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, a huge, dull
red half sphere.

We were within forty thousand miles of the Moon. A giant white
ball--all of its disc visible to the naked eye. It poised over the
bow, and presently, as the _Planetara_ swung upon its course for Mars,
it shifted sidewise. The light of it glared white and dazzling in our
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. 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 radioactive ore body was concentrated upon this
hemisphere of the Moon! It was unmistakable.

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

The tiny grids began quivering. Snap exclaimed triumphantly, "Here he
comes! By God, the message at last!"

Snap decoded it.

_Success! Stop for ore on your return voyage. Will give you our
location later. Success beyond wildest hopes._

Snap murmured, "That's all. He's got the ore!"

We were sitting in darkness, and abruptly I became aware that across
our open window, where the insulation barrage was flung, the air was
faintly hissing. An interference there! I saw a tiny swirl of purple
sparks. Someone--some hostile ray from the deck beneath us, or from
the spider bridge that led to our little room--someone out there was
trying to pry in!

Snap impulsively reached for the absorbers to let in the outside
light. But I checked him.

"Wait!" I cut off our barrage, opened our door and stepped to the
narrow metal bridge.

"You stay there, Snap!" I whispered. Then I added aloud, "Well, Snap,
I'm going to bed. Glad you've cleaned up that batch of work."

I banged the door upon him. The lacework of metal bridges seemed
empty. I gazed up to the dome, and forward and aft. Twenty feet
beneath me was the metal roof of the cabin superstructure. Below it,
both sides of the deck showed. All patched with moonlight.

No one visible down there. I descended a ladder. The deck was empty.
But in the silence somet