It's gonna be a bumpy ride, Shmoopers. So hold on tight. We've got a lot of explaining to do.
Like many of Blake's poems, the meter of "The Chimney Sweeper" is all over the place. A little iambic here, a little anapestic there.
Whoa whoa whoa. Iambic? Anapestic? Excuse me? Don't worry, we'll break it down.
First things first: in general, each line of the poem can be divided into four groups (called feet). We know there are four feet in each line because each line has four stressed syllables (with a bunch of unstressed ones peppered throughout to pad the ranks).
But there are several different types of feet employed. Take line 1 as an example:
When my mother died I was very young
Breaking this line up into feet might look a little something like this:
When my moth / er died / I was ve / ry young
So the first and third groups contain two unstressed syllables followed by a stressed syllable (this is called an anapest), and the second and fourth groups contain an unstressed syllable followed by a stress syllable. This is called an iamb, and it is the most common foot type in English.
"The Chimney Sweeper" contains lots of anapests (Blake really likes these) and lots of iambs, so we might think of this poem as being a mixture of anapestic and iambic tetrameter. We know, we know—he's breaking some rules. But hey, he's William Blake. We think he's earned the right.
The poem is divided into six stanzas, each of which contains four lines. Hey, that adds a nice little symmetry when you think about the fact that each line has four beats, doesn't it?
And in each stanza, the first two lines rhyme, and the last two lines rhyme. When two lines rhyme in succession, it's called a couplet (because it's like a cute little matchy couple).
You'll notice that as the poem progresses, the rhymes become less regular; for example, "dark" and "work" (21-22) and "warm" and "harm" (23-24) kind of rhyme, but not that well. This type of rhyme is often called a slant rhyme, or half-rhyme, or imperfect rhyme, and they have the eerie effect of unsettling us a bit. As we enter the dark last lines of the poem, the sing-songy perfect rhymes give way to wonkier ones. We're no longer at ease.