the heart convulsive learns

It's an Emily day, don't you think?

The Heart has narrow Banks
It measures like the Sea
In mighty — unremitting Bass
And Blue monotony

Till Hurricane bisect
And as itself discerns
It's insufficient Area
The Heart convulsive learns

That Calm is but a Wall
Of Unattempted Gauze
An instant's Push demolishes
A Questioning — dissolves.

—Emily Dickinson (1830-1886), "The Heart has narrow Banks," Poem 960, 1865. In this case, from the R.W. Franklin edition of The Poems of Emily Dickinson (Cambridge, MA: The Belknap Press of Harvard University Press, 1999).

Citing Dickinson is notoriously difficult, because both her manuscript history and her print history are fascinating and complex; she also wrote seven zillion poems. For those interested in manuscript studies and textual scholarship and lyric poetry and Dickinson, I highly recommend Virginia Jackson's Dickinson's Misery.