By the winding way which we followed along the mountain-top (and that this was the way we wished to follow the King's symbol and the pointing arrow plainly showed), we came presently close beside the rift in the cliffs through which the waters of the upper lake had been discharged upon the city in the valley below and so had buried it. And here we made a very surprising discovery—which was no less than that the great rift in the rocks through which the water had been let loose was not, as we had supposed, the result of some fierce convulsion of nature, but very plainly was the fiercer work of man. Along the face of the opening whence the water had poured forth the rock was grooved, showing that drill-holes had been made, close together, from the edge of the cliff backward to the lake that once had filled all the valley now lying bare and empty before us; and with the field-glass we could see that there was a like channelling of the rock upon the farther side of the break. And all doubt in our minds in regard to this matter was removed by our finding a vastly long drill—made of the bright, hard metal that we now were familiar with, yet could not at all understand its composition—lying close beside the chasm upon the bare rock.

"There has been the devil's own work here!" said Rayburn, as he fully took in this extraordinary situation. "Whoever did this must have spent months over it, perhaps years, working with such tools as these. They evidently went at it systematically, with the deliberate intention of drowning the whole crowd down below. From an engineering stand-point I must say that it's a good piece of work. See how cleverly they've picked out this particular spot, where the wall of rock went down almost perpendicularly into the lake, and so got the full value of the thrust of the water when their cuts were finished. If I'm not mistaken, there was a third line of drill-holes sunk in the middle of the mass that they meant to cut loose. That's the way I should have done it: then there would have been a little giving in the centre that would have helped to loosen the sides. But what a lot of incarnate devils they must have been to go at such a job!"

Truly, there was something chilling to the blood in the thought of the slow labor of them who had toiled here, day after day and month after month, until their ghastly purpose was accomplished, and they had slain a whole city without striking a single honest blow. Such vengeance upon an enemy as here was taken never had its equal for cold, malignant cruelty since the world began. Down in the valley below we had seen gleaming beneath the calm surface of the lake the bones of the thousands who had perished when this diabolical work was completed, and the waters bounded forth, shining and sparkling in the sunlight, on their mission of death. And whoever let them loose must have stood just where we now were standing; and at sight of what came of their long labor there must have been such joy as no hell could adequately punish in their black hearts.

Our bodies shuddered as we turned and left the scene of this tremendous tragedy; that was the more appalling to us because of the profound mystery in which was buried everything related to it save the fact that it had been.

For a long distance our way went onward beside the bare, deep valley that had been the basin of the lake, and so the thought of the horror which had been wrought so devilishly with its innocent waters lingered gloomily in our minds. Involuntarily we associated the unknown people of a long past time who had perpetrated this hideous wholesale murder with the people for whom we now were searching, and an uncertain dread filled our souls as to what might be our own fate should we end by finding what we sought. From the tender mercies of a race in which stealthy craft and cold, malignant cruelty evidently were such conspicuous characteristics, little was to be expected. Therefore, it was in a sombre mood, and with but little talk among us, that we went forward upon our way.

The path that we followed showed the same care in the making of it that we had found in the path leading down from the caÑon into the valley where the drowned city was. Throughout the length of it, by carrying it skilfully along the windings of the mountain-sides, an equable, easy grade was maintained; where it led across open spaces the loose stones had been cleared away and stood heaped along each side of it; where it skirted precipices the solid rock had been cut out in order to give a wider and a surer foothold; and here and there in its course crevices which traversed it were bridged with great slabs of stone. Rayburn was lost in admiration of the engineering skill that was shown in its construction, and declared that a very little extra work put on it would fit it for the laying of a line of rails.

The valley on our right, in which the lake had been, narrowed as we advanced; and as the path that we followed had a steadily rising grade (according to Rayburn's estimate, of a trifle more than three per cent.), the bottom of it fell away rapidly. As we reached what had been, as we found, the foot of the lake, we discovered fresh evidence of the enormous amount of labor that had been expended in order to make its waters an effective engine of destruction. Far in the depths beneath us, extending across the whole width of the valley—but here the valley had so narrowed that it was less a valley than a caÑon—we saw a high and vastly broad stone wall. It was then that we perceived fully the whole of the devilish design, and realized the years that must have been given to its execution. By the building of the wall the level of the lake had been raised fully three hundred feet, and so a head of water had been obtained strong enough to thrust out the mass of rock that had been loosened by drilling through its centre and at its sides. It would have been possible, also, for the rock that was to be broken away to be greatly thinned by quarrying its open face while the water was rising slowly after the great dam was built. Clearly, the whole work had been planned with a calm, diabolical ingenuity that assured with absolute certainty the accomplishment of the horrible purpose that those who labored at it had in view. It seemed impossible, but for the proof that we here had of it, that human hearts could have in them enough of purely devilish cruelty to spend years in thus working out to perfection so hideous a vengeance; and to me it seemed all the more dreadful because of the time that had passed since this most evil deed was done. Centuries had vanished, and the slayers—living out the few years of their lifetime—had perished from off the earth as utterly as had the slain; yet here the whole proof of the great crime that had been wrought lived on in enduring stone that was like to last until the very end of the world should come. Thus had these sinners left behind them, raised by their own hands, a monument telling of their sin; which sin had not even the redeeming quality of passionateness, but was slow and subtle and cruelly cold.

