The patterned sounds of poetry-rhythm, rhyme, alliteration, assonance-are often referred to as the "music of poetry." This is a useful and suggestive phrase, but an impotant reservation must be kept in mind: poetry can never be the music of pure sound. Poetry is made with words, which are in fact sounds when uttered, but these sounds are always meaningful in a way that the sounds of music cannot be. In music a sound may be recognized as associated with or imitative of a sound that occurs outside the musical composition-for instance, a bird's song or the sound of a cannon-but its acoustic message is independent of this association. In a song, words may have an instrumental accompaniment and will have an arrangement of pitch and duration that complements and complicates their effect. But the music in a poem is inseparable not only from the words chosen, but specifically from their meaning. Consider the difference between "whisper" and "whisker."
 

RHYTHM AND METER

Rhythm is something that seems to be instinctively loved and understood by all human beings.  Our very bodies are alive only so long as the rhythms of blood and breath continue.  Basically, rhythm is created by the repetition of an event in a sequence that is perceived as significant and often may be measured.  Some of the rhythmic events in a poem are measurable, but some are not.  Unlike the rhythm produced by a metronome, with exactly equal intervals between the beats, a poem is affected by human speech, which is a matter of breathing, uttering, and pausing, all impelled by movements of thought and feeling.  Consequently, certain elements of poetic rhythm are not measurable.  However, arrangements of syllables and syllable-stresses (the stress of a syllable is determined by how loud, how high-pitched, and how long it is, relative to other syllables around it) can be counted in their recurrence.  These arrangements are called feet.  Counting the stressed syllables, figuring out what kind of feet that constitute, and the number and sequence of feet in a particular line is called "scansion."  When you are asked to "scan" a poem, you are being asked to mark the stressed and unstressed syllables, to divide them into groups of two or three that comprise a foot, and to determine the prevailing pattern of feet in a line  This underlying pattern, different from the actual rhythm which sometimes follows and sometimes varies from the expected pattern, is called  the meter of that poem or section of a poem.

The human ear seems capable of recognizing consistently four different amounts of syllable stress, but for purposes of scansion, we usually reduce the varieties to two, called "stressed" (relative to adjacent syllables, and usually marked by a /) and "unstressed" (again, relative to adjacent syllables; to indicate an unstressed or less stressed syllable, many use a mark like a parenthesis on its side, but I  (P. Craddock) like to use an x).  Another device is to CAPITALIZE the stressed syllables and leave the unstressed syllables in lower case.  The placement of accents in words of two or more syllables is at least partially determined by standard pronunciation (of the time and place at which the poem was written).  For instance,  I can't choose to emphasize the middle syllable of "syllable" without appearing ridiculous (putting the emPHAsis on the wrong sylLAble.  But the stress or lack of stress on a one-syllable word is determined by the meaning of the statement, which may sometimes be determined by an individual interpretation. For example, "This is the face that launched a THOUsand ships" might be read "THIS is" or "This IS, " etc.  But there are constraints; you could not stress "that" instead of "launched," and if you stressed "the" instead of "face," you could not avoid implying a constrast with other, lesser faces that had also launched a thousand ships.  After the first pair of syllables in the line, therefore, the unavoidable conclusion is that there is a pattern of stressed and unstressed syllables in the line that goes x / x / x / x /.  Thus the rhythmic pattern is clear: the feet typically contain two syllables, and the feet are of the type called iambs.  Since there are five feet in the line, the length is named pentameter, from the Greek word for five (penta) plus the Greek word for measure.  The technical names for the various metrical line lengths are

• one-foot line  monometer
• two-foot line dimeter
• three-foot line trimeter
• four-foot line tetrameter
• five-foot line pentameter
• six-foot line hexameter
• seven-foot line heptameter

SOME ESPECIALLY IMPORTANT METRICAL FORMS

blank verse--unrhymed iambic pentameter.  Not to be confused with free verse.
heroic couplets--rhymed pairs of lines in iambic pentameter, most of which form a strong unit in themselves.  The difference between a heroic couplet and any old rhymed iambic pentamenter couplet is the way the heroic couplet calls attention to the two-line package.  In general, rhymed iambic pentameters are considered "heroic" if the majority of the pairs of lines end in a strong pause, such as the ones marked by periods, colons, exclamation points, semi-colons, and question marks. If, on the other hand, you hardly notice that the poem is written in couplets, as in Browning's "My Last Duchess," clearly the writer is not trying for the epigrammatic effect of heroic couplets.

SOME RHYTHMIC FORMS THAT ARE NOT DEPENDENT ON "FEET"

Syllable-stress meter has been the dominant form in English poetry between the fifteenth and twentieth centuries.  However, poems may use a measure that is not dependent on the stress or accent, but simply on the number of syllables; this type of poetry is called syllabic verse (Marianne Moore provides modern examples).  Another type of meter ignores the number of syllables and counts only the stressed syllables.  This was the method of Anglo-Saxon poetry, which had a number of different line patterns related to stressed syllables (marked by alliteration) and various kinds of pauses (the technical name for a pause in poetry is caesura, plural caesurae).  Recent poets like William Carlos Williams, Robert Creely, and others have worked with a short poetic line that seems to observe a flexible count of stresses.  Here is an example from Williams:

The YEAR PLUNges into NIGHT
and the HEART PLUNges
LOWer than NIGHT
to an EMPty, WINDswept PLACE
without SUN, STARS, or MOON
but a peCULiar LIGHT as of THOUGHT.

