Classification in the first sense, it is plain, is the same as “entry;” in the second {11} sense it is the same as “class-entry;” and in the third sense it is the same as the “logical arrangement” of the table on p. [12], under “Classed catalogue.”
It is worth while to ascertain the relation of subject and class in the subject-catalogue. Subject is the matter on which the author is seeking to give or the reader to obtain information; Class is, as said above, a grouping of subjects which have characteristics in common. A little reflection will show that the words so used partially overlap, [7] the general subjects being classes [8] and the classes being subjects, [9] but the individual subjects [10] never being classes.
[6] This note has little direct bearing on practice, but by its insertion here some one interested in the theory of cataloguing may be saved the trouble of going over the same ground.
[8] The subjects Animals, Horses, Plants are classes, a fact which is perhaps more evident to the eye if we use the terms Zoology, Hippology, Botany. The subdivisions of Botany and Zoology are obvious enough; the subdivisions of Hippology may be themselves classes, as Shetland ponies, Arabian coursers, Barbs, or individual horses, as Lady Suffolk, Justin Morgan.
[9] Not merely the concrete classes, Natural history, Geography, Herpetology, History, Ichthyology, Mineralogy, but the abstract ones, Mathematics, Philosophy, are plainly subjects. The fact that some books treat of the subject Philosophy and others of philosophical subjects, and that others treat in a philosophical manner subjects not usually considered philosophical, introduces confusion into the matter, and single examples may be brought up in which it seems as if the classification expressed the form (Crestadoro’s “nature”) or something which a friend calls the “essence” of the book and not its subject, so that we ought to speak of an “essence catalogue” which might require some special treatment; but the distinction can not be maintained. It might be said, for example, that “Geology a proof of revelation” would have for its subject-matter Geology but for its class Theology—which is true, not because class and subject are incompatible but because this book has two subjects, the first Geology, the second one of the evidences of revealed religion, wherefore, as the Evidences are a subdivision of Theology, the book belongs under that as a subject-class.
[10] It is plain enough that Mt. Jefferson, John Milton, the Warrior Iron-clad are not classes. Countries, however, which for most purposes it is convenient to consider as individual, are in certain aspects classes; when by the word “England” we mean “the English” it is the name of a class.
Class entry,
E. g., a book on repentance has class entry under Theology; its specific entry would be under Repentance.