She had slipped unseen through the yard-entrance and passed behind two or three small craft, so that she had fairly got her speed up before we saw her. Now she was flying down the stream, near in to the shore, going at a tremendous rate. Jones looked gravely at her and shook his head.

“She is very fast,” he said. “I doubt if we shall catch her.”

“We must catch her!” cried Holmes, between his teeth. “Heap it on, stokers! Make her do all she can! If we burn the boat we must have them!”

We were fairly after her now. The furnaces roared, and the powerful engines whizzed and clanked, like a great metallic heart. Her sharp, steep prow cut through the river-water and sent two rolling waves to right and to left of us. With every throb of the engines we sprang and quivered like a living thing. One great yellow lantern in our bows threw a long, flickering funnel of light in front of us. Right ahead a dark blur upon the water showed where the Aurora lay, and the swirl of white foam behind her spoke of the pace at which she was going. We flashed past barges, steamers, merchant-vessels, in and out, behind this one and round the other. Voices hailed us out of the darkness, but still the Aurora thundered on, and still we followed close upon her track.

“Pile it on, men, pile it on!” cried Holmes, looking down into the engine-room, while the fierce glow from below beat upon his eager, aquiline face. “Get every pound of steam you can.”

“I think we gain a little,” said Jones, with his eyes on the Aurora.

“I am sure of it,” said I. “We shall be up with her in a very few minutes.”