was interested to see how they would act. There was no mistaking his
attitude toward her and Adele was much more cordial to him than I had
expected.

"While I was waiting I got a key from the agent," he explained. "But I
didn't want to go in until you came."

Tresham opened the door and led the way upstairs, Miss Laidlaw following
closely. As we entered Creighton's shop, everything seemed to be in the
greatest disorder. Prints and books were scattered about, the tools were
lying about wherever they happened to have been left, all the models
were smashed or missing and a heap of papers in the fireplace showed
where many plans, letters and other documents had been burned.

We hurried into the big room. Sure enough, the demon motor itself was
gone! Creighton had unbolted it from the floor and some holes in the
boards had been plugged up. The room below was still locked and the
windows were covered with opaque paper on the inside.

"What do you suppose he has done with the motor?" asked Adele.

"The only clew is a junk dealer whom we don't know," I replied, as
Kennedy said nothing.

We looked about the place thoroughly, but could find nothing else.
Creighton seemed to have made a clean getaway in the early hours.

"I wish I could stay and help you," remarked Tresham at length. "But I
must be in court at ten. If there's anything I can do, though, call on
me."

"I'm going to find that engine if I have to visit every junk dealer in
New York," declared Miss Laidlaw soon after Tresham left.

"That's about all we can do, yet, I guess," remarked Kennedy, evidently
not much worried about the disappearance of the inventor.

Together we three closed up the workshop and started out with a list
from a trade publication giving all those who dealt in scrap iron and
old metal. In fact we spent most of the day going from one to another of
the junk shops. I never knew that there were so many dealers in waste.
They seemed to be all over the city and in nearly every section. It was
a tremendous job, but we mapped it out so that we worked our way from
one section to another.

We had got as far as the Harlem River when we entered one place and
looked about while we waited for someone in charge to appear.

I heard a low exclamation from Kennedy, and turned to look in the
direction he indicated. There, in a wagon from which the horse had been
unhitched, was the heavy base of the engine into which so many dollars
had been turned--sol