fact of liberation depends upon atomic configuration--a
fact which you and I figured out long ago. However, our figuring didn't
go far enough--it couldn't: we didn't know anything then. Copper happens
to be the most efficient of the few metals which can be decomposed at
all under ordinary excitation--that is, by using an ordinary coil, such
as we and the Fenachrone both use. But by using special exciters,
sending out all the orders of rays necessary to initiate the disruptive
processes, we can use any metal we want to. Osnome has unlimited
quantities of the heaviest metals, including radium and uranium. Of
course we can't use radium and live--but we can and will use uranium,
and that will give us something like four times the acceleration
possible with copper. Dunark, what say you snap over there and smelt us
a cubic mile of uranium? No--hold it--I'll put a flock of forces on the
job. They'll do it quicker, and I'll make 'em deliver the goods. They'll
deliver 'em fast, too, believe us--we'll see to that with a ten-ton bar.
The uranium bars'll be ready to load tomorrow, and we'll have enough
power to chase those birds all the rest of our lives!"

Returning to the projector, Seaton actuated the complex system of forces
required for the smelting and transportation of the enormous amount of
metal necessary, and as the three men again boarded their aerial
conveyance, the power-bar in the projector behind them flared into
violet incandescence under the load already put upon it by the new
uranium mine in distant Osnome.

The _Skylark_ lay stretched out over two miles of country, exactly as
they had last seen her, but now, instead of being water-white, the
ten-thousand-foot cruiser of the void was one jointless, seamless
structure of sparkling, transparent, purple inoson. Entering one of the
open doors, they stepped into an elevator and were whisked upward into
the control room, in which a dozen of the aged, white-bearded students
of Norlamin were grouped about a banked and tiered mass of keyboards,
which Seaton knew must be the operating mechanism of the extraordinarily
complete fifth-order projector he had been promised.

"Ah, youngsters, you are just in time. Everything is complete and we are
just about to begin loading."

"Sorry, Rovol, but we'll have to make a couple of changes--have to
rebuild the exciter or build another one," and Seaton rapidly related
what they had learned, and what they had decided to do.

"Of c