Answer: The spectacles represent the boys' only means of obtaining fire through reflecting the sun's rays, and fire itself is symbolic of survival and rescue.Jack snatches the glasses off Piggy's face to create the fire, despite Piggy's protestations, and his dependence upon them.
Persephone is the goddess of harvest and Demeter is the goddess of corn. I know this because I'm a geek and love the Percy Jackson series. Does this help?
