“But she can shift,” said one of the men.  “They must have been going slow through the fog; she’s creeping up to ten or twelve knots now, I should reckon.”

“Your reckoning’s a trifle out!” snapped Rogers, irritably, from the stern; “but she’s certainly showing us her heels.  Can’t we put somebody ashore and have her cut off lower down?”

“While we’re doing that,” cried Stringer, excitedly, “she would land somewhere and we should lose the gang!”

“That’s right,” reluctantly agreed Rogers.  “Can you see any of her people?”

Through the sheets of rain all peered eagerly.

“She seems to be pretty well loaded,” reported the man beside Stringer, “but I can’t make her out very well.”

“Are we doing our damnedest?” inquired Rogers.

“We are, sir,” reported the engineer; “she hasn’t got another oat in her!”

Rogers muttered something beneath his breath, and sat there glaring ahead at the boat ever gaining upon her pursuer.

“So long as we keep her in sight,” said Stringer, “our purpose is served.  She can’t land anybody.”

“At her present rate,” replied the man upon whose shoulders he was leaning, “she’ll be out of sight by the time we get to Tilbury or she’ll have hit a barge and gone to the bottom!”

“I’ll eat my hat if I lose her!” declared Rogers angrily.  “How the blazes they slipped away from the wharf beats me!”

“They didn’t slip away from the wharf,” cried Stringer over his shoulder.  “You heard what Sowerby said; they lay in the creek below the wharf, and there was some passageway underneath.”

“But damn it all, man!” cried Rogers, “it’s high tide; they must be a gang of bally mermaids.  Why, we were almost level with the wharf when we left, and if they came from below that, as you say, they must have been below water!”

“There they are, anyway,” growled Stringer.

Mile after mile that singular chase continued through the night.  With every revolution of the screw, the banks to right and left seemed to recede, as the Thames grew wider and wider.  A faint saltiness was perceptible in the air; and Stringer, moistening his dry lips, noted the saline taste.

The shipping grew more scattered.  Whereas, at first, when the fog had begun to lift, they had passed wondering faces peering at them from lighters and small steamers, tow boats and larger anchored craft, now they raced, pigmy and remote, upon open waters, and through the raindrift gray hulls showed, distant, and the banks were a faint blur.  It seemed absurd that, with all those vessels about, they nevertheless could take no steps to seek assistance in cutting off the boat which they were pursuing, but must drive on through the rain, ever losing, ever dropping behind that black speck ahead.

A faint swell began to be perceptible.  Stringer, who throughout the whole pursuit thus far had retained his hold upon the man in the bows, discovered that his fingers were cramped.  He had much difficulty in releasing that convulsive grip.