Two hours after the start the country again began taking on a sudden change.  From east and west the wild mountain ridges closed in, and with each mile’s progress the stream narrowed and grew swifter, until again it was running between chasm walls that rose black and silent over the adventurers’ heads.  Darker and gloomier became the break between the mountains.  Far above, a thousand feet or more, dense forests of red pine flung their thick shadows over the edge of the chasm, in places almost completely shutting out the light of day.  This was not like the other chasm.  It was deeper and darker and more sullen.  Under its walls the gloom was almost that of night.  Its solitude was voiceless; not a bird fluttered or chirped among its rocks; the lowest of whispered words sounded with startling distinctness.  Once Rod spoke aloud, and his voice rose and beat itself in the cavernous depths of the walls until it seemed as though he had shouted.  Now they ceased paddling, and Mukoki steered.  Noiselessly the current swept them on.  In the twilight gloom Rod’s face shone with singular whiteness.  Mukoki and Wabigoon crouched like bronze silhouettes.  It was as if some mysterious influence held them in its power, forbidding speech, holding their eyes in staring expectancy straight ahead, filling them with indefinable sensations that made their hearts beat faster and their blood tingle.

Softly, from far ahead, at last there came a murmur.  It was like the first gentle whispering of an approaching wind, the soughing of a breath among the pines at the top of the chasm.  But a wind among the trees rises, and then dies away, like a chord struck low and gently upon some soft-toned instrument.  This whisper that came up the chasm remained.  It grew no louder, and sometimes it almost faded away, until the straining ears of those who listened could barely detect it; but after a moment it was there again, as plainly as before.  Little by little it became more distinct, until there were no longer intervals when it died away, and at last Wabigoon turned in the bow and faced his companions, and though he spoke no word there was the gleam of a great excitement in his eyes.  Rod’s heart beat like a drum.  He, too, began to understand.  That moaning, whispering sound floating up the chasm was not the wind, but the far-away rumble of the third waterfall!

Mukoki’s voice broke the tense silence from behind.

“That the fall!”

Wabigoon replied in words scarcely louder than a whisper.  There was no joyful shouting now, as there had been at the discovery of the second fall.  Even Mukoki’s voice was so low that the others could barely hear.  Something between these chasm walls seemed to demand silence from them, and as the rumble of the cataract came more and more clearly to their ears they held their breath in voiceless anticipation.  A few hundred yards ahead of them was the treasure which men long since dead had discovered more than half a century before; between the black mountain walls that so silently guarded that treasure there seemed to lurk the spirit presence of the three men who had died because of it.  Here, somewhere very near, John Ball had been murdered, and Rod almost fancied that along the sandy edge of the chasm stream they might stumble on the footprints of the men whose skeletons they had discovered in the ancient cabin.