We were glad to turn from sight of this place and press onward into the caÑon, for such the valley now had become; and we found in the dark shadows which enveloped us in this deep cleft between the mountains a sombreness in keeping with the feelings in our hearts. So high above us towered the cliffs that at their top they seemed almost to meet, showing between them only a narrow ribbon of bright blue sky, and below us the chasm went down sheer for a thousand feet; a gloomy depth that our eyes could not have penetrated had there not gleamed at the bottom of it the foam and sparkle of a little stream. Here the path was hewn almost continuously out of the solid rock; and we could see that a like path was cut in the rock on the other side. That so prodigious a piece of work should be thus duplicated seemed to us a very astonishing waste of energy; for even Young did not have much faith in his own suggestion that two prehistoric railway companies had secured rights of way along the opposite sides of the caÑon, and had begun the building there of rival lines.

But the matter was explained, presently, by our finding that this other path was but a doubling of the path that we were on. As we rounded a turn in the caÑon we came suddenly to a broad natural ledge in the rock, over which hung a great projection of the cliff so that the sky above was hid from us. Here our path went off into the air, and began again on the other side of the vastly deep chasm, a good sixty feet away. "Rather long for a jump," was Rayburn's curt comment as we pulled up on the edge of the precipice and looked at each other blankly. Yet it was evident that those who had made with such great expense of toil and time these path-ways on the opposite sides of the caÑon had crossed in some way from the one to the other at this point, and the only surmise that seemed to fit the facts of the case was that there had been stretched across the chasm a swinging bridge of lianas—such as still are to be found spanning streams in the hot lands of Mexico—and that in the course of ages this had rotted entirely away. But as this bridge, if ever there had been one here, was absolutely gone, we found ourselves in as shrewdly strait a place as men well could be in. To go ahead was as clearly impossible as was the hopelessness of turning back upon our path. At the most, we could only return to the valley out of which we had climbed with such thankfulness; and rather than go back to die of starvation in that place, so beautiful and so desolate, there was not one of us but would have chosen to end all quickly by springing into the gulf above which we stood.

But while we thus stood in dreary contemplation of the miserable prospect before us, Young, as his habit was, was spying about him sharply, and so spied out a way of deliverance for us. The announcement of his discovery was made in a very characteristic way.

"You set up to be some punkins of an engineer, now don't you?" he said, addressing Rayburn. "But did you ever happen to hear of a bridge that was hung up at one end an' that was operated by swingin' it backward an' forward like a pendulum?"

"No," Rayburn answered, promptly and decisively, "I never did."

"So I thought," Young went on. "Well, you've admitted that in sev'ral things th' man who was in charge of construction on this line could have given you points, an' this swingin' bridge notion is one of 'em. I can't say that I think much of it. It wouldn't do in railroads, for sure; but there is a good deal to be said in favor of it when it helps folks out of such a hole as we're in now—an' if it still is in workin' order, that is just what it's going to do. There it is. Do you catch on?"

We all looked in the direction in which Young pointed, for his gesture was so earnest that even Fray Antonio and Pablo caught the meaning of it, and so saw—pendent from a point far up on the overhang of rock, and but indistinctly showing in the shadow—a great chain that at its lower end was caught in a metal hook set in the face of the cliff at the extreme back of the ledge on which we stood. For my part, I did not at once catch the meaning of Young's words even when I saw the chain, but Rayburn understood it all in a moment.

"By Jove!" he exclaimed, "that is a notion! You grab the end of it and just swing across to the other side!"

Young already had loosened the chain from the hook and was testing its strength by putting his weight on it. At the end of it was a crossbar big enough to get a good grip upon; and this, and the chain itself, were wrought of the bright, hard metal of which we had encountered so many specimens. The upper end was made fast high above us in the out-jut of rock, very nearly over the centre of the caÑon; so that no great force was required to carry whoever grasped the crossbar, and so swung out boldly, clear across the chasm to the ledge on the other side. But I confess that the thought of such a passage made me feel a little dizzy and sick; and never did I long to be safely back in my class-room at Ann Arbor as I did just then!

"It seems t' be all right," said Young, "but I guess you may as well take a pull on it with me, Rayburn. There'd be no fun in havin' it fetch away when a man was about half across, an' we may as well make th' thing sure." And then, as the chain still held firm under the double strain, he added, "Well, here goes;" and, so speaking, took a running start and went swinging out over the abyss.

My heart was in my mouth as he leaped forth and shot out from and far below us; but in a moment he rose along the curve that he was traversing and was safely landed on the other side. "It's a boss invention. Workin' it is just as easy as rollin' off a log," he called across to us; and to show how easily the passage was made, he instantly swung himself back again.

