It was a brilliant day, with very little wind; and having no further anxieties on the score of business, they felt free to experiment with the vessel in the air. They had no doubt of the power of the motor to generate sufficient speed to lift the hydroplane from the surface; their only concern was the stability of it when flying. Opening out the planes, which lay folded close to the vessel, like the wings of a dragonfly, when not required for aerial use, they fixed the collapsible stays and switched their motor on to the air tractor at the bows. The vessel was already planing under the stern propeller; she now rose from the water and sailed along for some time within a few feet of the surface. Then, tempted by the apparently favourable conditions, they rose gradually to a greater height, and felt very well pleased with their success.
Unluckily, however, they came suddenly upon an air pocket, caused no doubt by the difference between the temperature of the air above the banks and that of the cooler air above the river. The machine dropped with a rapidity that took them both by surprise, for as yet they were not very expert airmen. It plunged heavily into the water. They had provided themselves with air-bags, so that the immersion lasted only a few seconds; but the ignition of the engine was stopped, and they found themselves in the unfortunate position of being unable to use the vessel now even as a hydroplane.
With some difficulty they managed, with the help of their Chinese engineer, to get the machine to the bank. Recognizing the awkwardness of their situation if they should find themselves overtaken by night so far from home, they set to work energetically to overhaul the engine. It was a long time before they could make it work again. Meanwhile dusk was drawing on, and they were at least fifty miles from Sui-Fu. When at last they were satisfied that the engine would work well enough to propel them through the water, they knew that it would be quite dark before they reached home.
They pressed on with all the speed of which the engine was capable, keeping well out in the broad river in order to avoid the masses of reeds that fringed the banks. The sky grew darker and darker, though there was a little more light on the water than over the surrounding country. Suddenly their attention was attracted by a continuous whistling, evidently from the siren of a steamer some distance down stream. They felt some curiosity as to the reason of so prolonged a noise; but they had already learnt that in China people do such inconceivable things at such unusual times, looked at from the Western standpoint, that their interest was not seriously engaged.
"Some old buffer of a Chinaman amusing himself, I suppose," said Errington. "They seem to like to hear how much row they can kick up."
They were travelling at the rate of about twenty-five knots, and the whistling grew louder moment by moment. As they steered somewhat nearer to the bank, to take a short cut round a bend, they suddenly came in sight of a small steamer about three hundred yards ahead of them. It was now so nearly dark that the vessel was not very clearly distinguishable.
Almost as soon as they caught sight of it, the scream of the siren suddenly ceased; but immediately they became aware of a shrill babel of voices--cries and shouts in the high tones that Chinamen invariably employ. And as they drew swiftly nearer, they perceived that the vessel was surrounded by a number of sampans, the low punt-like boats used by the lightermen of the ports, and also by the pirates who infested the river.
A moment later they recognized the steamer. There were few vessels of the kind in these high reaches of the Yang-tse-kiang, and they had lived long enough at Sui-Fu to be able easily to distinguish them.
"It's Ting's vessel," said Errington.
Scarcely had he spoken when two or three pistol shots rang out. There was not a doubt that the steamer was being attacked. Burroughs, at the wheel, steered straight for it. Errington snatched up his revolver, but an uneasy suspicion suggesting itself to him, he snapped it, and found that its immersion had rendered it useless.