Final answer:
Captain Beatty demonstrates his secret knowledge of literature by quoting it, which is not common among firemen in 'Fahrenheit 451'.
Step-by-step explanation:
On the way back to the fire station in Ray Bradbury's Fahrenheit 451, Captain Beatty reveals his extensive knowledge of literature which the other firemen do not possess. He does this by quoting literature as they ride back. His quotations and references demonstrate that he has read and understood various works, despite the societal ban on books and reading. This action suggests to the reader, and to the protagonist Montag, that Beatty has a complex relationship with the material he is tasked with destroying.