know he did it for the best. And he may not have told me, for fear
I would worry. I can understand that. But why isn't he back now?"

Tom had been rather dreading that question. It was one he had
asked himself, and he had found no good answer for it. If there
had been such need of haste, that an airship had to be used. why
had not Mr. Damon come back ere this? Unless, as Tom feared to
admit, even to himself, there had been some accident.

Half a dozen theories flashed through his mind, but he could not
select a good, working one,--particularly as there were no clues.
Disappearing in an airship was the one best means of not leaving a
trace behind. An auto, a motor boat, a train, a horse and
carriage--all these could be more or less easily traced. But an
airship--

If Mr. Damon wanted to cover up his tracks, or if he had been
taken away, and his captors wanted to baffle pursuit, the best
means had been adopted.

"Now don't you worry," advised Tom to Mrs. Damon. "I know it looks
funny, but I think it will come out all right. Ned and I will do
all we can. Mr. Damon must have known what he was about. But, to
be on the safe side, we'll send out a general alarm through the
police."

"Oh, I don't know what I'd done if you hadn't come to help me!"
exclaimed Mrs. Damon.

"Just you leave it to me!" said the young inventor, cheerfully.