Presently he stopped the engine and listened. At first, he could hear only the ripple of the tide across some hidden shoal and the wash of the languid swell upon the invisible beach; but after a time a measured thud came out of the distance, and he knew that it was the beat of a steamer's screw.
"Between us and the land, I think," he said.
"Yes, sir; about two miles off," agreed the second officer.
"Then she must be going up the gutter, because there's not a fathom on the banks. We'll go ahead; there's enough water anywhere for us."
The launch swung round on a different course when her engines began to clank, and a man sounded now and then as they ran for the shoals. The lieutenant hardly expected to follow the channel; his object was to keep within hearing of the other vessel, and, if he were lucky, his work would be finished before the tide ebbed much. Suddenly a sharp, pulsatory roar came out of the dark.
"It looks as if she were on the ground and carrying plenty steam," he said, when he had ordered the engines to be stopped. "As they'll no doubt back her off, we'll wait a while, to give them time to ship their cargo."
For the next few minutes the crews of launch and gig listened eagerly. They knew that when the vessel ran aground the steam her stopped engines could not use had blown off. The roar died away, as was to be expected, when the machinery was restarted, hard-astern, but now that the immobility of the stranded craft increased the resistance, the thud of the screw was louder. Presently, it changed to a steady beat that drew away from them; and they knew she had got afloat and was steaming up-channel.
"Easy all, for half an hour!" said the lieutenant, looking at his watch.
The boats lay close together, rolling gently on the languid swell, while the men sat in relaxed attitudes and talked in low voices. Still, there was a feeling of suppressed excitement and it was a relief when their officer grasped the wheel.
"Let her go at half speed!" he ordered.