It's two in the morning, and the speaker is awake with nothing to do but small, aimless chores. He eats a bit of cold meat, probably standing in the kitchen, and dusts a picture in the corner. These are the kind of tasks people invent when sleep won't come and the house feels too quiet. The moon, "lighter than ice," is pale and chilly, and it adds to the sense of a cold, empty hour.
The last two lines carry the feeling. The comparison to a cat "taken out of a chimney alive" suggests someone who has been through something frightening and is still shaken, wary, wide-eyed. The poem never says what the speaker has been through, so we can only infer a lingering unease. He keeps watch for the sun as if daylight were a rescue. The mood is tense and lonely, but there is also a thread of relief in simply having survived the night.