Make a list of other kinds of books which are mainly or entirely expository in character.

Difficulties in Exposition.  Such are the purpose and use of exposition.  The difficulty of producing good exposition is evident from those two factors.  As it, exists everywhere, as it purposes to inform, its first requisite is clearness.  Without that quality it is as nothing.  When you direct a stranger how to reach a certain building in your town, of what value are your remarks unless they are clear?  When a scientist writes a treatise on the topic of the immortality of man, of what value are his opinions unless his statements are clear?  All the other qualities which prose may and should possess sink into subordinate value in exposition when compared with clearness.  Because of all three phases of exposition—­its universal use, its informative purpose, its essential clarity—­exposition is an all-important topic for the consideration and practice of the public speaker.  In its demand for clearness lies also its difficulty.  Is it easy to tell the exact truth, not as a moral exercise, but merely as a matter of exactness?  Why do the careless talkers speak so often of “a sort of pink” or “a kind of revolving shaft” or tack on at the end of phrases the meaningless “something” or “everything” except that even in their unthinking minds there is the hazy impression—­they really never have a well-defined idea—­that they have not said exactly what they want to say?

Clear Understanding.  Here then is the first requisite for the public speaker.  He must have no hazy impressions, no unthinking mind, no ill-defined ideas, no inexactness.  He must have a clear understanding of all he tries to tell to others.  Without this the words of a speaker are as sounding brass and tinkling cymbals.  Or he may deliver a great roar of words signifying nothing.  This is the fault with most recitations of pupils in school—­they do not get a clear understanding of the material assigned to them for mastery.  As a test of the degree of understanding, the recitation method serves admirably.  The lecture method of instruction—­clear though the presentation may be—­offers no manner of finding out, until the final examination, how much the pupil actually understands.  So far, in public speaking, the only way of learning that the student understands the principles and can apply them is to have him speak frequently to indicate his ability.  Can you not name among your associates and friends those whose explanations are lucid, concise, direct, unconfusing, and others whose attempts at exposition are jumbled, verbose, unenlightening?

Have you not criticized certain teachers by remarking “they may know their own subjects all right, but they couldn’t impart their knowledge to the class”?