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.