Sestets with Irregular Rhyme and Meter
"Dream Song 29" doesn't fit into any of the traditional forms. It's not, for example, a sonnet or a sestina. There isn't an easy label we can put on this one. But that's not to say Berryman wasn't working with form. It just happens to be one he came up with himself.
Berryman used pretty much the same form for all of the dream songs: three of those nice, tidy 6-line stanzas (called sestets in the poetry biz) that usually contain some pretty untidy, unpredictable content. So, on the bright side, you're only dealing with 18 lines. In many of the songs, Berryman used an overall metrical pattern: long lines with five metric feet and the short lines with three, in a LLSLLS order. But #29 doesn't stick to this pattern or strict meter.
The regular number of lines per stanza is one thing that gives this poem its form-y feel. But there is another element that adds to this feeling—the use of end rhyme. Each stanza contains two end-rhymes. But they come in different places:
Stanza 1: lines 2 and 5, lines 3 and 6
Stanza 2: lines 1 and 4, lines 2 and 5
Stanza 3: lines 2 and 5, lines 4 and 6
This irregular rhyme scheme adds to that sense of things being a little off. It feels at times like things are about to come together (about to get regular, normal) but they never quite do—kind of like that feeling in a dream where you are trying to get somewhere, but something keeps preventing you. The feeling that something is always just a little off reinforces the sense of dream world or hallucination, of something other than reality.
The same is true of the poem's irregular meter. Things start off regularly enough with a line of iambic pentameter:
There sat down, once, a thing on Henry's heart. (1)
But the meter soon starts to drift and for the rest of the poem the iambs come and go, mirroring the drift from reality to dream, or even from sanity to insanity.
Now, we knows you love rhyme as much as we do, so let's revisit those rhymes for a minute, specifically, those rhymes in stanza three. Notice anything different? Yup, they are, in fact, just repeated end words. What's up with that? Seems a little easy. Perhaps John was getting tired after writing the previous 28 songs. Well, maybe. But let's think about what the repetition does here.
The speaker is talking about something Henry does all the time: "Often he reckons, in the dawn, them up." The repetition, the same thing over and over, mirrors the obsessive reckoning that Henry does and his persistent sadness and guilt. It's the same actions, the same feelings, over and over again. Hey, it turns out ol' J.B. wasn't getting lazy after all.