Other unequal couplets are found in Herrick's A Thanskgiving to God for his House (a4a2) and Browning's Love among the Ruins (a6a2).
The equal couplet is used both continuously and, more rarely except with long lines, as a single stanza. Sometimes two or three couplets are combined into a larger stanza. The usual forms of the couplet used continuously are the 4-stress or short couplet ("octosyllabic") and the 5-stress or heroic couplet ("decasyllabic").
Short Couplet. The short couplet in duple iambic-trochaic movement has proved its worth by its long history and the variety of its uses. The English borrowed it from the French octosyllabic verse, and employed it chiefly for long narrative poems. Chaucer used it in his earlier work, the Book of the Duchess, and the House of Fame; Butler in the serio-comic Hudibras; Scott, Byron, Wordsworth, and Morris in their Romantic narrative verse. For lyric purposes it was used by Shakespeare and other dramatists, by Milton in L'Allegro and Il Penseroso, and since then by most of the greater and lesser poets. But its effect, especially in long poems, is often monotonous because of the rapid recurrence of the rimes, and its powers are somewhat limited. Except under expert handling it is likely to turn into a dog-trot, and it seems sometimes to lack dignity where dignity is required. On the whole it is better for swift movement, for the obvious reason that the line is short: the frequent repetition of the unit, both line and couplet, produces the effect of hurry.
Never has the short couplet revealed its flexibility to better advantage than in Milton's L'Allegro and Il Penseroso and in Coleridge's Christabel. In Christabel Coleridge believed he was inventing a new prosodic principle, that of counting the stresses rather than the syllables;[46] and though he erred with respect to the originality of his principle, he succeeded in getting a freer movement than the couplet had had since Chaucer. Some of the roughness of Chaucer's short couplets is probably due to the imperfections of our texts, and some also to the haste with which he wrote—it is in this metre that the fatal facility of certain poets has proved the worst bane—but the Chaucerian couplet stands as a prototype (though not literally a model) of the freer flow of Byron's[47] and Morris's couplets, in contrast to those of Scott and Wordsworth, which resemble the stricter, syllable-counting couplets of Chaucer's friend Gower.
The chief drawbacks of the short couplet, besides monotony, are the tendency to diffuseness of language and looseness of grammatical structure (as in Chaucer and Scott, for instance), and rime-padding, i. e., the insertion of phrases and sometimes even irrelevant ideas, for the sake of the rime.
The chief sources of variety are substitution, pause, run-on lines, and division. The first is very apparent in the much-quoted passage in Christabel:
The night is chill; the forest bare;
Is it the wind that moaneth bleak?
There is not wind enough in the air
To move away the ringlet curl
From the lovely lady's cheek—
There is not wind enough to twirl
The one red leaf, the last of its clan,
That dances as often as dance it can,
Hanging so light, and hanging so high,
On the topmost twig that looks up at the sky.
The pause offers more difficulties for the poet, and more opportunities; since the line is so short, and the rimes reinforce the regular metrical pause at the end of the line, important grammatical pauses cannot well occur in the middle of the line without danger of breaking the rhythm. The logical pause must, therefore, usually coincide with the metrical and thus emphasize unduly the line unit. Moreover, the quick return of the rime sound causes the couplet itself to be felt as a unit and produces what are called 'closed couplets,' in which the two lines contain an independent idea. To avoid irksome uniformity in this regard three devices are customary: to 'run-on' the meaning from one line to the next, thus momentarily obscuring the metrical pause, to 'run-on' the couplets themselves, and to divide the couplet so that the second verse belongs to a new sentence or independent clause.
And thus, when they appeared at last,
And all my bonds aside were cast,
These heavy walls to me had grown
A heritage—and all my own!
And half I felt as they were come5
To tear me from a second home.
With spiders I had friendship made,
And watched them in their sullen trade;
Had seen the mice by moonlight play—
And why should I feel less than they?10
We were all inmates of one place,
And I, the monarch of each race,
Had power to kill; yet, strange to tell!
In quiet we had learned to dwell.
My very chains and I grew friends,15
So much a long communion tends
To make us what we are:—even I
Regained my freedom with a sigh.
Byron, The Prisoner of Chillon.
In this passage, which is on the whole conservative and stiff in movement, observe (1) how the pause in the middle of ll. 4, 13, and 17 helps to vary the measure; (2) how many of the verses end with a logical as well as metrical pause; (3) how in ll. 3, 5,16, and 17 the meaning runs over without pause into the next lines; (4) how the first two couplets and the last two are run together, whereas the third and fourth are both closed and independent; and (5) how at ll. 9 and 10 the couplet is divided. This last device is not very frequent in the practice of any poet except Chaucer; it is well illustrated, however, in these lines from Shelley's With a Guitar to Jane: