I'm working on a poem with long lines and looking at the techniques Whitman used to give them music and structure. He used neither rhyme nor meter to make them work. In the first edition of Leaves of Grass the pages were wide enough to accommodate them. In later editions, designed to fit into a pocket for portability, Whitman changed the page size but not the line breaks.
Long lines give an expansive, rambling feeling that can be dangerous. If it truly sounds rambling, the reader loses interest in wading through all those words. By contrast, look at Whitman's first version of "Song of Myself" published in the first edition (1855) of Leaves:
But each man and each woman of you I lead upon a knoll,
My left hand hooks you round the waist,
My right hand points to landscapes of continents, and a plain public road.
The lines lead off short before launching into a long one. And the dialogue format -- the direct address to the reader -- provides an irresisible element of interest. We all sit up straighter when we're the subject of the conversation. Whitman was clever to bring the reader into his poems in the intimate address he uses, almost of a lover wooing.
But what can you do to make a long line irresistibly poetic if you don't want to woo the reader so obviously? I notice another trick in these and many other Whitman lines: the juxtaposition of the small, intimate details with a vast landscape. He was a master of the "pull-back shot
." He was cinematic before cinema was invented.
His other big device is repetition. In the lines above, the repetition is simple: "you" and "I." In other poems, a whole clause or sentence is repeated in a list poem.
This gives me the idea that the way to make long lines really work well is to find sonic devices that bring them back to lyric poetry's beginnings. I'm thinking assonance, alliteration, internal rhyme, slant rhyme, repetends. Perhaps even meter, though I find a line doesn't hold well beyond pentameter.