le without any sign of a cross-passage or a termination.

"Forward, and silence!" I breathed for a reply.

The end--at least, of the silence--came sooner than we had expected.
Hardly were the last words out of my mouth when a whirring noise
sounded behind us. We glanced over our shoulders as we ran, and at the
same instant an Inca spear flew by not two inches from my head and
struck the ground in front.

Not a hundred feet to the rear we saw a group of Incas rushing along
the passage toward us. Harry wheeled about, raising his spear, but I
grasped him by the arm, crying, "Run; it's our only chance!" The next
moment we were leaping forward side by side down the passage.

It would have fared ill with any who appeared to block our way in that
mad dash; but it remained clear. The corridor led straight ahead, with
never a turn. We were running as we had never run before; the black
walls flashed past us an indistinguishable blur, and the open doorways
were blended into one.

Glancing back over my shoulder, I saw that the small group of Incas was
no longer small. Away to the rear the corridor was filled with rushing
black forms. But I saw plainly that we were gaining on them; the
distance that separated us was twice as great as when we had first
started to run.

"How about it?" I panted. "Can you hold out?"

"If it weren't for this knee," Harry returned between breaths and
through clenched teeth. "But--I'm with you." He was limping painfully,
and I slackened my pace a little, but he urged me forward with an oath,
and himself sprang to the front. His knee must have been causing him
the keenest agony; his face was white as death.

Then I uttered a cry of joy as I saw a bend in the passage ahead. We
reached it, and wheeled to the right. There was solid wall on either
side; the series of doors was ended.

"We'll shake 'em off now," I panted.

Harry nodded.

A short distance ahead we came to another cross-passage, and turned to
the left. Glancing over my shoulder, I saw that our pursuers had not
yet reached the first turn. Harry kept in the lead, and was giving me
all I could do to keep up with him.

We found ourselves now in a veritable maze of lanes and cross-passages,
and we turned to one side or the other at every opportunity. At length
I grasped Harry by the arm and stopped him. We stood for two full
minutes listening intently. There was absolutely no sound of any kind.

"Thank Heaven!" Harry br