During the afternoon Dave made himself a good bow and also several arrows. The captain followed his example, and also cut several good-sized clubs. "We must arm ourselves as best we can," said Captain Broadbeam. "If those savages should happen to come this way we'll be at their mercy." It was almost sundown when Dave chanced to go down to the ocean front once more. He looked out to sea and then gave a cry that aroused all of the others. "A ship! A ship!" CHAPTER XX AN ATTACK IN THE DARK Dave's cry brought Captain Broadbeam to the shore in a hurry. "Where is the ship?" he demanded. "There!" and the young diver pointed with his hand. "You are right, lad. But she is not headed for this island." "Can she be the _Swallow_?" "I should say not." "Maybe she is the _Raven_." "It is possible, Dave. But she is not coming here, that is certain." "Shall we set up a shout?" "It will do no good. They could not hear us." "We might fly a signal of distress." "It is too dark for that now." Both watched the ship with interest. The captain was right, the vessel was not headed for the island, and in a few minutes it passed from view. "If that was a friendly vessel, it's a chance gone," was Dave's sober comment. "True, but it cannot be helped." As usual in the tropics, night came on quickly. There was no moon, but countless stars shone from on high. The birds ceased their songs, and presently all was quiet. "I suppose we may as well proceed to make ourselves comfortable," said Dr. Barrell. "Somebody has got to remain on guard," came from Dave, who was not inclined to forget that the gorilla was still at large. "We'll divide up the night into three watches of three hours each," said the captain. "I can take one watch, Dave another, and the doctor the third." So it was arranged, and it fell to Dave to go on guard first. "That suits me," said the young diver. "I hate to break in on my night's rest after I have once retired." A comfortable spot had been selected for all hands. It was located about two hundred feet from the shore, where there was a series of rocks and some trees. The doctor had fashioned some brushwood into a shack, and gathered additional brushwood for bedding. To keep himself awake Dave began to walk around the camp, and also made several trips down to the ocean front. He carried his bow and his arrows with him, to help guard against any surprise. On his second trip down to the shore he noticed a strange fire a long distance off. "That must be a camp-fire of some sort," he mused. "Perhaps it is that of the savages on that other island." He watched the fire for a quarter of an hour and gradually it died away, leaving the ocean as dark as before. It must be confessed that his day's tramping had made Dave sleepy, and it was all he could do to keep his eyes open. "I'll be glad when it comes my turn to go to bed," he thought.