He moved on in an oblique direction for several feet, now creeping over the tops of the foundation arches, now skirting the extremities of the protrusions in the ruined brickwork, now descending into dark, slimy, rubbish-choked chasms, until the rift suddenly diminished in all directions. For a moment Tristan paused and considered. He was almost tempted to retrace his steps, abandoning the purpose upon which he had come. Before him stretched interminable gloom, brooding, he knew not over what caverns and caves, inhabited by denizens of night. He moved onward, with less caution than he had formerly employed, when suddenly and without warning a considerable portion of brickwork fell with lightning suddenness from above. It missed him, else he should never had known what happened. But some stray bricks hurled him prostrate on the foundation arch, dislocating his right shoulder, and shattering his lantern into atoms. A groan of anguish rose to his lips. He was left in impenetrable darkness. For a short time Tristan lay as one stunned in his dark solitude. Then, trying to raise himself, he began to experience in all their severity the fierce spasms, the dull gnawings that were the miserable consequences of the injury he had sustained. His arm lay numbed by his side, and for the space of some moments he had neither the strength nor the will to even move the sound limbs of his body. But gradually the anguish of his body awakened a wilder and strange distemper in his mind, and then the two agonies, physical and mental, rioted over him in fierce rivalry, divesting him of all thoughts, save such as were aroused by their own agency. At length, however, the pangs seemed to grow less frequent. He hardly knew now from what part of his body they proceeded. Insensibly his faculties of thinking and feeling grew blank; he remained for a time in a mysterious, unrefreshing repose of body and mind, and at last his disordered senses, left unguided and unrestrained, became the victims of a sudden and terrible illusion. The black darkness about him appeared, after an interval, to be dawning into a dull, misty light, like the reflection on clouds which threaten a thunderstorm at the close of day. Soon this atmosphere seemed to be crossed and streaked with a fantastic trellis work of white, seething vapor. Then the mass of brickwork which had fallen in, grew visible, enlarged to an enormous bulk and endowed with the power of locomotion, by which it mysteriously swelled and shrank, raised and depressed itself, without quitting for a moment its position near him. And then, from its dark and toiling surface, there rose a long array of dusky shapes, which twined themselves about the misty trellis work above and took the palpable forms of human countenances.