"Sit still!" yelled Tom. At that instant he started the propeller.
The motor roared like a salvo of guns, and streaks of fire could be
seen shooting from one cylinder to the other, until there was a
perfect blast of explosions.

The speed of the propeller increased as the motor warmed up. Tom ran
to his seat and opened the gasoline throttle still more, advancing
the spark slightly. The roar increased. The lad darted a look at
Eradicate. The colored man's face was like chalk, and he was
gripping the upright braces at his side as though his salvation
depended on them.

"Steady now" spoke Tom, yelling to be heard above the racket. "Here
we go."

The Butter-fly was moving slowly across the level stretch of ground
which Tom used for starting his airships. The propeller was now a
blur of light. The explosions of the motor became a steady roar, the
noise from one cylinder being merged into the blast from the others
so rapidly that it was a continuous racket.

With a whizz the monoplane shot across the ground. Then, with a
quick motion, Tom tilted the lifting planes, and, as gracefully as a
bird, the little machine mounted upward on a slant until, coming to
a level about two hundred feet above the earth, Tom sent it straight
ahead over the roof of his house.

"How's this, Rad?" he cried. "Isn't it great?"