At the present time the tendency is towards close classification. It is a necessity in large libraries and an advantage in small ones. In this country the two great authorities on classification are Charles A. Cutter and Melvil Dewey. Both have devised and published schemes of classification which are generally recognized as having many excellent features. In both schemes the classification admits of very minute subdivisions. Dewey says that if the library has only one book on a certain minute subject, that book ought to be put in its own special class. It does not matter if there is no other book in the class. No one can fully understand what is meant by close classification until he has had considerable experience in classifying books. You can pick up the printed scheme of classification and run your eye over the numbers, but you will get comparatively little from them until you try to apply them. =Minute Bibliographical Classification.=—The following is a very important distinction in regard to close classification which should be carefully noted. It is one thing to classify books, but it is quite a different thing to classify articles in magazines for the bibliography of a subject. Magazine articles may be classified far more minutely than books can be. Take, for example, the Bibliographia Geologica, in which references are made to articles in geological magazines and publications of geological societies. Here the articles are classified according to Dewey. Dewey’s class 551 means physical geology. In this bibliography there is a particular article marked 551.795,513,111,044. That is to say the general subject of physical geology is subdivided in one-trillionth parts and this article is assigned to one of those parts. If one should apply for a library position and be told that he should have to classify the books as closely as this, he would probably never get the position. If he were given this article to classify, he would just as likely as not put it ten billion points out of the way. As a matter of fact, this bibliography is compiled by a number of experts in geology. There are similar bibliographies of botany, zoology and other natural sciences, all minutely classified and all compiled by experts.