Institutio Oratoria

There are some points, it is true, which are beyond the power of art to inculcate. For example if the case, tense or mood with which we have begun, produces a harsh rhythm, it must be changed. But is it possible to lay down any definite rule as to what the change of case, tense or mood should be? It is often possible to help out the rhythm when it is in difficulties by introducing variety through the agency of a figure. But what is this figure to be? A figure of speech or a figure of thought? Can we give any general ruling on the subject? In such cases opportunism is our only salvation, and we must be guided by consideration of the special circumstances.

Further with regard to the time-lengths, which are of such importance where rhythm is concerned, what standard is there by which they can be