"Now, no one but a most abandoned greaser would do that." To "wise the powers" is to give information to the Naval officers.
"The fellow who would wilfully tell on you would be worse than what you term a greaser," agreed Dave.
"Careful," warned Farley ironically.

"You know who told, or who caused the wise word to leak to the powers." "I don't," Dave denied bluntly.
"You're the sneak, yourself!" cried Farley angrily.
"I am not," spoke Dave, with clear denial.
"Do you mean to say I lie ?" demanded Midshipman Farley threateningly, as he took a step forward.
"Do you deliberately state that I informed upon you, or caused you to be informed upon ?" demanded Dave Darrin.
"Yes, I do! "Then you lie!" returned Darrin promptly.
With a suppressed yell Farley sprang at Darrin, and the latter struck out quickly..