So Tom guided the machine down. It went silently now, of
course, making, with the motor shut off, no more sound than a
falling leaf. Down to the soft, springy turf in the green meadow
Tom guided the machine. As it came to a stop, and he and Mr.
Damon got out, there was borne to their ears a wild cry:

"Help! Help!"


"DiD you hear that?" asked Tom Swift of his companion.

"Hear it? Bless my ear drums, I should say I did hear it! Some
one is in trouble, Tom. Caught in a bog, most likely, the same as
that spy chap who was at your place. That's it--caught in a bog!"

"There isn't any bog or swamp around here, Mr. Damon. If there
was I shouldn't have tried a landing. No, it's something else
besides that. Hark!"

Again the cry sounded, seeming to come from a point behind the
landing place of the silent airship. It was clear and distinct:

"Help! Help! They are--"

The voice seemed to die away in a gurgle, as though the
person's mouth had been covered quickly.

"He's sinking, Tom! He's sinking!" cried Mr. Damon. "I once
heard a man who almost drowned cry out, and it sounded exactly
like that!"

"But there isn't any water around here for any one to drown
in," declared Tom. "It's a big, dry meadow. I know where we are."

"Then what is it?"

"I don't know, but we're going to find out. Some one attacked
by some one else--or something, I should say," ventured the young

"Something! do you mean a wild beast, Tom?"

"No, for there aren't any of those here any more than there is
water. Though it may be that some farmer's bull or a savage dog
has got loose and has attacked some traveler. But, in that case I
think we would hear bellows or barks, and all I heard was a cry
for help."

"The same with me, Tom. Let's investigate;"

"That's what I intend doing. Come on. The airship will be all
right until we come back."

"Better take a light--hadn't you? It's dark, even if the moon
does show now and then," suggested Mr. Damon.

"Guess you are right," agreed Tom. Aboard his airship there
were several small but powerful portable electric lights, and
after securing one of these Tom and Mr. Damon started for the
spot whence the call for help had come. As they walked along,
their feet making no noise on the soft turf, they listened
intently for a repetition of the call for aid.

"I don't hear anything," said Tom, after a bit.

"Nor I," added Mr. Damon. "We don't know exactly which way to
go, Tom."

"That's right. Guess we'd better give him a hail; whoever it

Tom came to a halt, and raising his voice to a shout called:

"Hello there! What's the matter? We'll help you if you can tell
us which way to come!"

They both listened intently, but no voice answered them. At the
same time, however, they were aware of a sound as of hurrying
feet, and there seemed to be muttered imprecations not far away.
Tom and Mr. Damon looked in the direction of the sound, and the
young inventor flashed his light. But there was a clump of bushes
and trees at that point and the electrical rays did not penetrate
very far.

"Some one's over there!" exclaimed Tom in a whisper. "We'd
better go and see what it is."

"All right," agreed Mr. Damon, and he, too, spoke in a low

Why they did this when their previous talk had been in ordinary
tones, and when Tom had shouted so loudly, they did not stop to
reason about or explain just then. But later they both admitted
that they whispered because they thought there was something
wrong on foot--because they feared a crime was being committed
and they wanted to surprise the perpetrators if they could.

And it was this fact of their whispering that enabled the two
to hear something that, otherwise, they might not have heard. And
this was the sound of some vehicle hurrying away--an automobile,
if Tom was any judge. The cries for help had been succeeded by
stifled vocal sounds, and these, in turn, by the noise of wheels
on the ground.

"What does it all mean?" asked Mr. Damon in a whisper.

"I don't know," answered Tom, resolutely, "but we've got to
find out. Come on

They advanced toward the dark clump of trees and low bushes.
There was no need to be especially cautious in regard to being
silent, as their feet made little, if any, sound on the deep
grass. And, as Tom walked in advance, now and then flashing his
light, Mr. Damon suddenly caught him by the coat.

"What is it?" asked the young inventor.

"Look! Just over the top of that hill, where the moon shines.
Don't you see an automobile outlined?"

Tom looked quickly.

"I do," he answered. "There's a road from here, just the other
side of those trees, to that hill. The auto must have gone that
way. Well, there's no use in trying to follow it now. Whoever it
was has gotten away."

"But they may have left some one behind, Tom. We'd better look
in and around those trees."

"I suppose we had, but I don't believe we'll find anything. I
can pretty nearly guess, now, what it was."

"What?" asked Mr. Damon.

"Well, some chauffeur was out for a ride in his employer's car
without permission. He got here, had an accident--maybe some
friends he took for a ride were hurt and they called for help.
The chauffeur knew if there was any publicity he'd be blamed, and
so he got away as quickly as he could. Guess the accident--if
that's what it was--didn't amount to much, or they couldn't have
run the car off. We've had our trouble for our pains."

"Well, maybe you're right, Tom Swift, butt all the same, I'd
like to have a look among those trees," said Mr. Damon.

"Oh. we'll look, all right," assented Tom, "but I doubt if we
find anything."

And he was right. They walked in and about the little grove,
flashing the light at intervals, but beyond marks of auto wheels
in the dust of the road, which was near the clump of maples,
there was nothing to indicate what had happened.

