Dickinson uses a metaphor when she describes the “amazing sense” that poets “Distill” from “ordinary Meanings” as an “Attar”; an attar is a really intensely fragrant oil produced from flower petals or some other plant or flower. A metaphor is a comparison of two unalike things where one is said to be another, and this metaphor compares the intense meaning that poets seem to extract from even ordinary, everyday objects to a really intensely odorous perfume. Then, we non-poets wonder why we never realized the significance of such a thing before.

Dickinson then calls the poet “the Discloser,” as in one who discloses or exposes things which are not obvious to others. With the poet’s ability to make such “amazing sense” from “familiar species”—another metaphor meant to refer to everyday objects (these objects are like something living, an idea which makes them more interesting and fraught with secrets for the poet to disclose)—they entitle “Us—by Contrast / To ceaseless Poverty / Of portion [. . .].” In other words, poets’ peculiar abilities make the rest of us realize how poorly we perceive the world. We have less because we see and understand less than the poet; the poet does not literally “Rob” us of our portion, so Dickinson uses this metaphor of stealing to show us how the poet makes us aware of what we lack: the ability to see the world in all its fullness. It is like being robbed because we were not aware of our lack before. The poet, then, is rich and possesses “a Fortune / Exterior—to Time.” His fortune is not monetary and is not subject to Time’s ravages; it is intangible: it is perception.

Dickinson's poem is, of course, about poets and their art. Poets are able to distill a heady fragrance ("Attar") from "the familiar species / That perished by the Door." This can mean that poets turn everyday things into objects filled with meaning, but it is characteristic of Dickinson to use an oblique image of death to make this point: it's not clear what "familiar species" has "perished," but the idea is that out of the triviality of death, the poet is able to make something sublime. This split between the ordinariness of life and the heightened experience of poetry is returned to in the third and fourth stanzas. In the third stanza, the poet ("the Discloser") impoverishes ("entitles") everyone else ("us") through the power of their "picture" or imagery. This suggests a second sort of split—an internal one within Dickinson herself (her use of "us" suggests that the poet Dickinson is at odds with the person Dickinson, who is like the reader). In the final stanza, the work of the poet is at once a kind of "robbery," but one the "us" from the third stanza are "unconscious" of.

Looking at the final stanza in detail:

Of portion—so unconscious—

This line refers to the "portion" of meaning the poet has discovered, of which most people are unconscious (or the meaning itself is unconscious of its value, perhaps).

The Robbing—could not harm—

"Robbing" I read as the poetic act, the extraction of meaning from everyday things.

Himself—to Him—a Fortune—

The "himself" refers to Dickinson the person, one of "us" who is not "harmed" by the "robbery," while the "him" is the Poet (Dickinson, despite the masculine pronoun) who has stolen a "Fortune" in meaning.

Exterior—to Time—

This "Fortune" is "exterior" to time—that is, beyond death—because it will endure as art.

This poem is about poets and poetry. She defines what a “Poet” is (notice the capital letter) – one that is able to “distill amazing sense from ordinary Meanings (again, note the capital). The capital letters emphasize the importance of the words. What else is a Poet? An “attar so immense” – an attar is an odor, and this odor is from a “familiar species” – in this case, I believe she is referring to, again, “ordinary meanings.” So, a Poet is able to create something beautiful out of something simple.

A Poet can take his/her readers to an entirely different world through words. A beautiful poem forces one to look right at it – it captures you. It points out the poverty of the world outside of the beauty of poetry (Poverty –of portion). Realizing the beauty of poetry can be almost unconscious but once we realize it, it is with us forever, no one can steal it from us, because it is an image in our mind. Poetry is timeless – (exterior to Time).