at, and beside him, in the other, was a large package.

Nearer and nearer came the monoplane. It began to descend, very gently,
for well Tom Swift knew the danger of hitting the ground too hard with
the cargo he carried.

He described a circle in the air to check his speed. Then, gently as a
bird, he made a landing not far from the gun, the craft running easily
over one of the few level places on the side of the hill. Tom yanked on
the brake, and the iron-shod pieces of wood dug into the ground,
checking the progress of the monoplane on its bicycle wheels.

"Have you got it, Tom?" yelled Ned.

"I have," was the answer of the young inventor as he leaped from his
seat.

"Is it good powder?" asked the foreman, anxiously.

"I don't know," spoke Tom. "I didn't have time to look. I just rushed
up to where I had stored it, got some out and came back with the motor
at full speed. Ran into an airpocket, too, and I thought it was all up
with me when I began to fall. But I managed to get out of it. Say,
we're going to have it nip and tuck here to save the village."

"That's what!" agreed the foreman, as he helped Koku take the cans of
explosive.

"Wait until I look at it," suggested Tom, as he opened one. His trained
eye and touch soon told him that this explosive had not been tampered
with.

"It's all right!" he shouted. "Into the gun with it, and we'll see what
happens."

It was the work of only a few moments to put in the charge. Then, once
more, the breech-block was slotted home, and the trailing electric
wires unreeled to lead to the bomb-proof.

Tom Swift took one last look through the telescope sights of his giant
cannon. He changed the range slightly by means of the hand and
worm-screw gear, and then, with the others, ran to the shelter of the
cave. For, though the gun had stood the previous tests well, Tom had
used a heavier charge this time, both in the firing chamber and in the
projectile, and he wanted to take no chances.

"All ready?" asked the young inventor, as he looked around at his
friends gathered in the cave.

"I--I guess so," answered Ned, somewhat doubtfully.

Tom hesitated a moment, then, as his fingers stiffened to press the
electric button there sounded to the ears of all a dull, booming sound.

"The dam! It has given way!" cried Ned.

"That's it!" shouted the foreman. "Fire!"

Tom pressed the button. Once again was that awful tremor of the
earth--the racking shake--the terrific expl