"Though there was some sort of fracas," declared Tom. "Look
where the dust is trampled down. There were several men here,
perhaps skylarking, or perhaps it was a fight."

"Some one must have been hurt, or they wouldn't have cried for
help," said Mr. Damon.

"Well, that's so. But perhaps it was some one not used to
riding in autos, and he may have imagined the accident was worse
than it was, and called for help involuntarily. There is no
evidence of any serious accident having happened--no spots of
blood, at any rate," and Tom laughed at his own grimness. "It was
a new car, too, or at least one with new tires on."

"How do you know?" asked Mr. Damon.

"Tell by the plain marks of the rubber tread in the dust," was
the answer. "Look," and Tom pointed to the wheel marks in the
focus of his electric lamp. "It's a new tire, too, with square
protuberances on the tread instead of the usual diamond or round
ones. A new kind of tire, all right."

He and Mr. Damon remained for a few minutes looking about the
place whence had come the calls for help, and then the eccentric
man remarked:

"Well, as long as we can't do anything here, Tom, we might as
well travel on; what do you say?"

"I agree with you. There isn't any use in staying. We'll get
the Air Scout fixed up and travel back home. But this was
something queer," mused Tom. "I hope it doesn't turn out later
that a crime has been committed, and we didn't show enough
gumption to prevent it."

"We couldn't prevent it. We heard the cries as soon as we

"Yes, but if we had rushed over at once we might have caught
the fellows. But I guess it was only a slight accident, and some
one was more frightened than hurt. We'll have to let it go at

But the more he thought about it the more Tom Swift thought
there was something queer in that weird cry for help on the
lonely meadow in the darkness of the night.


The defect in the motor which had caused Tom Swift to shut off
the power and drift down to earth was soon remedied, once the
young inventor began an examination of the craft. One of the oil
feeds had become choked and this automatically cut down the
gasoline supply, causing one or more cylinders to miss. It was a
safety device Tom had installed to prevent the motor running dry,
and so being damaged.

Once the clogged oil feed was cleared the motor ran as before,
and just as silently, though, as Tom had said, he was not
entirely satisfied with the quietness, but intended to do further
work toward perfecting it.

"I'll start the propellers now, Mr. Damon," said Tom, when the
trouble had been remedied. "You know how to throw the switch,
don't you?"

"I guess so," was the answer. Mr. Damon and Tom had traveled so
often together in gasoline craft that the young inventor had
taught his friend certain fundamentals about them, and in an
emergency the eccentric man could help start an aeroplane. This
he now did, taking charge of the controls which could be operated
from his seat as well as from Tom's. Tom whirled the propellers,
and soon the motor was in motion.

Mr. Damon, once the big wooden blades were revolving, slowed
down the apparatus until Tom could jump aboard, after which the
latter took charge and soon speeded up the machine, sending it

As the green meadow, dimly seen in the light of the moon,
seemed to drop away below them, and the clump of trees vanished
from sight, both Tom and Mr. Damon wondered who it was that had
called for help, and if the matter were at all serious. They were
inclined to think it was not, but Tom could not rid himself of a
faint suspicion that there might have been trouble.

However, thoughts of his new silent Air Scout soon drove
everything else from his mind, and as he guided the comparatively
silent machine on its quiet way toward his own home he was
thinking how he could best improve the muffler.

"Well, here we are again, safe and sound," remarked Tom, as he
brought the craft to a stop in front of the hangar, and Jackson
and his helpers, who were awaiting the return, hurried out to
take charge.

"Yes, everything seems to point to success, Tom," agreed Mr.
Damon. "That is, unless the slight accident we had means

"Oh, no, that had nothing to do with the operation of the
silencer. But I'm going to do better yet. Some day I'll take you
for a ride in a silent machine which will make so little noise
that you can hear a pin drop."

"Well," remarked Mr. Damon' with a laugh, "I don't know that
listening to falling pins will give me any great amount of
pleasure, Tom, but I appreciate your meaning."

"Everything all right?" asked Mr. Swift, as he came out to hear
the details from his son. "Do you think you have solved the

"Not completely, but I'll soon be able to write Q. E. D. after
it. Some refinements are all that are needed, Dad."

"Glad to hear it. I was a bit anxious."

Mr. Swift questioned his son about the technical details of the
trip, asking how the motor had acted under the pressure caused by
so completely muffling the exhaust, and for some minutes the two
inventors, young and old, indulged in talk which was not at all
interesting to Mr. Damon. They went into the house, and Tom asked
to have a little lunch, which Mrs. Baggert set out for him.

"It's rather late to eat," said the young inventor, "but I
always feel hungry after I test a new machine and find that it
works pretty well. Will you join me in a sandwich or two, Mr.

"Why, bless my ketchup bottle, I believe I will."

And so they ate and talked. Tom was on the point of telling his
father something of the queer cry for help they had heard on the
lonely meadow when Mrs. Baggert produced a letter which she said
had come for Tom that afternoon, but had been mislaid by a new
maid who had been engaged to help with the housework.

"She took it to the shop after you had left, and only now told
me about it," explained Mrs. Baggert. "So I sent Eradicate for

"How long ago was that?" asked Tom, as he took the missive.

