In Chapter 2 of Lord of the Flies, most of the boys agree that they need to start a signal fire, but they are not sure how to do so since no one has any matches. Then, Jack gets the idea to use Piggy's glasses as "burning glasses." Though Piggy protests, the boys are successful in their efforts:
Ralph moved the lenses back and forth, this way and that, till a glossy white image of the declining sun lay on a piece of rotten wood. Almost at once a thin trickle of smoke rose up and made him cough. Jack knelt too and blew gently, so that the smoke drifted away, thickening, and a tiny flame appeared.
Eventually, the fire gets out of control (Piggy says, "Now you been and set the whole island on fire.") and the boy with the mulberry-colored birthmark goes missing. Even though he has the conch, Piggy is unable to get the attention and respect that holding the shell is supposed to bring. (This is partly because the fire has caused chaos, and partly because no one takes Piggy seriously.) Panic ensues, as the little children watch the flames and scream that they are afraid of "snakes."
In Chapter 2, Ralph mentions that it is important for the boys to build a signal fire so that passing ships will stop to rescue them. The boys agree and enthusiastically collect dry wood, but have no way of lighting the fire. Fortunately, Jack has the ingenious idea to use Piggy's glasses to magnify the sun's heat onto the wood. After Jack rips the glasses off of Piggy's face, Ralph takes them and focuses a ray from the sun onto the dry wood. Almost immediately, smoke begins to rise from the wood and the boys begin to blow until a tiny flame appears. The flame grows as the fire ignites and the boys start to celebrate their accomplishment. A strong wind ends up blowing sparks from the fire towards more brushwood down the side of the mountain, and a massive forest fire ignites. Unfortunately, the littlun with the mulberry-colored birthmark disappears in the forest fire, and he becomes the first casualty on the island.