Institutio Oratoria
Quintilian
Quintilian. Institutio Oratoria, Volume 1-4. Butler, Harold Edgeworth, translator. Cambridge, Mass; London: Harvard University Press, William Heinemann Ltd., 1920-1922.
Again rhythm more readily admits of rests [*](i.e. in the musical sense. ) although they are found in metre as well. Greater license is, however, admitted when the time is measured by the beat of the feet or fingers, [*](i.e. in musio. ) and the intervals are distinguished by certain symbols indicating the number of shorts contained within a given space: hence we speak of four or five time ( τετράσημοι, or πεντάσημοι ) and others longer still, the Greek σημεῖον indicating a single beat.
In prose the rhythm should be more definite and
For example, I have come across tiresome grammarians who attempted to force prose into definite metres, as though it were a species of lyric poetry. Cicero, [*]( See Or. xx. 67, sqq. ) indeed, frequently asserts that the whole art of prose-structure consists in rhythm and is consequently censured by some critics on the ground that he would fetter our style by the laws of rhythm.