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.
7
As I proceeded, the river became narrower and the current swift and turbulent--so swift in fact that it was with difficulty that I forced my craft upward at all. I could not have been making to exceed a hundred yards an hour when, at a bend, I was confronted by a series of rapids through which the river foamed and boiled at a terrific rate.
My heart sank within me. The sorapus nutshell had proved a false prophet, and, after all, my intuition had been correct--it was the left-hand channel that I should have followed.
Had I been a woman I should have wept. At my right was a great, slow-moving eddy that circled far beneath the cliff 's overhanging side, and to rest my tired muscles before turning back I let my boat drift into its embrace.
I was almost prostrated by disappointment. It would mean another half-day's loss of time to retrace my way and take the only passage that yet remained unexplored. What hellish fate had led me to select from three possible avenues the two that were wrong?
As the lazy current of the eddy carried me slowly about the periphery of the watery circle my boat twice touched the rocky side
of the river in the dark recess beneath the cliff. A third time it struck, gently as it had before, but the contact resulted in a different sound--the sound of wood scraping upon wood.
In an instant I was on the alert, for there could be no wood within that buried river that had not been man brought. Almost coinci-dentally with my first apprehension of the noise, my hand shot out across the boat's side, and a second later I felt my fingers gripping the gunwale of another craft.
As though turned to stone I sat in tense and rigid silence, straining my eyes into the utter darkness before me in an effort to discover if the boat were occupied.
It was entirely possible that there might be men on board it who were still ignorant of my presence, for the boat was scraping gently against the rocks upon one side, so that the gentle touch of my boat upon the other easily could have gone unnoticed.
Peer as I would I could not penetrate the darkness, and then I listened intently for the sound of breathing near me; but except for the noise of the rapids, the soft scraping of the boats, and the lapping of the water at their sides I could distinguish no sound. As usual, I thought rapidly.
A rope lay coiled in the bottom of my own craft. Very softly I gathered it up, and making one end fast to the bronze ring in the prow
I stepped gingerly into the boat beside me. In one hand I grasped the rope, in the other my keen long-sword.
For a full minute, perhaps, I stood motionless after entering the strange craft. It had rocked a trifle beneath my weight, but it had been the scraping of its side against the side of my own boat that had seemed most likely to alarm its occupants, if there were any.
But there was no answering sound, and a moment later I had felt from stem to stern and found the boat deserted.
Groping with my hands along the face of the rocks to which the craft was moored, I discovered a narrow ledge which I knew must be the avenue taken by those who had come before me. That they could be none other than Thurid and his party I was convinced by the size and build of the boat I had found.
Calling to Woola to follow me I stepped out upon the ledge. The great, savage brute, agile as a cat, crept after me.
As he passed through the boat that had been occupied by Thurid and the therns he emitted a single low growl, and when he came beside me upon the ledge and my hand rested upon his neck I felt his short mane bristling with anger. I think he sensed telepathi-cally the recent presence of an enemy, for I had made no effort to impart to him the nature of our quest or the status of those we tracked.
This omission I now made haste to correct, and, after the manner of green Martians with their beasts, I let him know partially by the weird and uncanny telepathy of Barsoom and partly by word of mouth that we were upon the trail of those who had recently occupied the boat through which we had just passed.
A soft purr, like that of a great cat, indicated that Woola understood, and then, with a word to him to follow, I turned to the right along the ledge, but scarcely had I done so than I felt his mighty fangs tugging at my leathern harness.
8
As I turned to discover the cause of his act he continued to pull me steadily in the opposite direction, nor would he desist until I had turned about and indicated that I would follow him voluntarily.
Never had I known him to be in error in a matter of tracking, so it was with a feeling of entire security that I moved cautiously in the huge beast's wake. Through Cimmerian darkness he moved along the narrow ledge beside the boiling rapids.
As we advanced, the way led from beneath the overhanging cliffs out into a dim light, and then it was that I saw that the trail had been cut from the living rock, and that it ran up along the river's side beyond the rapids.
For hours we followed the dark and gloomy river farther and farther into the bowels of Mars. From the direction and distance I knew that we must be well beneath the Valley Dor, and possibly beneath the Sea of Omean as well--it could not be much farther now to the