A reference to his map reassured him, and he went on. But now a fresh doubt assailed him. Suppose his lamp should go out: how would it be possible to get back? If he had been ready to give way to them there were hundreds of such fear-engendered thoughts ready to oppress him; but he fought against them steadily, and was the master as he plodded on, with his faintly marked shadow, distorted and broken as it fell upon the walls, forming his only companion in his quest. "Poor mother!" he thought once; "how alarmed she would be if she could see me now!" "But it must be done," he added, half aloud. "Ours is notoriously a fiery mine. Ah! it is foul here." For the lamp began to sputter and burn dimly within the gauze for a few minutes, till he reached a more open place, thinking--"If I can get this task done, I shall have made the mine comparatively safe, and who knows but the old workings may not prove, with our modern appliances, well worthy of carrying on?" He was so elated by these thoughts that the remainder of his dark subterranean journey seemed not one-half as difficult; and at last he seated himself on a block of stone fallen from the roof to consult his map. "Let me see," he said, half aloud, as, with the map spread upon his knees, he held his lamp so that the dim light might the better fall upon the canvas-backed paper; "I must be about here; and if so, according to this plan the old mine workings might be reached through this gallery, or this, or this." He ran his finger along the different lines drawn in red ink, and was studiously considering how it would be best to proceed if he could win his father, and, through him, the other proprietors, to his plans, when all at once he started up, listening attentively, for it seemed to him that he could hear a sound as of some one working with pick or bar away ahead of the place where he was seated, and not back in the yielding seams of the pit. _Tap_, _tap_, _tap_! Yes, there it was plainly enough, and from a part of the pit where there could be no working going on. What could it be? Nobody would be in that end of the mine. It was completely deserted. He did not believe anyone had been in that part of the great maze for months; there was nothing to bring a pitman there. "Now if I were a superstitious fellow," said Philip to himself, "and ready to believe in ghosts and goblins, I should run back and spread the news that this part of the pit is haunted by the restless spirit of some poor pitman who lost his life here years ago, and comes back to work. But I don't believe in that sort of story, and I'm going to see what it means."