ve dozed
off, but I was suddenly awakened by hearing a peculiar noise. I
sat up in alarm, and then I realized that Mr. Damon had not come
in."

"I was frightened then, and I called my maid. It was nearly one
o'clock, and my husband never stays out as late as that. We went
next door, and found that Mr. Blackson had not been out of his
house that evening. So it could not have been he to whom Mr. Damon
was speaking."

"We roused up other neighbors, and they searched all about the
grounds, thinking he might have been overcome by a sudden faint.
But we could not find him. My husband had disappeared--mysteriously
disappeared!" and the lady broke into sobs.

"Now don't worry," said Tom, soothingly, as he put his arms about
her as he would have done to his own mother, had she been alive,
"We'll get him back!"

"But how can you? No one knows where he is."

"Oh, yes!" said Tom, confidently, "Mr. Damon himself knows where
he is, and unless he has gone away voluntarily, I think you will
soon hear from him."

"What do you mean by--voluntarily?" asked the wife.

"First let me ask you a question," came from Tom. "You said you
were awakened by a peculiar noise. What sort of a sound was it?"

"Why, a whirring, throbbing noise, like--like--"

She paused for a comparison.

"Like an airship?" asked Tom, with a good deal of eagerness.

"That was it!" cried Mrs. Damon. "I was trying to think where I
had heard the sound before. It was just like the noise your
airship makes, Tom!"

"That settles it!" exclaimed the young inventor.

"Settles what?" asked Ned.

"The manner of Mr. Damon's disappearance. He was taken away--or
went away--in my airship--the airship that was stolen from my shed
last night!"

Mrs. Damon stared at Tom in amazement.

"Why--why--how could that be?" she asked.

Quickly Tom told of what had happened at his place.

"I begin to see through it," he said. "There is some plot here,
and we've got to get to the bottom of it. Mr. Damon either went
with these men in the airship willingly, or he was taken away by
force. I'm inclined to think he went of his own accord, or you
would have heard some outcry, Mrs. Damon."

"Well, perhaps so," she admitted. "But would he go away in that
manner without telling me?"

"He might," said Tom, willing to test his theory on all sides. "He
might not have wanted you to worry, for you know you dislike him
to go up an airships."

"Yes, I do. Oh, if I only thought he did