§ 5
All speakers must consider the sound of their sentences as well as their grammatical structure, and among all careful writers we find that attention is paid to the balance of clauses. Some orators go further than this; they emphasize contrasts or parallels by the repetition of similar sounds and even show a preference for certain rhythms, it being a maxim of late rhetoricians that prose, though not strictly metrical in the same way as verse, should possess a characteristic rhythm of its own.
Some authors go so far as to change the natural order of words for the purpose of escaping hiatus of open vowels, which are necessarily awkward to pronounce in rapid speech. This is familiar from the pages of Demosthenes, and what the later writers did systematically, Antiphon, and even Thucydides, seem to have done at times instinctively.
As regards the balance of clauses, a good example may be found in the opening of the Herodes speech:
τοῦ μὲν πεπείραμαι πέρα τοῦ προσήκοντος,
του δ’ ἐνδεής εἰμι μᾶλλον τοῦ συμφέροντος,
where the correspondence of the two clauses in equal numbers of syllables is noticeable. The next sentence shows the same sort of correspondence, though not quite so precise; but here the structure is more elaborate, since we have two clauses, each of two parts, contrasted both in whole and part:
A. οὗ μὲν γάρ μ’ ἔδει κακοπαθεῖν τῷ σώματι μετὰ τῆς αἰτίας τῆς οὐ προσηκούσης,
α. ἐνταυθοῖ οὐδέν μ’ ὠφέλησεν ἡ ἐμπειρία,