ks that way, from those figures."

"Say, wouldn't that make some bullet? Unstabilize a piece of copper in
that way and put it inside a rifle bullet, arranged to make a short
circuit on impact. By making the piece of copper barely visible you
could have the explosive effect of only a few sticks of dynamite--a
piece the size of a pea would obliterate New York City. But that's a
long way from our flying-machine."

"Perhaps not so far as you think. When we explore new worlds it might be
a good idea to have a liberal supply of such ammunition, of various
weights, for emergencies."

"It might, at that. Here's another point in equation 249. Suppose the
unstabilized copper were treated with a very weak current, not strong
enough to explode it? A sort of borderline condition? The energy would
be liberated, apparently, but in an entirely new way. Wonder what would
happen? I can't see from the theory--have to work it out. And here's
another somewhat similar condition, right here, that will need
investigating. I've sure got a lot of experimental work ahead of me
before I'll know anything. How're things going with you?"

"I have the drawings and blue-prints of the ship itself done, and
working sketches of the commercial power-plant. I am working now on the
details, such as navigating instruments, food, water, and air supplies,
special motors, and all of the hundred and one little things that must
be taken into consideration. Then, as soon as you get the power under
control, we will have only to sketch in the details of the power-plant
and its supports before we can begin construction."

"Fine, Mart, that's great. Well, let's get busy!"

CHAPTER IV

Steel Liberates Energy--Unexpectedly

DuQuesne was in his laboratory, poring over an abstruse article in a
foreign journal of science, when Scott came breezily in with a newspaper
in his hand, across the front page of which stretched great headlines.

"Hello, Blackie!" he called. "Come down to earth and listen to this tale
of mystery from that world-renowned fount of exactitude and authority,
the _Washington Clarion_. Some miscreant has piled up and touched off a
few thousand tons of T.N.T. and picric acid up in the hills. Read about
it, it's good."

DuQuesne read:

MYSTERIOUS EXPLOSION!

MOUNTAIN VILLAGE WIPED OUT OF EXISTENCE!
TWO HUNDRED DEAD, NONE INJURED!

FORCE FELT ALL OVER WORLD. CAUSE UNKNOWN.
SCIENTISTS BAFFLED.

HARPER'