One or two reports were heard from surrounding towns, to the
effect that several persons had heard a strange throbbing sound in
the night, that, possibly, was caused by the passage of the
airship overhead. One such report came from Waterford, the home
town of Mr. Damon.

"Let's go over there," suggested Ned, to his chum. "I'd like to
see our friend, and maybe we can get some other clues by
circulating around there."

"Oh, I don't know," spoke Tom, rather listlessly.

"Why not?" Ned wanted to know.

"Well, I ought to be working on my photo telephone," was the
answer. "I've got a new idea now. I'm going to try a different
kind of current, and use a more sensitive plate. And I'll use a
tungsten filament lamp in the sending booth."

"Oh, let your experiments go for a little while, Tom," suggested
Ned. "Come on over to Mr. Damon's. The trouble with you is that
you keep too long at a thing, once you start."

"That's the only way to succeed," remarked Tom. "Really, Ned,
while I feel sorry about the airship, of course, I ought to be
working on my telephone. I'll get the Eagle back sooner or later."

"That's not the way to talk, Tom. Let's follow up this clue."

"Well, if you insist on it I suppose I may as well go. We'll take
the little monoplane. I've fixed her up to carry double. I guess--"

Tom Swift broke off suddenly, as the telephone at his elbow rang.

"Hello," he said, taking off the receiver. "Yes, this is Tom
Swift. Oh, good morning, Mrs. Damon! Eh! What's that? Mr. Damon
has disappeared? You don't tell me! Disappeared! Yes, yes, I can
come right over. Be there in a few minutes. Eh? You don't know
what to make of it? Oh, well, maybe it can easily be explained.
Yes, Ned Newton and I will be right over. Don't worry."

Tom hung up the receiver and turned to his chum.

"What do you think of that?" he asked.

"What is it?"

"Why, Mr. Damon mysteriously vanished last night, and this morning
word came from his bankers that every cent of his fortune had
disappeared! He's lost everything!"

"Maybe--maybe--" hesitated Ned.

"No, Mr. Damon isn't that kind of a man," said Tom, stoutly. "He
hasn't made away with himself."

"But something is wrong!"

"Evidently, and it's up to us to find out what it is. I shouldn't
be surprised but that he knew of this coming trouble and started
out to prevent it if he could."

"But he wouldn't disappear and make his wife worry."

"No, that's so. Well, we'll have to go