He walked cautiously into the water in the direction of the sound. Soon he was beyond his depth; but, being an expert swimmer, kept on; his outstretched arms answering as antennæ of some huge water-spider, and guarding him from collision with the pillars.
The dripping sound became louder. Now it was just above his head. He felt his way with his hands until it became evident that he was at the end or side of the subterranean lake. But the shore was steep; indeed, a wall. Fixing his fingers into the crevices between the stones, he was able to raise himself half out of the water. Reaching up with one hand he felt the curved edge of a viaduct, by which the dark lake was evidently fed, or had been in earlier days. But, bah! The water now trickling through it was foul. The spring had been stopped, and the viaduct become a sewer; fed doubtless through its rents with the soakage of the city.
But might there not be an opening into the upper air? If not, a great human mole—especially if, to blind scratching power, he adds the skill of one trained in the art of engineering—can possibly make an opening.
The prisoner climbed into the viaduct. It was large enough to allow him to crawl a short distance. A faint glimmer of light proved the correctness of his surmise that it was connected with the surface. But fallen stones blocked his way. As he lay planning with fingers and brain for his further progress, voices sounded from the reservoir. They were those of two of the cut-throats returning. He pushed himself back to the opening. His captors had missed him at the island. If they knew of this sluice, or chanced to come upon it in their search, he was lost in his present position; for a pair of bare heels was the only weapon he could show against their sharp daggers. He let himself down into the water, and swam silently away. The light, however, from his captors' lamp came nearer.
"Hist!" said one. "He is yonder; perhaps by the devil's window."
The boat pushed directly toward the viaduct he had left.
While they explored the opening, which might well be called the window into the blackness of darkness of the nether world, their victim swam rapidly, keeping always in the shadow of the great pillars. But the boat was upon his track again.
The fugitive now made a fortunate discovery. Several feet below the surface of the water the base of each pillar projected far enough for standing room. This base had probably marked the height to which the water was originally allowed to rise. By standing upon one of these projections, he was able to move round the pillar, so as to keep its huge block between himself and his pursuers. Thus they passed him. By the light in the boat he could discern the ground or shore near which was the entrance.
Returning to coast the other side of the cavern, they had passed close by him, when, his foot slipping, he was projected into the water. The wretches hailed with grim joy the splash, and turned the boat in the direction of the noise. But, dropping beneath the surface, the man swam to a pillar near by, from which he watched their baffled circuit of his former retreat.
This chase could not be kept up endlessly. Plunging again under the water, he swam directly to the boat. Rising suddenly, he grasped its side with main weight and overturned it. The cries of the men and the splashing of the boat echoed a hundred times among the arches; while the hissing oil of the open lamp, which, poured on the surface of the water, blazed for a moment, made as near a representation of pandemonium as this world ever affords, except in the brain of the demented.