m corridors seeking their prey. The therns
fear the awful denizens of this cruel and hopeless world that they have
fostered and allowed to grow beneath their feet. The prisoners even
sometimes turn upon them and rend them. The thern can never tell from
what dark shadow an assassin may spring upon his back.

"By day it is different. Then the corridors and chambers are filled
with guards passing to and fro; slaves from the temples above come by
hundreds to the granaries and storerooms. All is life then. You did
not see it because I led you not in the beaten tracks, but through
roundabout passages seldom used. Yet it is possible that we may meet a
thern even yet. They do occasionally find it necessary to come here
after the sun has set. Because of this I have moved with such great
caution."

But we reached the upper galleries without detection and presently
Thuvia halted us at the foot of a short, steep ascent.

"Above us," she said, "is a doorway which opens on to the inner
gardens. I have brought you thus far. From here on for four miles to
the outer ramparts our way will be beset by countless dangers. Guards
patrol the courts, the temples, the gardens. Every inch of the
ramparts themselves is beneath the eye of a sentry."

I could not understand the necessity for such an enormous force of
armed men about a spot so surrounded by mystery and superstition that
not a soul upon Barsoom would have dared to approach it even had they
known its exact location. I questioned Thuvia, asking her what enemies
the therns could fear in their impregnable fortress.

We had reached the doorway now and Thuvia was opening it.

"They fear the black pirates of Barsoom, O Prince," she said, "from
whom may our first ancestors preserve us."

The door swung open; the smell of growing things greeted my nostrils;
the cool night air blew against my cheek. The great banths sniffed the
unfamiliar odours, and then with a rush they broke past us with low
growls, swarming across the gardens beneath the lurid light of the
nearer moon.

Suddenly a great cry arose from the roofs of the temples; a cry of
alarm and warning that, taken up from point to point, ran off to the
east and to the west, from temple, court, and rampart, until it sounded
as a dim echo in the distance.

The great Thark's long-sword leaped from its scabbard; Thuvia shrank
shuddering to my side.

CHAPTER VI

THE BLACK PIRATES OF BARSOOM

"What is it?"