In Fahrenheit 451 Faber says to Montag: "The salamander devours his tail." What does this mean? page 79

In Ray Bradbury’s depiction of a futuristic dystopian society in which possession of books is a serious crime, Fahrenheit 451, Guy Montag is a fireman.  Part of the uniform of the firemen is a badge on which is a symbol, a salamander.  In some ancient mythology, the salamander possesses special powers that enable it to be resistant or immune to fire.  Its significance, then, to the firemen in Bradbury’s novel is that the paradoxical relationship of the firemen in Fahrenheit 451 to fire itself is the converse of what would be expected.  Rather than extinguishing fires, these firemen start them for the purpose of burning books and punishing transgressors.  Bradbury’s narrative includes many references to the salamander to ensure that the reader draws the proper connection, as in the following quotes. The first is a reference to Montag’s initial encounter with Clarisse:

“. . .he knew his mouth had only moved to say hello, and then when she seemed hypnotized by the salamander on his arm and the phoenix-disc on his chest, he spoke again.”

. . .

“He still did not want outside light. He pulled out his igniter, felt the salamander etched on its silver disc, gave it a flick. . .”

“. . .his badge with the orange salamander burning across it.”

In Bradbury’s story, Montag, once a devoted servant of the government, is now transformed into a dedicated opponent who must, at least for now, retain the outward appearance of continued loyalty to that regime.  In his mind, however, he has broken with that regime and contemplates its destruction.  In his conversation with Professor Faber, he reveals the details of his plan to bring down the regime from within.  Faber initially reacts skeptically and cautiously to this suggestion of highly treasonous activity.  Faber greets Montag by stating “[t]he only way I could possibly listen to you would be if somehow the fireman structure itself could be burnt. . .”  As Montag describes his plan, which involves planting books in the homes of other firefighters, and in the firehouse itself, the professor responds,

"'[p]lant the books, turn in an alarm, and see the firemen's houses burn, is that what you mean?. . . It's an insidious plan, if I do say so myself.’ Faber glanced nervously at his bedroom door. ‘To see the firehouses burn across the land, destroyed as hotbeds of treason. The salamander devours his tail! Ho, God!’"

Faber is expressing his approval of Montag’s plan to frame his fellow firemen and bring about the collapse of the regime from within.  The “salamander,” the firefighters, represent that regime, and Montag hopes to facilitate its demise by playing it against itself.