"It is against the rules to admit strangers to the shop
grounds," said Tom. "Good-day!"

The president of the Universal Flying Machine Company did not
respond, but there was a look on his face as he turned away that,
had Tom seen it, might have caused him some uneasiness. But he
did not see. Instead, he resumed his talk with Mr. Damon.

"Tom, your idea is most interesting," declared the eccentric
man. "I hope you will be able to work it out!"

"I'm going to try," said the young inventor. "I hope that man--
Mr. Gale--didn't hear anything of what I was saying. He sneaked
up on us before I was aware any one was near but ourselves."

"I don't imagine he heard very much, Tom," said Mr. Damon. "He
may have heard you mention a silent motor--"

"That's just what I wish he hadn't heard," broke in Tom.
"That's the germ of the idea, and once it becomes known that I am
working on that-- Well, there's no use crying over spilled milk,"
and he smiled at the homely proverb. "I'll have to work in
secret, once I've started."

"Do you think the government would use it, Tom?" asked his
friend.

"I should think it would be glad to. Consider what a wonderful
part airships are playing in the present war. It really is a