He stood looking after them… as though he had perceived that they had come back accompanied by a ghost a-piece. – Charles Dickens, Little Dorrit

An idea, like a ghost (according to the common notion of ghosts), must be spoken to a little before it will explain itself. – Attributed to Dickens in Many Thoughts of Many Minds by Henry Southgate, 1862

As surely as you are a living man, so surely did that spectral anatomy visit my room again last night, grin in my face, and walk away with my trousers: nor was I able to spring from my bed, or break the chain which seemed to bind me to my pillow. – Thomas Ingoldsby, “The Spectre of Tappington,” 1837