Read it through once

Of course, I pretend to no originality in either the rhythm or meter of “The Raven.” The former is trochaic—the latter is octameter acatalectic, alternating with heptameter catalectic repeated in the refrain of the fifth verse, and terminating with tetrameter catalectic. Less pedantically—the feet employed throughout (trochees) consist of a long syllable followed by a short: the first line of the stanza consists of eight of these feet—the second of seven and a half (in effect two-thirds)—the third of eight—the fourth of seven and a half—the fifth the same—the sixth, three and a half. Now, each of these lines, taken individually, has been employed before, and what originality “The Raven” has, is in their combination into stanza: nothing even remotely approaching this combination has ever been attempted. The effect of this originality of combination is aided by other unusual and some altogether novel effects, arising from an extension of the application of the principles of rhyme and alliteration.