The great projectile was in readiness to be slung into the breech by means of the hoisting apparatus, for it weighed close to two tons.It was carefully inserted under Tom's supervision.It carried no bursting charge, for Tom's first shot was merely to establish the extreme range that his cannon would shoot.
"Now the powder," called the young inventor.To avoid accidents Koku handled this himself, the hoisting apparatus being dispensed with.Tom figured out that five hundred pounds of his new, powerful explosive would be about the right amount to use, and this quantity, divided into several packages to make the handling easier, was quickly inserted in the breech of the gun by Koku.
"Bless my doormat!" cried Mr.Damon, who stood near, looking nervously on."Don't drop any of that.""Me no drop," was the answer.
Tom was busily engaged in figuring on a bit of paper, and Ned, who looked over his shoulder, saw a complicated compilation that looked to he a combination of geometry, algebra, differential calculus and other higher mathematics.
"What are you doing, Tom?" he asked.
"I'm trying to confirm my own theories by means of figures, to see if I can really reach that farthest target.""What, not the one thirty miles away.
"That's it, Ned.I want to get a thirty-mile range if I can." "It isn't possible, Tom.""Bless my tape measure! I should say not!" cried Mr.Damon.
"We'll see," replied Tom, quietly."Put in the primer, Ned; and, Koku,close the breech and slot it home."
In a few seconds the great gun was ready for firing.
"Now," said Tom, "this thing may be all right, and it may not.The only thing that can cause an accident will be a flaw in the steel.No one can guard against that.So, in order to be on the safe side, we will all go into the bomb-proof, and I will fire the gun from there.The wires are long enough."They all agreed that this was good advice, and soon the steel men and Tom's friends were gathered in a sort of cave that had been hollowed out in the side of the hill, and at an angle from the big gun.
"If it does burst--which I hope it won't," said Tom, "the pieces will fly in straight lines, so we will be safe enough here.Ned, are you are ready at the instruments?""Yes, Tom."
"I want you to note the registered muzzle velocity.Mr.Damon, you will please read the pressure gauge.After I press the button I'm going to watch the landing of the projectile through the telescope."The gun had been pointed, as I have said, at the farthest target--one thirty miles away, telescope sights on the giant cannon making this possible.
"All ready!" cried Tom."All ready," answered Ned.
There was a tense moment; Tom's thumb pressed home the electric button, and then came the explosion.
It seemed for a moment as if everyone was lifted from his feet.They had all stood on their tiptoes, and opened their mouths to lessen the shock, but even then it was terrific.The very ground shook--from the roof of their cave small stones and gravel rattled down on their heads.Their ear-drums were numbed from the shock.And the noise that filled the valley seemed like a thousand thunderbolts merged into one.
Tom rushed from the bombproof, dropping the electric button.He caught sight of his gun, resting undisturbed on the improvised carriage.
