As we advanced up the river which winds beneath the Golden Cliffs out of the bowels of the Mountains of Otz to mingle its dark waters with the grim and mysterious Iss the faint glow which had appeared before us grew gradually into an all-enveloping radiance.
The river widened until it presented the aspect of a large lake whose vaulted dome, lighted by glowing phosphorescent rock, was splashed with the vivid rays of the diamond, the sapphire, the ruby, and the countless, nameless jewels of Barsoom which lay incrusted in the virgin gold which forms the major portion of these magnificent cliffs.
Beyond the lighted chamber of the lake was darkness--what lay behind the darkness I could not even guess.
To have followed the thern boat across the gleaming water would have been to invite instant detection, and so, though I was loath to permit Thurid to pass even for an instant beyond my sight, I was forced to wait in the shadows until the other boat had passed from my sight at the far extremity of the lake.
Then I paddled out upon the brilliant surface in the direction they had taken.
When, after what seemed an eternity, I reached the shadows at the upper end of the lake I found that the river issued from a low aperture, to pass beneath which it was necessary that I compel Woola to lie flat in the boat, and I, myself, must need bend double before the low roof cleared my head.
Immediately the roof rose again upon the other side, but no longer was the way brilliantly lighted.Instead only a feeble glow emanated from small and scattered patches of phosphorescent rock in wall and roof.
Directly before me the river ran into this smaller chamber through three separate arched openings.
Thurid and the therns were nowhere to be seen--into which of the dark holes had they disappeared? There was no means by which I might know, and so I chose the center opening as being as likely to lead me in the right direction as another.
Here the way was through utter darkness.The stream was narrow--so narrow that in the blackness I was constantly bumping first one rock wall and then another as the river wound hither and thither along its flinty bed.
Far ahead I presently heard a deep and sullen roar which increased in volume as I advanced, and then broke upon my ears with all the intensity of its mad fury as I swung round a sharp curve into a dimly lighted stretch of water.
Directly before me the river thundered down from above in a mighty waterfall that filled the narrow gorge from side to side, rising far above me several hundred feet--as magnificent a spectacle as I ever had seen.
But the roar--the awful, deafening roar of those tumbling waters penned in the rocky, subterranean vault! Had the fall not entirely blocked my further passage and shown me that I had followed the wrong course I believe that I should have fled anyway before the maddening tumult.
Thurid and the therns could not have come this way.By stumbling upon the wrong course I had lost the trail, and they had gained so much ahead of me that now I might not be able to find them before it was too late, if, in fact, I could find them at all.
It had taken several hours to force my way up to the falls against the strong current, and other hours would be required for the descent, although the pace would be much swifter.
With a sigh I turned the prow of my craft down stream, and with mighty strokes hastened with reckless speed through the dark and tortuous channel until once again I came to the chamber into which flowed the three branches of the river.
Two unexplored channels still remained from which to choose;nor was there any means by which I could judge which was the more likely to lead me to the plotters.
Never in my life, that I can recall, have I suffered such an agony of indecision.So much depended upon a correct choice;so much depended upon haste.
The hours that I had already lost might seal the fate of the incomparable Dejah Thoris were she not already dead--to sacrifice other hours, and maybe days in a fruitless exploration of another blind lead would unquestionably prove fatal.
Several times I essayed the right-hand entrance only to turn back as though warned by some strange intuitive sense that this was not the way.At last, convinced by the oft-recurring phenomenon, I cast my all upon the left-hand archway; yet it was with a lingering doubt that I turned a parting look at the sullen waters which rolled, dark and forbidding, from beneath the grim, low archway on the right.
And as I looked there came bobbing out upon the current from the Stygian darkness of the interior the shell of one of the great, succulent fruits of the sorapus tree.
I could scarce restrain a shout of elation as this silent, insensate messenger floated past me, on toward the Iss and Korus, for it told me that journeying Martians were above me on that very stream.
They had eaten of this marvelous fruit which nature concentrates within the hard shell of the sorapus nut, and having eaten had cast the husk overboard.It could have come from no others than the party I sought.
Quickly I abandoned all thought of the left-hand passage, and a moment later had turned into the right.The stream soon widened, and recurring areas of phosphorescent rock lighted my way.
I made good time, but was convinced that I was nearly a day behind those I was tracking.Neither Woola nor I had eaten since the previous day, but in so far as he was concerned it mattered but little, since practically all the animals of the dead sea bottoms of Mars are able to go for incredible periods without nourishment.
Nor did I suffer.The water of the river was sweet and cold, for it was unpolluted by decaying bodies--like the Iss--and as for food, why the mere thought that I was nearing my beloved princess raised me above every material want.