“All right, old man.”

“Don’t waste any time; they’ll probably start for us the instant we sit up.  Be sure you get your feet free at the first stroke; feel them well with your left hand first.  Are you ready?”

“Yes.”  And his voice was now calm and perfectly steady.

“Then—­one, two, three—­go!”

We bent and cut and sprang to our feet, and dashed for the wall.  There was a sound of rushing feet—­our backs hugged the kindly rock—­I heard Harry’s shout, “Here they come!”—­dim, rushing forms—­fingers clutching at my throat.

I felt the blade of my knife sink into soft and yielding flesh, and a warm, thick liquid flow over my hand and arm.

Chapter VIII.

The dance of the sun.

It seemed to me then in the minutes that followed that there were thousands of black demons in that black hole.  At the first rushing impact I shouted to Harry:  “Keep your back to the wall,” and for response I got a high, ringing laugh that breathed the joy of battle.

The thing was sickening.  Harry is a natural fighting man; I am not.  Without the wall at our backs we would have been overpowered in thirty seconds; as it was, we were forced to handle half a dozen of them at once, while the others surged in from behind.  They had no weapons, but they had the advantage of being able to see us.

They clutched my throat, my arms, my legs, my body; there was no room to strike; I pushed the knife home.  They fastened themselves to my legs and feet and tried to bring me down from beneath; once, in slashing at the head of one whose teeth were set in my calf, I cut myself on the knee.  It was difficult to stand in the wet, slippery pool that formed at my feet.

Suddenly I heard a sound that I understood too well—­the curious, rattling sound of a man who is trying to call out when he is being strangled.

“Harry!” I cried, and I fought like a wild man to get to him, with knife, feet, hands, teeth.  I reached his coat, his arm; it was dangerous to strike so near him in the dark, but I felt him sinking to the ground.

Then I found the taut, straining fingers about his throat, and lunged forward with the knife—­and the fingers relaxed.

Again we were fighting together side by side.

As their bodies fell in front of us we were pressed harder, for those behind climbed up on the corpses of their fellows and literally descended on our heads from the air.  We could not have held out much longer; our breath was coming in quick, painful gasps; Harry stumbled on one of the prostrate brutes and fell; I tried to lift him and was unequal to the task.

It appeared to be the end.

Suddenly there rang throughout the cavern a sound as of a gigantic, deep-toned bell.  The walls sent it back and forth with deafening echoes; it was as though the mountain had descended with one tremendous crash into its own bowels.