On arriving at the scene of the wreck, Errington found that to all appearance this had been purely accidental. He arranged for the salvage of the goods, and the forwarding of them in another junk, and then set off in the early afternoon on the return journey. 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.