Thirty miles, Ned! Think of that! A two-ton projectile being shot thirty miles!"
"It"s great, Tom!" yelled his chum, clapping him on the back, and capering about. "It"s the longest shot on record."
"It certainly is," declared the foreman of the steel workers, who had helped in casting many big guns. "No cannon ever made can equal it. You win, Tom Swift!"
"Bless my armor plate!" gasped Mr. Damon. "What attacking ship against the Panama Ca.n.a.l could float after a shot like that."
"Not one," declared Tom; "especially after I put a bursting charge into the projectile. We"ll try that next."
By means of compressed air the gases and some particles of the unexploded powder were blown out of the big cannon. Then it was loaded again, the projectile this time carrying a bursting charge of another explosive that would be set off by concussion.
Once more they retired to the bombproof, and again the great gun was fired. Once more the ground shook, and they were nearly deafened by the shock.
Then, as they looked toward the distant hillside, they saw a shower of earth and great rocks rise up. It was like a sand geyser. Then, when this settled back again, there was left a gaping hole in the side of the mountain.
"That does the business!" cried Tom. "My cannon is a success!"
The last shot did not go quite as far as the first, but it was because a different kind of projectile was used. Tom was perfectly satisfied, however. Several more trials were given the gun, and each one confirmed the young inventor in his belief that he had made a wonderful weapon.
"If that doesn"t fortify the Panama Ca.n.a.l nothing will," declared Ned.
"Well, I hope I can convince Uncle Sam of that," spoke Tom, simply.
The muzzle velocity and the pressure were equal to Tom"s highest hopes.
He knew, now, that he had hit on just the right mixture of powder, and that his gun was correctly proportioned. It showed not the slightest strain.
"Now we"ll try another bursting sh.e.l.l," he said, after a rest, during which some records were made. "Then we"ll call it a day"s work. Koku, bring up some more powder. I"ll use a little heavier charge this time."
It was while the gun was being loaded that a horseman was seen riding wildly down the valley. He was waving a red flag in his hand.
"Bless my watch chain!" cried Mr. Damon. "What"s that?"
"It looks as though he was coming to give us a warning," suggested the steel foreman.
"Maybe someone has kicked about our shooting," remarked Ned.
"I hope not," murmured Tom.
He looked at the horseman anxiously. The rider came nearer and nearer, wildly waving his flag. He seemed to be shouting something, but his words could not be made out. Finally he came near enough to be heard.
"The dam! The dam!" he cried. "It"s bursting. Your shots have hastened it. The cracks are widening. You"d better get away!" And he galloped on.
"Bless my toilet soap!" gasped Mr. Damon.
"I was afraid of this!" murmured Tom. "But, since our shots have hastened the disaster, maybe we can avert it."
"How?" demanded Ned.
"I"ll show you. All hands come here and we"ll shift this gun. I want it to point at that big white stone!" and he indicated an immense boulder, well up the valley, near the place where the two great gulches joined.
CHAPTER XVIII
THE DOPED POWDER
"What are you going to do, Tom?" cried Ned, as he, with the others, worked the hand gear that shifted the big gun. When it was permanently mounted electricity would accomplish this work. "What"s your game, Tom?"
"Don"t you remember, Ned? When we were talking about the chance of the dam bursting, I said if the current of suddenly released water could be turned into the other valley, the people below us would be saved."
"Yes."
"Well, that"s what I"m going to do. I"m going to fire a bursting sh.e.l.l at the point where the two valleys come together. I"ll break down the barrier of rock and stone between them."
"Bless my shovel and hoe!" cried Mr. Damon.
"If we can turn enough of the water into the other valley, where no one lives, and where it can escape into the big river there, the amount that will flow down this valley will be so small that only a little damage will be done."
"That"s right!" declared the steel foreman, as he caught Tom"s idea.
"It"s the only way it could be done, too, for there won"t be time to make the necessary excavation any other way. Is the gun swung around far enough, Mr. Swift?"
"No, a little more toward me," answered Tom, as he peered through the telescope sights. "There, that will do. Now to get the proper elevation," and he began to work the other apparatus, having estimated the range as well as he could.
In a few seconds the giant cannon was properly trained on the white rock. Meanwhile the horseman, with his red flag, had continued on down the valley. In spite of his warning of the night before, it developed that a number had disregarded it, and had remained in their homes. Most of the inhabitants, however, had fled to the hills, to stay in tents, or with such neighbors as could accommodate them. Some lingered to move their household goods, while others fled with what they could carry.
It was to see that the town was deserted by these late-stayers that the messenger rode, crying his warning as did the messenger at the bursting of the Johnstown dam twenty-odd years ago.
"The projectile!" cried Tom, as he saw that all was in readiness.
"Lively now! I can see the top of the dam beginning to crumble," and he laid aside the telescope he had been using.
The projectile, with a heavy charge of bursting powder, was slung into the breech of the gun.
"Now the powder, Koku!" called Tom. "Be quick; but not so fast that you drop any of it."
"Me fetch," responded the giant, as he hastened toward the small cave where the explosive was kept. As the big man brought the first lot, and Ned was about to insert it in the breech of the gun, behind the projectile, Tom exclaimed:
"Just let me have a look at that. It"s some that I first made, and I want to be sure it hasn"t gone stale."
Critically he looked at the powerful explosive. As he did so a change came over his face.
"Here, Koku!" the young inventor said. "Where did you get this?"
"In cave, Master."
"Is there any more left?"
"Only enough for this one shoot."