"Oh, an hour ago," answered Mrs. Baggert, with a smile. "But
don't blame poor Rad for that. He wanted to deliver the letter to
you personally, and so did Koku. The result was your giant kept
after Rad, trying to get the letter from him, and Rad kept
hiding and slinking about for a chance to see you himself until I
saw what was going on, a little while ago, and took the letter
myself. Else you might never have gotten it, so jealous are those
two," and Mrs. Baggert laughed.

"Guess it isn't of much importance," Tom said, as he tore open
the envelope. "It's from the Universal Flying Machine Company, of
New York, and I imagine they're trying to get me to reconsider my
refusal to link up with them."

"Yes," he went on, as he read the missive, "that's it. They've
raised the amount to thirty thousand a year now, Dad, and they
say they feel sure I shall regret it if I do not accept.

"This is a bit queer, though," went on the young inventor.
"This letter was written three days ago, but it reached Shopton
only to-day. And it says that unless they hear from me at once
they will have to take steps that will cause me great
inconvenience. They have nerve, at any rate, and impudence, too!
I won't even bother to answer. But I wonder what they mean, and
why this letter was delayed?"

"The mails are all late on account of the transportation
congestion caused by moving troops to the camps," said Mr. Damon.
"Some of my letters are delayed a week. But, as you say, Tom,
these fellows are very impudent to threaten that way."

"It's all bluff," declared Tom. "I'm not worrying. And now,
Dad, since I've almost reached the top of the hill with my Air
Scout, I may be able to help you on that new electric motor
you're puzzling over."

"I wish you would, Tom. I am trying to invent a new system of
interchangeable brush contacts, but so far I've been unable to
make them work. However, there is no great hurry about that. If
you are going to offer your silent machine to the government
finish that first. We need all the aircraft we can get. The
battles on the other side seem to be all in favor of the Germans,
so far."

"We haven't got into our stride yet," declared Mr. Damon. "Once
Uncle Sam gets the boys over there in force, there'll be a
different story to tell. I only wish--"

At that moment the telephone set up an insistent ringing,
breaking in on Mr. Damon's remarks.

"I'll answer," said Tom, as Mrs. Baggert moved toward the
instrument, which was an extension from the main one.

"Hello!" called the young inventor into the transmitter, and as
he received an answer a look of pleasure came over his face.

"Yes, Mary, this is Tom," he said. He remained silent a moment,
while it was evident he was listening to the voice at the other
end of the wire. Then he suddenly exclaimed:

"What's that? Tell him to come home? Why, he isn't here. I just
came in and--what--wait a minute!"

With a rather strange look on his face Tom covered the mouth-
piece of the instrument with his hand, and, turning to his
father, asked:

"Is Mr. Nestor here?"

"No," replied Mr. Swift slowly, "He was here, though. He came a
little while after you and Mr. Damon started off in the Air
Scout. But he didn't stay. Said he wanted to see you about
something and would call again."

"Oh," remarked the young man. "I didn't know he had been

"I meant to tell you," said Mrs. Baggert; "but getting the
lunch made me forget it, I guess."

Tom uncovered the transmitter of the telephone again, and spoke
to Mary Nestor.

"Hello," he said. "I was wrong, Mary. Your father was here, but
he left when he found I wasn't at home. How long ago? Wait a
minute and I'll inquire.

"How long ago did Mr. Nestor leave?" asked the young inventor
of the housekeeper. "Nearly an hour," he said into the
instrument, after he had received the answer. Then, after
listening a moment, he added: "Yes, I guess he'll be home soon
now. Probably stopped down town to see some of his friends. Yes,
Mr. Damon and I tried out the Air Scout. Yes, she worked pretty
well, for a starter, but there is something yet to be done. Oh,
yes, now I'll have time to come over to see you, and take you for
a ride too. We won't have to talk through a speaking tube,
either. Tell your father I am sorry I was out when he called.
I'll come to see him to-morrow, if he wants me to. Yes--yes. I
guess so!" and Tom laughed, it being evident that his remarks at
the end of the conversation had to do with personal matters.

"A telegram has come for Mr. Nestor and they were anxious that
he should get it," Tom explained to his little audience as he
hung up the receiver and put aside the telephone. "I wonder what
he wanted to see me about?"

"He didn't say," replied Mrs. Baggert.

Mr. Damon, Tom, and his father remained in conversation a
little while longer, and the eccentric man was thinking that it
was about time for him to return home, when the telephone rang

"Hello," answered Tom, as he was nearest the instrument. "Oh,
yes, Mary, this is he. What's that? Your father hasn't reached
home yet? And your mother is worried? Oh tell her there is no
cause for alarm. As I said, he probably stopped on his way to see
some friends."

Tom listened for perhaps half a minute to a talk that was
inaudible to the others in the room, and they noticed a grave
look come over his face. Then he said:

"I'll be right over, Mary. Yes, I'll come at once. And tell
your mother not to worry. I'm sure nothing could have happened.
I'll be with you in a jiffy!"

As Tom Swift hung up the receiver he said:

"Mr. Nestor hasn't reached home yet, and as he promised to
return at once in case he didn't find me, his wife is much
worried. I'll go over and see what I can do."

"I'll come along!" volunteered Mr. Damon. "It isn't late yet."

