He thought of the letter in his pocket, and the desire grew strong within him to read it again. He took it out, unfolded it, and held it close to the light, but there seemed to be a mist before his eyes and he could not distinguish the words. He knew what it contained, though, and that was sufficient for him. He was Robert Burnham's son. His father had been brave and manly; so would he be. His father would have kept up heart and courage to the end, no matter what fate faced him. He determined that the son should do no less. He would be worthy of his parentage, he would do all that lay in his power to accomplish his own safety; if he failed, the fault should not be his. He folded and replaced the letter, picked up his oil-can, fastened his lamp to his cap and started down the chamber. He felt that he was strong with the strength of inspiration. It seemed to him, too, that he was very light in body. It seemed almost as though he were treading on air, and he thought that he was moving very fast. In reality his steps were heavy and halting, and his way down the long chamber was devious and erratic. His fancied strength and elasticity were born of the fever in his blood. He came to the heading. He knew, now, which way to turn, and he passed down it in what he thought was rapid flight. But here was the fall again. What was to be done now? His last attempt to get around it had been disastrous. He would not try that plan again. He would work his way through it this time and keep to the heading. He climbed slowly up over the fallen rock and coal and let himself down upon the other side. But it took his breath away, this climbing, and he had to wait there a little while to recover it. There was a clear space before him, though, and he made good progress through it till he came again to the fall. In this place the rock was piled higher and it was more difficult of ascent. But he clambered bravely up, dragging his oil-can with him; then he moved out along the smooth, sloping surfaces of fallen slate, keeping as close as possible to the wall of the heading, climbing higher and higher, very slowly now, and with much labor, stopping often to rest. He came, at last, to a place where the space between the fallen rock and the roof above it was so narrow that he could scarcely squeeze his slender body through it. When he had done so he found himself on the edge of a precipice, a place where a solid mass had fallen like a wall, and had made a shelf so high that the feeble rays of Ralph's lamp would not reach to the bottom of it. The boy crawled, trembling, along the edge of this cliff, trying to find some place for descent. The oil-can that he carried made his movements cumbersome; the surface of the rock was smooth and hard to cling to; his limbs were weak and his fingers nerveless. He slipped, the can fell from his hand, he tried to recover it, slipped further, made a desperate effort to save himself, failed, and went toppling over into the darkness.