e a
terrific economic problem, but at the same time it will solve the
difficulties of the great companies who have been fermenting grain
residues for alcohol. The castor bean growers are also going to bring
down their prices a lot when this machine kills the market. They will
also be more anxious to extract the carbon from the cornstalks for
reducing ores of iron and of other metals."

As the ship flew high above the Transcontinental plane, the men
discussed the economic values of the different applications of Arcot's
discoveries from the huge power stations they could make, to the cooling
and ventilating of houses.

"Dick, you mentioned the cooling effect on New York City; with the
millions on millions of these machines that there will be, with huge
power plants, with a thousand other different applications in use, won't
the terrific drain of energy from the air cause the whole world to
become a little cooler?" asked Fuller.

"I doubt it, Bob," said Arcot slowly. "I've thought of that myself.
Remember that most of the energy we use eventually ends up as heat
anyway. And just remember the decillions of ergs of energy that the sun
is giving off! True, we only get an infinitesimal portion of that
energy--but what we do get is more than enough for us. Power houses can
be established very conveniently in the tropics, where they will cool
the air, and the energy can be used to refine metals. That means that
the surplus heat of the tropics will find a use. Weather control will
also be possible by the direction-control of great winds. We could set
huge director tubes on the tops of mountains, and blow the winds in
whatever direction best suited us. Not the blown wind itself, but the
vast volume of air it carried with it, would be able to cool the
temperate zones in the summer from the cold of the poles, and warm it in
winter with the heat of the tropics."

After a thoughtful silence, Arcot continued, "And there is another thing
it may make possible in the future--a thing that may be hard to accept
as a commercial proposition. We have a practically inexhaustible source
of energy now, but we have no sources of minerals that will last
indefinitely. Copper is becoming more and more rare. Had it not been for
the discoveries of the great copper fields of the Sahara and in Alaska,
we wouldn't have any now. Platinum is exhausted, and even iron is
becoming more and more valuable. We are facing a shortage of metals. Do
you realize