In Lord of the Flies, how does Ralph summon the others?

In chapter one of "The Lord of the Flies", Ralph and Piggy
find a conch in the sand (a big sea shell).  In order to summon the others, hoping that
they would follow the sound, he blows into the shell.  At that moment a deep loud noise
was made and was heard throughout the forest.  After some time, this is how all of the
children find one another.  Consequently, the conch becomes a symbol for order.  During
one of their early meetings, the children determine that the person holding the conch
will have the opportunity to speak freely, and that everyone else would listen. 
Therefore, when the conch is destroyed later on in the novel, so is the order and
civility within the group.