yllable appears; and it is a general rule, that,
in the last measure of any verse, supernumerary unaccented syllables can be
admitted without destroying the original character of the measure.

s. 538. See the verses in the section on double rhymes. Here the original
character of the measure is x a throughout, until we get to the words
_diss['e]ver_ and _for ['e]ver_, and afterwards to _men do['u]bt it_, and
_abo['u]t it_. At the first view it seems proper to say that in these
last-mentioned cases x a is converted into x a x. A different view,
however, is the more correct one. _Diss['e]ver_ and _for ['e]ver_, are
rather x a with a syllable over. This extra syllable may be expressed by
the sign _plus_ ( + ), so that the words in point may be expressed by x a
+, rather than by x a x. It is very clear that a measure whereof the last
syllable is accented (that is, measures like x a, _pres['u]me_, or x x a,
_caval['i]er_), can only vary from their original character on the side of
excess; that is, they can only be altered by the addition of fresh
syllables. To subtract a syllable from such feet is impossible; since it is
only the last syllable that is capable of being subtracted. If that last
syllable, however, be the accented syllable of the measure, the whole
measure is annihilated. Nothing remains but the unaccented syllable
preceding; and this, as no measure can subsist without an accent, must be
counted as a supernumerary part of the preceding measure.

s. 539. With the measures a x, a x x, x a x, the case is different. Here
there is room for syllable or syllables to be subtracted.

Que['e]n and h['u]ntress, ch['a]ste and fa['i]r,
N['o]w the s['u]n is la['i]d to sl['e]ep,
Seated ['i]n thy s['i]lver cha['i]r,
St['a]te in w['o]nted spl['e]ndour ke['e]p.
H['e]sper['u]s inv['o]kes thy l['i]ght,
G['o]ddess, ['e]xquis['i]tely br['i]ght.--BEN JONSON.

In all these lines the last measure is deficient in a syllable, yet the
deficiency is allowable, because each measure is the last one of the line.
The formula for expressing _fa['i]r_, _sl['e]ep_, _cha['i]r_, &c. is not a,
but rather a x followed by the _minus_ sign (-), or a x-.

A little consideration will show that amongst the English measures, x a and
x x a naturally form single, a x and x a x double, and a x x treble rhymes.

s. 540. The chief metres in English are of the formula x a. It is only a
few that are known by fixed names. These are as follows: