ed Ballon Expedition thought they
had found it on the Moon, shortly after its merit was discovered. A
new type of ore--a lode of it is there somewhere, without doubt."

He added vehemently, "Do you understand now why we should be
suspicious of this George Prince? He has a criminal record. He has a
thorough technical knowledge of radium ores. He associates with
Martians of bad reputation. A large Martian company has recently
developed a radiactum engine to compete with our Earth motor. There is
very little radiactum available on Mars, and our government will not
allow our own supply to be exported. What do you suppose that company
on Mars would pay for a few tons of richly radioactive radiactum such
as Grantline may have found on the Moon?"

"But," I objected, "That is a reputable Martian company. It's backed
by the government of the Martian Union. The government of Mars would
not dare--"

"Of course not!" Captain Carter exclaimed sardonically. "Not openly!
But if Martian Brigands had a supply of radiactum I don't imagine
where it came from would make much difference. The Martian company
would buy it, and you know that as well as I do!"

Halsey added, "And George Prince, my agents inform me, seems to know
that Grantline is on the Moon. Put it all together, lads. Little
sparks show the hidden current.

"More than that: George Prince knows that we have arranged to have the
_Planetara_ stop at the Moon and bring back Grantline's ore.... This
is your last voyage this year. You'll hear from Grantline this time,
we're convinced. He'll probably give you the signal as you pass the
Moon on your way out. Coming back, you'll stop at the Moon and
transport whatever radiactum ore Grantline has ready. The Grantline
Flyer is too small for ore transportation."

Halsey's voice turned grimly sarcastic. "Doesn't it seem queer that
George Prince and a few of his Martian friends happen to be listed as
passengers for this voyage?"

In the silence that followed, Snap and I regarded each other. Halsey
added abruptly:

"We had George Prince typed that time we arrested him four years ago.
I'll show him to you."

He snapped open an alcove, and said to his waiting attendant "Flash on
the type of George Prince."

Almost at once, the image glowed on the grids before us. He stood
smiling sourly before us as he repeated the official formula:

"My name is George Prince. I was born in Greater New York twenty-five
years ago."

I gazed at