Dickinson turns Summer from a season into a woman who has stepped out of the room and left her belongings behind. A hat sits on a shelf and a glove lies in a drawer, like the clutter in any hallway. But the shelf is "boundless" and the drawer is "sylvan", so the house she has wandered out of seems to be the whole sky and the whole forest. The poem sets a homely scene against an enormous one and never lets either cancel the other.
The first stanza is an invitation to a small crime. A ribbon has slipped loose "Unobserved", and the speaker whispers, "Snatch it for yourself." Beauty here is not something to admire from a distance. It is something to grab quickly and privately, before anyone notices. I read the abandoned hat as a hint that the season is already slipping away, since things left behind suggest someone has gone, though the poem never says so outright. If that is right, the message is urgent: summer's gifts drop without ceremony, and only an alert reader will catch one.
The second stanza loses that confidence. A "supple Glove" is tucked away, and then the grammar buckles: "Wheresoe'er, or was she -- / The demand of Awe?" No tidy paraphrase survives. One possible reading is that the speaker asks where Summer has gone, or whether she was ever really here, and that the only answer left is awe. The sentence breaks off as if the speaker were overwhelmed. After the playful tone of the first stanza, this is a real change. The thief becomes a worshipper, or at least someone who has run out of words.
The sound of the poem supports this shift. The lines alternate between seven syllables and five, a hymn-like pattern pared down. "Summer laid her simple Hat" walks along on four beats, and "On its boundless Shelf" shortens to three, so the line seems to drop, like the object it describes. The only clean rhyme comes in the first stanza, where "Shelf" meets "yourself", and it lands on the command that closes the stanza. The first and third lines ("Hat" and "slipt") do not rhyme with anything. In the second stanza, "Drawer" and "Awe" chime only if the final r is softened, so the rhyme is shakier just where the sense gets harder to hold.
Individual words reward a slow look. "Simple" and "supple" are near twins, sharing their s, p and l sounds while meaning different things, one plain and one pliant. A supple glove keeps the shape of a hand, so the word quietly suggests a body that is no longer there. "Sylvan" is a grand, Latinate word, and setting it beside something as ordinary as a drawer is part of the poem's comedy and part of its wonder. The capital letters give Hat, Shelf, Ribbon, Glove, Drawer and Awe the same weight, so a glove and an overwhelming emotion stand on equal footing. The dashes work as breaths. One comes just before the ribbon slips, and another before the question that the poem cannot finish. Even the spelling "slipt" is quicker and quieter than "slipped", which suits something that goes unobserved.
What makes the poem worth reading is how it handles a subject that tempts most writers toward large statements. A season is about as big a theme as nature offers, and Dickinson shrinks it to a few objects on a shelf. She gives the poem a mischievous second-person voice that urges the reader to act, and then she ends on a question rather than a lesson. The reader is left holding something, perhaps the ribbon, perhaps the open question, and has to decide what to do with it. Her gaps and broken syntax are not flaws in this poem. The strange last lines, which seem to say more than they can explain, are where its feeling of awe actually comes from.