uieted to a whisper.

"Power ready," came the signal of the small brain built into it.

F-2 took control of its energies and again forces played, but now they
were the forces of the giant machine. The sky darkened with heavy
clouds, and a howling wind sprang up that screamed and tore at the tiny
rounded hull that was F-2. With difficulty he held his position as the
winds tore at him, shrieking in mad laughter, their tearing fingers
dragging at him.

The swirl and patter of driven rain came--great drops that tore at the
rocks, and at the metal. Great jagged tongues of nature's forces, the
lightnings, came and jabbed at the awful volcano of erupting energy that
was the center of all that storm. A tiny ball of white-gleaming force
that pulsated, and moved, jerking about, jerking at the touch of
lightnings, glowing, held immobile in the grasp of titanic force-pools.

For half an hour the display of energies continued. Then, swiftly as it
had come, it was gone, and only a small globe of white luminescence
floated above the great hulking machine.

F-2 probed it, seeking within it with the reaching fingers of
intelligence. His probing thoughts seemed baffled and turned aside,
brushed away, as inconsequential. His mind sent an order to the great
machine that had made this tiny globe, scarcely a foot in diameter. Then
again he sought to reach the thing he had made.

"You, of matter, are inefficient," came at last. "I can exist quite
alone." A stabbing beam of blue-white light flashed out, but F-2 was not
there, and even as that beam reached out, an enormously greater beam of
dull red reached out from the great power plant. The sphere leaped
forward--the beam caught it, and it seemed to strain, while terrific
flashing energies sprayed from it. It was shrinking swiftly. Its
resistance fell, the arcing decreased; the beam became orange and
finally green. Then the sphere had vanished.

F-2 returned, and again, the wind whined and howled, and the lightnings
crashed, while titanic forces worked and played. C-R-U-1 joined him,
floated beside him, and now red glory of the sun was rising behind them,
and the ruddy light drove through the clouds.

The forces died, and the howling wind decreased, and now, from the black
curtain, Roal and Trest appeared. Above the giant machine floated an
irregular globe of golden light, a faint halo about it of deep violet.
It floated motionless, a mere pool of pure force.

Into the thought-appar