"Yes, do come," urged Tom. "But I suppose when we get there
we'll find our friend has arrived safely. We'll go over in the
electric runabout."


Tom Ssift's speedy little electric car was soon at the door in
readiness to take him and Mr. Damon to the Nestor home. The
electric runabout was a machine Tom had evolved in his early
inventive days, and though he had other automobiles, none was
quite so fast or so simple to run as this, which well merited the
name of the most rapid machine on the road. In it Tom had once
won a great race, as has been related in the book bearing the
title, "Tom Swift and His Electric Runabout."

"Mary didn't telephone again, did she?" Tom asked his father,
as he stopped at the house to get Mr. Damon, having gone out to
see about getting the electric runabout in readiness.

"No," was the answer. "The telephone hasn't rung since."

"Then, I guess, Mr. Nestor can't have arrived home," said Tom.
"It's a bit queer, his delay, but I'm sure it will be explained
naturally. Only Mary and her mother are alone and, very likely,
they're nervous. I'll telephone to let you know everything is all
right as soon as I get there," Tom promised his father and Mrs.
Baggert as he drove off down the road, partly illuminated by the
new moon.

Rapidly and almost as silently as his Air Scout Tom Swift drove
the speedy car down the highway. It was about three miles from
his home to that of Mary Nestor, and though the distance was
quickly covered, to Tom, at least, the space seemed interminable.
But at length he drove up to the door. There were lights in most
of the rooms, which was unusual at this time of night.

The sound of the wheels had not ceased echoing on the gravel of
the drive before Mary was out on the porch, which she illuminated
by an overhead light.

"Oh, Tom," she cried, "he hasn't come yet, and we are so
worried! Did you see anything of father as you came along?"

"No," was Tom's answer. "But we didn't look for him along the
road, as we came by the turnpike, and he wouldn't travel that
way. But he will be along at any moment now. You must remember
it's quite a walk from my house, and--"

"But he was on his bicycle," said Mary. "We wanted him to go in
the auto, but he said he wanted some exercise after supper, and
he went over on his wheel. He said he'd be right back, but he
hasn't come yet."

"Oh, he will!" said Tom reassuringly. "He may have had a
puncture, or something like that. Bicyclists are just as liable
to them as autoists," he added with a laugh.

"Well, I'm sure I hope it will be all right," sighed Mary. "I
wish you could convince mother to that effect. She's as nervous
as a cat. Come in and tell us what to do."

"Oh, he'll be all right," declared Mr. Damon, adding his
assurances to Tom's.

They found Mrs. Nestor verging on an attack of hysteria. Though
Mr. Nestor often went out during the evening, he seldom stayed

"And he said he'd be right back if he found you weren't at
home, Tom," said Mrs. Nestor. "I'm sure I don't know what can be
keeping him!"

"It's too soon to get worried yet," replied the young inventor
cheerfully. "I'll wait a little while, and then, if he doesn't
come, Mr. Damon and I will go back over the road and look
carefully. He may have had a slight fall--sprained his ankle or
something like that--and not be able to ride. We came by the
turnpike, a road he probably wouldn't take on his wheel. He's all
right, you may be sure of that."

Tom tried to speak reassuringly, but somehow, he did not
believe himself. He was beginning to think more and more how
strange it was that Mr. Nestor did not return home.

"We'll wait just a bit longer before setting out on a search,"
he told Mary and her mother. "But I'm sure he will be along any
minute now."

They went into the library, Mary and her mother, Tom and Mr.
Damon. And there they sat waiting. Tom tried to entertain Mary
and Mrs. Nestor with an account of his trial trip in the Air
Scout, but the two women scarcely heard what he said.

All sat watching the clock, and looking from that to the
telephone, which they tried to hope would ring momentarily and
transmit to them good news. Then they would listen for the sound
of footsteps or bicycle wheels on the gravel walk. But they heard
nothing, and as the seconds were ticked off on the clock the
nervousness of Mrs. Nestor increased, until she exclaimed:

"I can stand it no longer! We must notify the police--or do

"I wouldn't notify the police just yet," counseled Tom. "Mr.
Damon and I will start out and look along the road. If it should
happen, as will probably turn out to be the case, that Mr. Nestor
has met with only a simple accident, he would not like the
notoriety, or publicity, of having the police notified."

"No, I am sure he would not," agreed Mary. "Tom's way is best,

"All right, just as you say, only find my husband," and Mrs.
Nestor sighed, and turned her head away.

"Even if Mr. Nestor had had a fall," reasoned Tom, "he could
call for help, and get some one to telephone, unless--"

And as he reasoned thus Tom Swift gave a mental start at his
own use of the word "help."

That weird cry on the lonely meadow came back to him with
startling distinctness.

"Come on, Mr. Damon!" cried Tom, in a voice he tried to make
cheerful. "We'll find that Mr. Nestor is probably walking along,
carrying his disabled bicycle instead of having it carry him.
We'll soon have him safe back to you," he called to the two

"I wish I could go with you, and help search," observed Mary.

"Oh, I couldn't bear to be left alone!" exclaimed her mother.

"We'll telephone as soon as we find him," called Tom to Mrs.
Nestor, as he and Mr. Damon again got into the runabout and
started away from the place.

