t would be description. To
tell in exact terms what the automobile is, to name its characteristic
parts and explain their workings, would be exposition; so would an
explanation of the nature of "fear." But to create a mental image of a
particular automobile, with its glistening body, graceful lines, and
great speed, would be description; and so would a picturing of fear
acting on the emotions of a child at night. Exposition and description
often intermingle and overlap, but fundamentally they are distinct.
Their differences will be touched upon again in the chapter on
"Description."

Exposition furthermore does not include an account of how events
happened--that is narration. When Peary lectured on his polar
discoveries he explained the instruments used for determining latitude
and longitude--that was exposition. In picturing his equipment he used
description. In telling of his adventures day by day he employed
narration. In supporting some of his contentions he used argument. Yet
he mingled all these forms throughout the lecture.

Neither does exposition deal with reasons and inferences--that is the
field of argument. A series of connected statements intended to convince
a prospective buyer that one automobile is better than another, or
proofs that the appeal to fear is a wrong method of discipline, would
not be exposition. The plain facts as set forth in expository speaking
or writing are nearly always the basis of argument, yet the processes
are not one. True, the statement of a single significant fact without
the addition of one other word may be convincing, but a moment's thought
will show that the inference, which completes a chain of reasoning, is
made in the mind of the hearer and presupposes other facts held in
consideration.[12]

In like manner, it is obvious that the field of persuasion is not open
to exposition, for exposition is entirely an intellectual process, with
no emotional element.

_The Importance of Exposition_

The importance of exposition in public speech is precisely the
importance of setting forth a matter so plainly that it cannot be
misunderstood.

"To master the process of exposition is to become a clear
thinker. 'I know, when you do not ask me,'[13] replied a
gentleman upon being requested to define a highly complex idea.
Now some large concepts defy explicit definition; but no mind
should take refuge behind such exceptions, for where definition
fails, oth