Who said we can use this to call the others. have a meeting in lord of the flies?

When the boys are on the island in Lord Of The Flies, Ralph and Piggy are quick to find that there are no adults on the island. They decide that everyone should be called together for a meeting. By using a conch shell that was discovered by Ralph in the weeds, Piggy discovers that they can blow the conch to summon all the children.