k. Then he noticed a pale glow come into
being among the stars on the eastern horizon.

"Hello," he muttered again. "So we're going to have a moon? In the
last quarter, but still it ought to light me up from this beach."

A moment later the horns of the crescent had come above the black rim
of the sea. Dan waited, swinging his arms and tramping up and down on
the sand, until the silvery moon had cleared the horizon and
illuminated the rugged face of the cliff with pale white radiance.

He chose a path to the top of the cliff and clambered up, emerging in
a jungle-like thicket of brush. Picking his way with the greatest
caution, yet scratching his naked skin most painfully, he made his way
for a few yards through the brush to a point of vantage from which he
could look about.

He was, he perceived, in a narrow valley or ravine, with rugged black
walls rising sheer on either side. The silvery light of the crescent
moon fell upon the rank jungle that covered the narrow floor of the
canyon, which rose and dwindled as it penetrated inland.

* * * * *

Gazing up the canyon, Dan gasped in amazement at what he saw.

Mars, the red planet, hung bright and motionless, low in the western
sky, gleaming with deep bloody radiance. Directly beneath it, bathed
in the white light of the moon, was a bare, rocky peak that seemed the
highest point of the island. And upon that highest pinnacle, that
chanced to be just below the ruddy star, was an astounding machine.

Three slender towers, of a white metal that gleamed in the moonlight
with the silvery luster of aluminum, rose from the rocky peak. They
supported, in a horizontal position, an enormous metal ring. It must
be, Dan reckoned swiftly, at least a hundred feet in diameter, and
held a hundred feet above the summit of the mountain.

The huge ring gleamed with a strange purple radiance. A shimmering
mist of red-violet light surrounded it. An unknown force seemed to
throb within the mighty ring, drawing the mantle of purple haze about
it.

And suspended inside the ring and below it was a long, slender needle
of dazzling white light. To Dan, from where he stood in the canyon, it
seemed a fine, sharp line, though he knew it must be some kind of
pointer, luminous with the strange force pulsing through it.

The strange needle wavered a little, with quick, uncertain motions.
The brilliance of its light varied oddly; it seemed to throb with a
queer,