dozen of them. Remember, this place was designed not
only to protect itself, but Earth, too."

"They can still pull, can't they?"

"They'll stop pulling when they get their fingers burned. In the
meantime, why not use some of those IP ships to bring in a few more
cargoes of charged mercury?"

"They aren't good for much else, are they? I wonder if those fellows
have anything more we don't know?"

"Oh, probably. I'm going to work on that crumbler thing. That's the
first consideration now."

"Why?"

"So we can move a ship. As it is, even those two we built aren't any
good."

"Would they be anyway?"

"Well--I think I might disturb those gentlemen slightly. Remember, they
each have a nose-beam eighteen feet across. Exceedingly unpleasant
customers."

"Score: Strangers; magnetic field, atomic bombs, atomic power, crumbler
ray. Home team; UV beams."

Kendall grinned. "I'd heard you were a pessimistic cuss when battle
started--"

"Pessimistic, hell, I'm merely counting things up."

"McClellan had all the odds on Lee back in the Civil War of the
States--but Lee sent him home faster than he came."

"But Lee lost in the end."

"Why bring that up? I've got work to do." Still smiling, Kendall went to
the laboratory he had built up in the "Lunar Bank." Devin was already
there, calculating. He looked unhappy.

"We can't do anything, as far as I can see. They're using an electric
field all right, and projecting it. I can't see how we can do that."

"Neither can I," agreed Kendall, "so we can't use that weapon. I really
didn't want to anyway. Like the neutron gun which I told Commander
McLaurin would be useless as a weapon, they'd be prepared for it, you
can be sure. All I want to do is fight it, and make their projection
useless."

"Well, we have to know how they project it before we can break up the
projection, don't we?"

"Not at all. They're using an electric field of very high frequency, but
variable frequency. As far as I can see, all we need is a similar
variable electric field of a slightly different frequency to heterodyne
theirs into something quite harmless."

"Oh," said Devin. "We could, couldn't we? But how are you going to do
that?"

"We'll have to learn, that's all."

* * * * *

Buck Kendall started trying to learn. In the meantime, the Mirans were
taking over Jupiter. There were three IP stations on the planet itself,
but they were vastly hindered by the thi