bearing upon his.  From the titles, the brief descriptions, and (sometimes) the tables of contents upon the cards he can select intelligently the books he needs.  For instance, if he is searching for arguments to support a new kind of city government he could discard at once several books cataloged as follows, while he could pick unerringly the four which might furnish him the material he wants.  These books are listed under the general topic “Cities.”

The Spirit of Youth and the City Streets.  Old English Towns.  Municipal Administration.  The Modern City and its Problems.  Personality of American Cities.  Historic Towns of the Southern States.  Romantic Germany.  Cities of Italy.  American Municipal Progress.

Cross references are also valuable.  In addition to books cataloged under the topic consulted, others grouped under other subjects may contain related information.  Here are three actual cross references taken from a library catalog.

    Land:  Ownership, rights, and rent.  See also conservation,
    production, agriculture.

    Laboring classes:  Morals and habits.  See also ethics,
    amusements, Sunday.

    Church.  See also church and state, persecutions.

The continual use of a library will familiarize a student with certain classes of books to which he may turn for information.  If he is permitted to handle the books themselves upon the shelves he will soon become skilful in using books.  Many a trained speaker can run his eye over titles, along tables of contents, scan the pages, and unerringly pick the heart out of a volume.  Nearly all libraries now are arranged according to one general plan, so a visitor who knows this scheme can easily find the class of books he wants in almost any library he uses.  This arrangement is based upon the following decimal numbering and grouping of subject matter.

LIBRARY CLASSIFICATION

000 to 090, General works.  Bibliography.  Library economy.  Cyclopedias.  Collections.  Periodicals.  Societies, museums.  Journalism, newspapers.  Special libraries, polygraphy.  Book rarities.

100 to 190, Philosophy.  Metaphysics.  Special topics.  Mind and body.  Philosophic systems.  Mental faculties, psychology.  Logic, dialectics.  Ethics.  Ancient philosophers.  Modern.

200 to 290, Religion.  Natural Theology.  Bible.  Doctrinal dogmatics, theology.  Devotional, practical.  Homiletic, pastoral, parochial.  Church, institutions, work.  Religious history.  Christian churches and sects.  Ethnic, non-christian.

300 to 390, Sociology.  Statistics.  Political science.  Political economy.  Law.  Administration.  Associations, institutions.  Education.  Commerce, communication.  Customs, costumes, folklore.

400 to 490, Philology.  Comparative.  English.  German.  French.  Italian.  Spanish.  Latin.  Greek.  Minor literatures.