between Mars and Jupiter and built into a world of his own, swinging
it through space as he willed, and cloaking it with invisibility to
baffle those who marveled at how he came and went, unseen, on his
various errands. This was the mighty rock fortress in which lay the
key-stone of his mounting power. This his lonely, unsuspected home,
come for a while to rest....

Hawk Carse scanned it closely.

It lay roughly head-on to him, its nearest massive, craggy end lying
some three miles from where he hung. On that end lived the life of the
asteroid, and were located all Ku Sui's works. On a space planed flat
in the rock, rested the dome, like an inverted quarter-mile-wide bowl
of glittering glasslike substance, laced inside with spidery
supporting struts--the half bubble from inside which men guided the
mass. Therein an artificial atmosphere was maintained, even as on any
space-ship, and there lay the group of buildings, chief of which was
the precious laboratory in which were the coordinated brains to whom
the Hawk had made his promise.

Carse lowered the glasses, and again the Jupiter-light poured normally
around him, the valley hushed and seemingly empty once more. He put
through his call to Friday and Ban, giving them simple directions how
to find him. And twenty-five minutes after that, he saw, looking back
down the ridge, their two giant metallic figures come twisting and
turning in noiseless flight through the top lanes of the jungle below,
and they were together.

* * * * *

It was seldom that Friday would intrude his thoughts when with his
master and his master's friends, so when he arrived he merely surveyed
the asteroid through his glasses and was silent. But Ban Wilson, after
a long, comprehensive stare, during which one could almost feel the
amazement leaping through him, sputtered:

"By jumping Jupiter, Carse--I never would've believed it! That Ku
Sui's sure a genius! To have that whole asteroid there, man, and to
take it with him wherever he wants to go! Look at it! Fifteen, twenty
miles long, it must be! And that dome--"

"Yes," said the Hawk shortly, "but easy on that now. We've work to do,
and it's got to be done quickly. Now listen:

"There are two main port-locks in the dome for space-ships, and the
starboard one has a smaller man-size lock beside it. We're going to
the smaller one. There'll no doubt be a guard on watch at it, so to
him we're Ku Sui and the two m