Who was the first child to show up when Ralph blew the conch in the novel Lord of the Flies?

In Chapter 1, Ralph spots a shiny object in the lagoon but isn't sure what it is. Piggy quickly points out that Ralph is looking at a valuable conch shell. Piggy suggests to Ralph that he use the conch to call the others. Ralph proceeds to blow as hard as he can into the conch which makes a loud, booming noise. Piggy then spots a short boy who seems to be six years old, walking down the beach about a hundred yards away. When the boy reaches Piggy and Ralph, Piggy helps him onto the platform. Ralph continues to blow the conch while Piggy asks the boy his name. The little boy tells Piggy his name is Johnny, and he politely sits down on the platform and waits for the other boys to show up. Golding describes Johnny as a well built innocent littlun at the beginning of the novel. He is also the smallest boy on the island next to Percival.