e indicated one, "but it isn't very satisfactory. So if you
have anything to say--"

"In the language of the poets," interrupted Mary, "if I have words to
spill, prepare to spill them now. Well, I haven't! Now I'm here, go
ahead! I shall probably be too frightened to talk, anyhow."

"Oh, no you won't--after the first little sensation," Tom assured her.
"You'll be crazy about it. Come on, Jackson!" he called to the
mechanician. "Start the ball rolling!"

Tom was in his place, his goggles and cap well down over his face, and
he was adjusting the switch as the mechanic prepared to spin the
propellers.

Suddenly a man came running from the Swift house, waving his arms not
unlike the blades of an aircraft propeller, he also shouted, but Tom,
whose ears were covered with his fur cap, could not hear. However,
Jackson did, and stopped whirling the blades, turning about to see what
was wanted.

"Why, it's Mr. Damon!" exclaimed Tom, as he caught sight of the excited
man. "Hello, what's the matter?" the youth asked, pulling aside one
flap of his head-covering so he might hear the answer.

"Tom! Wait a minute! Bless my mouse trap!" exclaimed Mr. Damon, "I want
to speak to you!" He was panting from his run across the field. "I just
got to your house--saw your father--he said you were going up with Miss
Nestor, but--bless my dog biscuit--"

"Can't stop now, Mr. Damon!" answered Tom, with a laugh. "I have only
just succeeded, by hard work, in getting Mary to a point where she has
consented to take a sky ride. If I stop now she'll back out and I'll
never get her in again. See you when I come back," and Tom pulled the
covering over his ear once more.

"But, Tom, bless my shoe laces! This is important!"

"So's this!" answered Tom, with a grin. He saw, by the motion of Mr.
Damon's lips, what the latter had said.

Around swung the propeller blades. The gasoline vapor in the cylinders
was being compressed.

"Contact!" called Tom sharply, as he pressed the switch to give the
igniting spark at the proper moment. The mechanic had stepped back out
of the way, in case there should be a premature starting of the
powerful engine, in which event the blades would have cut him to pieces.

"Wait, Tom! Wait! This is very important! Bless my collar button, Tom
Swift, but this is--"

Bang! Bang! Bang!

With a series of explosions, like those of a machine gun, the motor
started, and further talk was out of the question. Tom turned on mo