The signal fire burns on the mountain, and later on the beach, to attract the notice of passing ships that might be able to rescue the boys. As a result, the signal fire becomes a barometer of the boys’ connection to civilization. In the early parts of the novel, the fact that the boys maintain the fire is a sign that they want to be rescued and return to society. When the fire burns low or goes out, we realize that the boys have lost sight of their desire to be rescued and have accepted their savage lives on the island. The signal fire thus functions as a kind of measurement of the strength of the civilized instinct remaining on the island. Ironically, at the end of the novel, a fire finally summons a ship to the island, but not the signal fire. Instead, it is the fire of savagery—the forest fire Jack’s gang starts as part of his quest to hunt and kill Ralph.
