in
combination with the other forms of discourse.

_Exposition is that form of discourse which seeks to explain a term or
a proposition._ Text-books, books of information, theses, most
histories, many magazine articles, and newspaper leaders are of this
class of literature.

_Argument is that form of discourse which has for its object the proof
of the truth or falsity of a proposition._

_Persuasion is that form of discourse the purpose of which is to
influence the will._

Difficulty in distinguishing.

Though these definitions seem to set apart the great classes of
literature, and to insure against any danger of confusion, it is not
always easy to place individual pieces of literature in one of these
divisions. Whittier's "Barbara Frietchie" and Stevenson's "Treasure
Island" are narrative beyond any question; but what about "Snow-Bound"
and "Travels with a Donkey" by the same authors? Are they narration or
description? In them the narrative and descriptive portions are so
nearly equal that one hesitates to set them down to either class; the
reader is constantly called from beautiful pictures to delightful
stories. The narrative can easily be separated from the descriptive
portions; but when this has been done, has it been decided whether the
whole piece is narration or description?

When a person takes up the other forms of discourse, the difficulty
becomes still greater. Description and narration are frequently used
in exposition. If a boy should be asked to explain the working of a
steam engine, he would, in all likelihood, begin with a description of
an engine. If his purpose was to explain how an engine works, and was
not to tell how an engine looks, the whole composition would be
exposition. So, too, it is often the easiest way to explain what one
means by telling a story. The expression of such thoughts would be
exposition, although it might contain a number of stories and
descriptions.

Narration and description may be found in a piece of exposition; and
all three may be employed in argument. If a person should wish to
prove the dangers of intemperance, he might enforce his proof by a
story, or by a description of the condition of the nervous system
after a drunken revel. And one does not need to do more than explain
the results of intemperance to a sensible man to prove to him that he
should avoid all excesses. The explanation alone is argument enough
for such a person. Still, is such an explanatio