this, and it isn't often I get a
chance for a moonlight airship ride. Go a little lower, if you please,
and we'll see if we attract any attention from the inhabitants of the
earth. We'll see if they can possibly hear the machine, though I don't
see how they can."

And they did not. Tom piloted the machine over Shopton, sailing
directly over the center of the town, where there was a big crowd
walking about. Though the airship sailed only a few hundred feet above
their heads, not a person was aware of it, since the craft's lights
were put out for this test.

"That settles it," said Mr. Terrill. "You have succeeded, Tom Swift!"

But Tom was not yet satisfied. He wanted a longer test. Hardly knowing
why he did it he sent the craft in the direction of Mary Nestor's home.
As he sailed across her lawn he saw, in the moonlight, that she and her
mother were walking in the garden. They did not look up as the
aircraft passed over their heads, and were totally unaware of its
presence, unless they caught a glimpse of it as it flitted silently
along, like some great bird of the night.

"It is perfectly wonderful!" declared Mr. Terrill, and he spoke in
ordinary tones, that carried perfectly to the ears of Tom and Mr. Damon.

"Wonderful!" cried the eccentric man. "Bless my chimney, but it's the
greatest invention in the world! Yes, it is! Don't tell me it 'isn't!"

And no one did.

Passing the Nestor home, the saddened occupants of which were unaware
of the passage, Tom sent the Air Scout about in a circle, intending to
proceed to the hangar. And then, some whim, perhaps, caused him to
guide Silent Sam out toward the lonely hut. Mr. Damon and Mr. Tenrill
seemed perfectly content to sail on and on indefinitely in the
moonlight. Tom thought he would take them over a lonely neighborhood,
and then bring them back.

In a little while the craft was directly over the stretch of country
where the aeroplane accident bad occurred, and where Tom and Jackson
had found the deserted hut.

Rather idly Tom looked down, wondering if the Secret Service men were
on the watch and if they had discovered anything.

Suddenly Tom was aware of an automobile moving along the field path
toward the cabin. There were two men in the car, both on the front
seat, and as Tom looked down the brilliant moonlight showed him the
figure of another man, behind, and huddled in the tonneau of the car.
The aeroplane was low enough for all these details to be seen