Even if redundant, often it can't hurt to state the obvious. It becomes apparent soon after the chapter begins that "the shell" referred to here is, in fact, the conch that is used to call the boys to a gathering. Of course, when blown into, the conch makes a sound. Thus, "The Sound of the Shell" is born as a chapter.
To say the significance ends here would be a great understatement. The conch, of course, becomes one of the most important symbols in the novel. Note the description:
Between the point, worn away into a little hole, and the pink lips of the mouth, lay eighteen inches of shell with a slight spiral twist and covered with a delicate embossed pattern.
The description of the conch is as beautiful as the democracy it symbolizes. Yes, the boy currently holding the conch is the one allowed to speak at the gathering. However, it would be incorrect to assume that the conch in question only symbolizes power. It is important to note that this important shell symbolizes power in an organized society. In itself, the behavior in this first chapter is a tribute to democracy, ... a democracy that wanes quickly.
I find it ironic that Ralph fails at his first attempt to blow into the conch. It's as if the boy wasn't suited for organized society from the beginning! Ha! Of course, the significance of the shell presents itself even more so when the conch becomes ignored and even broken! It's as if organized society no longer exists on the beach. Rules are no longer important. Democracy is smashed. Piggy is ignored, then killed.
Symbolism of the Title of "Lord of the Flies"
Chapter 1 is called "The Sound of the shell" This refers to the conch shell which Piggy finds on the beach. He gives the shell to Ralph and shows him how to blow it. When Ralph blows into the shell all of the other children assemble. It is decided that, during meetings, whoever holds the horn may talk. The horn thus comes to symbolize power, but it also represents order and rules, without which there can be no civilization. In a way, it is like a judge's gavel. It in itself has no power, but it represents the power of the judge and his right to rule in the courtroom. In the end, as the boys have become savages, the shell first becomes less effective and then is shattered, just as is Piggy.