“Yes, that must be it, Tom.  What would you advise me to do?  I am so frightened over this!”

“Do?  Don’t you do anything!” cried Tom.  “We’ll fool these rascals yet.  If they got those papers they might release Mr. Damon, or they might not—­fearing he would cause their arrest later.  But we’ll have him released anyhow, and we’ll save what is left of your fortune.  Put those land papers in a safe-deposit box, and let me do the rest.  I’m going to catch those fellows!”

“But how, Tom?  You don’t know who they are.  And a mere message over a telephone won’t give you a clue to where they are.”

“Perhaps not an ordinary message,” agreed Tom.  “But I’m going to try some of my new inventions.  You said they told you they were going to call again?”

“That’s what they said, Tom.”

“Well, when they do, I want to be here.  I want to listen to that message.  If you will allow me, I’ll take up my residence here for a while, Mrs. Damon.”

“Allow you?  I’ll be only too glad if you will, Tom.  But I thought you were going to try to get some clue from the drug store where the mysterious message came from.”

“I’ll let Ned Newton do that.  I want to stay here.”

Tom telephoned to Ned to meet him at Mrs. Damon’s house, and also to bring with him certain things from the laboratory.  And when Ned arrived in an auto, with various bits of apparatus, Tom put in some busy hours.

Meanwhile Ned was sent to the drug store, to see if any clues could be obtained there as to who had sent the message.  As Tom had feared, nothing could be learned.  There were several automatic ’phones in the place, and they were used very often during the day by the public.  The drug clerks took little or no notice of the persons entering or leaving the booths, since the dropping of a coin in the slot was all that was necessary to be connected with central.

“Well, we’ve got to wait for the second call here,” said Tom, who had been busy during Ned’s absence.  He had fitted to Mrs. Damon’s telephone a recording wax phonograph cylinder, to get a record of the speaker’s voice.  And he had also put in an extension telephone, so that he could listen while Mrs. Damon talked to the unknown.

“There, I guess we’re ready for them,” said Tom, late that afternoon.  But no queer call came in that day.  It was the next morning. about ten o’clock, after Mrs. Damon had passed a restless night, that the telephone bell rang.  Tom, who was on the alert, was at his auxiliary instrument in a flash.  He motioned to Mrs. Damon to answer on the main wire.

“Hello,” she spoke into the transmitter.  “Who is this?”

“Are you Mrs. Damon?” Tom heard come over the wire in a deep voice, and by the manner in which Mrs. Damon signalled the young inventor knew that, at the other end of the line, was the mysterious man who had spoken before.

CHAPTER XIX