The methods and movements by which this commonness is turned into length or shortness for the purposes of the poet are obvious enough, and in practice undeniable; though the processes of professional phonetics sometimes tend to obscure or even to deny them. Every well-educated and well-bred Englishman, who has been accustomed to read poetry and utter speech carefully, knows that when he emphasises a syllable like "and," "if," "the," etc., it becomes what the Germans would call versfähig—capable of performing its metrical duty—in the long position; that when he does not, it is not so capable. Every one knows in practice, though it may be denied in theory, that similar lengthening[17] follows the doubling of a consonant after a short vowel, or the placing of a group of consonants of different kinds after it—the vowel-sound running, as it were, under the penthouse of consonants till it emerges. Extreme loudness and sharpness would have the same effect in conversation, but, unless very obviously suggested by sense, would escape notice in silent reading. Not very seldom, the mere art of the poet will get weight enough on a short syllable to fit it for its place as "long," or conjure away from a long one length enough to enable it to act as "short."
At any rate, it is with these two values, and with syllables endowed with them by custom, incidental effect, place, sense, the poet's sleight of hand, or otherwise, that the English poet deals; and has dealt, ever since a period impossible to nail down with exactness to year or decade, but beginning, perhaps, early in the twelfth century and perfecting itself in the thirteenth and later. And impartial examination of the whole facts from that period shows that he deals with them on a system, in early times no doubt almost or quite unconsciously adopted, but perfectly recognisable. In still earlier or "Old" English verse this system is not discernible at all; in the earliest period of "Middle" English it is discernible, struggling to get itself into shape. Later, with advances and relapses, it perfects itself absolutely. Its principles are as follows:—
Intermediate rules of arrangement.
Every English verse consists of a certain number of feet, made up of long and short syllables, each of which is of equal consequence in the general composition of the line.
The correspondence of the foot arrangements between different lines constitutes the link between them, and determines their general character.
Some interim rules of feet (expanded in note).
But this correspondence need not be limited to repetition of feet composed of a fixed and identical number of syllables in the same order; on the contrary, the best verse admits of large substitution of feet of different syllabic length, provided—(1) that these are equal or nearly equal in prosodic value to those for which they are substituted; (2) that the substituted feet go rhythmically well with those next to which they are placed.[18]
A fuller list of observed rules for English verse generally will be found in the next chapter, but between the two a set of remarks, specially on the foot, may be extracted from the larger History, vol. i. pp. 82-84.
Every English verse which has disengaged itself from the versicle[1] is composed, and all verses that are disengaging themselves therefrom show a nisus towards being composed, of feet of one, two, or three syllables.
The foot of one syllable is always long, strong, stressed, accented, what-not.[19]