Suddenly a sound like heavy peals of thunder reverberated through the water. At a motion from Mr. Lacelle, Eric looked quickly upward, and saw a school of tiny fish, darting with great velocity towards them, and several large fishes in pursuit of the little ones. On they came, straight towards Eric and Mr. Lacelle; but just before reaching them, they turned sharply off in the opposite direction; as they turned, the noise increased to a heavy peal, and ceased as they passed from sight. "How wonderful!" exclaimed Eric, involuntarily; and his voice sounded like roaring and screaming, though he had spoken quite softly. Mr. Lacelle then held at arm's length a small cartridge, which he signalled, by the lines, for the men above to ignite. Almost instantly it exploded. Eric was perfectly astounded by the effects of the report. It seemed as if huge rocks had fallen upon his helmet; and such a crashing, rending sound as accompanied the shock! It was quite as much as he was able to bear in the way of noise. Mr. Lacelle told him afterwards, that the noise of the report in the air would be no louder than that of a common fire-cracker. Eric hoped that Mr. Lacelle would make no more experiments in sound, and the diver did not seem at all anxious to do so. It was rather awe-inspiring, Eric thought, to be walking easily about at the bottom of the sea, knowing that around and above him lay the mighty element of death. And there, under the water, the eighth psalm came into his mind, and he realized its beauty as he had never been able to before. He walked around, picking up shells and curious plants, and being careful to keep near Mr. Lacelle, who was making some calculations about the building of a huge bridge, contemplated by the king. Several large fish swam lazily up to Eric, eyed him curiously, and let themselves be patted upon the back. "How amused Nettie would be!" he thought, and wished the huge fish were less inquisitive, as he did not particularly fancy them. He was quite interested in the flowers, which were as brilliant and beautiful as any upon the land, when suddenly he discovered a heap of shells quite similar to those which Mr. Lacelle had described the day before. He put several handfuls of them into his diver's basket, and then, moving off a few steps, he watched to see what they would do. When all was quiet, they moved slowly at first, then more rapidly, and all crawled away in the same direction. "That is very curious," thought Eric to himself. "I wish I knew what they are."