. We are masters still; masters of the world, and of the
forest men.

"You have revolutionized the tactics of warfare with your explosive
rockets and your strategy of fighting from concealed positions, miles
away, where we cannot find you with our beams. You have driven our ships
from the air, and you may destroy our cities. But we shall be gone.

"Down these tunnels we shall depart to our new cities, deep under
ground, and scattered far and wide through the mountains. They are
nearly completed now.

"You will never blast us out of these, even with your most powerful
explosives, because they will be more difficult for you to find than it
is for us to locate a forest gunner somewhere beneath his leafy screen
of miles of trees, and because they will be too far underground."

"But," I objected, "man cannot live and flourish like a mole continually
removed from the light of day, without the health-giving rays of the
sun, which man needs."

"No?" San-Lan jeered. "Wild tribesmen might not be able to, but we are a
civilization. We shall make our own sunlight to order in the bowels of
the earth. If necessary, we can manufacture our air synthetically; not
the germ-laden air of Nature, but absolutely pure air. Our underground
cities will be heated or refrigerated artificially as conditions may
require. Why should we not live underground if we desire? We produce all
our needs synthetically.

"Nor will you be able to locate our cities with electronic indicators.

"You see, Rogers, I know what is in your mind. Our scientists have
planned carefully. All our machinery and processes will be shielded so
that no electronic disturbances will exist at the surface.

"And then, from our underground cities we will emerge at leisure to wage
merciless war on your wild men of the forest, until we have at last done
what our forefathers should have done, exterminated them to the last
beast."

* * * * *

He thrust his jeering face close to mine. "Have you any answer to that?"
he demanded.

My impulse was to plant my fist in his face, for I could think of no
other answer. But I controlled myself, and even forced a hearty laugh,
to irritate him.

"It is a fine plan," I admitted, "but you will not have time to carry it
through. Long before you can complete your new cities you will have been
destroyed."

"They will be completed within the week," he replied triumphantly. "We
have not been asleep, and our m