Tom heard the words above the
queer, buzzing, humming sound. "You are keeping me too long. I
think you are up to some game, but it won't do you any good, Mrs.
Damon. I'll 'phone you to-morrow where to send the papers. And if
you don't send them--if you try any tricks--it will be the worse
for you and Mr. Damon!"

There was a click, that told of a receiver being placed back on
the hook, and the voice ceased. So, also, did the queer, buzzing
sound over which Tom puzzled.

"What can it have been?" he asked. "Did you hear it, Mrs. Damon?"

"What, Tom?"

"That buzzing sound."

"Yes, I heard, but I didn't know what it was. Oh, Tom, what shall
I do?"

"Don't worry. We'll see if anything happened. They may have caught
that fellow. If not I'll plan another scheme."

Tom's first act was to call up the telephone exchange to learn
where the second call had come from. He got the information at
once. The address was in the suburbs. The man had not gone to the
drug store this time.

"Did the detective get out to that address?" asked Tom eagerly of
the manager.

"Yes. As soon as we were certain that he was the party you wanted,
your man got right after him, Mr. Swift."

"That's good, I hope he catches him!" cried the young inventor. "We'll
have to wait and find out."

"He said he'd call up and let you know as soon as he reached the
place," the telephone manager informed Tom.

There was nothing to do but wait, and meanwhile Tom did what he
could to comfort Mrs. Damon. She was quite nervous and inclined to
be hysterical, and the youth thought it wise to have a cousin, who
had come to stay with her, summon the doctor.

"But, Tom, what shall I do about those papers?" Mrs. Damon asked
him. "Shall I send them?"

"Indeed not!"

"But I want Mr. Damon restored to me," she pleaded. "I don't care
about the money. He can make more."

"Well, we'll not give those scoundrels the satisfaction of getting
any money out of you. Just wait now, I'll work this thing out, and
find a way to catch that fellow. If I could only think what that
buzzing sound was--"

Then, in a flash, it came to Tom.

"A sawmill! A planing mill!" he cried. "That's what it was! That
fellow was telephoning from some place near a sawmill!"

The telephone rang in the midst of Tom's excited comments.

"Yes--yes!" he called eagerly. "Who is it--what is it?"

"This is Larsen--the private detective you sent."

"Oh, yes, you were at the drug store."

"Yes