Official Gazette of the U. S. Patent Office

Since July 1952, the Official Gazette of the U. S. Patent Office has listed each week s patents in three groups—general and mechanical, chemical, and electrical. In ten recent weeks (September to November 1960) patents in the chemical group ranged from 18 to 26% of the total, averaging 20%. 

The United States Patent Oflfice classifies its patents into some 350 main classes, each of which is divided into many subclasses. There are now about 45,000 of these subclasses. Titles of the classes and subclasses are listed in the "Manual of Classification of Patents (54). Revision of this classification is a continuous process. As classes are revised and new definitions for them are written, these are pubhshed first in the Official Gazette of the U. S. Patent Office and later in the Classification Bulletin issued at intervals by the Patent Office. 

Official Gazette of the United States Patent Office, Superintendent of Documents, U. S. Government... 

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