countries, towns, animals, plants, minerals, diseases, &c, have been
omitted, the aim being to furnish an Index of Subjects on which books
are written, and not a Gazetteer or a Dictionary of all the nouns in the
language. Such subjects will be found as special chapters or sections
of books on the subjects given in the Index. The names of individual
subjects of biographies will be found in the Class List of Biography.
Omissions of any of the more general subjects will be supplied when
brought to notice.

In arranging the books on the shelves, the absolute location by shelf and
book number is wholly abandoned, the relative location by class and book
number being one of the most valuable features of the plan. The class
number serves also as the location number and the shelf number in common
use is entirely dispensed with. Accompanying the class number is the
_book_ number, which prevents confusion of different books on the same
subject. Thus the first Geometry catalogued is marked 513-1; the second
513-2, and so on to any extent, the last number showing how many books
the library has on that subject. The books of each section are all
together, and arranged by book numbers, and these sections are also
arranged in simple numerical order throughout the library. The call
number 513-11 signifies not the 11th book on shelf 513; or alcove 5,
range 1, shelf 3, as in most libraries, but signifies the 11th book in
subject 513 or the 11th Geometry belonging to the library. In finding the
book, the printed numbers on the backs are followed, the upper being the
class and the lower the book number. The class is found in its numerical
order among the classes as the shelf is found in the ordinary system: the
book in its numerical order in the class. The shelves are not numbered,
as the increase of different departments, the opening of new rooms, and
any arrangement of classes to bring the books most circulated nearest to
the delivery desk, will bring different class numbers on a given shelf.