trap that the light be switched on. Otherwise no picture could be transmitted over the wire. And the plan of having the man write down a message to Mr. Damon was arranged with that end in view. The man would need a light to see to write, and Tom's apparatus must be lighted in order to make it work. The plot was coming along finely.
"There!" exclaimed the man at the other end the wire. "I have a light now. Go ahead with your message, Mrs. Damon. But make it short. I can't stay here long."
Then Mrs. Damon began dictating the message she and Tom had agreed upon. It was as long as they dared make it, for they wanted to keep the man in the booth to the last second.
"Dear Husband," began Mrs. Damon. What the message was does not matter. It has nothing to do with this story. Sufficient to say that the moment the man began writing it down, as Tom could tell over the sensitive wire, by the scratching of the pencil—at that moment Tom, knowing the light was on in the distant telephone booth, switched on the picture-taking apparatus. His receiving apparatus at once indicated that the image was being made on the sensitive plate.
It took only a few seconds of time, and with the plate in the holder Tom hastened to the dark
