"I'm not quite ready for that yet," replied the young inventor.
"I have several improvements to make. But, when they are
finished, I'll let Uncle Sam know what I have. Then it's up to
him."

"And you must be careful, Tom, that some of your rivals don't
hear of your success and get it away from you," warned Mr. Damon,
as Tom guided the Air Scout along the aerial way--an unlighted
and limitless path in the silent darkness.

"Oh, they'll have to get up pretty early in the morning to do
that!" boasted Tom, and afterward he was to recall those words
with a bit of chagrin.

On and on they sailed, and as Tom increased the speed of the
motor, and noted how silently it ran, he began to have high hopes
that he had builded better than he knew. For even with the motor
running at almost full speed there was not noise enough to hinder
talk between himself and Mr. Damon.

Of course there was some little sound. Even the most perfect
electric motor has a sort of hum which can be detected when one
is close to it. But at a little distance a great dynamo in
operation appears to be silence itself.

"I can go this one better, though," said Tom as he sailed along
in the night. "I see where I've made a few mistakes in the baffle
plate of the silencer. I'll correct that and--"

As he spoke the machine gave a lurch, and the motor, instead of