TESTING THE WALLER GUN
Tom looked at Ned in dismay. After all their work and planning, to be
thus thwarted, and by a mere technicality! As they stood there, hardly
knowing what to do, the sound of a tremendous explosion came to their
ears from behind the big pile of earth and concrete that formed the
bomb-proof around the testing ground.
"What's that?" cried Ned, as the earth shook.
"Just trying some of the big guns," explained the sentry, who was not a
bad-natured chap. He had to do his duty. "You'd better move on," he
suggested. "If anything happens the government isn't responsible, you
know."
"I wish there was some way of getting in there," murmured Tom.
"You can see General Waller after the test, and he will probably
countersign the permit," explained the sentry.
"And we won't see the test of the gun I'm most interested in," objected
Tom. "If I could only--"
He stopped as he noticed the sentry salute someone coming up from the
rear. Tom and Ned turned to behold a pleasant-faced officer, who, at
the sight of the young inventor, exclaimed:
"Well, well! If it isn't my old friend Tom Swift! So you got here on my
permit after all?"
"Yes, Captain Badger," replied the lad, and then with a rueful face he
added: "But it doesn't seem to be doing me much good. I can't get into
the proving grounds."
"You can't? Why not?" and he looked sharply at the sentry.
"Very sorry, sir," spoke the man on guard, "but General Waller has left
orders, Captain Badger, that no outsiders can enter the proving grounds
when his new gun is being tested unless he countersigns the permits.
And he's engaged just now. I'm sorry, but--"
"Oh, that's all right, Flynn," said Captain Badger. "It isn't your
fault, of course. I suppose there is no rule against my going in
there?" and he smiled.
"Certainly not, sir. Any officer may go in," and the guard stepped to
one side.
"Let me have that pass, Tom, and wait here for me," said the Captain.
"I'll see what I can do for you," and the young officer, whose
acquaintance Tom had made at the tests when the government was
purchasing some aeroplanes for the army, hurried off.
He came back presently, and by his face the lads knew he had been
successful.
"It's all right," he said with a smile. "General Waller countersigned
the pass without even looking at it. He's so excited over the coming
test of his gun that he hardly knows what he is doing. Come on in,
boys. I'll go with you."
"Then they haven't tested his gun yet?" Asked Tom, eagerly, anxious to
know whether he had missed anything.
"No, they're going to do so in about half an hour. You'll have time to
look around a bit. Come on," and showing the sentinel the
counter-signed pass, Captain Badger led the two youths into the proving
grounds.
Tom and Ned saw so much to interest them that they did not know at
which to look first. In some places officers and firing squads were
testing small-calibre machine guns, which shot off a round with a noise
like a string of firecrackers on the Chinese New Year's. On other
barbettes larger guns were being tested, the noise being almost
deafening.
"Stand on your tiptoes, and open your mouth when you see a big cannon
about to be fired," advised Captain Badger, as he walked alongside the
boys.
"What good does that do?" inquired Ned.
"It makes your contact with the earth as small as possible--standing on
your toes," the officer explained, "and so reduces the tremor. Opening
your mouth, in a measure, equalizes the changed air pressure, caused by
the vacuum made when the powder explodes. In other words, you get the
same sort of pressure down inside your throat, and in the tubes leading
to the ear--the same pressure inside, as outside.
"Often the firing of big guns will burst the ear drums of the officers
near the cannon, and this may often be prevented by opening the mouth.
It's just like going through a deep tunnel, or sometimes when an
elevator descends quickly from a great height. There is too much
outside air pressure on the ear drums. By opening your mouth and
swallowing rapidly, the pressure is nearly equaled, and you feel no
discomfort."
The boys tried this when the next big gun was fired, and they found it
true. They noticed quite a crowd of officers and men about a certain
large barbette, and Captain Badger led them in that direction.
"Is that General Waller's gun?" asked Tom.
"That's where they are going to test it," was the answer.
Eagerly Tom and Ned pressed forward. No one of the many officers and
soldiers grouped about the new cannon seemed to notice them. A tall
man, who seemed very nervous and excited, was hurrying here and there,
giving orders rapidly.
"How is that range now?" he asked. "Let me take a look! Are you sure
the patrol vessels are far enough out? I think this projectile is going
farther than any of you gentlemen have calculated."
"I believe we have correctly estimated the distance," answered someone,
and the two entered into a discussion.
"That excited officer is General Waller," explained Captain Badger, in
a low voice, to Tom and Ned.
"I guessed as much," replied the young inventor. Then he went closer to
get a better look at the big cannon.
I say big cannon, and yet it was not the largest the government had. In
fact, Tom estimated the calibre to be less than twelve inches, but the
cannon was very long--much longer in proportion than guns of greater
muzzle diameter. Then, too, the breech, or rear part, was very thick
and heavy.
"He must be going to use a tremendous lot of powder," said Tom.
