What might have been the effects of the melancholy into which she was fast sinking, it is hard to tell, had not the unexpected return of the one for whose loss she was grieving, restored her once more to her wonted health and spirits. And here we might lay down our pen, and call our story finished, did we not think that justice to the reader, required that we should explain some things connected with the mysterious, cavern not yet accounted for. How the Indian entered the cave on the night when Hellena fancied she had seen a ghost, and how she made her escape, has been explained, but we have not yet explained how the noises were produced which so alarmed the pirates. It will be remembered that the sleeping place of Black Bill was a recess in the wall of the cavern. Now in the wall, near the head of the negro's bed, there was a deep fissure or crevice. It happened that Bill while lying awake one night, to amuse himself, put his month to the crevice and spoke some words, when to his astonishment, what he had said, was repeated over and over, again. Black Bill in his ignorance and simplicity, supposed that the echo, which came back, was an answer from some one on the other side of the wall. Having made this discovery, he repeated the experiment a number of times, and always with the same result. After awhile, he began to ask questions of the spirit, as he supposed it to be, that had spoken to him. Among other things he asked if the devil was coming after master. The echo replied, "The debil comin' after master," and repeated it a great many times. Bill now became convinced that it was the devil himself that he had been talking to. On the night when the pirates were so frightened by the fearful groan, Bill was lying awake, listening to the captain's story. When he came to the part where he describes the throwing the boy's father overboard, and speaks of the horrible groan, Bill put his mouth to the crevice, and imitated the groan, which had been too deeply fixed in his memory ever to be forgotten, giving full scope to his voice. The effect astonished and frightened him as well as the pirates. With the same success he imitated the Indian war-whoop, which he had learned while among the savages. The next time that the pirates were so terribly frightened, the alarm was caused by Fire Cloud after his visit to the cave on the occasion that he had been taken for the devil by Bill, and an Indian ghost by Hellena. Fire Cloud had remained in another chamber of the cavern connected with the secret passage already described, and where the echo was even more wonderful than the one pronounced from the opening through which the negro had spoken. Here he could hear all that was passing in the great chamber occupied by the pirates, and from this chamber the echoes were to those who did not understand their cause, perfectly frightful.