n the different cylinders. Then he stepped back
while Tom threw on the switch. This was not one of the self-starting
types, of which Tom possessed one or two.

"Contact!" cried Tom sharply, and the man stepped forward to give the
big blades a final turn that would start the motor. There was a
muffled roar and then a steady staccato blending of explosions. Tom
raced the motor while his men held the machine in place, and then,
satisfied that all was well, the young inventor gave the word, and the
craft raced over the ground, to soar aloft a little later.

Tom, Ned and Mr. Damon could look down to the meadow where the bonfire
was blazing. A crowd had collected, but the heat of the blaze kept them
at a good distance. Then, as many of the throng caught sight of the
airship overhead, there was a new interest for them.

Tom had told Ned and Mr. Damon, before the trio had entered the
machine, what he wanted them to do. This was to toss the chemicals
overboard at the proper time. Of course in his perfected apparatus Tom
hoped to have a device by which he could drop the fire extinguishing
elements by a mere pressure of his finger or foot, as bombs were
released from aircraft during the war. But this would serve for the
time being.

Nearer and nearer the blaze the airship approached until it was almost
above it. Tom had had some experience in bomb-dropping, and knew when
to give the signal.

At last the signal came. Mr. Damon and Ned heaved over the side the
metal containers of the powerful chemicals.

Down they went, unerring as an arrow, though on a slant, caused by the
impetus given them by the speed of the airship.

Tom and his friends leaned over the side of the machine to watch the
effect. They could see the chemicals strike the blaze, and it was
evident from the manner in which the fire died down that the containers
had broken, as Tom intended they should to scatter their contents.

"Hurray!" cried Ned, forgetting that he could not be heard, for no head
telephones were used on this occasion and the roar of the motor would
drown any human voice. "It's working, Tom!"

Truly the effect of the chemicals was seemingly to cause the fire to go
out, but it was only a momentary dying down. Koku and Rad had made a
fierce, yet comparatively small, conflagration, and though for a time
the gas generated by Tom's mixture dampened the blaze, in a few
seconds--less than half a minute--the flames were shooting higher than
ever.