The Dewey or Decimal system of classification [From the Introduction to the Decimal classification and Relative index.

Published by the Library Bureau, $5.] The field of knowledge is divided into nine main classes, 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 classes, are marked nought, and form a tenth class.

Each class 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.