Jack doesn’t consider himself “a chief . . . in truth” until he accomplishes the theft of Piggy’s glasses. In this way, Jack symbolizes a twisted Prometheus, stealing fire from the humans to profit the savages as opposed to stealing from the gods to benefit humans. Note that originally he and his group of choirboys were to play the role of Prometheus in maintaining the fire, maintaining a visual plea to civilization for rescue and quick return home.
Ralph’s connection with his civilized self fades even more rapidly now, although he fights to maintain it and is baffled by the “curtain” that seems to fall when he tries to stress the importance of the fire. When the twins question the value of keeping the fire lit, Ralph “tried indignantly to remember. There was something good about a fire.” Piggy, of course, instantly knows what this good is, as his connection to civilization remains very strong because it offers him protection that is lacking on the island.
Piggy is so intent on preserving some remnant of civilization on the island that he not only remains loyal to Ralph but to the concept of civilized discourse represented by the conch. He assumes, improbably enough, that Jack’s raiders have attacked them to get the conch. Just as he takes for granted that Ralph has not lost his focus on rescue and home, he figures that Jack still places a value on what the conch represents when obviously Jack has abandoned all that, preferring the life of savagery. Jack’s leadership is based on fear; he has abandoned the conch for the dance.
The loss of his glasses to the savages literally renders Piggy more helpless and ineffectual and symbolically deprives Ralph of his intellectual counselor. The alert reader understands that Piggy will be the next victim.
