It was a vague sort of consolation to find that his wrist watch, which was guaranteed to stand any amount of tough handling on land or sea or air, had stood up to this last test. It was still ticking smoothly over, and he could time his laborious progress by the luminous dial. The floor of the tunnel seemed to be practically level, and long-forgotten eroding waters had worn it flat and eaten the jaggedness off the irregularities which had survived, so that worming along on his stomach was not so arduous as it might have been. Once he cracked his head against a wall of rock right in his path, and so found that the passage took a twist to the right. After that, he felt his way gingerly, and thus circumnavigated the subsequent windings uninjured. Always he made sure that the air blew on his face, and by that means he saved himself the expenditure of much time and energy on following up a side branch which must have been a blind alley. He went on like this for over an hour, and at the end of that time, raising himself slowly to his feet, he found that the roof had receded far enough to allow him to proceed upright, which was an improvement. Still he felt his way forward very carefully with feet and hands, for he had no desire to step over the edge of a small precipice or run his head against a sudden dip of the rock above. He kept one hand on the wall to steer by and worked patiently on. The darkness had that pitchy intensity which torments the eyes and rasps the nerves to a shrieking rawness. He understood then as never before the full agony of blindness. Queer flashes of crimson rocketed across his sight, and the strain of transferring all his reliance to his sense of touch was working him up into a quivering torment of fraying ganglions. There was a terrible desire to sink down on the stone and crawl aimlessly about till sleep and forgetfulness came. Then this was replaced by the struggling of a childish terror to unthrone his reason and set him pounding helpless fists against the rock—to rush madly into the blackness till he crashed against another wall and was flung broken and screaming to the ground—to give up the attempt altogether and stand raving and cursing this false blindness, praying recklessly for the relief of death. For all the darkness that cloaks the world under the sky is as dazzling sunshine to the awful numbing terror of the darkness in the places under the earth where there had never been light since the beginning.