This is one of the many things which can only be learned by doing.

Give fiction no cla.s.s number, but an author number or "book-mark"

only, as explained in a later chapter. Give all biography a single letter as its cla.s.s number, and follow this by the author number.

Distinguish all juvenile books, whether fiction or other, by writing before their numbers some distinguishing symbol.

Take up first, in cla.s.sification proper, the subjects of history and travel, which will be found comparatively easy.

It is easier to cla.s.sify 25 or 50 books at a time in any given cla.s.s than it is to cla.s.sify them singly as you come to them in the midst of books of other cla.s.ses. Consequently, group your books roughly into cla.s.ses before you begin work on them.

As soon as a book is cla.s.sified enter it at once in your shelf-list--explained in a later chapter--and see that an author-card for it is put in the author catalog--explained later--with its proper number thereon.

If, after you have made up your mind, from an examination of the t.i.tle-page, or table of contents, or a few pages here and there, what subject a book treats of in the main, you are still in doubt in what cla.s.s to place it, consider what kind of readers will be likely to ask for it, and in what cla.s.s they will be likely to look for it, and put it into that cla.s.s. In doubtful cases the catalogs of other libraries are often good guides.

Keep your cla.s.sification as consistent as possible. Before putting a book, about which there is any opportunity for choice, in the cla.s.s you have selected for it, examine your shelf-list and see that the books already there are of like nature with it.

Cla.s.sify as well as you can, and don't worry if you find you have made errors. There are always errors. Don't get into the habit of changing.

Be consistent in cla.s.sifying, and stick by what you have done.

CHAPTER XXI

The Dewey or Decimal system of cla.s.sification

[From the Introduction to the Decimal cla.s.sification and Relative index. Published by the Library Bureau, $5.]

The field of knowledge is divided into nine main cla.s.ses, and these are numbered by the digits 1 to 9. Cyclopedias, periodicals, etc., so general in character as to belong to no one of these cla.s.ses, are marked nought, and form a tenth cla.s.s. Each cla.s.s is similarly separated into nine divisions, general works belonging to no division having nought in place of the division number. Divisions are similarly divided into nine sections, and the process is repeated as often as necessary. Thus 512 means Cla.s.s 5 (Natural science), Division 1 (Mathematics), Section 2 (Algebra), and every algebra is numbered 512.

The books on the shelves and the cards in the subject catalog are arranged in simple numerical order, all cla.s.s numbers being decimals.

Since each subject has a definite number, it follows that all books on any subject must stand together. The tables show the order in which subjects follow one another. Thus 512 Algebra precedes 513 Geometry, and follows 511 Arithmetic.

In the book after the tables of the cla.s.ses arranged in their numerical order is an index, in which all the heads of the tables are arranged in one simple alphabet, with the cla.s.s number of each referring to its exact place in the preceding tables. This index includes also, as far as they have been found, all the synonyms or alternative names for the heads, and many other entries that seem likely to help a reader find readily the subject sought. Though the user knows just where to turn to his subject in the tables, by first consulting the index he may be sent to other allied subjects, where he will find valuable matter which he would otherwise overlook.

The claims of the system may be summed up as follows: compared with other systems it is less expensive; more easily understood, remembered, and used; practical rather than theoretical; brief and familiar in its nomenclature; best for arranging pamphlets, sale duplicates, and notes, and for indexing; susceptible of partial and gradual adoption without confusion; more convenient in keeping statistics and checks for books off the shelves; the most satisfactory adaptation of the card catalog principle to the shelves. It requires less s.p.a.ce to shelve the books; uses simpler symbols and fewer of them; can be expanded, without limit and without confusion or waste of labor, in both catalogs and on shelves, or in catalogs alone; checks more thoroughly and conveniently against mistakes; admits more readily numerous cross references; is unchangeable in its call-numbers, and so gives them in all places where needed, as given in no other system; in its index affords an answer to the greatest objection to cla.s.s catalogs, and is the first satisfactory union of the advantages of the cla.s.s and dictionary systems.

The Decimal system is used by a large number of libraries in this country, and has gained recognition and has been put to use by some librarians and men of science in Europe.

Divisions

000 General Works 010 Bibliography.

020 Library Economy.

030 General Cyclopedias.

040 General Collections.

050 General Periodicals.

060 General Societies.

070 Newspapers.

080 Special Libraries. Polygraphy.

090 Book Rarities.

100 Philosophy 100 Metaphysics.

120 Special Metaphysical Topics.

130 Mind and Body.

140 Philosophical Systems.

150 Mental Faculties. Psychology.

160 Logic.

170 Ethics.

180 Ancient Philosophers.

190 Modern Philosophers.

200 Religion 210 Natural Theology.

220 Bible.

230 Doctrinal Theol. Dogmatics.

240 Devotional and Practical.

250 Homiletic. Pastoral. Parochial.

260 Church. Inst.i.tutions. Work.

270 Religious History.

280 Christian Churches and Sects.

290 Non-Christian Religions.

300 Sociology 310 Statistics.

320 Political Science.

330 Political Economy.

340 Law.

350 Administration.

360 a.s.sociations and Inst.i.tutions.

370 Education.

380 Commerce and Communication 390 Customs. Costumes. Folk-lore.

400 Philology 410 Comparative.

420 English.

430 German.

440 French.

450 Italian.

460 Spanish.

470 Latin.

480 Greek.

490 Minor Languages.

500 Natural Science 510 Mathematics.

520 Astronomy.

530 Physics.

540 Chemistry.

550 Geology.

560 Paleontology.

570 Biology.

580 Botany.

590 Zoology.