But his foot did not slip, and he reached the top in safety. A little ravine lay at his feet, and on the other side of this, close to the river bank, there stood a stone tower. Eager to examine this curiosity, Carl partly ran, and partly slid down the hill, which was much less steep on that side, and ran across the ravine to the base of the tower. It was all that was left of an old castle. Many of the stones had fallen from the top, and some from its sides, and it was a very shaky-looking affair. But Carl did not care for this. The walls were very thick, and he felt sure the large broken pinnacle at the top was broad enough for him to stand on. It would be great fun to stand on that! He forgot his promise to his mother, and began at once to climb; sometimes lifting himself up by taking hold of projecting stones, and sometimes working up by putting feet and hands into crevices in the wall. He was not half way up when he made a mis-step. He felt that he was slipping, and clutched frantically at a projecting stone. He grasped the stone with both hands, but alas! it shook with the grasp, and Carl knew that it was giving way. He hung thus but a moment, though it seemed a long period to him, for he had time to think of his home, and his father, and mother, and little sisters, and that he should never see them more. He wondered if they would ever know what had become of him, and would learn, that he did die, finally, in a fool-hardy adventure, as everybody had always said he would. Then the stone rolled out from the wall, and out of Carl’s hands, falling some thirty feet, and plunging into the water with great force. And down went Carl, right in its track. This part of the river was the home of a kind, and beautiful Water-Lady, called by the Germans a Nix. Looking up through the water (for she spent nearly all her time at the bottom of the river) she saw Carl climb the hill, and was so much pleased with his skilful climbing and his bright face, that when he reached the top of the hill, she floated up to the surface of the water to see what he would do next. She watched him down the hill, and across the ravine; but, when he stood looking up to the top of the ruined tower, the Nix guessed that he was thinking of climbing it; and she determined to draw him away from this dangerous place. The Nixies play upon the harp lovely music that mortals may not hope to play. So the Nix went down to the bottom of the river and soon reappeared on the surface with a graceful harp, made of beaten gold. She left the river, and, standing among the water plants at the foot of the hill Carl had climbed, she played soft, sweet strains of fairy music on her harp. In this way she thought she would beguile him from the dangerous tower back to the hill; and, when he was safe, she would disappear; for the Nixies do not care to be seen of mortals.