They set off along the waterway, Errington instructing Lo San to stop at the opening into the pool, and report, before paddling farther, whether he saw any sign of the enemy. On reaching this point, they found neither boat nor men; it was clear that Errington had guessed rightly.
As soon as the hydroplane was well out on the pool, the tow-rope was cast off, the planes were outspread, and Errington started the engine, setting the vessel straight towards the channel leading to the river. When it had gathered speed, a touch on the elevator sent it aloft, and Errington steered to the right, intending to strike the river about half-a-mile lower down than the mouth of the channel. He kept fairly low, so that the flying boat should be concealed from the gunboat by the intervening trees.
They came to the river, and instantly saw with alarm that their precaution was futile. In a recess of the opposite bank, with black smoke pouring from its funnel, lay the gunboat. The small boat was at that moment being taken on board. The rebels had chosen this position to lie in wait, partly to be out of the current, partly to cut off the escape of the hydroplane down the river if it eluded the search parties.
Errington at once steered the machine back towards the land. He dared not risk a straight flight down-stream, within range of the guns; another mishap might put the engine wholly out of action, and in spite of the expenditure of petrol, flying must be kept up for some minutes longer. That he did wisely was immediately proved. A fusillade broke out from the deck of the gunboat, and in another half-minute the machine guns opened fire. Luckily they had been trained hurriedly, and the shots went wide of the mark. Before they could be fired again the flying boat was out of sight behind the trees.
It was some minutes before Errington ventured to direct his course again towards the river. Everybody on board the flying boat expected that the rebels would by this time have come to the conclusion that pursuit was hopeless. The vessel alighted safely on the stream, and bearing in mind the necessity of husbanding the petrol, Errington thought he might now let it drift along on the current.
But he was disabused in a very short time. For some miles the river wound with such frequent curves that only short stretches of it were visible in either direction. Thus it was with a shock of surprise that the occupants of the flying boat discovered, on nearing the end of a straight reach, that the gunboat was coming down at full speed scarcely half-a-mile behind them. Errington at once started the engine; the vessel cut round the curve, and planed along at a rate far exceeding the maximum of which the gunboat was capable.
"We can easily keep ahead as long as the petrol lasts," said Burroughs; "but it seems as if the beggars know by instinct that we're running short. The worst of it is that we've several long straight reaches to navigate a little lower down, and there they can fire at us as they please."
"Wouldn't it be better to go ahead full speed until the petrol gives out?" said Errington. "We could gain at least a dozen miles on the gunboat."
"And still be forty from Sui-Fu, absolutely helpless."
"Why not run up some creek, then, and hide until she has passed or given it up?"