ed feet in the air. Up there he traveled back and forth, in
circles, and in figure eights, desiring to test the machine in
various capacities.

Suddenly the engine stopped, and to those below, anxiously watching,
the silence became almost oppressive, for Tom had somewhat
descended, and the explosions had been plainly heard by those
observing him. But now they ceased!

"His engine's stalled!" cried Garret Jackson.

Mr. Swift heard the words, and looked anxiously up at his son.

"Is he in any danger?" gasped Mr. Damon.

No one answered him. Like some great bird, disabled in mid flight,
the monoplane swooped downward. A moment later a hearty shout from
Tom reassured them.

"He shut off the engine on purpose," said Mr. Jackson. "He is
vol-planing back to earth!"

Nearer and nearer came the BUTTERFLY. It would shoot downward, and
then, as Tom tilted the planes, would rise a bit, losing some of the
great momentum. In a series of maneuvers like this, the young
inventor reached the earth, not far from where his father and the
others stood. Down came the BUTTERFLY, the springs of the wheel
frame taking the shock wonderfully well.

"She's all right--regular bird!" cried Tom, in enthusiasm, when the
machine had come to a stop after rolling over the ground, and he had
leaped out. "We'll make a good flight to-morrow, Mr. Damon, if the
weather holds out this way."

"Good!" cried the eccentric man. "I shall be delighted."

They made the start early the next morning, there being hardly a
breath of wind. There was not a trace of nervousness noticeable
about Mr. Damon, as he took his place in the seat beside Tom. The
lad had gone carefully over the entire apparatus, and had seen to it
that, as far as he could tell, it was in perfect running order.

"When will you be back, Tom?" asked his father.

"To-night, perhaps, or to-morrow morning. I don't know just what Mr.
Fenwick wants me to do. But if it is anything that requires a long
stay, I'll come back, and let you know, and then run down to
Philadelphia again. I may need some of my special tools to work
with. I'll be back to-night perhaps."

"Shall I keep supper for you?" asked Mrs. Baggert, the housekeeper.

"I don't know," answered Tom, with a laugh. "Perhaps I'll drop down
at Miss Nestor's, and have some apple turnovers," for he had told
them or the incident of hiring the new cook. "Well," he went on to
Mr. Damon, "are you all ready?"

"As ready as I ever shall be.