“Files—the hardest and best made!” he told himself. “They’ll cut through anything but a diamond. Luck’s with me, after all. They didn’t know I had these! Oh, boy!” Everything seemed changed now! Though he was held fast, though he was in some secret dungeon, hope sang a song of joy in his heart. For a moment Tom debated with himself as to the best end of the chain at which to begin filing. It would be more comfortable with that leg-iron off his ankle, but by feeling it in the darkness he could tell that it was broad and thick. It would take some time for even the keen, hard file to cut through it. “I’ll file through one of the links close to the leg-iron,” decided Tom. “That won’t leave much to carry around, and it won’t take long to cut through a link—that is, unless they’re made of case-hardened steel.” But the chain was of the ordinary sort, made of soft iron, and it did not take the young inventor long, practiced as he was in the use of tools, to file apart one of the links. True it was not easy in the darkness, and, more than once, the file slipped and cut Tom’s hands or fingers, for he changed from left to right and back to left in using the file, having taught himself to be ambidextrous in many operations. At last he could feel that the link was nearly severed and then, inserting the small ends of the two files in it, he pried them apart. This leverage broke the thin remaining bit of iron and Tom was free. That is, he was free to move about as he pleased, but he was still within the dark cave, and where it was he could not imagine. “I’ve got to feel my way about,” he told himself. “It’s as dark as the inside of a pocket.” So dark was it that Tom had to tread cautiously and with outstretched hands lest he bump into some obstruction. Whether he was moving toward the steps down which he had come or in the opposite direction, Tom had no means of knowing. His sense of touch alone guided him. He could feel that he was walking along a tunnel, but the size of it he could only guess at. Then, suddenly, on making an elbow turn, he saw, glimmering in the distance, a faint light. It was the light of day, Tom knew, and by that he realized that he had been held captive all night. “That makes it bad,” he mused. “Dad will have done a lot of worrying about me, I’m afraid. But I guess I’ll soon be out of here.” Then, to his ears, came the murmur of voices—voices strange to him. So faint was the light in the distance that it was of no service to him where he stood waiting in the darkness; waiting for he knew not what. The voices increased in loudness, showing that the speakers were approaching. Then he heard footsteps echoing strangely in the hollow tunnel. “If there’s going to be a fight I’d better get ready for it,” Tom told himself fiercely. He stooped and began feeling about on the ground for a loose rock or a club. But he could find nothing. Then like a flash it came to him.