[§ 667]. The rationale of so remarkable a phænomenon as regularity of accent in verses considered to have been composed with a view to quantity only has yet to be investigated. That it was necessary to the structure of the metres in question is certain.
[§ 668]. Cæsura.—The cæsura of the classical metrists is the result of—
1. The necessity in the classical metres (as just indicated) of an accented syllable in certain parts of the verses.
2. The nearly total absence in the classical languages of words with an accent on the last syllable.
From the joint effect of these two causes, it follows that in certain parts of a verse no final syllable can occur, or (changing the expression) no word can terminate.
Thus, in a language consisting chiefly of dissyllables, of which the first alone was accented, and in a metre which required the sixth syllable to be accented, the fifth and seventh would each be at end of words, and that simply because the sixth was not.
Whilst in a language consisting chiefly of either dissyllables or trisyllables, and in a metre of the same sort as before,
if the fifth were not final, the seventh would be so, or vice versa.
[§ 669]. Cæsura means cutting. In a language destitute of words accented on the last syllable, and in a metre requiring the sixth syllable to be accented, a measure (foot) of either the formula x a, or x x a (i. e., a measure with the accent at the end), except in the case of words of four or more syllables, must always be either itself divided, or else cause the division of the following measures—division meaning the distribution of the syllables of the measure (foot) over two or more words. Thus—
a. If the accented syllable (the sixth) be the first of a word of any length, the preceding one (the fifth) must be the final one of the word which went before; in which case the first and last parts belong to different words, and the measure (foot) is divided or cut.