All saw him, and, as the airship rushed downward it could be
seen that he was a fellow dressed in ragged garments, a veritable
tramp.

"I guess that fire didn't happen," said Tom significantly. "It
was deliberately set. Oh, if we can only get there before it
gains too much headway!"

"I like to catch that fellow!" exclaimed Koku, shaking his big
fist at the retreating tramp. "I fix him!"

On rushed the airship, and the man who had probably started the
fire, glanced up at it. Tom suddenly turned the lens of his
Wizard Camera toward him. The mechanism inside, which had been
stopped, started clicking again, as the young inventor switched
on the electric current.

"What are you doing?" cried Ned, as he guided the airship
toward the shop, whence clouds of smoke were rolling.

"Taking his picture," replied Tom. "It may come in useful for
evidence."

But he was not able to get many views of the fellow, for the
latter must have suspected what was going on. He quickly made a
dive for the bushes, and was soon lost to sight. Tom shut off his
camera.

"Bless my life preserver!" cried Mr. Damon. "There comes your
father, Tom, and Mrs. Baggert! They've got buckets! They're going