Institutio Oratoria

However I shall speak of the different ideals a little later: my immediate task is to teach the student elementary rules which are essential if correctness of structure is to be attained. There are then in the first place two kinds of style: the one is closely welded and woven together, while the other is of a looser texture such as is found in dialogues and letters, except when they deal with some subject above their natural level, such as philosophy, politics or the like.

In saying this, I do not mean to deny that even this looser texture has its own peculiar rhythms which are perhaps the most difficult of all to analyse. For dialogues and letters do not demand continual hiatus between vowels or absence of rhythm, but on the other hand they have not the flow or the compactness of other styles, nor does one word lead up so inexorably to another, the structural cohesion being loose rather than non-existent.