had so
mysteriously disappeared, and he would have given a good deal to know
just how Andy got possession of them, and how he knew enough to use
them.

"He, or some one whom he hired, must have gotten into our house mighty
quickly that day," mused Tom, "and then skipped out while dad fell into
a little doze. It was a mighty queer thing, but it's lucky it was no
worse."

The time was approaching for the big aviation meet. Tom's craft was in
readiness, and had been given several other trials, developing more
speed each time. Additional locks were put on the doors of the shed,
and more burglar-alarm wires were strung, so that it was almost a
physical impossibility to get into the Humming-Bird's "nest" without
arousing some one in the Swift household.

"And if they do, I guess we'll be ready for them," said Tom grimly. He
had been unable to find out who it was that had attempted once before
to damage the monoplane, but he suspected it was the ill-favored man
who was working with Andy.

As for Mr. Swift, at times he seemed quite well, and again he required
the services of a physician.

"You will have to be very careful of your father, Tom," said Dr.
Gladby. "Any sudden shock or excitement may aggravate his malady, and
in that case a serious operation will be necessary."

"Oh, we'll take good care of him," said the lad; but he could not help
worrying, though he tried not to let his father see the strain which he
was under.

It was some days after this, and lacking about a week until the meet
was to open, when a peculiar thing happened. Tom had given his
Humming-Bird a tryout one day, and had then begun to make arrangements
for taking it apart and shipping it to Eagle Park. For he would not fly
to the meet in it, for fear of some accident. So big cases had been
provided.

"I'll take it apart in the morning," decided Tom, as he went to his
room, after seeing to the burglar alarm, "and ship her off. Then Mr.
Damon and I will go there, set her up, and get ready to win the race."

Tom had opened all the windows in his room, for it was very warm. In
fact it was so warm that sleep was almost out of the question, and he
got up to sit near the windows in the hope of feeling a breeze.

There it was more comfortable, and he was just dozing off, and
beginning to think of getting back into bed, when he was aware of a
peculiar sound in the air overhead.

"I wonder if that's a heavy wind starting up?" he mused. "Good luck,