d as so much scrap!

Kennedy examined it quickly, while I questioned a man who appeared from
behind a shed in the rear. It was useless. He could give no clew that
we already could not guess. He had just bought it from a man who seemed
anxious to get rid of it. His description of the man tallied with
Creighton. But that was all. It gave us no chance to trace him.

"Look," exclaimed Kennedy eagerly, bending closer over the motor. "This
is one of the neatest perpetual motion frauds I ever heard of."

He had turned the heavy base of the motor upward. One glance left me
with little wonder why Creighton had so carefully bolted the machine to
the floor. In the base were two rectangular apertures to allow a belt to
run over a concealed pulley on the main shaft of the machine in the
case. Evidently, when the circuit from the Daniell cells was closed, the
pulley, somehow, was thrown into gear. It was loose and the machine
began to revolve slowly at first, then faster and with great show of
power. The pounding, as Kennedy had surmised, was due to the flywheel
not well balanced.

"Well," I remarked, "now that we have found it, I don't see that it does
us much good."

"Only that we understand it," returned Craig. "I left that geophone down
there in the room next door which I hired. I think, if Miss Laidlaw will
take us down there, I'd like to get it."

He spoke with a sort of easy confidence which I knew was hard to be
assumed in the face of what looked like defeat. Had Craig deliberately
let Creighton have a chance to get away, in order that he might convict
himself?

In silence, with Miss Laidlaw at the wheel, we went downtown again to
the room which Craig had hired next to Creighton's workshop. As we
approached it, he leaned over to Miss Laidlaw.

"Stop around the corner," he asked. "Let's go in quietly."

We entered our bare little room and Kennedy set to work as though to
detach the geophone, while I explained it to our client.

"What's the matter?" she interrupted in the middle of my explanation,
indicating Kennedy.

He had paused and had placed the receivers to his ears. By his
expression I knew that the instrument was registering something.

"Someone is in the lower room of the shop next door," he answered,
facing us quickly. "If we hurry, we'll have him cornered."

Miss Laidlaw and I went out and around in front, while Craig dashed
through a back door to cut off retreat that way.

"What's that? Hurry!" excl