the gun to
exactly the proper pitch. Of course, any shorter range could, within
certain limits, also be reached.

The gun was pointed slantingly up the valley, and there was ample room
to attain the thirty-mile range without doing any damage.

At the head of the valley, some miles from where the giant cannon was
mounted, was an immense dam, built recently by a water company for
impounding a stream and furnishing a supply of drinking water for a
distant city. At the other end of the valley was the thriving village
of Preston. A railroad ran there, and it was to Preston station that
Tom's big gun had been sent, to be transported afterward, on specially
made trucks, drawn by powerful autos, to the place where it was now
mounted.

Tom had been obliged to buy a piece of land on which to build the
temporary carriage, and also contract for a large slice of the opposite
mountain, as a target against which to fire his projectiles.

The valley, as I have said, was desolate. It was thickly wooded in
spots, and in the centre, near the big dam, which held back the waters
of an immense artificial lake, was a great hill, evidently a relic of
some glacial epoch. This hill was a sort of division between two
valleys.

Tom, Ned, Mr. Damon, with Koku, and some of the employees of the steel
company, had hired a deserted farmhouse not far from the place where
the gun was being mounted. In this they lived, while Tom directed
operations.

"The paper says 'clear' tomorrow," read Ned, on his return. "'Clear,
with freshening winds.'"

"That means rain, with no wind at all," declared Tom, with a sigh.
"Well, it can't be helped. As Mr. Damon says, it will clear some time."

"Bless my overshoes!" exclaimed the odd gentleman. "It always has
cleared; hasn't it?"

No one could deny this.

There came a slackening in the showers, and Tom and Ned, donning
raincoats, went out to see how the work was progressing. They found
the men from the steel concern busy at the great piece of engineering.

"How are you coming on?" asked Tom of the foreman.

"We could finish it in two days if this rain would only let up,"
replied the man.

"Well, let's hope that it will," observed Tom.

"If it doesn't, there's likely to be trouble up above," went on the
foreman, nodding in the direction of the great dam.

"What do you mean?"

"I mean that the water is getting too high. The dam is weakening, I
heard."

"Is that so? Why, I thought they had made