“He’s heading her in for the strait,” said Riggs.  “He had better allow for that tide-rip that comes down through, or she’ll have her head swung round at this speed before he knows where he is at.”

The steamer seemed to be gradually losing headway, and the throbbing of her engines was becoming less pronounced.  I observed, also, that the smoke from her funnel was beginning to hang over her and curl down upon the bridge.  But, in spite of her slowing down, the musical ripple at her bow increased, and Riggs said it was due to the set of the current against us, which came through the channel very strong, as the island cut out a deep current and brought it to the surface of the sea in the narrow passage between the island and the mainland.

“It’s a bad hole in there,” he said.  “He needs more speed to handle her right in there and—­”

“Something is up!” I told him, as I saw Thirkle listen a second and step quickly to the engine-room telegraph and throw it over.

I could hear the sharp clang of the bell; but the next instant there was a terrific roar, and the superstructure began to vomit steam through the engine-room skylight just abaft the little wheel-house.

“The boilers!” yelled Riggs.  “She’s blowing off, and there is a steam-pipe gone, or somebody below has opened her whole insides up.”

The Kut Sang was a white volcano amidships, and I saw Thirkle yelling frantically, and Buckrow and Long Jim appeared in the passage below and yelled to Thirkle, waving their arms, and then dashed up the ladder to the bridge.

Suddenly they started back and grouped themselves about Petrak at the wheel with drawn weapons, and the next instant I saw a half-dozen forms emerge from the welter of steam and dash at the pirates.

They were Chinese and Filipino stokers, but one of them seemed to be the leader, and he wore an engineer’s cap and was stripped to the waist.  I saw the puffs of smoke from the pistols of the four pirates—­Petrak put his back to the wheel and fired over Thirkle’s shoulder—­but the awful racket of the steam-pipes drowned the reports.

Two of the Chinese fell at the first volley, and a third, evidently wounded, turned in his tracks and jumped over the rail.  Another hacked viciously at Thirkle with a long knife, but he could not reach him.  Thirkle stood with his feet wide apart, and his helmet on the back of his head and fired coolly and swiftly.

The Filipino in the engineer’s cap dropped the iron bar with which he had advanced in the rush, and put both hands to his stomach, and stood within six feet of Thirkle, looking at him in a surprised way, and finally threw up his hands as if he had lost his balance and curled over backward to the deck.

A Filipino toppled over the bridge-rail and struck in a heap on the fore-deck, and lay still, but I could not tell whether it was the fall or a bullet that had killed him.