(A) CADENCE

We know that poets vary meter to accommodate speech rhythms.  Some rhythmic variations within poems have nothing to do with meter.  One of these is cadence, the rise and fall of the voice, the connections and pauses that make up any utterance.  If we take a bit of conversation such as "I THINK | you were CRAzy || to come OUT here | in this WEATHer ||| but I'm GLAD you CAME," we note pauses of different lengths, and an overall intonation pattern that tells us, for example, that we are hearing a statement, not a question, or an exclamation.  In "My Last Duchess," the pause-pattern might be read as follows:

That's my LAST duchess | painted on the wall, ||
Looking | as if she were alive ||| I call
That piece a wonder, | now; || Fra Pandolf's hands
Worked busily a day, | and || there she stands.|||

(B) REPETITION AND PARALLELISM

In unrhymed, unmetrical verse, the cadences become far more important, because rhyme and meter are not present to draw attention away from all the nuances of pace, pitch, loudness, and intonation.  Consider the cadences in the following passage from Robert Creeley's poem "The Rhythm":

If in death | I am dead,||
then in life| also|
dying, || dying ||
...
And the women | cry || and die.|||
The little children |
grow only to old men.||
The grass | dries, ||
the force goes.|||

In the following passage from T. S. Eliot's "The Love Song of J. Alfred Prufrock," repetition of the "time" phrases puts a counter-rhythm into play within the underlying iambic rhythm:

    And indeed there will be time
    For the yellow smoke that slides along the street
    Rubbing its back upon the window-panes;
    There will be time, there will be time
    To prepare a fame to meet the faces that you meet;
    There will be time to murder and create,
    And time for all the works and days of hands
    That lift and drop a question on your plate;
    Time for you and time for me,
    And time yet for a hundred indecisions,
    And for a hundred visions and revisions,
    Before the taking of a toast and tea.

Repetition of a word usually involves, as it does here, the repetition of an idea with variations, as well as the parallelism of grammatical forms.  Through the King James version of the Bible, Hebrew poetry has had a very deep influence on poetry in English, and for that matter, on prose also.  Its building of rhythmic movements by means of the balanced repetition of ideas and the parallelism of sentence form is seen in these verses from the Book of Job:

I went mourning without the sun:
I stood up, and I cried in the congregation,
I am a brother to dragons,
    and a companion to owls
My skin is black upon me,
    and my bones are burned with heat.
My harp also is turned to mourning,
    and my organ into the voice of them that weep. (Job 30: 28-31)

About a century after the American Revolution, Walt Whitman started a second American Revolution--this time in the field of poetry.  His free-verse rhythms used, among other resources, the rhythmic structures of biblical poetry.  The opening lines of his Song of Myself  illustrate this:

I celebrate myself, and sing myself,
And what I assume you shall assume,
For every atom belonging to me as good belongs to you.
I loaf and invite my soul,
I lean and loaf at my ease observing a spear of summer grass.

I have of late--but wherefore I know not--lost all my mirth, foregone all custom of exercises; and indeed it goes so heavily with my disposition that this goodly frame, the earth, seems to me a sterile promontory; this most excellent canopy, the air, look you, this brave o'erhanging firmament, this majestical roof fretted with golden fire, why it appears no other thing to me but a foul and pestilent congregation of vapours.  What a piece of work is a man! How noble in reason! How infinite in faculty! In form, in moving, how express and admirable!  in action how like an angel! in apprehension how like a good! the beauty of the world! the paragon of animals! And yet to me what is this quintessence of dust?  Man delights no me; no, nor woman neither, though, by your smiling, you seem to say so. (Hamlet Act 2, sc. 2)

Just as meter can be employed for an infinite variety of effects, so can non metrical rhythms.  The nature of any poem, lyric of otherwise, will determine which type of rhythm the poet uses and the way he or she uses it.  Many modern poets have things to say that they feel can be said better in nonmetrical rhythms.  Good free verse has its own kind of rhythm, as does much good prose.  There are also various kinds of free verse.  The verse movement, which continues to develop, covets for poetry the rich resources of prose, but not necessarily to the exclussion of syllable stress patterns, freely employed.  As we have seen, the order of meter is based on syllable and stress patterns.  The rhythmic order of non-metrical poetry--free verse--is based on breath and pause patterns and grammatical patterns.  But these forms of order are not absolutely separated from each other.

According to William Butler Yeats,

The purpose of rhythm, it has always seemed to me is to prlong the moment of contemplation, the moment when we are both asleep and awake, which is the one moment of creation, in which, by hushing  us with an alluring monotony, while it holds us waking by variety, to keep us in that state of perhaps real trance, the mind, liberated from the pressure of the will, is unfolded in symbols.  (Ideas of Good and Evil, 1903; pp. 247-48)