If you're familiar with ballads and/or hymns, you know that they are typically written in short quatrains, with alternating rhyming lines. Dickinson's favorite brand of stanza is known as the hymn stanza or the ballad stanza, and she used it in the majority of poems that she wrote. In a hymn stanza, the first and third line in every stanza is made up of eight syllables, or four feet. Each foot (or pair of syllables) is made up of a pair of syllables: one unstressed and one stressed. (To hear what that sounds like, say the word "allow" out loud. You should hear a da-DUM pattern). That pattern, folks, is called an iamb. You probably recognize iambs from Shakespeare, but if they are giving you some trouble, just remember the following line:
To be or not to be
This line from Hamlet may be the most famous set of iambs in the English language. It should sound to you like: da-DUM da-DUM da-DUM. Hopefully it helps you "feel" what an iamb is.
Dickinson herself was a big Shakespeare fan, and she uses iambic meter in most of her poems. Check out lines 3 and 4:
A Re son ance of Em er ald
A Rush of Coch i neal
Since the first line contains four iambic feet, we would say that it is written in iambic tetrameter, where "tetra"means four. And since the second line contains three iambic feet, we would say that it is written in iambic trimeter, where "tri" signals three. As it turns out that formula—of alternating lines of iambic tetrameter and trimeter—is the mark of a ballad, which is what we've got on our hands here.
Still, we have to say that this poem mostly fits the ballad form. If you check out the first line, though, you'll notice a bit of a hiccup in that iambic pattern:
A Route of Ev an es cence
All you iamb experts out there will recognize that the da-DUM of the iambic pattern doesn't quite hold up at the end of the line. Instead of a da-DUM when get a DA-DUM: two stressed syllables back to back. Woah. But what's it all mean?
Well, on a technical level, Dickinson is sneaking in a spondee here (a spondee is just the poetic term for a pair of stressed syllables). Sure, sneaking spondees in just sounds like a ton of laughs, but we think she might also have a reason for doing so. If you think about it, this poem is about journeys: the journey that the hummingbird takes, and the journey that the speaker's mind is on in observing this hummingbird. In both cases, it's not exactly a straightforward trip. So, why would we expect a poem to keep a straightforward rhythmic pattern? This little metrical jolt is a very subtle cue that we might be in for some unexpected twists and turns as we get further into the poem. And, as it turns out, we are!