"The children hung on their mothers' backs (like monkeys, Mary thought)" (100) (simile)
Mary sees native women with their children in her store in a racist way, comparing them to monkeys and thereby distinguishing them from her conception of what it means to be a civilized human—or indeed, to be human at all.
"She collapsed in a storm of tears" (200) (metaphor)
Mary has several emotional breakdowns over the course of the novel. The metaphor of a rainstorm renders the intensity of her emotion, while also suggesting implicitly the lack of rain in the veld.
Moses as spider (metaphor)
Mary hallucinates the image of the vengeful and dominant Moses as a spider crawling over her roof. This represents his dark power over her and her sense of not being able to escape him.
"She was inside a bubble of fresh light and colour" (203) (metaphor)
Towards the end of the novel, Mary sees the few minutes before sunrise as an external manifestation of the hope in her own heart. However, just like a bubble, her hopes burst once the sun crests over the horizon and sheds light on her surroundings.
"…as if they had not just that moment driven knives into her heart" (42-3) (metaphor)
Mary is very sensitive to others' opinions of her, to the point that she feels subtle criticisms with a physiological intensity.