a giant searchlight which could be played at will along
the face of the dam, to make its examination the more easy and exact by
night. The steady stream of this light was a fixed factor, being held
at such a position as would cover the greatest amount of the dam face.

Now, as Sim Gage topped the grade, gravel crunching under his feet, a
trifle out of breath with his climb, since the incline itself was a
thing of magnificent distances, he saw the searchlight of the power dam
begin a performance altogether new in his own experience.

The great shaft of light rose up abruptly to a position vertical, a
beam of light reaching up into the sky. An instant, and it began to
swing from side to side. It swung sharply clear against the bald face
of the mountain at the farther end of the dam. It swept down the
canyon itself, or to its first great bend. It rose again and swept
across the dark-fringed summit of the mountains on the hither side of
the stream. Not once, but twice, this was done.

It was a splendid and magnificent thing itself, this giant eye,
illuminating and revealing, fit factor in a wild and imposing panorama
of the night. But why? No one ever had known the searchlight to be
used in this way. What orders had been given? What did these zig-zag
beams up and down the surface of the sky indicate? Was it a signal, or
was some one playing with the property of the Company, there in the
cupola of the light station?

Sim Gage reached the side of the plant just as the light came down to
its original duty of watching the face of the dam. At first there was
not any sound.

"Who's there?" he called out. No answer came. It seemed to him that
he heard some sort of movement in the little rock house.

"Halt! Who goes there?" he called out in a formula he had learned.

He got no answer, but he heard a thud as of a body dropping out of the
window of the further side of the house, against the slope of the dam
which lay above it.

He ran around the corner of the little building, rifle at the ready,
only to see a scrambling figure, bent over, endeavoring to reach the
top of the dam, where the smooth roadway ran from side to side of the
great gorge. That way lay no escape. The sentry was across yonder,
and would soon return. This way, toward the east, a fugitive must go
if he would seek any point of emergence from these surroundings.

"Halt! Halt there! Halt, or I'll fire!" cried Gage. "Halt!" He
called it