"They're stopped," he cried gleefully, "at least for a little. A piece of rock as big as a house gently slid from above onto their precious heads. It may have blocked them off completely."

We hurried forward then; Harry helped Desiree, while I painfully brought up the rear. At every few steps they were forced to halt and wait for me, though I did my utmost to keep up with them. Harry had taken my spear that I might have both hands to help me over the rocks.

Climbing, sliding, jumping, we left the Incas behind; no sound came from the rear. I began to think that they had really been completely shut off, and several times opened my mouth to call to Harry to ask him if it would not be safe to halt; for every movement I made was torture.

But each time I choked back the cry; he thought it was necessary to go on and I followed.

This lasted I know not how long; I was staggering and reeling forward like a drunken man, so little aware of what I was doing that when Harry and Desiree finally stopped at the beginning of a level, unbroken stretch in the lane, I stumbled directly against them before I knew they had halted.

"Go on!" I gasped, struggling to my feet in a mania.

Harry stooped over to a.s.sist me and set me with my back resting against the wall. Desiree supported herself near by, scarcely able to stand.

"We can go no farther," said Harry. "If they come--"

As he spoke I became aware of a curious movement in the wall opposite--a movement as of the wall itself. At first I thought it a delusion produced by my disordered brain, but when I saw Desiree's astonished gaze following mine, and heard Harry's cry of wonder as he turned and saw it also, I knew the thing was real.

A great portion of the wall, the entire side of the pa.s.sage for a length of a hundred feet or more, was sliding slowly downward.

Glancing above I saw a s.p.a.ce of several feet where the rock had departed from its bed. The only noise audible was a low, grating sound like the slow grinding of a gigantic millstone.

None of us moved--if there were danger we would seem to have welcomed it. Suddenly the great ma.s.s of rock appeared to halt in its downward movement and hang as though suspended; then with a sudden jerk it seemed to free itself, swaying ponderously toward us; and the next moment it had fallen straight down into some abyss below, thundering, tumbling, sliding with terrific velocity.

There was a deafening roar under our feet, the ground rocked as from an earthquake, and it seemed as though the wall against which we stood was about to fall in upon us. Dust and fragments of rock filled the air on every side, and one huge boulder, detached from the roof above, came tumbling at our feet, missing us by inches.

We were completely stunned by the cataclysm, but in a moment Harry had recovered and run to the edge of the chasm opposite thus suddenly formed. Desiree and I followed.

There was nothing to be seen save the blackness of s.p.a.ce. Immediately before us was an apparently bottomless abyss, black and terrifying; the side descended straight down from our feet. Looking across we could see dimly a wall some distance away, smooth and with a faint whiteness.

On either side of us other walls extended to meet the farther wall, smooth and polished as gla.s.s.

"The Incas didn't do that, I hope," said Harry, turning to me.

"Hardly," I answered; and in my absorbing interest in the phenomenon before me I half forgot my pain.

I moved to the edge of one of the walls extending at right angles to the pa.s.sage, but there was little to be made of it. It was of soft limestone, and most probably the portion that had disappeared was granite, carried away by the force of its own weight.

"We are like to be buried," I observed, returning to Harry and Desiree.

"Though for that matter, even that can hardly frighten us now."

"For my part," said Harry, with a curious gravity beneath the apparent lightness of his words, "I have always admired the death of Porthos.

Let it come, and welcome."

"Are we to go further?" put in Desiree.

Just as Harry opened his mouth to reply a more decisive answer came from another source. The rock that had fallen, obstructing the path of the Incas, must have left an opening that Harry had missed; or they had removed it--what matter?

In some way they had forced a pa.s.sage, for as Desiree spoke a dozen spears whistled through the air past our heads and we looked up to see a swarm of Incas climbing and tumbling down the face of a boulder over which we had pa.s.sed to reach our resting-place.

I have said that we had halted in a level, unbroken stretch that still led some distance ahead of us. At its farther end could be seen a group of rocks and boulders completely choking the lane, Beyond, other rocks arose to a still greater height--the way appeared to be impa.s.sable.