Pablo had manifested signs of strong uneasiness while this talk and action were in progress, and in a very anxious tone he now inquired: "But how will it be with the Wise One, seÑor?"

"Why, gettin' him across will be as easy as open an' shut," Young answered, speaking in English to Rayburn and to me. "We'll just rig him in th' rope slings again, an' make him fast to th' chain, an' give him a good boost to start him, and over he'll go before he fairly knows he's started."

But when we came to apply this brisk statement of the case practically, we found it by no means easy of execution. El Sabio grew restive as we arranged the slings of rope about his body, evidently remembering, fearfully, the strange journey that he had made in the air when we had rigged him in a like manner in order to trice him up to where the stair began; and he grew yet more restive as we fastened the rope slings to the end of the chain. Rayburn had crossed to the other side—passing the chain back by weighting it with a rock—and stood ready to receive El Sabio when he was swung across. But partly owing to a want of skill in our management of him, yet more to his own unruliness—for just as we started him, with a strong push, he clapped down his fore-feet upon the edge of the cliff and so checked his swing outward—he did not swing within reach of Rayburn's hands. And so he came back towards us again, and then out once more towards Rayburn; and so swung slowly and yet more slowly until at last he hung motionless over the very middle of the gulf, with nothing between him and the rocks below but a thousand feet of air. And then El Sabio began to kick with a vigor that set to rattling every link in the chain!

Pablo was cast by this mischance into a veritable frenzy of fright; and we were most seriously frightened also—not only because the destruction of the poor ass was imminent, but because of the danger which menaced ourselves. Our party was divided, and should the chain give way, under stress of El Sabio's kicks and plunges, all possibility of our coming together again was at an end. Rayburn might leave us and go on; and so, perhaps, save his own life. But for the rest of us there would be no hope. Behind us was death by starvation. In front of us was this impassable gulf.

From Pablo, who was quite wild with dreadful anticipations of the parting of the chain and the loss to him forever of his friend, least was to be expected in the strait wherein we were; yet it was from Pablo that our rescue came. With a quick apprehension of the needs of the case, he rove a running-knot in the end of one of the pack-ropes, and with a dexterous cast of this improvised lasso set the loop of it about El Sabio's neck as that unfortunate animal for a moment ceased his strugglings and hung still. And then we all strained on the rope together, and in a minute had El Sabio safely with us again; but in such a state of terror that pity for him wrung our hearts.

But the limpness which the reaction from such deadly fear threw him into made handling him easy; and this time, when we launched him forth (taking the precaution, however, to fasten one end of a rope to the chain), he went sailing across the full width of the chasm, and Rayburn in a moment had him landed in safety. The instant that the chain was loosened Pablo hauled it back, and an instant later swung lightly across the caÑon, and straightway fell to fondling the terrified creature and comforting him with all manner of tender words. And he so piteously besought us to give El Sabio one good drink that we passed the water-keg and the bucket across, and permitted the poor ass to drink half of our stock of water without debate of the sacrifice. Indeed, this refreshment was so necessary to him that without it I doubt if he could have gone on.

While El Sabio thus gathered courage and strength again, Young swung over to the other side, and we passed our stores across from ledge to ledge—having ropes made fast to the chain, and so steadying each load from the one side while we hauled from the other. This was easy work, and we quickly finished it. When it was ended I braced myself for the flying journey through the air across that gulf so deep that the bottom of it was lost in black shadows, through which the sparkling water faintly gleamed; and my heart so throbbed within me as I took the bar in my hands, with the knowledge that should I lose hold of it death waited for me below in those dark shadows, that my breath came irregularly and I heard a dismal ringing in my ears. Yet I had less to fear than either of the others who had crossed before me, for the ropes still were fast to the chain; and should I not swing far enough I would be helped to safety by my companions. But for shame, I should have made my body fast to the chain by a rope sling, and so have gone across as our stores had gone rather than as a man. But my pride forbade my surrender in this fashion to my fears; and it was a lucky thing for me that it did.

Holding the bar in my hands, I ran briskly across the ledge, and, with a strong kick on the edge of the cliff to give me additional impetus, I went spinning out into space. For an age, as it seemed to me, I sank rapidly; while that horrible feeling possessed me—the like of which people subject to sea-sickness feel as the ship drops away beneath them into the trough of the sea—of falling away from my own stomach. And then, just as my strength seemed to be failing, and my hold on the bar loosing, I perceived that I was rising again; and this put a little fresh heart in me, and I tightened my grip on the bar. Ten seconds, no doubt, was the full extent of the time that my passage consumed; but it seemed to me then, and it seems to me still as I think of it, a long ten years. And a thrill of terror goes through me as I think also of how near I then came to a horrible death; for at the very moment that I reached the farther side of the caÑon there was a little tinkling sound in the air above me, and the bar that I held was twitched out of my hands, and then came a loud jingling of metal on rock, and as I turned quickly I saw a gleam of sunlight catch the great chain as it went twisting downward into the black gulf below.