"Cast off the tack, Tom, and let the sail fly!" shouted George, and the lad had scarcely time to obey the order when the squall burst furiously upon them. The sail streamed out in the wind like a great banner from the top of the mast, lashing furiously, and shaking the boat to her keel. The crazy craft careened gunwale-to, notwithstanding that George had put his helm promptly up, and in another moment she would undoubtedly have gone over with them; but just as the water was beginning to pour in over the gunwale, _crack_! went the mast and the thwart with it over the side. The boat was nearly half full of water, and in their anxiety to free her, and get her before the wind, the mast and sail parted company from the boat, and they never saw them again. The squall lasted about five minutes, and then passed off, leaving only a gentle breeze behind it. As soon as this was the case, they had a look round for the strange sail, and made her out--a topsail-schooner-- about a mile and a half distant. George saw that there was still a chance for them, so they out oars and pulled vigorously. All was going well, when, to their intense surprise, the craft, after approaching to within little more than a quarter of a mile of them, suddenly put up her helm, and, wearing round, stood away upon a south-westerly course. With one accord George and Tom started to their feet and shouted lustily and repeatedly, "Ship ahoy! _Ship ahoy_! Ship ahoy!" until their throats were so strained that their voices failed them, and they became unable to utter another sound. It was all to no purpose; their cries attracted not the slightest notice; the schooner ran rapidly away from them and at last George in despair laid in his oar, flung himself down in the sternsheets, and covered his eyes with his hands, to shut out the tantalising sight. Half an hour afterwards the reason for this extraordinary conduct on the part of the schooner became apparent, the upper canvas of a large ship under a heavy press of sail appearing in the south-east quarter. That this ship was a man-o'-war was evident at a glance, from the cut of her sails; and the course which she was steering, together with her large spread of canvas, showed that she was in pursuit of the schooner. The first impulse of those in the boat was to out oars and pull toward her, but five minutes' work sufficed to show them that their chance was almost hopeless; the frigate would pass them at a distance of about six miles, and with every eye on board her intently fixed upon the chase, what prospect was there, in that uncertain light, of so small an object as the boat being seen at so great a distance? Nevertheless, they toiled on with dogged perseverance, and did not abandon their efforts until the frigate had passed them, and her topsails had sunk below the horizon. Then indeed they laid in their oars, and directed their whole attention to Walford, whose condition became more alarming every moment.