"What do you think of it, Tom?" asked the eccentric man, when
they were once more on the road.

"Why, nothing much--as yet," Tom said. "That is, I think
nothing more than a simple accident has happened, if, indeed, it
is anything more than that he has delayed to talk to some

"Would he delay this long?"

"I don't know."

"And then, Tom--bless my spectacles! what of that cry we heard?
Could that have been Mr. Nestor?"

There! It was out! The suspicion that Tom had been trying to
keep his mind away from came to the fore. Well, he might as well
race the issue now as later.

"I've been thinking of that," he told Mr. Damon. "It might have
been Mary's father calling for help."

"But we looked, Tom, near the trees, and couldn't discover
anything. If he had been calling for help--"

Mr. Damon did not finish.

"He may have fallen from his wheel and been hurt," said Tom, as
he turned the electric runabout into the highway that Mr. Nestor
would, most likely, have taken on his way from Shopton. "Then be
may have called for help, and some autoists, passing, may have
heard and taken him away."

"Yes, but where, Tom? Whoever called for help was taken away,
that's sure. But where?"

"To some hospital, I suppose."

"Then hadn't we better inquire there? There are only two
hospitals of any account around here. The one in Shopton and the
one in Waterfield. My wife is on the board of Lady Managers
there. We could call that hospital up and--"

"We'll look along the road first," said Tom. "If we begin to
make inquiries at the hospitals there will be a lot of questions
asked, and a general alarm may be sent out. Mr. Nestor wouldn't
like that, if he isn't in any danger. And it may turn out that he
has met an old friend, and has been talking with him all this
while, forgetting all about the passage of time."

They were now driving along the highway that led from the
little suburb where Mr. Nestor lived, to the main part of
Shopton, just beyond which was Tom's home. This section was
country-like, with very few houses and those placed at rather
infrequent intervals. The road was a good one, though not the
main-traveled one, and Mr. Nestor, as was known, frequently used
it when he rode his bicycle, an exercise of which he was very

As Tom and Mr. Damon drove along, they scanned, as best they
could in the light from the young moon and the powerful lamps on
the runabout, every part of the highway. They were looking for
some dark blot which might indicate where a man had fallen from
his wheel and was lying in some huddled heap on the road. But
they saw nothing like this, much to their relief.

"Do you know, Tom," said Mr. Damon, when they were nearing the
town, and their search, thus far, had been in vain, "I think
we're going at this the wrong way."

"Why, so?"

"Because Mr. Nestor may have fallen, and been hurt, and have
been carried into any one of a dozen houses along the road. In
that case we wouldn't see him. We've passed over the most lonely
part of the journey and haven't seen him. If the accident
occurred near the houses his cries would have brought some one
out to help him. He is well known around here, and, even if he
were unconscious and couldn't tell who he was, he could be
identified by papers in his pockets. Then his family would be
notified by telephone."

"Perhaps you are right, Mr. Damon. We may be wasting time this
way. What do you suggest?" asked Tom.

"That we don't delay any longer, but call up the hospitals at
once. If he isn't in either of those he must be in some house,
and in such condition that his identity cannot be established. In
that event it is a case for the police. We haven't found him, and
I think we had better give the alarm."

Tom Swift thought it over for a moment. Then he came to a
sudden decision.

"You're right!" he told Mr. Damon. "We mustn't waste any more
time. He isn't along the road he ought to have traveled in coming
from my house to his home--that's sure. But before I call up the
hospitals I want to try out one more idea."

"What's that, Tom?"

"I want to go to the place where we heard that cry for help."

"Do you think that could have been Mr.

"It may have been. We'll go and take another look around there.
Some man was evidently hurt there, and was taken away. We may get
a clew. The lights on the runabout will give us a better chance
to look around than we had by the little pocket lamp. We'll try
there, and, if we don't find anything, then I'll call up the


With the speedy runabout it did not take Tom Swift and Mr.
Damon long to reach the place where the Air Scout had been
grounded a few hours before, and where they had heard the cry for
help. All was as dark and as silent as when they had been there

But, as Tom had said, the lights from his electric runabout
would give a brilliant illumination, and these he now directed
toward the clump of trees whence the cry for help had seemed to

"Doesn't appear to have been visited by any one since we were
here," remarked Torn, as he observed the marks of the new
automobile tire in the dust. "Now we'll look about more

This they did, but they were about to give up in despair and
start for the nearest telephone to call up the hospitals, when
Mr. Damon gave an exclamation.

"What is it?" asked Tom.

"Something bright and shining!" said his companion. "I saw it
gleam in the light of the lamps. You nearly put your foot on it,
Tom. Just step back a moment."

Tom did so, and the eccentric man, with another exclamation,
this time of satisfaction, reached down and picked something up
from the dusty road.

"It's a watch!" he exclaimed. "A gold watch! And it's been
stepped on, evidently, or run over by an auto. Not much damaged,
but the case is a bit bent and scratched. It's stopped, too!" he
added as he held it to his ear.

"What time does it show?" asked Tom.

"Eight forty-seven," answered Mr. Damon, as he consulted the
dial. "Why, Tom, that was just about when we heard the cries for

"Yes, it must have been. Let me see that watch."

No sooner had the young inventor taken the timepiece into his
hands than he, too, uttered a cry of amazement.

