Descriptive writing

Bleak House opens with a picture of London: "Fog everywhere. Fog up the river, where it flows among green aits and meadows; fog down the river". What is the main effect of repeating the word fog?

Dickens moves from "Fog on the Essex marshes, fog on the Kentish heights" to "fog cruelly pinching the toes and fingers" of a ship's boy. How does the focus change?

"Dogs, undistinguishable in mire. Horses, scarcely better; splashed to their very blinkers." Why might Dickens write these without main verbs?

The gas lamps in the shops are lit two hours early, "as the gas seems to know, for it has a haggard and unwilling look." Which technique is this?

Hardy begins: "A Saturday afternoon in November was approaching the time of twilight, and the vast tract of unenclosed wild known as Egdon Heath embrowned itself moment by moment." What does this opening suggest about how the description is structured?

Hardy writes that "The face of the heath by its mere complexion added half an hour to evening". What does this suggest?