This statement comes in the context of Piggy's confrontation with Jack in Chapter Four. Piggy accuses Jack of negligence in allowing the fire to die, thus missing an opportunity to signal a passing ship. Jack responds by punching him in the stomach. A scuffle ensues, and Jack knocks Piggy's glasses off by slapping him across the face. One lens breaks, and by saying "Jus' you wait," Piggy means that he is going to get back at Jack for this offense, which has left him with only "one eye." Jack, of course, finds this very funny, and mocks Piggy to the delight of some of the other children, who laugh at him. The incident marks a turning point for Jack and Ralph, whose relationship becomes more adversarial.