But there was no time for deliberation or the weighing of chances, and we turned and made for the pile of rocks, with the Incas rushing after us.

There Desiree and I halted in despair, but with a great oath Harry brushed us aside and leaped upon a rock higher than his head with incredible agility. Then, lying flat on his face and extending his arms downward over the edge, he pulled first Desiree, then myself, up after him. The whole performance had occupied a scant two seconds, and, waiting only to pick up the three spears he had thrown up the sloping surface of the rock to another yet higher and steeper.

"Why don't we hold them here?" I demanded. "They could never come up that rock with us on top."

Harry looked at me.

"Spears," he said briefly; and, of course, he was right. They would have picked us off like birds on a limb.

We scaled the second rock with extreme difficulty, Harry a.s.sisting both Desiree and me; and as we stood upright on its top I saw the Incas scrambling over the edge of the one below. Two or three of them had already started to cross; many more were coming up from behind; and one, as he made the top and arose to his feet, braced himself on the sloping rock and raised a spear high above his head.

At sight of him I started, crying to Harry and Desiree. They turned.

"The king!" I shouted; and I saw a shudder of terror run over Desiree's face as she, too, recognized the black form below. At the same instant the spear darted forward from the hand of the Child of the Sun, but it landed harmlessly against the rock several feet away.

The next moment the Inca king had bounded across the rock toward us, followed by a score of others.

I was minded to try my luck with his own weapon, but we had no spears to waste, and Harry was dragging Desiree forward and shouting to me to follow. I turned and ran after them, and just as we let ourselves down into a narrow crevice below the Incas appeared over the edge of the rock behind.

Somehow we scrambled forward, with the Incas at our heels. Sharp corners of projecting rocks bruised our faces and bodies; once my leg bent double under me as I fell from a ledge onto a boulder below, and I thought it was broken; but Harry jerked me to my feet and I struggled on.

Harry seemed possessed of the strength of ten men and the heart of a thousand. He pulled Desiree and me up and over boulders and rocks as though we had been feathers; the Lord knows how he got there himself!

Half of the time he carried Desiree; the other half he supported me.

His energy and exertions were t.i.tanic; even in the desperate excitement of our retreat I found time to marvel at it.

We did not gain an inch; our pursuers kept close behind us; but we held our own. Now and then a stray spear came hurtling through the air or struck the rock near us, but they were infrequent and we were not hit.

One, flying past my head, stuck in a crevice of the rock and I grasped the shaft to pull it out, but abandoned my effort when I heard Harry shouting to me from the front to come to his aid.

He and Desiree were standing on the rim of a ledge that stood high above the ground of the pa.s.sage. At its foot began a level stretch leading straight ahead as far as we could see.

"We must lift her down," Harry was saying.

He let himself over the ledge, hung by his hands, and dropped. "All right!" he called from below; and I lay flat on the rock while Desiree scrambled over the edge, holding to my hands. For a moment I held her suspended in my outstretched arms; then, at a word from Harry, I let her drop. Another moment and I was over myself, knocking Harry to the ground and tumbling on top of him as he stood beneath to break my fall.

By then the Incas had reached the top of the ledge above us, and we turned and raced down the long stretch ahead. I was in front; Harry came behind with Desiree.

Suddenly, as I ran, I felt a curious trembling of the ground beneath my feet, similar to the vibrations of a bridge at the pa.s.sing of a heavy load.

Then the ground actually swayed beneath me; and, realizing the danger, I sent a desperate shout to Harry over my shoulder and bounded forward.

He was at my side on the instant, with Desiree in his arms.

The ground rocked beneath our feet like a ship in a storm; and, just as I thought we were gone, my foot touched firm rock as I pa.s.sed a yawning crevice a foot wide under me.

One more leap to safety, and we turned just in time to see the floor of the pa.s.sage which we had traversed disappear into some abyss beneath with a shattering roar.

We stood at the very edge of the chasm thus suddenly formed, gazing at each other in silent wonder and awe.

"The beggars are stopped now," said Harry finally. "That break in the game is ours."