"He is," answered Captain Badger. "Some of us think he is going to use
too much, but he says it is impossible to burst his gun. He wants to
make a long-range record shot, and maybe he will."
"That's a new kind of breech block," commented Tom, as he watched the
mechanism being operated.
"Yes, that's General Waller's patent, too. They're going to fire soon."
I might explain, briefly, for the benefit of you boys who have never
seen a big, modern cannon, that it consists of a central core of cast
steel. This is rifled, just as a small rifle is bored, with twisted
grooves throughout its length. The grooves, or rifling, impart a
twisting motion to the projectiles, and keep them in a straighter line.
After the central core is made and rifled, thick jackets of steel are
"shrunk" on over the rear part of the gun. Sometimes several jackets
are put on, one over the other, to make the gun stronger.
If you have ever seen a blacksmith put a tire on a wheel you will
understand what I mean. The tire is heated, and this expands it, or
makes it larger. It is put on hot, and when it cools it shrinks,
getting smaller, and gripping the rim of the wheel in a strong embrace.
That is what the jackets of steel do to the big guns.
A big rifled cannon is loaded from the rear, or breech, just as is a
breech-loading shotgun or rifle. That is, the cannon is opened at the
back and the projectile is put in by means of a derrick, for often the
projectiles weigh a thousand pounds or more. Next comes the
powder--hundreds of pounds of it--and then it is necessary to close the
breech.
The breech block does this. That block is a ponderous piece of steel,
quite complicated, and it swings on a hinge fastened to one side of the
rear of the gun. Once it is swung back into place, it is made fast by
means of screw threads, wedges or in whatever way the inventor of the
gun deems best.
The breech block must be very strong, and held firmly in place, or the
terrific force of the powder would blow it out, wreck the gun and kill
those behind it. You see, the breech block really stands a great part
of the strain. The powder is between it and the projectile, and there
is a sort of warfare to see which will give way--the projectile or the
block. In most cases the projectile gracefully bows, so to speak, and
skips out of the muzzle of the gun, though sometimes the big breech
block will be shattered.
With eager eyes Tom and Ned watched the preparations for firing the big
gun. The charge of powder was hoisted out of the bomb-proof chamber
below the barbette, and then the great projectile was brought up in
slings. At the sight of that Tom realized that the gun was no ordinary
one, for the great piece of steel was nearly three feet long, and must
have weighed nearly a thousand pounds. Truly, much powder would be
needed to send that on its way.
"I'm afraid, General, that you are using too much of that strong
powder," Tom heard one officer say to the inventor of the gun. "It may
burst the breech."
"Nonsense, Colonel Washburn. I tell you it is impossible to burst my
gun--impossible, sir! I have allowed for every emergency, and
calculated every strain. I have a margin of safety equal to fifty per
cent."
"Very well, I hope it proves a success."
"Of course it will. It is impossible to burst my gun! Now, are we ready
for the test."
The gun was rather crude in form, not having received its final polish,
and it was mounted on a temporary carriage. But even with that Tom
could see that it was a wonderful weapon, though he thought he would
have put on another jacket toward the muzzle, to further strengthen
that portion.
"I'm going to make a gun bigger than that," said Tom to Ned. He spoke
rather louder than he intended, and, as it was at a moment when there
was a period of silence, the words carried to General Waller, who was
at that moment near Tom.
"What's that?" inquired the rather fiery-tempered officer, as he looked
sharply at our hero.
"I said I was going to make a larger gun than that," repeated Tom,
modestly.
"Sir! Do you know what you are saying? How did you come in here,
anyhow? I thought no civilians were to be admitted today! Explain how
you got here!"
Tom felt an angry flush mounting to his cheeks.
"I came in here on a pass countersigned by you," he replied.
"A pass countersigned by me? Let me see it."
Tom passed it over.
"Humph, it doesn't seem to be forged," went on the pompous officer.
"Who are you, anyhow?"
"Tom Swift."
"Hum!"
"General Waller, permit me to introduce Tom Swift to you," spoke
Captain Badger, stepping forward, and trying not to smile. "He is one
of our foremost inventors. It is his type of monoplane that the
government has adopted for the coming maneuvers at Panama, you may
recall, and he was very helpful to Uncle Sam in stopping that swindling
on the border last year--Tom and his big searchlight. Mr. Swift,
General Waller," and Captain Badger bowed as he completed the
introduction.
"What's that. Tom Swift here? Let me meet him!" exclaimed an elderly
officer coming through the crowd. The others parted to make way for
him, as he seemed to be a person of some importance, to judge by his
uniform, and the medals he wore.
"Tom Swift here!" he went on. "I want to shake hands with you, Tom! I
haven't seen you since I negotiated with you for the purchase of those
submarines you invented, and which have done such splendid service for
the government. Tom, I'm glad to see you here today."
The face of General Waller was a study in blank amazement.