How does Oscar Wilde use imagery in The Canterville Ghost?

Imagery:

“Far away beyond the pine-woods,' he answered, in a low dreamy voice, 'there is a little garden. There the grass grows long and deep, there are the great white stars of the hemlock flower, there the nightingale sings all night long. All night long he sings, and the cold, crystal moon looks down, and the yew-tree spreads out its giant arms over the sleepers.”

For the next three Saturdays, accordingly, he traversed the corridor as usual between midnight and three o’clock, taking every possible precaution against being either heard or seen. He removed his boots, trod as lightly as possible on the old worm-eaten boards, wore a large black velvet cloak, and was careful to use the Rising Sun Lubricator for oiling his chains.