“Why, what object could he have in that?” asked Captain Jack.

“Blessed if I know,” replied Eph.  “But that’s the way I size the fellow up.  Now, take that time you were knocked senseless, back in Dunhaven.  Who could have done that?  The more I think about Sam Truax, the more I suspect him as the fellow who stretched you out.”

“Again, what object could he have?” inquired Benson.

“Blessed if I know.  What object could anyone have in such a trick against you?  It was a state prison job, if the fellow had been caught at the time.”

“Well, there’s one thing Truax was innocent of, anyway,” laughed Captain Jack.  “He didn’t have any hand in the way I was tricked and robbed by the mulatto.”

“Blamed if I’m so sure he didn’t have a hand in that, too,” contended Eph Somers, stubbornly.

“Yet Mr. Pollard recommended him,” urged Jack.

“Yes, and a fine fellow Dave Pollard is—­true as steel,” put in Hal Hastings, quietly.  “Yet you know what a dreamer he is.  Always has his head in the air and his thoughts among the stars.  He’d as like as not take a fellow like Truax on the fellow’s own say-so, and never think of looking him up.”

“Oh, we’ve no reason to think Truax isn’t honest enough,” contended Jack Benson.  “He’s certainly a fine workman.  As to his being sulky, you know well enough that’s a common fault among men who spend their lives listening to the noise of great engines.  A man who can’t make himself heard over the noise of a big engine hasn’t much encouragement to talk.  Now, a man who can’t find much chance to talk becomes sulky a good many times out of ten.”

“We’ll have trouble with that fellow, Truax, yet,” muttered Eph.

“Oh, I hope not,” Jack answered, then added, significantly: 

“If he does start any trouble he may find that he has been trifling with the wrong crowd!”

Very little more thought was given to the sulky one.  The submarine boys and their companion, Williamson, enjoyed Saturday and Sunday ashore.

All of them might have felt disturbed, however, had they known of one thing that happened.

The naval machinists aboard the first submarine boat, the “Pollard,” now owned by the United States Government, found something slightly out of order with the “Pollard’s” engine that they did not know exactly how to remedy.

Sam Truax, hanging around the Basin that Sunday forenoon, was called upon.  He gladly responded to the call for help.  For four hours he toiled along in the “Pollard’s” engine room.  Much of that time he spent there alone.

The job done, at last, Truax quietly received the thanks of the naval machinists and went ashore again.

Yet, as he turned and walked toward the main gate of the grounds, there was a smile on Sam Truax’s face that was little short of diabolical.

“Now, if I can only get the same chance at the ‘Farnum’s’ engines!” he muttered, to himself.  “If I can, I think Mr. Jack Benson will find himself out of favor with his company, for his company will be out of favor with the Navy Department at Washington!”