Edward Thomas begins with a plain declaration of appetite: "To-day I want the sky." There is no scene-setting, just a wish, and the word "To-day" tells us at once that this is a mood rather than a settled philosophy. What follows is an unusual nature poem. Instead of celebrating the hedges, cows and woods that fill so much writing about the English countryside, Thomas climbs above them in imagination until they look small, and then makes them something worse than small: weeds and mud.
The first twelve lines are built as a climb. The speaker passes up a ladder of living things, from "the last man's house" and "his hedges, and his cows" to "sheep and rook", and finally to "buzzards only above". Each rung is more remote from human company. The sentence barely pauses on the way, running through short lines of three or four beats until it arrives at "nothing but sky". That last phrase is hungry rather than peaceful. Thomas never describes the sky. He wants it for its emptiness, for the fact that "nought deters / The desire of the eye".
At line 13 the poem reverses direction. "I sicken of the woods" is blunt and almost physical, and the trees are dismissed as "hedge-trees", ordinary and countless. Then comes the surprise: the sky becomes "the river of air / Leagues deep, leagues wide", and the land is its "floor". The speaker is no longer a climber looking down but a creature at the bottom of the water looking up. The break after "where" leaves the reader hanging for a moment before the speaker lands in the comparison: "I am like a fish". The fish is a tench, a freshwater fish that lives among "weeds and mud", and the "wealden clay" he stands on seems to carry the same heaviness. Judging by the imagery, the clay stands for a mood as much as a place, a day when the mind feels stuck.
The last ten lines are the most thoughtful. Even the tench, we are told, sometimes floats up "among the lily leaves" and sees the sky, and it does not mind if it sees nothing, because it "grieves / Not if he nothing sees". The fish is luckier than the man because it does not know what it is missing. The speaker's knowledge is the trouble: "While I, I know that trees / Under that lofty sky / Are weeds, fields mud." The stumbling repetition of "I, I" sounds like someone admitting something. The poem ends with a wish, "Would arise and go far / To where the lilies are," and the phrase "arise and go" recalls the opening of Yeats's "The Lake Isle of Innisfree". The destination is a little unexpected. After so much talk of sky, the speaker wants lilies, which float on the surface where the muddy world meets the air. It is possible that he wants a threshold rather than a total escape.
The form helps the voice sound like thinking aloud. The poem is written in rhymed couplets, but many of the rhymes are loose: "house" and "cows", "move" and "above", "furze" and "deters". That slight mismatch stops the poem ringing like a nursery rhyme and keeps it close to speech. The vocabulary is mostly single-syllable and plain, with little decoration. One sound does return insistently. "Sky" opens the poem and ends line 12, "eye" sits beside it, and in the closing lines "sky" rhymes with "I". The looking self and the thing it longs for are linked by sound long before the poem admits that the longing is a burden.
The poem matters because it turns a familiar world upside down using one sustained metaphor. It does not settle the speaker's restlessness, and it does not pretend that wanting the sky is noble or that the fish's ignorance is shameful. It simply holds the feeling still long enough for us to recognise it: a day when the everyday world looks like mud, and the awareness of something larger makes it harder to bear.