I. NATURE OF EXPOSITION

I. NATURE OF EXPOSITION
What is exposition, and how does it differ from narration and description? Let us illustrate.
If we were describing some familiar and typical scenes on a canal, we should be very likely to include, among other things, a description of a lock,—the narrow gates with the inrushing water and the slowly rising boat, the waste-weirs in the bank, the lock- keeper and his house, and so on. Now if we were describing this to people accustomed to seeing locks, we should naturally select the features that seemed most interesting or picturesque to us. But what if a reader who had never seen a lock should pick up the paper and ask, What is it all about? What are the gates for? Why is the lock there? How does it work? We should then have to write a very different paper. We should have to show how a series of locks divides a running stream into still stretches of water at different levels, thus saving the water from being wasted, and allowing boats to be towed easily in both directions; how the double set of gates is arranged; how the water is allowed to flow into or out of the gates; and so on, until the principles upon which locks are built and operated are as clear to the reader as to us.
Or, it may be that we are writing of a visit to a great newspaper building, where we have been shown through the establishment. We speak of our call at the manager's office, of the dirty, curly-headed little guide he sends for, of our talk with the old Scotch typesetter, of how Kenneth rubbed his sleeve against an ink-roller in the pressroom, of the amazing rapid¬ity with which the cylinder press was turning out printed, cut, and folded papers. We have made an interesting narrative out of our experience. But again, we may be asked to explain the process of printing a paper, from the writing up of the news to the delivery of the printed sheet to the distributing wagons. We have to begin over, and, though using the same material, treat it in an entirely different manner, so that the reader will understand the way in which each process contributes towards the final product.
We have, then, two subjects, a description of a lock, and a narrative of a visit to a newspaper building, both of which are capable of being made into exposi¬tions. How? By viewing them in a different way, thereby changing the subject-matter, and by adopting a new manner of treatment. We shall take up these considerations separately.
31. Point of View.—We can keep the point of view clear by imagining a particular reader, with definite
interests, to whom we are addressing ourselves. This reader does not care to hear the special things we have seen or done; for the time being, strange or picturesque circumstances, if accidental, do not in¬terest him in the least. He wants to know how things work, what they are for, how they fulfil their purpose. It is, therefore, not Iffiey Lock as we saw it that we must tell him about, but locks in general, the principles of which may be shown by explaining Iffley Lock; not the incidents of our visit to the New York Herald Building, but the process of printing great daily newsp'apers, as shown by the practice of the Herald.
This change in the purpose of our writing may be indicated by a change in the title as well. To be sure we can fitly explain the way in which locks work, by means of the one we know best, and entitle our paper "Iffiey Lock." But "Canal Locks" leaves less doubt in the reader's mind that the general principles of locks are to be explained, and for that reason it is perhaps the better title. "The Printing of a Great Newspaper" is similarly a more accurate title for an exposition than is "A Visit to the Herald Office."
32. Treatment.—The method of treatment, also, distinguishes our present work from narration and description. Remembering that our interest is now in the general principle rather than in the special example, we may note three things:
We must eliminate the personal element in what we have to say. The picturesque appearance of the
lock-keeper, the accident to the plate-cylinder in the pressroom, no matter how they may have interested us, do not belong to the explanation we are now writing and must be resolutely kept out of our paper.
We must be sure to include everything that belongs to the exposition, even if it did not interest or impress us. We may not have noticed particularly those holes at the bottom of the gates in the lock through which the water is first allowed to run, but they are important, for all that; and though the typesetting machines may not have been working when we went through the newspaper building, we cannot omit men¬tion of them simply on that account.
We must take up the parts of our subject in their natural order, so that one thing will lead to another, and the reader may easily follow the course of our explanation. It may be that we observed the different features of the lock one by one simply as they chanced to strike our eye, but that is no reason why we should jumble up the details when we are explaining them to another. Nor, because we happened to go through the pressroom before we saw the typesetters, should we reverse the natural order in telling about the process of printing.