Watching the djinn flicker like a flame in the wind reminded Watson of the stories he had heard about the creatures, that they were beings of smokeless fire so powerful they must be bound forever in servitude for the safety of the world.
"What is your first wish, Master?" it purred. "Power? Wealth? Love? Anything at all. It shall be yours."
While Watson merely gaped, Holmes offered his advice. "Wish for something small, Watson, something that won't matter. And for pity's sake, be specific!"
Small and specific . . .
"I wish for an English florin, genuine, dated 1877."
"Granted."
(The buying power of a florin in 1882 is roughly $25 today, U.S.)