A friend of mine, who is a man of letters and a philosopher, said to me one day, as if between jest and earnest: “Fancy! since we last met, I have discovered a haunted house in the midst of London.”“Really haunted?—and by what—ghosts?”“Well, I can’t answer that question; all I know is this: six weeks ago my wife and I were in search of a furnished apartment. Passing a quiet street, we saw on the window of one of the houses a bill, ‘Apartments, Furnished.’ The situation suited us: we entered the house—liked the rooms—engaged them by the week—and left them the third day. No power on earth could have reconciled my wife to stay longer; and I don’t wonder at it.”“What did you see?”“It was not so much what we saw or heard that drove us away, as it was an undefinable terror which seized both of us whenever we passed by the door of a certain unfurnished room, in which we neither saw nor heard anything. Accordingly, on the fourth morning I summoned the woman who kept the house and attended on us, and told her that the rooms did not quite suit us, and we would not stay out our week. She said, dryly: ‘I know why; you have stayed longer than any other lodger. Few ever stayed a second night; none before you a third. But I take it they have been very kind to you.’“‘They—who?’ I asked, affecting to smile.“‘Why, they who haunt the house, whoever they are...