"Do you recognize it?" asked Mr. Damon, in great excitement.

"It's Mr. Nestor's watch!" cried Tom. "He must have fallen
here, and been hurt. It was Mr. Nestor who cried for help, and
who was taken away by the autoists. They've probably taken him to
some hospital. There's been an accident all right."

Tom and Mr. Damon were of one mind now in thinking that Mr.
Nestor had met with some mishap on the road--an automobile
accident most likely--and that he was the person who had called
for help.

"If they had only answered when we hallooed at them," said Tom,
"we wouldn't be in all this stew now. We could have told the
strangers who came to his aid who he was, and we might even have
taken him to the hospital in the airship."

"Well, it's too late to think of that now," returned Mr. Damon.
"We had better get into communication with him as soon as we can,
and then send word to his wife and daughter. I hope he isn't
badly hurt."

Tom hoped so, too, with all his heart.

There was nothing to do but to get back in the runabout and
make all speed for the nearest telephone, and Tom Swift lost
little time in doing this. They found a drug store which was open
a little later than usual, and at once Tom went into the booth
and called up the Shopton hospital. He was well known there, as
he and his father were liberal supporters of the institution,
which was a private affair. Many of Tom's men were treated at the
dispensary, and, as accidents were of more or less frequent
occurrence at the works, the young inventor had frequent
occasions to call up the place.

"Mr. Nestor would ask to be taken there, as it's nearest his
home--that is, if he was able to speak," Tom said to Mr. Damon,
who agreed with him. There was a little delay in getting the
hospital on the wire, but when Tom had it, and was talking to the
superintendent, he was rather surprised, to tell the truth, to be
told that Mr. Nestor had not been brought in.

"We haven't had any accident cases all day, nor to-night, Mr.
Swift," the superintendent reported. "Was this some one special
you were inquiring about?"

For Tom, determining not to give Mr. Nestor's name, except as a
last resort, had merely inquired whether any recent accident
cases had been brought in.

"I'll let you know later, Mr. Millard," he told the
superintendent, not exactly answering the question. He hung up
the receiver, and, opening the door of the booth, said to Mr.
Damon: "He isn't there."

"Then try Waterfield," was the suggestion; and Tom did so,
though he could not imagine why an injured man, such as Mr.
Nestor might prove to be, should be taken as far as Waterfield,
when the hospital at Shopton was nearer.

"Unless," he told Mr. Damon, "the people which ran down Mary's
father didn't know about our hospital."

The reply from the institution in Mr. Damon's home town was
just as discouraging as had been the answer from Shopton. At
first, when Tom inquired, the head nurse had said there was an
accident case at that moment being brought in. Tom was all
excitement until she went to inquire the name and circumstances,
and then he learned that it was the case of a little boy who had
fallen downstairs at his home and broken a leg. There was no
record of any one answering the description of Mr. Nestor having
been brought in that evening.

"Hum! This is getting to be mysterious," mused Tom, as he came
out of the booth. "What shall we do--go back and tell Mrs. Nestor
and Mary, or communicate with the police?"

"Why not try the Alexian Hospital?" asked Mr. Damon. "That's
away over in Center-fiord, to be sure, but it's more likely to be
known to passing tourists than either of our institutions around
here, especially if the autoists were strangers."

"That's so," agreed Tom. The Alexian Hospital was operated
under the direction of the Brothers of that faith, and was well
known in that part of the state. Often cases of persons who had
been injured by passing automobiles had been taken there for
treatment, for, as Mr. Damon had said, it was well known, and
Centerford was the nearest large city.

"I can just about see how it happened," said Tom. "They ran Mr.
Nestor down, and stopped to pick him up after they heard his
cries for help. And the Alexian Hospital was the first one they
thought of. We should have called that up first."

But once more disappointment awaited the young inventor and his
friend. Word came back over the wire that no accident case, which
bore any resemblance to Mary's father, had been brought in.

"Well, I'm stumped!" exclaimed Tom. "What shall we do now, Mr.

"Much as I dislike it," said the eccentric man who was too much
worried, now, to do any "blessing," which was his favorite
expression, "I think we ought to communicate with Mrs. Nestor.
She will be very anxious."

"I guess we'll have to," said Tom. "But wait! I'll call up my
house first, and see if he has gone back there."

But Mr. Nestor had not done this, and Mrs. Baggert, who
answered the telephone, said Mary had been calling frantically
for Tom, as her mother was now on the verge of complete collapse.

"No help for it," said Tom, ruefully. "We've got to tell 'em we
have no news, and can't find him."

And, hearing this, Mrs. Nestor did collapse, and a doctor was
called in.

Thereupon Tom, who with Mr. Damon had gone back to the Nestor
home, took charge of matters, sending for Mrs. Nestor's sister to
come and stay with her and take charge of the house.

"You'll need some one to stay with you," he told Mary.

"Yes, I shall," she admitted, trying bravely not to give way to
her emotion. "Oh, Tom, I wish you could stay, too. I'm sure
something dreadful must have happened to poor father. Please stay
and help us find him!"

"I will," Tom promised. "As soon as your aunt comes I'll take
Mr. Damon home, and then I'll give the rest of my time to you."

