MATERIALS & METHODS
The New Columbia Encyclopedia: Pointed implement used in writing or drawing to apply graphite or a similar colored solid to any surface, esepcially paper. From prehistoric times lumps of colored earth or chalk were used as markers. The Egyptians ruled lines with metallic lead, as did medieval monks. The so-called lead pencil--a rod of graphite encased in wood--came into use in the 16th cent. From the late 18th cent. pulverized graphite was mixed with clay to bind it and to provide different degreess of hardness--the more clay, the harder the pencil. Today the mixture is forced through dies, cut to the required length, and kiln-fired. The rods are laid in grooves of a thin board, a similar board is placed over them, and the wood is shaped into pencils, usually of round or hexagonal cross section. Pencils are also manufactured with cores of colored pigments mixed with clay and wax and of other materials. Mechanical pencils are commonly made of metal or plastic, the cones (or leads) being advanced by operating a screw mechanism or a propel-repel ejector mechanism. [Harris, William H., and Judith S. Levey, eds. The New Columbia Encyclopedia. New York and London: Columbia University Press, 1975.]
The contents of this site, including all images and text, are for personal, educational, non-commercial use only. The contents of this site may not be reproduced in any form without proper reference to Text, Author, Publisher, and Date of Publication [and page #s when suitable].