Dave set to work to gather some firewood, thinking a good fire would serve to keep them comfortable in case of a heavy rain. "I shouldn't be surprised if we got a heavy one, when it does come," remarked Captain Broadbeam, as he gazed at the sky. "Storms in the tropics are apt to prove severe," said Doctor Barrell. Having collected the firewood, Dave went out with his bow and arrows to see if he could bring down some more birds. At first he moved but a short distance from the camp, but presently he saw some extra fine birds at a distance and followed them toward the north shore of the island. He had just brought down one bird and was trying for a second when the storm broke and the rain began to come down heavily. "This is severe, and no mistake," he murmured. "Guess I'll have to find shelter unless I want to get soaked." Not far away were some tall rocks, backed up by a clump of bushes and vines. The young diver moved towards the rocks on the run. He was but a few feet away when he saw an opening in front of him--a split in the rocks of unknown depth. He tried to step back to safety, but it was too late. His feet slipped and down he went for several yards. "Hullo, this won't do!" he cried. "I don't want to get into another underground cave!" He tried to climb up the rocks, but again his feet slipped and he went down a yard or two more. This time he struck a solid flooring of rocks, so to descend further was impossible. "Thank fortune the hole isn't any deeper," he said half aloud. The fall had shaken him up somewhat and for the minute he remained where he was, trying to get back his breath. He noticed that the rocks around him were all perfectly smooth, but did not realize what this meant until he tried to crawl to the top of the opening. He could not get a hold anywhere, and as often as he got up a foot or two, he slipped back again. "Well, this is provoking, to say the least," he muttered. "How in the world am I to get out of here?" The rain was now pouring down steadily, and in a very few minutes he was wet to the skin. "If I had a rope or a pole I might get out," he reasoned. But he had absolutely nothing with which to help himself. A quarter of an hour went by and then to Dave's alarm he found the water pouring into the hole steadily from a rivulet above. Soon the water was up to his ankles and it arose steadily to his knees. The storm was now on in all of its fury, and in the forest he could hear the trees swaying and snapping under the pressure of the high wind that was blowing. Again he made an effort to crawl out of the opening. But the rocks were now wet and slippery and afforded no foothold whatever. The wind was increasing steadily until it blew a regular hurricane. High overhead he saw some branches of trees sailing through the air. "I hope those in camp are safe," he said to himself.