ransmuted elements of soil
for it?"

"Correct," replied X-5638.

"But still we are helpless. We have not the power to combat their
machines. They use the Ultimate Energy known to exist for six hundred
years, and still untapped by us. Our screens cannot be so powerful, our
beams so effective. What of that?" asked Roal.

"Their generators were automatically destroyed with the capture of the
ship," replied X-6349, "as you know. We know nothing of their system."

"Then we must find it for ourselves," replied Trest.

"The life-beams?" asked Kahsh-256799, one of the Man-rulers.

"They affect chemical action, retarding it greatly in exothermic
actions, speeding greatly endothermic actions," answered X-6221, the
greatest of the chemist-investigators. "The system we do not know. Their
minds cannot be read, they cannot be restored to life, so we cannot
learn from them."

"Man is doomed, if these beams cannot be stopped," said C-R-21, present
chief of the machine rulers, in the vibrationally correct, emotionless
tones of all the race of machines. "Let us concentrate on the two
problems of stopping the beams, and the Ultimate Energy till the
reenforcements, still several days away, can arrive." For the
investigators had sent back this saddening news. A force of nearly ten
thousand great ships was still to come.

In the great Laboratories, the scientists reassembled. There, they fell
to work in two small, and one large group. One small group investigated
the secret of the Ultimate Energy of annihilation of matter under Roal,
another investigated the beams, under Trest.

But under the direction of MX-3401, nearly all the machines worked on a
single great plan. The usual driving and lifting units were there, but a
vastly greater dome-case, far more powerful energy-generators, far
greater force-beam controls were used and more tentacles were built on
the framework. Then all worked, and gradually, in the great dome-case,
there were stacked the memory-units of the new type, and into these fed
all the sensation-ideas of all the science-machines, till nearly a tenth
of them were used. Countless billions of different factors on which to
work, countless trillions of facts to combine and recombine in the
extrapolation that is imagination.

Then--a widely different type of thought-combine, and a greater
sense-receptor. It was a new brain-machine. New, for it was totally
different, working with all the vast knowledge accumulated in