ma rays."

* * * * *

But our receiving shield was dark, untouched. We tried taking hydrogen
photographic impressions of the visible moon surface. A sequence of
them, with stereoscopic lenses, forty-eight to the second. Our
mirror-grid gave the magnified images; the spectro-heliograph, with its
wave-length selection, pictured the mountain-levels, and slowly
descended into the deepest seas.

There was nothing.

Yet in those moon caverns--a million million recesses amid the crags of
that tumbled, barren surface--the pin-point of movement which might have
been Grantline's expedition could so easily be hiding! Could he have the
ore insulated, fearing its Gamma rays would betray its presence to
hostile watchers?

Or might disaster have come to him? Or he might not be upon this
hemisphere of the moon at all....

My imagination, sharpened by fancy of a lurking menace which seemed
everywhere about the Planetara this voyage, ran rife with fears for
Johnny Grantline. He had promised to communicate this voyage. It was
now, or perhaps never.

Six-thirty came and passed. We were well beyond the earth's shadow now.
The firmament blazed with its vivid glories; the sun behind us was a
ball of yellow-red leaping flames. The earth hung, opened to a huge,
dull-red half-sphere.

* * * * *

We were within some forty thousand miles of the moon. Giant white
ball--all of its disc visible to the naked eye. It poised over the bow,
and presently, as the Planetara swung upon her course for Mars, it
shifted sidewise. The light of it glared white and dazzling in our tiny
side windows.

Snap, with his habitual red celluloid eyeshade shoved high on his
forehead, worked over our instruments.

"Gregg!"

The receiving shield was glowing a trifle! Gamma rays were bombarding
it! It glowed, gleamed phosphorescent, and the audible recorder began
sounding its tiny tinkling murmurs.

Gamma rays! Snap sprang to the dials. The direction and strength were
soon obvious. A richly radio-active ore body, of considerable size, was
concentrated upon this hemisphere of the moon! It was unmistakable.

"He's got it, Gregg! He's--"

The tiny helio mirrors began quivering. Snap exclaimed triumphantly,
"Here he comes! By God, the message at last! Bar off that light!"

* * * * *

I flung on the absorbers. The moonlight bathing the little room went
into them and