m.

To this end he had his airship in waiting, and as soon as he had
developed the picture he planned to rush off to the vicinity of
the sawmill, and make a prisoner of the man whose features would
be revealed to him over the wire.

It was a hazardous plan--a risky one--but it was the best that he
could evolve. Tom had instructed Mrs. Damon to keep the man in
conversation as long as possible, in order to give the young
inventor himself time to rush off in his airship. But of course
the man might get suspicious and leave. That was another chance
that had to be taken.

"If I had thought of it in time," said Tom, musingly, as he paced
up and down in the library waiting for the 'phone to ring, "if I
had thought of it in time I would have rigged up two plates--one
for a temporary, or looking-glass, picture, and the other for a
permanent one. In that way I could rush off as soon as I got a
glimpse of the fellow. But it's too late to do that now. I'll have
to develop this plate."

Waiting is the most wearisome work there is. Tom and Ned found
this to be the case, as they sat there, hoping each moment that
the telephone bell would ring, and that the man at the other end
of the wire would be the mysterious stranger. Mrs. Damon, too,
felt the nervous strain.

"This is about the hour he called up yesterday," said Tom, in a
low voice, after coming back from a trip to the window to see that
his airship was in readiness. He had brought over to help in
starting it, for he was using his most powerful and speedy craft,
and the propellers were hard to turn.

"Yes," answered Mrs. Damon. "It was just about this hour, Tom. Oh,
I do hope--"

She was interrupted by the jingle of the telephone bell. With a
jump Tom was at the auxiliary instrument, while Mrs. Damon lifted
off the receiver of her own telephone.

"Yes; what is it?" she asked, in a voice that she tried to make
calm.

"Do you know who this is?" Tom heard come over the wire.

"Are you the--er--the person who was to give me an address where I
am to send certain papers?"

"Yes. I'm the same one. I'm glad to see that you have acted
sensibly. If I get the papers all right, you'll soon have your
husband back. Now do as I say. Take down this address."

"Very well," assented Mrs. Damon. She looked over at Tom. He was
intently listening, and he, too, would note the address given. The
trap was about to be sprung. The game had walked into it. Just
which telephone was being