s troubles of his own--if the Third Planet doesn't get him the
Fenachrone will, and the Third Planet is the more pressing danger. That
lets him out. We've got nearly six months before the Fenachrone can get
back here...."

"But how can they possibly find us here, or wherever we'll be by that
time, Dick?" asked Dorothy. "The battle was a long way from here."

"With that much start they probably couldn't find us," Seaton replied
soberly. "It's the world I'm thinking about. They've got to be stopped,
and stopped cold--and we've got only six months to do it in.... Osnome's
got the best tools and the fastest workmen I know of...." his voice died
away in thought.

"That sort of thing is in your department, Dick."

Crane was calm and judicial as always. "I will, of course, do anything I
can. But you probably have a plan of campaign already laid out?"

"After a fashion. We've got to find out how to work through this zone of
force or we're sunk without a trace. Even with rays, screens, and ships
equal to theirs, we couldn't keep them from sending a vessel to destroy
the earth; and they'd probably get us too, eventually. They've got a lot
of stuff we don't know about, of course, since I took only one man's
mind. While he was a very able man, he didn't know all that all the rest
of them do, any more than any one man has all the earthly science known.
Absolutely our only chance is to control that zone--it's the only thing
they haven't got. Of course, it may be impossible, but I won't believe
that, until I've exhausted a lot of possibilities. Dunark, can you spare
a crew to build us a duplicate of that Fenachrone ship, besides those
you are going to build for yourself?"

"Certainly. I will be only too glad to do so."

"Well, then, while Dunark is doing that, I suggest that we go to this
Third Planet, abduct a few of their leading scientists, and read their
minds. Then do the same, visiting every other highly advanced planet we
can locate. There is a good chance that, by combining the best points of
the warfares of many worlds, we can evolve something that will enable us
to turn back these invaders."

"Why not send a copper torpedo to destroy their entire planet?"
suggested Dunark.

"Wouldn't work. Their detecting screens would locate it a thousand
million miles off in space, and they would ray it. With a zone of force
that would get through their screens, that would be the first thing I'd
do. You see, every thought comes b