"That doesn't make any difference, Dad. It was a wire just the
same. But I'm not going into that just now, though later I may
want to send photographs by wire. What I'm aiming at is to make an
apparatus so that when you go into a telephone booth to talk to a
friend, you can see him and he can see you, on a specially
prepared plate that will be attached to the telephone."

"You mean see him as in a looking-glass, Tom?"

"Somewhat, yes. Though I shall probably use a metal plate instead
of glass. It will be just as if you were talking over a telephone
in an open field, where you could see the other party and he could
see you."

"But how are you going to do it, Tom?"

"Well, I haven't quite decided. I shall probably have to use the
metal called selenium, which is very sensitive to light, and which
makes a good or a poor electrical conductor according as more or
less light falls on it. After all, a photograph is only lights and
shadows, fixed on sensitive paper or films."

"Well, Tom, maybe you can do it, and maybe you can't. I admit
you've used some good arguments," said Mr. Swift. "But then, it
all comes down to this: What good will it be if you can succeed in
sending a picture over a telephone wire?"

"What good, Dad? Why, lots of good. Just think how important it
will be in business, if you can make sure that you are talking to