early a week now, and it is likely to last a week
longer."

"It's beastly," declared his chum. "How can you test your gun in this
weather?"

"I can't. I've got to wait for it to clear."

"Bless my rubber boots! it's just got to stop some time," declared Mr.
Damon. "Don't worry, Tom."

"But I don't like this delay. I have heard that General Waller has
perfected a new gun--and it's a fine one, from all accounts. He has
the proving grounds at Sandy Hook to test his on, and I'm handicapped
here. He may beat me out."

"Oh, I hope not, Tom!" exclaimed Ned. "I'm going to see what the
weather reports say," and he went to hunt up a paper.

It was several weeks after the completion of Tom's giant cannon. In the
meanwhile the gun had been moved by the steel company to a
little-inhabited part of New York State, some miles from the plant. The
gun had been mounted on an improvised carriage, and now Tom and his
friends were waiting anxiously for a chance to try it.

The work was not complete, for the steel company employees had been
hampered by the rain. Never before, it seemed, had there been so much
water coming down from the clouds. Nearly every day was misty, with
gradations from mere drizzles to heavy downpours. There were
occasional clear stretches, however, and during them the men worked.

A few more days of clear weather would be needed before the gun could
be fastened securely to the carriage, and then Tom could fire one of
the great projectiles that had been cast for it. Not until then would
he know whether or not his cannon was going to be a success.

Meanwhile nothing more had been heard or seen of the spy. He appeared
to have given up his attempts to steal Tom's secret, or to spoil his
plans, if such was his object.

The place of the test, as I have said, was in a deserted spot. On one
side of a great valley the gun was being set up. Its muzzle pointed up
the valley, toward the side of a mountain, into which the gigantic
projectile could plow its way without doing any damage. Tom was going
to fire two kinds of cannon balls--a solid one, and one containing an
explosive.

The gun was so mounted that the muzzle could be elevated or depressed,
or swung from side to side. In this way the range could be varied. Tom
estimated that the greatest possible range would be thirty miles. It
could not be more than that, he decided, and he hoped it would not be
much less. This extreme range could be attained by elevating