哼声

哼 = 亨 + 口 : In front of the engine ((e)ng1), Joseph Henry (亨) finally has the idea how to build his coil and exclaims "hurrah!", accidentally throwing away Hamlet's (h) mandarin (口) so Hamlet just says "humph!" (哼).

声 = 士 + 尸 + 丨 : Sherlock Holmes (sh) hears the terrifying sound (声) of bone (丨) on stone in front of the engine ((e)ng1), and he's sure that there must be a ghost (尸). Indeed it's only the bachelor (士) who wants to scare Sherlock.