How does the author use imagery in the novel, Young Fu of the Upper Yangtze?

Lewis evokes the physical reality of the streets of Chungking, for example, in poetic images: "The air was heavy with steaming sunshine, and cracks between the flagstones of the street hissed through the accumulated filth of ages, like miniature geysers."

When Young Fu sees his first snowfall in the hills beyond Chungking, he is "bewitched under the spell of this white magic. Beautiful like white jade...soft, like silk in a cocoon." An old peasant tells him that snow is the "wintry breath of the Dragon."