“I’ll take you in one of my cars,” said Tom, who had several automobiles.  “I don’t want to see you strain that injured leg of yours.”

“You’re very good—­especially after I tangled up your wireless aerials; but I didn’t see them until I was right into them,” apologized Mr. Halling.

“They’re a new kind of wire,” said Tom, “and are not very plain to see.  I must put up some warning signs.  But don’t worry about damaging them.  They were only up temporarily anyhow, and I was going to take them down to arrange for my photo telephone.”

“Photo telephone, eh?  Is that something new?”

“It will be—­if I can get it working,” said Tom, with a smile.

A little later Tom had taken Mr. Halling home, and then he set about making arrangements for repairing the damaged airship.  This took him the better part of a week, but he did not regret the time, for while he was working he was busy making plans for his newest invention—­the photo telephone.

One afternoon, when Tom had completed the repairs to the airship, and had spent some time setting up an experimental telephone line, the young inventor received a call from his chum, Ned Newton.

“Well, well, what are you up to now?” asked Ned, as he saw his chum seated in a booth, with a telephone receiver to his ear, meanwhile looking steadily at a polished metal plate in front of him.  “Trying to hypnotize yourself, Tom?”

“Not exactly.  Quiet, Ned, please.  I’m trying to listen.”

Ned was too familiar with his chum’s work to take offense at this.  The young banker took a seat on a box, and silently watched Tom.  The inventor shifted several switches, pressed one button after another, and tilted the polished metal plate at different angles.  Then he closed the door of the little telephone booth, and Ned, through the ground glass door, saw a light shining.

“I wonder what new game Tom is up to?” Ned mused.

Presently the door opened, and Tom stuck out his head.

“Ned, come here,” he invited.  “Look at that metal plate and see if you can notice anything on it.  I’ve been staring at it so steadily that my eyes are full of sticks.  See what you can make out.”

“What is this?” asked Ned.  “No trick; is it?  I won’t be blown up, or get my eyes full of pepper; will I?”

“Nonsense!  Of course not.  I’m trying to make a photo telephone.  I have the telephone part down pat, but I can’t see anything of the photo image.  See if you can.”

Ned stared at the polished plate, while Tom did things to it, making electrical connections, and tilting it at various angles.

“See anything, Ned?” asked Tom.

The other shook his head.

“Whom am I supposed to see?” he asked.

“Why, Koku is at the other end of the wire.  I’m having him help me.”

Ned gazed from the polished plate out of a side window of the shop, into the yard.