work to be done while I'm gone with Ban. You must
take your assistants and Dr. Ku up to the asteroid in the air-car and
transfer down here all the equipment Dr. Ku says he'll need. Be
extremely careful with the case of coordinated brains. If you possibly
can, have everything in readiness by the time Ban and I return with
the four bodies."

Ban Wilson, in his suit, entered the laboratory. The Hawk gestured him
to the door which led to the tree-shaft to the surface.

"But, Carse, _what_ bodies? Where can you get four more living human
bodies?" Leithgow cried.

"No time, now, Eliot!" the Hawk rapped out, turning at the door. "Just
do as I say--and hurry! I'll get them!"

And he was gone.

CHAPTER X

_The Promise Fulfilled_

Although puzzled by the Hawk's promise, Leithgow could only put his
trust in it and go ahead with the preparations as he had been
directed. He took two of his three laboratory assistants off their
hurried manufacture of quantities of the V-27, and with Ku Sui went
out into the air-car. Passing by way of tube and lake and air, they
were quickly inside the dome on the asteroid, and then into Ku Sui's
laboratory, where Friday waited on guard.

Completely docile and friendly, the Eurasian indicated the various
instruments and devices he would need for the operations, and these
were transported quickly. Then came the case of coordinated brains.
Dr. Ku detached in connections with expert fingers, and all but
Leithgow took a corner and carried it with infinite care to the
air-car outside.

"Do I stay here, suh?" Friday asked the Master Scientist in a
whisper. Though informed of the change in Dr. Ku effected by the V-27,
he was still very suspicious of him. "Seems to me he's a bit too meek
and mild, suh. I think I ought to go down and watch him."

Eliot Leithgow did not quite know what answer to give. The Eurasian
forced the decision.

"I will need," he observed, in his new, frank voice, "all the
assistance you can possibly give me. I am faced by a tremendous task,
and the use of every man will be necessary. I would suggest, Master
Leithgow that the Negro be brought down."

And so Friday came and the asteroid was left unguarded. A mistake,
this turned out to be, but under the circumstances Eliot Leithgow
could hardly be blamed for it. There was so much on their minds, so
much work of vital importance, so desperate a need for speed, that
quite naturally other considerations were subordi