nd even a good chemist
is likely to fail--as this one did, as far as time went."

"What are you going to do about it?" Ned asked.

"I don't know," and Tom spoke slowly, "I hoped I was done with all that
sort of thing," he went on; "fighting enemies whom I have never
knowingly injured. But it seems they are still after me. Well, Ned,
this gives us something to do, at all events."

"You mean trying to find out who these fellows are?"

"Yes; that is, if you are willing to help."

"Well, I guess I am!" cried the bank clerk with sparkling eyes. "I
wouldn't ask anything better. We've been in things like this before,
Tom, and we'll go in again--and win! I'll help you all I can. Now,
let's see if we can pick up any other clues. This is like old times!"
and Ned laughed, for he, like Tom, enjoyed a good "fight," and one in
which the odds were against them.

"We sure will have our hands full," declared the young inventor.
"Trying to solve the problem of carrying guns on an aerial warship, and
finding out who set this fire."

"Then you're not going to give up your aerial warship idea?"

"No, indeed!" Tom cried. "What made you think that?"

"Well, the way your father spoke--"

"Oh, dear old dad!" exclaimed Tom affectionately. "I don't want to
argue with him, but he's dead wrong!"

"Then you are going to make a go of it?"

"I sure am, Ned! All I have to solve is the recoil proposition, and, as
soon as we get straightened out from this fire, we'll tackle that
problem again--you and I. But I sure would like to know who put this in
my red shed," and Tom looked in a puzzled manner at the empty fire bomb
he still held.

Tom paused, on his way to the house, to put the bomb in one of his
offices.

"No use letting dad know about this," he went on. "It would only be
something else for him to worry about."

"That's right," agreed Ned.

By this time nearly all evidences of the fire, except for the blackened
ruins of the shed, had been cleared away. High in the air hung a cloud
of black smoke, caused by some chemicals that had burned harmlessly
save for that pall. Tom Swift had indeed had a lucky escape.

The young inventor, finding his father quieted down and conversing
easily with Mr. Damon, who was blessing everything he could think of,
motioned to Ned to follow him out of the house again.

"We'll leave dad here," said Tom, "and do a little investigating on our
own account. We'll look for clues while they're fresh."