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
