The fire in Chapter 2 of Lord of the Flies certainly does foreshadow events that will follow as the boys cannot rely on guidance from "the grown ups" anymore and "we shall have to look after ourselves." The conch has been established as the call to order and the boys are encouraged as "sooner or later, we shall be rescued." Talk of making a fire excites them all - Jack especially - and they rush off, following Jack who has the idea to use Piggy's glasses to start the fire. His abrupt manner panics Piggy who eventually gets his glasses back, as the fire begins but unfortunately appears to fade as "there wasn't any smoke."
The evening sun is significant in this chapter and the fact that, despite their differences the boys have been able to work together; even Jack - "we're not savages.We're English." The irony of this comment will become evident later. Just as the boys are coming to a consensus and Jack is going to help by splitting up his choir so they can watch the fire that will have to be relit, "smoke was rising here and there" and before long "the flames...crept as a jaguar" and within minutes the area was "savage with smoke and flame."
The boys confusion is evident as the fire is a "splendid, awful sight." The fire brings out hysteria in the boys - "shrieking with laughter" - and also aggression - even Piggy! The realization that the little'un with the birthmark could be missing - even dead- as a result of the wildfire renders Piggy,Ralph and Jack speechless. They cannot comprehend what future lies ahead but stand there "fearfully, unbelieving ..." Their actions have potentially caused harm and "on the unfriendly side of the mountain," the fire continues. Their future is ominous and the out-of-control fire a warning!
The fire indicates that the boys' behavior is going to spiral out of control just as the fire does. The fire basically goes wild as does the behavior of the boys in future chapters of the book.
I believe that the fire can represent the boy’s instability, and as the fire grows out of control, it will burn until it has nothing left. Just like the boys, they will continue to spiral down to a savage nature until there is no one to stop one another.