With that he applied one of the wrenches and gave it a turn. Instantly one of the electric motors in the engine-room began to vibrate.

Almost imperceptibly the bow of the "Dodger" began to rise. Lieutenant Jack, intent on preserving an even keel as nearly as possible, passed on to the middle station with his wrench.

Just as he applied the tool the electric motor ceased running.

"What's the matter, Mr. Hastings?" Jack inquired quietly. "Something blow out of the motor?"

The submarine remained slightly tilted up at the bow.

"I don't know, sir, as yet, what has happened," Hal Hastings answered back. "I'm going over the motor now."

In a moment more he stepped into the cabin, a much more serious look than usual on his fine face.

"This, looks like the man Morton's work," Hal announced holding a small piece of copper up before the eyes of the midshipmen. "Gentlemen, do you notice that the under side of this plate has been filed considerably?"

"Yes, sir," nodded Dan Dalzell, a queer look crossing his face.
"Won't the motor operate without that plate being sound?"

"It will not."