Charles Dickens uses an interesting verb "echoes" to talk about how the prisoners are feeling in the sentence "some passing vehicle echoes mournfully." The adverb "mournfully" describes the echoes as being deathlike. "echoes" means the deathlike noises are going through their heads and has a mental and physical effect on the prisoners, and allows the reader to imagine hearing the noises in the cell.
Missing word in first sentence... Capital letter missing...