The plan of the following Classification and Index was developed early in
1873. It was the result of several months' study of library economy as
found in some hundreds of books and pamphlets, and in over fifty personal
visits to various American libraries. In this study, the author became
convinced that the usefulness of these libraries might be greatly
increased without additional expenditure. Three years practical use of
the system here explained, leads him to believe that it will accomplish
this result; for with its aid, the catalogues, shelf lists, indexes, and
cross-references essential to this increased usefulness, can be made more
economically than by any other method which he has been able to find.
The system was devised for cataloguing and indexing purposes, but it was
found on trial to be equally valuable for numbering and arranging books
and pamphlets on the shelves.

The library is first divided into nine special libraries which are called
Classes. These Classes are Philosophy, Theology, &c., and are numbered
with the nine digits. Thus Class 9 is the Library of History; Class 7,
the Library of Fine Art; Class 2, the Library of Theology. These special
libraries or Classes are then considered independently, and each one is
separated again into nine special Divisions of the main subject. These
Divisions are numbered from 1 to 9 as were the Classes. Thus 59 is the
9th Division (Zoology) of the 5th Class (Natural Science). A final
division is then made by separating each of these Divisions into nine
Sections which are numbered in the same way, with the nine digits. Thus
513 is the 3d Section (Geometry) of the 1st Division (Mathematics) of the
5th Class (Natural Science). This number, giving Class, Division, and
Section, is called the Classification or Class Number, and is applied to
every book or pamphlet belonging to the library. All the Geometries
are thus numbered 513, all the Mineralogies 549, and so throughout the