Why does Piggy continually remind Jack that he has the conch?
When Ralph first spots the conch in the lagoon Piggy tells him,
"I knew a boy who had one of those, on his garden wal it was, they
are ever so valuable." He later tells Ralph that the boy, "he used
to blow it to make a noise," and explains to Ralph that the boy
blew from his diaphragm in order to get a noise from the conch
shell. So although Ralph actually finds, recovers and blows the
conch. Piggy identifies it correctly and informs Ralph that it can
be blown.