And this Tom did, sending word home that he would remain at the
Nestor's all night and part of the next day.

Tom got but little sleep that night. He communicated with the
police and saw to it that a general alarm was sent out. He called
up all hospitals within a radius of fifty miles, but could get no
trace of any injured man whose description resembled that of Mr.

"What can have happened?" asked Mary tearfully.

"Well, the way I figure it out is this," said Tom. "Your father
left my house soon after Mr. Damon and I did in the Air Scout.
Mr. Nestor was riding his bicycle, and he must have been run into
by an automobile. That is how his watch was damaged and that was
when Mr. Damon and I heard the cries for help."

"Oh, do you think he was badly hurt?" asked Mary.

"No, I don't," and Tom answered truthfully. "The voice sounded
as though he was in pain, certainly, but it was strong and
vigorous, and not at all as though he was dangerously hurt."

"And what do you think happened to him after he was hurt?"
asked Mary.

"The autoists took him away," decided Tom. "In fact, we heard
the machine go, but of course we never connected the call for
help and what followed with your father. The autoists took him


"I should say to some hospital. Perhaps a private one of which
we know nothing, and which may be near here. I'll get a full list
from the Board of Health to-morrow. Or it may be that the
autoists, seeing the damage they had done, took your father to
the home of one of themselves, and summoned a doctor there."

"Why would they do that?"

"Well, they may have been so frightened they didn't realize
what they were doing, or they may have thought he would get
better treatment in a private house, if he were not badly
injured, than if he should be taken to a hospital. It may have
been that one of the persons in the auto was a physician, and
wished to try his own skill on the man he had hurt."

"You make me feel more comfortable, Tom," said Mary. "But, even
supposing all this, why couldn't they telephone to us that my
father was all right? He always carries an identification card
with him, and if he were unconscious it could be ascertained who
he was."

"That's what I can't understand," said Tom frankly. "It puzzles
me. But we'll find him--never fear!"

And so he kept on with his telephone inquiries, while a
physician and her sister ministered to Mrs. Nestor. The night was
very, very long, and no good news came in.


Slowly the dawn broke through the mists of darkness, and made
the earth light. The sun came straggling in through cracks in the
shutters in the home of Mr. Nestor, the gradually increasing
gleam paling the electric lights, in the glare of which Tom
Swift, Mary, and her aunt sat, waiting for some word of the
missing man. But none came.

"What shall we do now?" asked Mary, as she looked at Tom.

"Oh, there's lots to do," he said, trying to make his voice
sound cheerful. "We'll be busy all day. I sent word to have one
of my touring cars ready to hurry to any part of the country the
moment we should get word from your father."

"And do you think we shall get word, Tom?" the girl went on

"Of course we shall!" he cried. "Word may come in at any time.
Now get ready, eat a good breakfast, and then you can go with me
as soon as we hear anything definite. Come, we'll have

"I can't eat a thing!" protested Mary.

"Oh, yes you can," said her aunt, who was a cheerful sort of
person. "I'll see about getting something for you and Mr. Swift,
and see that your mother is all right."

She left the room to give orders to the servant about the meal,
and returned to say that Mrs. Nestor was sleeping quietly. She
had been given a sedative. Mary managed to eat a little, and she
gave Tom the address of several friends who were called up in the
vain hope that, somehow, Mr. Nestor might have gone to see them.

"Tom, what do you really think has happened?" asked Mary again,
as they sat facing one another in the library, during a respite
from the telephone.

Tom Swift repeated, to the girl his theory of what had happened
with an assumption of confidence he did not altogether feel.

His prediction of a speedy end to the suspense did not come
true that day, nor for many days. No news was heard of Mr.
Nestor. After the first day, when there was no information and
when no reports came of any one of his description having been
hurt in an automobile accident or having been taken to any
hospital, the police started an energetic search.

The authorities in all near-by cities were notified, and all
thought of keeping from the public what had happened was given
over. Tom's story, of how he and Mr. Damon had heard the cry for
help on the lonely meadow, was printed in the papers, though the
young inventor did not say that he had been out trying his new
aeroplane. That was a detail not needed in the finding of Mr.

But Mary's father was not found. The mystery regarding his
disappearance deepened, and there was no trace of him after he
had left Tom's house that eventful evening. Persons living along
the roads he might have taken in riding his bicycle were
questioned, but they had seen nothing of him, nor were they aware
of any accident. Tom's testimony and that of Mr. Damon was all
the clew there was.

"I don't believe he's dead!" stoutly declared the young
inventor, when this dire possibility had been hinted at. "I
believe the persons who were responsible for the accident are
afraid to reveal his whereabouts until he recovers from possible
injuries. You'll see! Mr. Nestor will come back safe!"

And, somehow, though her mother was skeptical, Mary believed
what Tom said.

The search was kept up, but without result, and Tom aided all
he could. But there was not much he could do. The police and
other authorities were at a total loss.

In the intervals of visiting Mary and her mother, and doing
what he could for them, Tom worked on his new motor. He knew that
he was on the right track and that all that was needed now was to
make certain refinements and adjustments in the apparatus he had
already constructed, so that it would operate more quietly.

