action was made manifest.

"This will do the trick!" cried Ned. "I'm certain it will."

"I didn't have much fear that it wouldn't," said Tom. "But I hoped the
other would be better, for it is a much cheaper mixture to make, and
that will count when you come to sell it to big cities."

"But the fire is certainly dying down," declared Mr. Baxter.

And this was true. As container after container of the bomb type fell
in different parts of the burning lumberyard, while Tom coursed above
it, the flames began to be smothered in various sections.

And from the watching crowds, as well as from the hard-working members
of the Shopton fire department, came cheers of delight and
encouragement as they saw the work of Tom Swift's aerial fire-fighting
machine.

For he had, most completely, subdued what threatened to be a great
fire, and when the last of his bombs had been dropped, so effective was
the blanket of fire-dampening gases spread around that the flames just
naturally expired, as it were.

As Tom had said, the absence of wind was in his favor, for the
generated gases remained just where they were wanted, directly over the
fire like an extinguishing blanket, and were not blown aside as would
otherwise have been the case.

And, by the peculiar manner in which his chemicals were mixed, Tom had
made them practically harmless for human beings to breathe. Though the
fire-killing gases were unpleasant, there was no danger to life in
them, and while several of the firemen made wry faces, and one or two
were slightly ill from being too close to the chemicals, no one was
seriously inconvenienced.

"Well, I. guess that's all," said Tom, when the final bomb had been
dropped. "That was the last of them, wasn't it, Ned?"

"Yes, but you don't need any more. The fire's out--or what isn't can be
easily handled by the hose lines."

"Good!" cried Tom. "But, all the same, I wish I had been able to make
the first mixture work."

"Perhaps I can help you with that," suggested Mr. Baxter.

And the following day, after Tom had received the thanks of the town
officials and of the fire department for his work in subduing the
lumberyard blaze, the young inventor called Josephus Baxter in
consultation.

"I feel that I need your help," said the young inventor. "You have been
at this chemical study longer than I, and I am willing to pay you well
for your work. Of course I can't make up to you the loss of your dye
formulae. But while you