Writing: Second of three kinds of sentences -- Periodic

Flip sides of Grecian coin

There are three notable kinds of sentences.

1. Balanced
2. Periodic
3. Loose

Periodic and loose sentences are flip sides of the same coin. In this post we'll take a close look at periodic sentences.

The meaning of a period sentence is delayed until its end. 
Subordinate clauses or modifying phrases precede the main clause, and the whole sentence must be read before the reader can make any sense of it. 

Example: As I looked on him, his countenance expressed the utmost extent of malice and treachery. 

Used judiciously, the period sentence creates suspense. 
  
William Minto writes that the periodic "style" may be applied to the structure of a paragraph or essay:

Obviously the same method may be applied on a larger scale than the sentence. It may be, and often is, applied to paragraphs, and often in a way to articles, sermons, and addresses. A speaker often indulges in several consecutive sentences of general reflections before he discloses the precise application of them. A journalist often in like manner reserves the point of his remarks for the end of a paragraph or an article. This is in effect a periodic arrangement.

Periodic style can lend force and eloquence to writing.  

...[M]ajestic writing, the grand style, whether in verse or in prose, is impossible without periodic structure. The opening of Paradise Lost is periodic; so are Wordsworth's finest sonnets; so is Othello's speech before the Signors of Venice. 

Used injudiciously, the period sentence exhausts the reader. 

Looked at from the reader's point of view, the effect of periodic structure—of holding phrases or clauses or sentences in suspense—is to impose a certain strain on the attention. The reader has nothing to attach them to till the key-word conies, and his attention is consequently excited to a higher pitch, if it is excited at all. This strain of attention is exhausting; some readers are incapable of it altogether, and no reader is capable of sustaining it for long. The main danger in the use of the periodic style is that you either never catch your reader's attention, or lose hold of it before you reach the object of your unattached expressions.

You must have something important to say, something that will reward the reader for the strain upon his intellect. Nothing is more tedious than to hear a speaker slowly evolving periods up to a familiar application ... Majesty of manner without majesty of matter is ludicrous, like all affectations.

Source: Minto.