From the fact, however, of our being to leeward of him and the wind bearing our shout away, Jackson unfortunately did not appear to hear us. At all events, he made no sign in response whatever, still swimming onwards in the direction of the ship, but leisurely, as if ignorant of any new source of danger. Captain Miles grew intensely excited, as, indeed, we all were by this time; so, jumping up on the poop bulwarks and holding on to the mizzen shrouds, he repeated the cry of warning, all hands taking it up as before in one hoarse shout. "Shark! shark! Look out, man alive! He's now close in upon you, and coming up fast astern!" This time Jackson caught our hail, but still, evidently mistook its import. He thought we only called to him by way of encouraging him to strike out more vigourously for the ship, and he waved his hand in acknowledgment of the signal; then he breasted the waves anew in fine style, although taking it quite easy as if thoroughly confident in himself and not a bit alarmed. The reason he made for the _Josephine_ was that he did not perceive the boat, which he had not seen lowered; and, besides this, it was every now and then hidden from view as it sank down between the ridges of the rollers, while, in addition, his face was turned in the opposite direction to that in which the little craft was approaching him. The captain was in a perfect agony. "Shark! shark!" he again screamed, more than cried, out. "For heaven's sake, strike out, man, or you're lost!" Then, all at once, Jackson appeared to grasp the meaning of the warning; and, looking behind him hurriedly, he caught sight of the cruel monster that was swimming after him, stroke by stroke and ready to sheer up alongside when it thought the proper opportunity had arrived for seizing its prey. It must have given the poor fellow an awful sensation! He could not but have realised the fearful doom that possibly awaited him; for we could, in a moment, even at that distance, notice his face change--a terror-stricken look coming over it in place of its previously buoyant expression. The brave fellow, however, uttered never a word, but only continued swimming on towards us in grim desperation. "Pull, Marline, for God's sake, pull!" shouted out Captain Miles to the mate and those with him in the boat; but, although the men made the water churn up over the bows of the gig in their mad haste to urge it forwards, the relentless shark was quicker in its movements and crept up closer to poor Jackson. It was close in his rear, while the boat was yet thirty or forty yards away; and then, like a flash of lightning, we saw the monster's gleaming white stomach as it threw itself over on its back and opened its wide maw lined with rows of serrated teeth. "My God!" exclaimed Captain Miles, turning away his head, "they are too late!"