Great suggestion, bob.
It turns out Gail was right, and if I’d read more [closely], I’d know it from the text! Here’s a snippet of dialog from The Inimitable Jeeves:
“I say, Jeeves,” I said.
“Sir?”
“Mix me a stiffish brandy and soda.”
“Yes, sir.”
“Stiffish, Jeeves. Not too much soda, but splash the brandy about a bit.”
More on that here (thanks to the unimpeachable Esquire Magazine).
Thank you, Gail!