In this paper it is proposed to be argued that the tendency in Latin known as the ‘Iambic Law’ is actuated by one cause, and one only—viz., the intensity of the prior syllable of the two. ‘Intensity’ means higher tone and increased force of utterance (plus sonat, Keil, 4, 426; acuto accentu elatum, as Charisius (K. I, p. 227) says of ut exclamatory). It is of three kinds:
(1) Initial—proper to the first syllable of a disyllabic, tetrasyllabic, or pentesyllabic word of a sentence or (as Bentley first noted) of a verse.
(2) Appropriate to the sense of interrogatives (which therefore must normally stand first) and other words of natural emphasis, such as ego, or the expletives pol, malum, or imperatives, or words like at and sed, before which there is a pause in Latin.
(3) Attaching to particular words in a particular context because of the meaning of the sentence (cf. Donat. ad Phorm. 341, acuenda uox in eo quod ait, ‘tibi’).