"I acted on it"

Sherwood Smith had a fun review over on Goodreads of one of Patrick O'Brian's seafaring tales (The Surgeon's Mate, in case you're curious--full review here), and in it she featured this snippet of conversation, from when the characters talk about Hamlet's grave while their ship is being fired upon from Elsinore:

"So there he lies," said Jack, his telescope leveled. "Well, well: we must all come to it. But it was a capital piece, capital. I never laughed so much in my life."

"A capital piece ind...