trouble to read it. Why should you, when you undertake to make an explanation, throw on your reader the labor of applying your principles to realities?

Moreover, unless you give examples of the facts on which you base your explanation, you have no assurance that your reader may not apply your meaning to an entirely different set of facts. Your real object, especially if your explanation have any argumentative purpose, is to make him look at the facts which you are explaining in the same way that you do. Green's "Short History of England" is throughout a notable example of this use of specific facts in explanation, a method of which Macaulay was the first famous exemplar. So Mr. Bryce1 illustrates the conflict between national and state authority by telling of a sheriff in California who, in obedience to the state law, cut off the queue of a Chinese prisoner, Ho Ah Kow, and who later suffered judgment in a suit brought before the Federal court. And Mill in his "Political Economy" makes up instances of supposititious velvet manufacturers or bricklayers by whom he can test and make concrete the abstract proposition which he is working out. In all these cases not only do the writers make their exposition easier to read, but they make it more thorough and more lucid.

Both these dangers, then, the danger of ambiguity in the use of general terms, and the danger of undue abstraction, lie chiefly in the tendency of lazy thinkers to deal in somebody else's general terms rather than

1 "American Commonwealth," New York, 1893, vol. i. p. 331.

in their own immediate perceptions and knowledge of facts. They point to a precept which lies behind. all explanation: never undertake to explain a subject which you have not thought out thoroughly for yourself.

18. Closely akin to the use of specific examples, and even more nearly to the analogy which I have followed throughout this discussion, is the use in explanation of diagrams and figures. In any explanation of a machine or of the situation of places or in any comparison of growths, a figure will accomplish what pages of description will not do. Tyndall in his lecture on geysers made his explanation both simple and effective by having on the platform the apparatus of which he prints a picture (see page 207) in the report of his lectures. Wherever explanation can be done by means of an appeal to the eye it is sure to be more efficient because it puts many facts simultaneously before the mind of the reader. In practice, therefore, make free use of diagrams and figures; in what are called scientific descriptions, which are explanations of machines or of natural structure or of methods of construction, or in any of the manifold other discussions in which your reader is to grasp the shapes of things, one figure is worth many pages of exposition. So in geological or geographical discussions, in descriptions of wars or battles, in theories of the movement of population, in the multitude of discussions which deal with the explanation of things in space and time, figures and diagrams are

at once an economy and an aid to the understanding: often they are the only effective means of giving your reader a comprehensive view of the whole subject.

It is very easy, on the other hand, to run the method into the ground and to break the pages of an exposition with fantastic and useless figures. Such are the figures in manuals of literature, when they attempt to go beyond chronology; or the exercise called, with fitting barbarism, "diagramming" of sentences, which has been used in schools to heighten the miseries of English grammar; or the attempt to use diagrams or figures in books of abstract reasoning in more than a metaphorical way. Such errors probably rest on the idea that there is some virtue in the diagram apart from its service in the explanation, and that therefore ingenuity in the devising of such diagrams is valuable for its own sake. As a matter of fact, it is to be doubted whether diagrams are useful in any explanations except those which are concerned with questions of proportion or of actual relations in time or space; even then they should be used only for an obvious gain in brevity or in lucidity. The rule here is the same that applies to the use of figures of speech: use diagrams and figures only when they will save space and clumsy circumlocution; then use them freely.

19. Finally in expository writing as in all other you cannot neglect the appeal to your readers' feelings. I shall speak more at length on this subject when I come to that kind of expository writing which

is also argumentative or critical; but I may point out now that no one but an intellectual fop will take pride in the smallness of his audience, and that the stronger the good sense of a writer the more respect he has for a non-professional audience. With the average reader, the interest of an explanation lies in the fact that it puts what is already familiar to him in a new light; and the more familiar these things are and the more vividly they are put before his mind the more will the explanation please him. Elizabeth, for example, in Green's exposition, flirting with the Duke d'Alençon or breaking out in rage against Cecil and Burleigh; the Chinaman whom Mr. Bryce tells of; the explosion of the mock-geyser which Tyndall describes, shooting its cork up to the ceiling; the calculations of Mill's velvet manufacturer; - these are things with which we can have sympathy, things which impinge on like experiences which we ourselves have had. Accordingly when they are written down in a book they at once group themselves with like experiences in our own memory; thus they take on the warmth and intimacy which infuses every one's own mental life. Henceforth the new facts become the children of your experience in nearly the same way that distinguishes the sensations you have felt and the ideas you have thought. In all explanations which are to leave any permanent mark on your reader's thought, then, the feelings which are inseparable from concrete things have an essential share. You cannot afford to neglect the interest of your reader and for the average reader you can be sure

of arousing it only by grafting your explanation into the things he has himself known.

Nor is the power of pure style to be neglected by any one who is writing an explanation. It is common enough, especially in this country, to think that science and even philosophy have no relation to literature; in looking for examples of exposition I have been struck by the fact that those which were clear and at the same time cultivated in style were mostly to be found among the writings of Englishmen. No one who reads the lectures of Tyndall or Huxley or chapters by Green or Mr. Bryce, can help feeling the value of the finish and amenity of their style. Apart from all such questions of cultivation, however, if you wish to infuse into your explanation the color of your own thought, you must pay attention to your style. A naturally modulated rhythm is the only way in which without obtrusiveness you can put your own feelings into your writing: your interest in what you write ought to give life and variety to the way in which you write. Often even an unskilful writer will, by the force of his feeling for the subject, so color and enrich his explanation as to cover up his unskilfulness with the pen. Darwin's "Memoirs" illustrate this principle he complains more than once of his unfitness for writing, and of the drudgery which it caused him; but when you turn to the "Origin of Species" you find none of the awkwardness of which he complains. Though it is in no sense an ornamental style, it is highly expressive; for it sets forth not only the bare facts and the conclusions but also the great-minded