General Cautions
For these reasons certain principles of caution can be laid down. The first caution is, do not take too much for granted on the reader's part. First of all take stock of your reader and his knowledge of the subject and then write in accordance with your discoveries. If, in explaining the bicycle to a Fiji Islander, you fail to note that the two wheels are placed tandem rather than parallel, he may form a thoroughly queer notion of the machine. And your protest, "Why, I supposed he would know that!" is in vain. This caution does not mean that you must adopt a tone of condescension, must say, "Now children," and patter on, but that you will not omit any important part of the explanation unless you are sure that your reader is acquainted with it. The second caution, which is corollary with the first, is that you do not substitute for the gaps in the written information the silent knowledge that is in your own mind. The danger here lies in the fact that, knowing your subject well, you will write part of it and think the rest. Having for a long time practiced the high hurdles, for example, when you come to explain them you will run the paradoxical risk of being so thoroughly acquainted with the subject that you will actually omit much vital information and thus make your treatment thin. And the third caution is, avoid being over technical. An expert can always understand plain English; a layman, on the other hand, can soon become hopelessly bewildered in a sea of technicalities. Treatment of technicalities demands sense, therefore; when a term is reasonably common its presence can do no harm, but when a term is known only to the few, substitute for it, when writing for the many, plain English, or define your terms.