"The lines [of Beowulf] do not go according to a tune. They are founded on a balance; an opposition between two halves of roughly equivalent phonetic weight, and significant content, which are more often rhythmically contrasted than similar. They are more like masonry than music" (30). 

Tolkien, J. R. R. "The Monsters and the Critics." The Monsters and the Critics and Other Essays. London: Harper Collins, 2006. Print.