Chapter 10 opens with Piggy and Ralph lamenting what happened, in the previous chapter, to Simon. They know that they are losing the battle against order and reason, which is what the conch shell represents. Piggy's glasses are the means of making fire and they symbolize intellect, or the ability to think intelligently. In the middle of the chapter, Jack is holding counsel with his tribe of boys, which is the vast majority of the boys. He does so without the conch shell that Ralph has used in his meetings to democratically let anyone who wishes to speak, speak. The reason Jack doesn't need the shell is because his is not a democracy. Jack is a dictator - what he says, goes. The shell's symbolism and meaning has been decreasing and it is now nothing more than a shell despite the fact that Piggy will try one last time in chapter 11 to use the shell to speak to order and reason. At the end of the chapter, Jack's tribe raids the remnants of Ralph's tribe. They are after one prize. Piggy says he thought they came for the conch shell because he naively still believes it represents order and reason. Then Piggy tearfully tells Ralph that it wasn't the conch, after all, that they came for. It was his glasses. Now Ralph's group is without the ability to make fire and Jack's tribe has that ability. So the chapter is about the shell and how it has come to mean nothing and about the glasses that Jack's tribe steals, symbolizing that Jack's tribe, now in possession of fire, are the leaders on the island.