"Absorbing the vibrations from the exhaust, caused by the
exploded gases in the cylinders, does the trick," Tom told his

"But there is enormous pressure to overcome, Tom. You must be
sure your muffler will stand the strain. Otherwise she is going
to blow out a gasket some day, when you least expect it. Then the
sudden resumption of pressure outside the cylinders is going to
cause a change in the equilibrium, and you may turn turtle in the

"I've thought of that," said Tom. "At worst it can't be any
more than looping the loop. But I'll make the muffler doubly

"Better provide an auxiliary chamber to take care of part of
the exhaust in case your main apparatus breaks," advised the
older inventor, and Tom said he would. He did, too, for he valued
his father's expert advice.

Meanwhile he was busy fitting one of his latest aeroplanes with
the new motor. The motor he and Mr. Damon had used in their
flight was one patched up from an old one. But now Tom was
working on a complete new one, made after his revised model, and
in which the silencer was an integral part, instead of being
built on.

While giving Mary and her mother all the assistance in his
power, Tom still found time to work on his new, pet scheme. He
had matters now where he did not fear any tampering with his
plans, for he had filed away his papers in a safe place, and was
making his new machine from memory.

"But if some one got in and had a look at the inside of your
silencer he could see how it is constructed, couldn't he?" asked
Ned Newton.

"Yes," assented Tom, "But they're not going to get in very
easily. Koku sleeps in the experiment shop now, and my machine is

"Oh, well that explains your confidence. I feel sorry for the
burglar who makes the attempt, once Koku wakes up. Heard anything
more from those Universal people?"

"No, not directly. I understand they are working hard on some
new type of plane for army use, but I haven't bothered my head
about them. I'm too much occupied with my own affairs and trying
to help Mary."

"Very strange about Mr. Nestor, isn't it?"

"Worse than strange," said Tom. "If this keeps on, and he isn't
heard from, it will be tragic pretty soon."

"He must be held a prisoner somewhere," declared Ned.

"It begins to look that way," assented Tom. "Though who would
have an object in that I can't understand. He had no enemies, as
far as is known, and his business affairs were in excellent
shape. Unless, as I said, the persons who ran him down are,
through fear, keeping him hidden until he recovers, I can't
imagine what has become of him."

"Well, it certainly is a puzzle," said Ned. And Tom agreed with
his chum.

It was about a week after the disappearance of Mr. Nestor that
Mr. Damon came over to see Tom.

"Bless my shoe laces, Tom!" exclaimed the eccentric man, "but
you are as busy as ever." For he found the young inventor in the
experiment shop, surrounded by a mass of papers and all sorts of
mechanical devices.

"Yes, I'm working a little," said Tom. "But you are just in
time. Come on out, I want to introduce you to Silent Sam."

"'Silent Sam!'" exclaimed Mr. Damon. "Have you been taking a
new trip to the Land of Wonders? Have you brought back some new
kind of servant?"

"Not exactly a servant," said Tom with a laugh, "though I hope
Silent Sam will serve me well."

"'Silent Sam?' What does it mean? Is that a joke?" asked the
puzzled Mr. Damon.

"I hope it doesn't turn out a joke," replied Tom. "But come on,
I'll introduce you to him, Mr. Damon."

He led the way to one of the big hangars where his various
machines of the air were housed. On the way Mr. Damon asked about
news of Mr. Nestor, but was told there was none.

Tom Swift opened the big, swinging doors and pulled aside an
enveloping canvas curtain. There stood revealed a big aeroplane,
of somewhat new pattern, the wings gleaming like silver from the
varnish that had been applied. In shape it was not unlike the
machines already in use, except that the propellers were of
somewhat different design.

The engine was mounted in front, and even with his slight
knowledge of mechanics Mr. Damon could tell that it was
exceedingly powerful. But it was certain devices attached to the
engine that attracted his attention, for they were totally
different from any on any other aeroplane, though they bore some
resemblance to apparatus on the plane in which Tom and the
eccentric man had made the night flight.

"Is this your new machine, Tom?" asked Mr. Damon.


"Well, I don't see anything of that fellow you spoke of--Silent

"This is Silent Sam," returned Tom, with a laugh. "I've named
my new noiseless aeroplane -Ämy Air Scout--I've named that Silent
Sam. Wait until you hear it, or rather, don't hear it, and I
think you'll agree with me. Silent Sam for Uncle Sam!"

"Good!" cried Mr. Damon. "Bless my dictionary, but that's a
good name! Does it sail silently, Tom?"

"I'll let you judge presently. Silent Sam is all ready for his
first trial, and I'll be glad to have you with me. Now, I'll

Tom suddenly ceased speaking and held up a hand to enjoin
silence. Then, while Mr. Damon watched, the young inventor began
moving noiselessly toward the rear of the big shed, inside which
was his new machine.


"Who's there?" suddenly called Tom, and in such a sharp voice
that Mr. Damon started, ready as he was for something unusual.

There was no answer and Tom suddenly switched on all the lights
in the shed. Up to then there had been only a few glowing--just
enough for him to show the new Air Scout to his friend.

"Who's there?" asked Tom again, sharply.

"Bless my opera glasses, Tom!" cried Mr. Damon, "but are you
seeing things?"

"No; but I'm hearing them," answered Tom with a short laugh.


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