Tom Swift and His Giant Cannon Part 14

"Now you can go, Rad," announced Tom, when they reached the lonely field where, pointing toward a big hill, was the little cannon.

"Good, Ma.s.sa Tom!" cried the colored man, and from the way in which he hurried off no one would ever suspect him of having rheumatic joints.

"Say, that stuff looks just like Swiss cheese," remarked Ned, as Tom opened the box of explosive. It would be incorrect to call it powder, for it had no more the appearance of gunpowder, or any other "powder,"

than, as Ned said, swiss cheese.

And, indeed, the powerful stuff bore a decided resemblance to that peculiar product of the dairy. It was in thin sheets, with holes pierced through it here and there, irregularly.

"The idea is," Tom explained, "to make a quick-burning explosive. I want the concussion to be scattered through it all at once. It is set off by concussion, you see," he went on. "A sort of cartridge is buried in the middle of it, after it has been inserted in the cannon breech.

The cartridge is exploded by a primer, which responds to an electric current. The thin plates, with holes corresponding to the centre hole in a big grain of the hexagonal powder, will, I hope, cause the stuff to burn quickly, and give a tremendous pressure. Now we'll put some in the steel tube, and see what happens."

Even Tom was a little nervous as he prepared for this latest test. But he was not nervous enough to drop any of those queer, cheese-like slabs. For, though he knew that a considerable percussion was needed to set them off, it would not do to take chances. High explosives do not always act alike, even under the same given conditions. What might with perfect safety be done at one time, could not be repeated at another.

Tom knew this, and was very careful.

The powder, as I shall occasionally call it for the sake of convenience, though it was not such in the strict sense of the word--the powder was put in the small cannon, together with the primer.

Then the wires were attached to it, and extended off for some distance.

"But we won't attach the battery until the last moment," Tom said. "I don't want a premature explosion."

The projectile was also put in, and Tom once more looked to see that the armor plate was in place. Then he adjusted the various gauges to get readings of the power and energy created by his new explosive.

"Well, I guess we're all ready," he announced to his friends. "I'll hook on the battery now, and we'll get off behind that other hill. I had Koku make a sort of cave there--a miniature bomb-proof, that will shelter us."

"Do you think the blast will be powerful enough to make it necessary?"

asked Mr. Damon.

"It will, if this larger quant.i.ty of explosive acts anything like the small samples I set off," replied the young inventor.

The electric wires were carried behind the protecting hill, whither they all retired.

"Here she goes!" exclaimed Tom, after a pause.

His thumb pressed the electric b.u.t.ton, and instantly the ground shook with the tremor of a mighty blast, while a deafening sound reared about them. The earth trembled, and there was a big sheet of flame, seen even in the powerful sunlight.

"Something happened, anyhow!" yelled Tom above the reverberating echoes.

CHAPTER XIII

CASTING THE CANNON

"Come on!" yelled Ned. "We'll see how this experiment came out!" and he started to run from beneath the shelter of the hill.

"Hold on!" shouted Tom, laying a restraining hand on his chum's shoulder.

"Why, what's the matter?" asked Ned in surprise.

"Some of that powder may not have exploded," went on the young inventor. "From the sound made I should say the gun burst, and, if it did, that gelatin is bound to be scattered about. There may be a ma.s.s of it burning loose somewhere, and it may go off. It ought not to, if my theory about it being harmless in the open is correct, but the trouble is that it's only a theory. Wait a few seconds."

Anxiously they lingered, the echoes of the blast still in their ears, and a peculiar smell in their nostrils.

"But there's no smoke," said Mr. Damon. "Bless my spygla.s.s! I always thought there was smoke at an explosion."

"This is a sort of smokeless powder," explained Tom. "It throws off a slight vapor when it is ignited, but not much. I guess it's safe to go out now. Come on!"

He dropped the pushb.u.t.ton connected with the igniting battery, and, followed by the others, raced to the scene of the experiment. A curious sight met their eyes.

A great hole had been torn in the hillside, and another where the improvised gun had stood. The gun itself seemed to have disappeared.

"Why--why--where is it?" asked Ned.

"Burst to pieces I guess," replied Tom. "I was afraid that charge was a bit too heavy."

"No, here it is!" shouted Mr. Damon, circling off to one side. "It's been torn from the carriage, and partly buried in the ground," and he indicated a third excavation in the earth.

It was as he had said. The terrific blast had sheared the gun from its temporary carriage, thrown it into the air, and it had come down to bury itself in the soft ground. The carriage had torn loose from the concrete base, and was tossed off in another direction.

"Is the gun shattered?" asked Tom, anxious to know how the weapon had fared. It was, in a sense, a sort of small model of the giant cannon he intended to have cast.

"The breech is cracked a little," answered Mr. Damon, who was examining it; "but otherwise it doesn't seem to be much damaged."

"Good," cried Tom. "Another steel jacket will remedy that defect. I guess I'm on the right road at last. But now to see what became of that armor plate."

"Dinner plate not here," spoke Koku, who could not understand how there could be two kind of plates in the world. "Dinner plate gone, but big hole here, and he indicated one in the side of the hill.

"I expect that is where the armor plate is," said Tom, trying not to laugh at the mistake of his giant servant. "Take a look in there, Koku, and, if you can get hold of it, pull it out for us. I'm afraid the piece of nickel-steel armor proved too much for my projectile. But we'll have a look."

Koku disappeared into the miniature cave that had been torn in the side of the bill. It was barely large enough to allow him to go in. But Tom knew none other of them could hope to loosen the piece of steel, imbedded as it must be in the solid earth.

Presently they heard Koku grunting and groaning. He seemed to be having quite a struggle.

"Can you get it, Koku?" asked Tom. "Or shall I send for picks and shovels."

"Me get, Master," was the m.u.f.fled answer.

Then came a shout, as though in anger Koku had dared the buried plate to defy him. There was a shower of earth at the mouth of the cave, and the giant staggered out with the heavy piece of armor plate. At the sight of it Tom uttered a cry.

"Look!" he shouted. "My projectile went part way through and then carried the plate with it into the side of the hill. Talk about a powerful explosive! I've struck it, all right!"

It was as he had said. The projectile, driven with almost irresistible force, had bitten its way through the armor plate, but a projection at the base of the sh.e.l.l had prevented it from completely pa.s.sing through.

Then, with the energy almost unabated, the projectile had torn the plate loose and hurled it, together with its own body, into the solid earth of the hillside. There, as Koku held them up, they could all see the sh.e.l.l imbedded in the plate, the point sticking out on the other side, as a boy might spear an apple with a sharp stick.

"Bless my spectacle case!" cried Mr. Damon. "This is the greatest ever!"

"It sure is," agreed Ned. "Tom, my boy, I guess you can now make the longest shots on record."