mooth, gliding motion, with now and then an upward
tilt, which showed that Tom was coming down from the upper regions in a
series of long glides. The engine had stopped, and the cessation of the
thundering noise made it possible for Tom and his passenger to talk
without the use of the speaking tube.

"All right?" asked Mr. Damon.

"All right," Tom answered, and a little later the machine was rolling
gently over the turf of a large field, a mile or so from the camp.

Before Tom and Mr. Damon could get out of their seats, a man, seemingly
springing up from some hollow in the ground, walked toward them.

"Had an accident?" he asked, in what he evidently meant for a friendly
voice.

"A little one, easily mended," Tom answered.

He was about to take off his goggles, but at sight of the man's face a
change came over the countenance of Tom Swift, and he replaced the eye
protectors. Then Tom turned to Mr. Damon, as if to ask a question, but
the stranger came so close, evidently curious to see the aircraft at
close quarters, that the young inventor could not speak without being
overheard.

Tom got out his kit of tools to repair the broken control, and the man
watched him curiously. As he tinkered away, something was stirring
among the past memories of the inventor. A question he asked himself
over and over again was:

"Where have I seen this man before? His face is familiar, but I can't
place him. He is associated with something unpleasant. But where have I
seen this man before?"

Chapter II

Tom's Indifference

"Did you make this machine yourself?" asked the stranger of Tom, as the
young inventor worked at the damaged part of his craft.

Mr. Damon had also alighted, taken off his goggles, and was looking
aloft, where the army aircraft were going through various evolutions,
and down below, where the young soldiers were drilling under such
conditions, as far as possible, as they might meet with when some of
their number went "over the top." Mr. Damon was murmuring to himself
such remarks as:

"Bless my fountain pen! look at that chap turning upside down! Bless my
inkwell!"

"I beg your pardon," remarked Tom Swift, following the remark of the
man, whose face he was trying to recall. It was not that Tom had not
heard the question, but he was trying to gain time before answering.

"I asked if you made this machine yourself," went on the man, as he
peered about at the Hawk. "It isn't like any I've ever se