“But you will. Don’t you fool yourself on that,” exclaimed the furious man, flinging out of the office with muttered imprecations on his lips.

“That feller needs a short cruise in ther brig,” commented old Tom, as Anderson dashed out of the place.

“I’m sorry to have had to get rid of him, for he was a competent workman,” said Mr. Lockyer. “But he has been becoming altogether too aggressive of late. By the way, I wonder where that chap Gradbarr is. I want to interview him, too, and find out how he happened to turn on that gas. It’s a horrible suspicion to have; but it looks to me almost like a deliberate attempt to wreck the craft.”

“That’s the way it looks to me, too, sir,” agreed Ned.

“By the way,” said Mr. Lockyer suddenly, “do you boys know anything about thread-cutting? I’d like to get that pipe connection fitted up to-night.”

“I guess we can help you,” said Ned, and, accordingly, they retraced their steps to the submarine shed. The workmen had all left by this time, but they found the tools they needed, and soon had the measurements of the connection, and the required pitch of the screw to be cut on the new pipe. This done, they started for the machine shop to finish up the work. Sim, however, who was still white and shaky after his experience, was ordered home by Mr. Lockyer.

“You’ve done enough for one day, Sim,” he said. “Be off home now, and report bright and early to-morrow.”

As Sim made off, the inventor looked after him.

“There’s a lad that has the makings of a fine man in him,” he said. “He applied here for work some weeks ago, and, being short of a helper, I gave him a job. He knew something about metal working, as his father was formerly blacksmith here. The man died some time ago, and since then I guess Sim and his mother have had a hard time to get along. That hundred dollars will look very large to them.”