"It may have been a sea-bird; for we are so near the day, some of them are probably in motion. Was it large?" "Of the size of a man's head, apparently; but this is by no means all. Here, farther to the north, I distinguished three objects in motion, wading in the water, near the point where the rocks are never bare." "They may have been herons; the bird is often found in these low latitudes, I believe. I can discover nothing." "I would to God, I may have been mistaken, though I do not think I could be so much deceived." Paul Blunt caught his arm, and held it like one who listened intently. "Heard you that?" he whispered hurriedly. "It sounded like the clanking of iron." Looking around, the other found a handspike, and passing swiftly up the heel of the bowsprit, he stood between the knight-heads. Here he bent forward, and looked intently towards the lines of chains which lay over the bulwarks, as bow-fasts. Of these chains the parts led quite near each other, in parallel lines, and as the ship's moorings were taut, they were hanging in merely a slight curve. From the rocks, or the place where the kedges were laid to a point within thirty feet of the ship, these chains were dotted with living beings crawling cautiously upward. It was even easy, at a second look, to perceive that they were men stealthily advancing on their hands and feet. Raising the handspike, Mr. Blunt struck the chains several violent blows. The effect was to cause the whole of the Arabs--for it could be no others--suddenly to cease advancing, and to seat themselves astride the chains. "This is fearful," said Mr. Sharp; "but we must die, rather than permit them to reach the ship." "We must. Stand you here, and if they advance, strike the chains. There is not an instant to lose." Paul Blunt spoke hurriedly, and, giving the other the handspike, he ran down to the bitts, and commenced loosening the chains from their fastenings. The Arabs heard the clanking of the iron-rings, as he threw coil after coil on the deck, and they did not advance. Presently two parts yielded together beneath them, and then two more. These were the signals for a common retreat, and Mr. Sharp now plainly counted fifteen human forms as they scrambled back towards the reef, some hanging by their arms, some half in the water, and others lying along the chains, as best they might. Mr. Blunt having loosened the chains, so as to let their bights fall into the sea, the ship slowly drifted astern, and rode by her cables. When this was done, the two young men stood together in silence on the forecastle, as if each felt that all which had just occurred was some illusion. "This is indeed terrible," exclaimed Paul Blunt. "We have not even a pistol left! No means of defence--nothing but this narrow belt of water between us and these barbarians! No doubt, too, they have fire-arms; and, as soon as it is light, they will render it unsafe to remain on deck."