"Well, maybe not," replied Ned. "But it's worth thinking about. I
believe if General Waller could prevent you from inventing your big
gun, he would."

The days that followed were busy ones for Tom. He worked on the powder
problem from morning to night, scoring many failures and only a few
successes. But he did not give up, and in the meanwhile drew tentative
plans for the big gun.

One evening, after a hard day's work, he went to the library where his
father was reading.

"Tom," said Mr. Swift, "do you remember that old fortune hunter, Alec
Peterson, who wanted me to go into that opal mine scheme?"

"Yes, Dad. What about him? Has he found it?"

"No, he writes to say he reached the island safely, and has been
working some time. He hasn't had any success yet in locating the mine;
but he hopes to find it in a week or so."

"That's just like him," murmured Tom. "Well, Dad, if you lose the ten
thousand dollars I guess I'll have to make it up to you, for it was on
my account that you made the investment."

"Well, you're worth it, Tom," replied his father, with a smile.

CHAPTER XII

A POWERFUL BLAST

"Look out with that box, Koku! Handle it as though it contained a dozen
eggs of the extinct great auk, worth about a thousand dollars apiece.

"Eradicate! Don't you dare stumble while you're carrying that tube. If
you do, you'll never do it again!"

"By golly, Massa Tom! I--I's gwine t' walk on mah tiptoes all de way!"

Thus Eradicate answered the young inventor, while the giant, Koku, who
was carrying a heavy case, nodded his head to show that he understood
the danger of his task.

"So you think you've got the right stuff this time, Tom?" asked Ned
Newton.

"I'm allowing myself to hope so, Ned."

"Bless my woodpile!" cried Mr. Damon. "I--I really think I'm getting
nervous."

It was one afternoon, about two weeks after Tom had made his first test
of the new powder. Now, after much hard work, and following many other
tests, some of which were more or less successful, he had reached the
point where he believed he was on the threshold of success. He had
succeeded in making a new explosive that, in the preliminary tests, in
which only a small quantity was used, gave promise of being more
powerful than any Tom had ever experimented with--his own or the
product of some other inventor.

And his experiments had not always been harmless. Once he came within a
narrow margin of blowing up the shop and hims