They began using it a bit too late this time, but they
had located the radio-produced interference caused by the ship's
invisibility apparatus, and they were sending a beam of interfering
radio energy at us. We are invisible only by reason of the vibration of
the molecules in response to the radio impressed oscillations. The
molecules vibrate in tune, at terrific frequency, and the light can pass
perfectly. What will happen, however, if someone locates the source of
the radio waves? It'll be simple for them to send out a radio beam and
touch our invisible ship with it. The two radio waves impressed on us
now will be out of step and the interference will instantly make us
visible. We can no longer attack them with our atomic hydrogen blast, or
with the gas--both are useless unless we can get close to them, and we
can't come within ten miles of them now. Those bombs of theirs are
effective at that distance."

Again he fell silent, thinking--hoping for an idea that would once more
give them a chance to combat the Kaxorians. His three companions,
equally depressed and without a workable idea, remained silent. Abruptly
Arcot stood up.

"I'm going to speak with the Commander-in-Field here. Then we can start
back for Sonor--and maybe we had better head for home. It looks as
though there is little we can do here."

Briefly he spoke to the young Venerian officer, and told him what he had
learned about the ship. Perhaps they could fly it to Sonor; or it could
be left there undestroyed if he would open a certain control just before
he left. Arcot showed him which one--it would drain out the power of the
great storage tank, throwing it harmlessly against the clouds above. The
Kaxorians might destroy the machine if they wanted to--Arcot felt that
they would not wish to. They would hope, with reason, they might
recapture it! It would be impossible to move that tremendous machine
without the power that its "tank" was intended to hold.

VII

Slowly they cruised back to Sonor, Arcot still engrossed in thought.
Would it be that Venus would fall before the attack of the mighty
planes, that they would sweep out across space, to Earth--to Mars--to
other worlds, a cosmic menace? Would the mighty machines soon be
circling Earth? Guided missiles with atomic warheads could combat them,
perhaps, as could the molecular motion machines. Perhaps these could be
armored with twenty-inch steel walls, and driven into the great
propellers