it to stand any sort of a
flood."

"They evidently didn't count on one like this. They've got the engineer
who built it up there, and they're doing their best to strengthen it. I
also heard that they're preparing to dynamite it to open breeches here
and there in it, in case it is likely to give way suddenly."

"You don't mean it! Say, if it does go out with a rush it will wipe out
the village."

"Yes, but it can't hurt us," went on the foreman. "We're too high up on
the side of the hill. Even if the dam did burst, if the course of the
water could be changed, to send it down that other valley, it would do
no harm, for there are no settlements over there," and he pointed to
the distant hill.

It was near this hill that Tom intended to direct his projectiles, and
on the other side of it was another valley, running at right angles to
the one crossed by the dam.

As the foreman had said, if the waters (in case the dam burst) could be
turned into this transverse valley, the town could be saved.

"But it would take considerable digging to open a way through that side
of the mountain, into the other valley," went on the man.

"Yes," said Tom, and then he gave the matter no further thought, for
something came up that needed his attention.

"Have you your explosive here?" asked the foreman of the young inventor
the next day, when the weather showed signs of clearing.

"Yes, some of it," said Tom. "I have another supply in a safe place in
the village. I didn't want to bring too much here until the gun was to
be fired. I can easily get it if we need it. Jove! I wish it would
clear. I want to get out in my Humming Bird, but I can't if this keeps
up." Tom had brought one of his speedy little airships with him to
Preston.

The following day the clouds broke a little, and on the next the sun
shone. Then the work on the gun went on apace. Tom and his friends were
delighted.

"Well, I think we can try a shot tomorrow!" announced Tom with delight
on the evening of the first clear day, when all hands had worked at
double time.

"Bless my powder-horn!" exclaimed Mr. Damon. "You don't mean it!"

"Yes, the gun is all in place," went on the young inventor. "Of course,
it's only a temporary carriage, and not the disappearing one I shall
eventually use. But it will do. I'm going to try a shot tomorrow.
Everything is in readiness."

There came a knock on the door of the room Tom had fitted up as an
office in the old farmhouse.