ars are part of the cars, but--Beings of
the Moon! That they are either metal monsters endowed with brains or
tiny creatures irrevocably attached to the cars themselves!"

"But how," said Sarka at last, "are we to be sure? I can understand
what Dalis might do if the Moon-men granted his wish for an alliance
with them. It is easy to understand why his Gens would follow his
lead, for with the Moon forced outward from the Earth faster than his
Gens could retreat, there is but one direction for his Gens to
go--toward the Moon! They would go to the Moon as captives and trust
the keen brain of Dalis to gain the mastery, sooner or later, over the
Moon-men. And then...."

"And then--?" repeated Sarka the Elder.

"Then, Dalis has already been inspired by the speed with which those
aircars travel! You will remember that he did not take kindly to
leaving the Earth and making his abode on some other planet! But why
could he not do so, combine forces and knowledge with the people of
that planet--and then return to Earth in alliance with them?--after we
have depleted our forces by placing a large portion of our people on
Mars and Venus and Saturn?"

"Sarka, my son," said Sarka's father, "before we continue with our
flight to Mars, we must know the truth! We must somehow learn exactly
what is going on on the Moon! If you could reach the Moon, alone,
undetected, and bring back a report...."

* * * * *

For a moment he left it there, and the faces of all three were gray
with worry and abysmal fear.

"I can't go bodily, father," said Sarka at last, "but you remember my
secret exit dome, to the right of the observatory, from which I have
never yet dared exit from this place for fear that it might cost me my
life?"

Sarka the Elder nodded, while Jaska looked puzzled. Another evidence
of the fact that Sarka had not always trusted her, for she knew
nothing of a secret exit dome. Sarka's eyes, as he looked at Jaska,
mutely asked her forgiveness, which she gave him with her smile.

"I remember, son, and now?..."

"Surely it is worth risking one's life to know what new menace looms
over the children of men!"

"What is the use of this secret dome?" asked Jaska softly.

"It is merely an elaboration of the regular exit dome, combined with
certain phases of our atom-distintegrators, and the principle involved
in the anti-gravitational ovoids. I step into the secret exit dome,
garbed for flight Outside,