The day is done, and the darkness Falls from the wings of Night, (lines 1-2)
We think it really matters that the first image in this poem is natural. We're not talking about six o'clock pm, or dinnertime. We're talking about the change between day and night which is something that nature controls completely. So, from the first words, we're dealing with the natural world. Then we get that really strong image of the "wings of Night" as if the nighttime was some kind of huge bird (another natural image). We're talking about the wide outdoors here, not some stuffy office or tidy living room.
As a feather is wafted downward From an eagle in his flight. (lines 3-4)
This finishes off that great big opening image. It's actually easy to imagine if you think about it for a moment, isn't it? Think about the way darkness rolls down the sky, bit by bit, and you can almost imagine it falling as light and soft as a feather. This makes nature sound calm, quiet and soothing. That's important for this poem, because, after all, it's all about how poetry can help you to relax.
I see the lights of the village Gleam through the rain and the mist, (lines 5-6)
Now he brings man and the natural world together. We can see the village, the human world, but only through a curtain of rain and mist. Nature and man are related to each other here, but they don't quite come together. This rain and mist image comes up again later, when he uses it to try to describe the relationship between sorrow and sadness (lines 11-12). Do you see how images of nature are woven through this poem without quite being allowed to take over? It's a little like the bass line in a song – it's always there if you listen, but it doesn't usually dominate.