They advanced, picking their way still more carefully than before, peering into the darkness ahead, occasionally turning to look behind them. The floor of the adit at first sloped slightly downwards, but at length appeared to become level. The air was close and stuffy. Sam, following his young master, and seeing the weird shadows cast on the walls by the smoking flame, was soon in a cold sweat, not so much of fear as of nervous anticipation. His dread of ghosts had disappeared with knowledge; but it was knowledge of a negative kind. He knew there were no ghosts, but his imagination conjured up nameless terrors. More than once he was tempted to retreat, but he was too apprehensive even to halt long enough to strike a light and kindle his own candle, and the sight of Dick’s tall form moving steadily on in front of him helped him to pluck up courage. When they had been walking for a few minutes, Sam suddenly hurried forward and caught Dick by the arm. "I heerd summat!" he whispered hoarsely. Dick stopped. Far from comfortable himself, the touch of Sam’s hand made him jump, and the thumping of his heart was almost audible. They listened intently; no sound struck upon their ears. "It must have been a falling stone," said Dick. "Suppose the roof fell on us, same as it did in the cave!" murmured Sam. "’Tis not likely. Don’t get jumpy, Sam. Let us go on." Again they advanced; a few steps brought them to another adit branching to the right; but a glance at this revealing no struts, Dick decided not to change his course until he had thoroughly explored the passage in which he was. In a few minutes he came to another adit, this time on the left, and this also he passed by for the same reason, and because it was narrower than any of those he had hitherto seen. Now the floor seemed to ascend gradually, and shortly afterwards became much more uneven. At length he stopped short, and waited until Sam came up with him. "Look at this," he whispered. Sam looked, and saw a narrow plank bridge, about seventeen feet long, spanning a black, yawning chasm. "’Tis an old mine shaft," said Dick. "We must cross the bridge." "Will it bear us, think ’ee?" said Sam timorously. "It will, if it bears smugglers carrying tubs. We must try." Dick leant forward and probed the planks with the muzzle of his fowling-piece. "’Tis firm and steady," he said. "I will go first. Don’t start until I get across. The candle will give you more light than it gives me." "I don’t like to see ’ee do it," said Sam, almost whimpering. "If ye fall, ’twill be yer grave." But Dick had already set his foot on the bridge. He trod warily, moving almost by inches until he reached the middle. Then he quickened his pace, and covered the second half in three swift strides. "’Tis quite safe," he whispered, turning at the end. "Didn’ it wamble?" "No." "Not a little teeny bit?" "Come, come, I am heavier than you." "Well, I woll."