Very soon afterwards they encountered a difficulty which they might have foreseen. The river narrowed to little more than a gorge, through which the water poured in swift swirling volume. A junk was being hauled against the current by a hundred "trackers" on the bank. The channel on one side was obstructed by the tow-ropes; on the other there was not room for the flying boat to pass, because of the rocks that projected into the stream, even though the planes had been folded back. There was nothing for it but to draw into the side, and wait until the vessel had passed. This wasted five minutes of valuable time. The gunboat would, of course, be delayed in the same way; but the gorge was fairly straight, and if she gained the upper end before the fugitives had escaped at the lower, the flying boat would be at the mercy of her guns. Almost immediately after the boat had run in to the bank a shot whistled overhead. Luckily the junk had now passed. Its deck was crowded with Chinamen gazing curiously at the flying boat. At the sound of the shot they yelled with fright, and ran for shelter beneath the port gunwale. A second shot from the gunboat struck away one of the junk’s yards, many of the trackers dropped their ropes and ran for their lives, and the unwieldy vessel fell away towards mid-stream, forming an effective screen against the guns. Profiting by this diversion, Errington again put the engine at speed, and the flying boat raced down the river, out of the gorge, into a broad straight reach that extended apparently for miles. Burroughs glanced into the petrol tank: it was almost empty. All that they had remaining was a little in the bottom of the can which had been pierced by the bullet. Lo San poured this into the tank. Up to this time the Englishmen had retained their confidence; but the accumulated misfortunes of the last few minutes plunged them in desperate anxiety. The drifting of the junk across the stream might be expected to check the gunboat for at least ten minutes, during which they would be safe from gunfire. But as soon as the gunboat got clear, she would have a free field, and unless the flying boat could arrive at the farther end of the long straight reach before the guns could be brought into action, she could hardly escape. Only one course was possible: to use up all the remaining petrol for a last flight. Then the issue was in the hands of Fate. The planes were thrown back. Running on at full speed, the vessel skimmed the surface, rose into the air, and flew along at the rate of fifty miles an hour. The occupants of various sampans, fishermen casting their nets from the banks, men and women at work in the paddy fields beyond, gazed with amazement at the strange object flying over the middle of the river. Before it came to the end of the straight reach the petrol was all consumed; the vessel sank upon the surface; and behind, the gunboat could be seen steaming after it in full career.