“I know,” nodded Captain Jack.  “I’d hate to hurt a fine fellow’s feelings.  Yet—­confound it, I do want to win this burst of speed.  It means, perhaps, the quick sale of this boat to the Navy.  If we’re beaten it means, to the Secretary of the Navy, that he already has our best boat, and he might not see the need of buying the ‘Farnum’ at all.”

“Give Williamson two or three minutes more,” begged Hal.  “You might tell Eph, though, to repeat, and repeat, the signal for top speed.  That’ll show Williamson we’re losing.”

Jack Benson walked to the conning tower, instructing Eph Somers in a low tone.

“I’ve signaled twice, since the first time,” Eph replied.  “But here goes some more.”

“I wonder what’s going wrong with our engines, then,” muttered Captain Jack, uneasily.

“It ain’t in careless steering, anyway,” grumbled Eph.  “I’m going as straight as a chalk line.”

“I noticed that,” Captain Jack admitted.

He continued to look worried, for, by this time, the “Pollard” was at least a good two hundred and fifty yards to the good in the lead.

“I’m afraid,” muttered Hal, rejoining Benson, “that I’ll simply have to go below.”

“I’m afraid so,” nodded Jack.  “We simply can’t afford to lose this or any other race to the ‘Pollard.’”

“Williamson knows that fully as well as we do, though,” Hal Hastings went on.  “And Williamson—­”

Of a sudden Hal stopped short.  He half staggered, clutching at a rail, while his eyes stared and his lips twitched.

“Why—­why—­there’s Williamson—­aft on the deck!” muttered Hastings.

“What!”

Jack, too, wheeled like a flash.  Back there in a crowd of cadets stood the machinist upon whom the submarine boys were depending for the best showing that the “Farnum” could make.

“Williamson up here!” gasped Hal.  “And—­”

“That fellow, Truax, all alone with the motors!” hissed Captain Jack.  Then, after a second or two of startled silence: 

“Come on, Hal!”

The naval cadets were too much absorbed in watching the race to have overheard anything.  Williamson, too, standing at the rail, looking out over the water, had not yet discovered that Hal Hastings was up from the engine room.

Jack Benson stole below on tip-toe, though with the machinery running so much stealth was not necessary.  Right behind him followed Hal.

As the two gained the doorway of the engine room Sam Truax had his back turned to them, and so did not note the sudden watchers.

There was a smile of malicious triumph on Truax’s face as he turned a lever a little way over, thus decreasing the ignition power of the motors.

Both Jack and Hal could see that the gasoline flow had been turned on nearly to the full capacity.  It was the poor ignition work that was making the motors respond so badly.  A little less, and a little less, of the electric spark that burned the gasoline, and air mixture—­that was the secret of the gradually decreasing speed, while all the time it looked as though the “Farnum” was doing her level best to win the race.