He let fly an oath at this, and his tone was dangerous; no wonder if the lad was half crazed!  I steadied him as well as I could with word of encouragement, and instructed him to turn about and proceed to the right of his original position.  I, also, turned to the left.

Our hope of meeting lay in the probability that the ledge surrounded a circular body of water and was continuous.  At some point, of course, was the entrance of the stream which had carried us, and at some other point there was almost certainly an outlet; but we trusted to luck to avoid these.  Our chances were less than one in a thousand; but, failing that, some other means must be invented.

The simplest way would have been for me to take to the water and swim across to Harry, counting on his voice as a guide; but the conflicting echoes produced by the slightest sound rendered such an attempt dangerous.

I crept along that wet, slimy, treacherous surface, it seemed, for hours.  I could see nothing—­absolutely nothing; everything was black void; it was hard to appreciate reality in such a nightmare.  On the one side, nameless dangers; on the other, the unseen, bottomless lake; enough, surely, to take a man’s nerve.  My fear for Harry killed anxiety on my own account.  We kept continually calling: 

“Harry!”

“Yes.”

“Steady.”

“Yes.  I’m coming along.  I say, we’re closer, Paul.”

I hesitated to agree with him, but finally there was no longer any doubt of it.  His voice began to reach me almost in natural tones, which meant that we were near enough for the vibrations to carry without interference from the walls.

Nearer still it came; it was now only a matter of a few feet; Harry gave a cry of joy, and immediately afterward I heard his low gasp of terror and the sound of his wild scrambling to regain a foothold.  In his excitement he had forgotten caution and had slipped to the edge of the water.

I dared not try to go to his assistance; so I crouched perfectly still and called to him to throw himself flat on his face.  How my eyes strained despairingly as I cursed the pitiless darkness!  Then the scrambling ceased and the boy’s voice sounded: 

“All right, Paul!  All right!  Gad, I nearly went!”

A minute later I held his hand in mine.  At that point the incline was at a sharp angle, and we lay flat on our backs.  For many minutes we lay silently gripping hands; Harry was trembling violently from nervous fatigue, and I myself was unable to speak.

What strength is there in companionship!  Alone, either of us would probably have long before succumbed to the strain of our horrible situation; but we both took hope and courage from that hand-clasp.

Finally he spoke: 

“In Heaven’s name, where are we, Paul?”

“You know as much as I do, Harry.  This cursed darkness makes it impossible even to guess at anything.  According to Felipe, we are being entertained by the devil.”