The speaker has already talked about the skylark being connected to heaven and the spirit realm. Now we just keep heading higher and higher up.
This is one of the ideas that the poem keeps coming back to: the freedom and beauty and joy of the sky and flight. It's as if we were flying up along with the bird.
From the earth thou springest
That flight up continues here. We jump up with the skylark, springing into the air, away from the earth.
This seems like a good spot to talk about the rhythm of this poem. The first four lines in every stanza are made up of beats called troches, where a stressed syllable comes before an unstressed one (like in the words "Spirit "or "Heaven").
So in this line, we have three separate troches: "From the / earth thou / springest." See how that goes? DA-dum, DA-dum, DA-dum.
The only exception to that rhythm is in the last line of each stanza. Check out the "Form and Meter" section for more about that.
Like a cloud of fire;
Now the speaker tries out a simile. He compares the bird to a "cloud of fire."
So what does that even mean? Well, on the one hand, it's kind of a scary, intense, and unexpected image to connect to a bird. On the other hand, it makes sense if we remember that this bird is more like a spirit than an animal.
The blue deep thou wingest,
There's a really cool moment of reversal here. When we hear the words "blue deep," we think of the ocean. In this case, though, it refers to the sky.
That mixing of sea and sky contributes to the joyful, topsy-turvy feeling of ecstasy in this poem. Ordinary reality seems to melt away into a fierce mix of color and music and movement.
And singing still dost soar, and soaring ever singest.
We just love the way this line leaps and swoops. To us it feels just like a bird in flight. The speaker really captures the joy and the freedom of the skylark—singing and soaring, soaring and singing.
If you want extra poetry-nerd bonus points here (because that's what Shmoop is all about) you might be interested to know that this line is an example of chiasmus. That's a technique where a poet switches the order of words in a line. First the skylark sings and soars, then it's the other way around.
Also, you might have noticed that this is the end of the poem's second stanza (a group of lines that work like a paragraph of a poem). By now we can see a pattern of five line stanzas. It turns out that every stanza in this poem has five lines, and there are 21 stanzas in all. Check out our "Form and Meter" section for more about that.