Our destination, Thuvia said, was a distant storeroom where arms
and ammunition in plenty might be found. From there she was to
lead us to the summit of the cliffs, from where it would require
both wondrous wit and mighty fighting to win our way through the
very heart of the stronghold of the Holy Therns to the world without.

"And even then, O Prince," she cried, "the arm of the Holy Thern is
long. It reaches to every nation of Barsoom. His secret temples
are hidden in the heart of every community. Wherever we go should
we escape we shall find that word of our coming has preceded us, and
death awaits us before we may pollute the air with our blasphemies."

We had proceeded for possibly an hour without serious interruption,
and Thuvia had just whispered to me that we were approaching our
first destination, when on entering a great chamber we came upon
a man, evidently a thern.

He wore in addition to his leathern trappings and jewelled ornaments
a great circlet of gold about his brow in the exact centre of which
was set an immense stone, the exact counterpart of that which I
had seen upon the breast of the little old man at the atmosphere
plant nearly twenty years before.

It is the one priceless jewel of Barsoom. Only two are known to
exist, and these were worn as the insignia of their rank and position
by the two old men in whose charge was placed the operation of the
great engines which pump the artificial atmosphere to all parts
of Mars from the huge atmosphere plant, the secret to whose mighty
portals placed in my possession the ability to save from immediate
extinction the life of a whole world.