f Tubes are less your
own invention than we thought?"

Tommy shrugged.

"In any case, Earth is safe."

"Is it?" insisted Denham. "You say they understood at once when you
talked of dimension-travel. Ask the old chap there."

* * * * *

Tommy frowned, then labored with the question. The bearded old man
spoke gravely. At his answer, Tommy grimaced.

"Datl's gone looking for the cave their legends tell of," he said
reluctantly. "He's the lad who wanted the city to gas Earth with some
ghastly stuff they know of, and move over when the gas was harmless
again. But the cave has been lost for centuries, and it's in the
torrid zone--which _is_ torrid! We're near the North Pole of this
planet, and it's tropic here. It must be mighty hot at the equator.
Datl took a ship and supplies and sailed off. He may be killed. In any
case it'll be some time before he's dangerous. Meanwhile, as I said,
we're marooned."

"And more," said Denham deliberately. "By the time the authorities
halfway believed me, and Von Holtz could talk, there were more deaths
from the Death Mist. It wiped out a village, clean. So when it was
realized that I'd caused it--or that was their interpretation--and was
the only man who could cause it again, why, the authorities thought it
a splendid idea for me to come through the Tube. They invited me to
commit suicide. My knowledge was too dangerous for a man to have. So,"
he added grimly, "I have committed suicide. We will not be welcomed
back on Earth, Tommy."

Tommy made an impatient gesture.

"Worry about that later," he said impatiently. "Right now there's a
war on. Rahn's desperate, and the prisoners we took this morning say
Jacaro and his gunmen are there, advising them. Ragged Men have joined
in to help kill civilized humans. And they've still got aircraft."

"Which can still bombard this city," observed Denham. "Can't they?"

Tommy pointed to the many-colored beams of light playing through the
sky overhead.

"No. Those lights were invented to guide night-flying planes back
home. They're static lights--cold lights, by the way--and they
register powerfully when a static-discharge propeller comes within
range of them. If Rahn tries a night attack, Aten and I take off and
shoot them down again. That's that. But we've got to design gas masks
for these people, and I think I can persuade the Council to send over
and take all Rahn's aircraft away to-morrow. But the real em