In the exposition of "The Signalman" by Charles Dickens, the narrator calls to the signalman below in the tunnel. Startled greatly by his call, the signalman turns this way and that. Finally, the man signals for the narrator to descend; when they are close to each other, the signalman displays an attitude of "such expectation and watchfulness" that the narrator wonders. As he is able to converse with the man, he comes to understand that the signalman is greatly troubled, but he will not explain. However, when the narrator declares his intention to make a second visit, the signalman says he will reveal the reasons for his consternation.
Upon his second visit at eleven in the evening, the signalman tells the narrator that he has decided to reveal his reasons for being so startled the previous day. He tells the narrator that a ghost has appeared to him before, saying the very words that the narrator has. He describes the spectre as having
"The left arm...across the face and the right arm is waved. Violently waved."
And, he demonstrates this violent waving for the narrator. The signalman tells the narrator that the spectre was standing by the red warning light; his voice is hoarse from shouting and it cries, "Lookout! Lookout!" and then "Halloa Below there! Look out!" just as the narrator has done the previous night.