The first two paragraphs of chapter four in Lord of the Flies by William Golding are pure description, and they concern the play of light on the island at different times of the day. More importantly, Golding reveals that the boys on the island are now having bad dreams during the day as well as having nightmares at night.
Mornings are the most pleasurable times, when the air is fresh and sweet and the sun is bright. It is a
time when play was good and life so full that hope was not necessary and therefore forgotten.
Of course, this implies that it is not always so on the island.
At noon the heat turns everything into a shimmering opalescence and the heat grows unbearable. The boys generally try to find some shade and take an afternoon nap. This is the time when what Piggy proclaims are "mirages" begin to happen.
Strange things happened at midday. The glittering sea rose up, moved apart in planes of blatant impossibility; the coral reef and the few stunted palms that clung to the more elevated parts would ﬂoat up into the sky, would quiver, be plucked apart, run like raindrops on a wire or be repeated as in an odd succession of mirrors. Sometimes land loomed where there was no land and ﬂicked out like a bubble as the children watched.
These illusions combine with the "angry eye" of the sun, and the entire experience is disconcerting for the boys, adding to their general sense of unrest.
The end of the afternoon is another pleasant time, but the boys understand that night is once again drawing near.
When the sun sank, darkness dropped on the island like an extinguisher and soon the shelters were full of restlessness, under the remote stars.
Nights are the worst times for the boys; this has been established since the beginning of the sojourn on the island (chapter two), and it is clear that things have not improved.
Even though this passage is primarily description, Golding also uses it to advance both the plot of the story and the theme of disintegrating civilization.