Her voice, subdued and low, breathed a sweetness that seemed almost to be of another world. My ear quivered with the vibrations, and long after she was silent the last mellow note floated through my brain.

Suddenly I became conscious of another sound, scarcely less musical.

It, too, was low; so low and faint that at first I thought my ear deceived me, or that some distant echo was returning Desiree's song down the dark tunnel.

Gradually, very gradually, it became louder and clearer, until at length I recognized it. It was the rush of water, unbroken, still low and at a great distance. I turned to remark on it to Harry, but Desiree took the words from my mouth.

"I seem to hear something--like the surf," she said. "That isn't possible, is it?"

I could have smiled but for the deep note of hope in her voice.

"Hardly," I answered. "I have heard it for several minutes. It is probably some shallows. We must look sharp."

Another fifteen minutes, and I began to notice that the speed of the current was increasing. The sound of the rushing water, too, was quite distinct. Still the raft moved more and more swiftly, till I began to feel alarmed. I turned to Harry:

"That begins to sound like rapids. See that the spears are fastened securely, and stand ready with your oar. Sit tight, Desiree."

One thing was certain: there was nothing to do but go ahead. On both sides the walls of the tunnel rose straight up from the surface of the water; there was nowhere room for a landing-place--not even a foot for a purchase to stay our flight. To go back was impossible; at the rate the current was now carrying us we could not have held the raft even for a moment without oars.

Soon we were gliding forward so swiftly that the raft trembled under us; from the darkness ahead came the sound of the rapids, now increased to a roar that filled the tunnel and deafened us. I heard Harry shouting something, but could not make out the words; we were shooting forward with the speed of an express train and the air about us was full of flying water.

The roar of the rapids became louder and louder. I turned for an instant, shouting at the top of my voice: "Flat on your faces, and hold on for dear life!" Then I dropped down with my oar under me, pa.s.sing my feet under two of the straps and clinging to two others with my hands.

Another few seconds pa.s.sed that seemed an hour. The raft was swaying and lurching with the mad force of the current. I called out again to Harry and Desiree, but my words were completely drowned by the deafening, stunning roar of the water. All was darkness and confusion.

I kept asking myself: "Why doesn't it come?" It seemed an age since I had thrown myself on my face.

Suddenly the raft leaped up under me and away. It seemed as though some giant hand had grasped it from beneath and jerked it down with tremendous force. The air was filled with water, lashing my face and body furiously. The raft whirled about like a cork. I gripped the straps with all the strength that was in me. Down, down we went into the darkness; my breath was gone and my brain whirled dizzily.

There was a sudden sharp lurch, a jerk upward, and I felt the surface of the water close over me. Blinded and dazed, I clung to my hold desperately, struggling with the instinct to free myself. For several seconds the roar of the cataract sounded in my ears with a furious faintness, as though it were at a great distance; then I felt the air again and a sudden cessation of motion.

I opened my eyes, choking and sputtering. For a time I could see nothing; then I made out Desiree's form, and Harry's, stretched behind me on the raft. At the same instant Harry's voice came:

"Paul! Ah, Desiree!"

In another moment we were at her side. Her hands held to the straps on each side with a grip as of death; we had to pry off each of her fingers separately to loosen them. Then we bent her over Harry's knee and worked her arms up and down, and soon her chest heaved convulsively and her lungs freed themselves of the water they had taken. Presently she turned about; her eyes opened and she pressed her hands to her head.

"Don't say 'Where am I?'" said Harry, "because we don't know. How do you feel?"

"I don't know," she answered, still gasping for breath. "What was it?

What did we do?"

I left them then, turning to survey the extent of our damage. There was absolutely none; we were as intact as when we started. The provisions and spears remained under their straps; my oar lay where I had fallen on it. The raft appeared to be floating easily as before, without a scratch.

The water about us was churned into foam, though we had already been carried so far from the cataract that it was lost behind us in the darkness; only its roar reached our ears. To this day I haven't the faintest idea of its height; it may have been ten feet or two hundred.

Harry says a thousand.

We were moving slowly along on the surface of what appeared to be a lake, still carried forward by the force of the falls behind us. For my part, I found its roar bewildering and confusing, and I picked up my oar and commenced to paddle away from it; at least, so I judged.

Harry's voice came from behind:

"In the name of goodness, where did you get that oar?"

I turned.

"Young man, a good sailor never loses an oar. How do you feel, Desiree?"

"Like a drowned rat," she answered, but with a laugh in her voice.

"I'm faint and sick and wet, and my throat is ready to burst, but I wouldn't have missed that for anything. It was glorious! I'd like to do it again."

"Yes, you would," said Harry skeptically. "You're welcome, thank you.

But what I want to know is, where did that oar come from?"

I explained that I had taken the precaution to fall on it.

"Do you never lose your head?" asked Desiree.

"No, merely my heart."

"Oh, as for that," she retorted, with a lightness that still had a sting, "my good friend, you never had any."

Whereupon I returned to my paddling in haste.

Soon I discovered that though, as I have said, we appeared to be in a lake--for I could see no bank on either side--there was still a current. We drifted slowly, but our movement was plainly perceptible, and I rested on my oar.

Presently a wall loomed up ahead of us and I saw that the stream again narrowed down as it entered the tunnel, much lower than the one above the cataract. The current became swifter as we were carried toward its mouth, and I called to Harry to get his spear to keep us off from the walls if it should prove necessary. But we entered exactly in the center and were swept forward with a rush.

The ceiling of the tunnel was so low that we could not stand upright on the raft, and the stream was not more than forty feet wide. That was anything but promising; if the stream really ran through to the western slope, its volume of water should have been increasing instead of diminishing. I said nothing of that to Harry or Desiree.

We had sailed along thus without incident for upward of half an hour, when my carelessness, or the darkness, nearly brought us to grief.

Suddenly, without warning, there was a violent jar and the raft rebounded with a force that all but threw us into the water. Coming to a bend in the stream, the current had dashed us against the other bank.

But, owing to the flexibility of its sides, the raft escaped damage. I had my oar against the wall instantly, shoving off, and we swung round and caught the current again round the curve.

But that bend was to the left, as the other had been, which meant that we were now going in exactly the opposite direction of that in which we had started! Which, in turn, meant the death of hope; we were merely winding in and out in a circle and getting nowhere. Harry and Desiree had apparently not noticed the fact, and I said nothing of it. Time enough when they should find out for themselves; and besides, there was still a chance, though a slim one.

Soon the bed of the stream became nearly level, for we barely moved.

The roof of the tunnel was very low--but a scant foot above our heads as we sat or crouched on the raft. It was necessary to keep a sharp lookout ahead; a rock projecting from above would have swept us into the water.

The air, too, was close and foul; our breath became labored and difficult; and Desiree, half stifled and drowsy, pa.s.sed into a fitful and broken sleep, stirring restlessly and panting for air. Harry had taken the bow and I lay across the stern. Suddenly his voice came, announcing that we had left the tunnel.

I sat up quickly and looked round. The walls were no longer to be seen; we had evidently entered a cavern similar to the one in which we had embarked.

"Shall we lay off?" I asked, stepping across to Harry's side.

He a.s.sented, and I took the oar and worked the raft over to the left.

There was but little current and she went well in. In a few minutes we were in shallow water, and Harry and I jumped off and shoved her to the bank.

Desiree sat up, rubbing her eyes.