The Columbia Encyclopedia, Sixth Edition. 2001-07.
pencil
pointed implement used in writing or drawing to apply graphite or a similar colored solid to any surface, especially 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 degrees 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 cores (or leads) being advanced by operating a screw mechanism or a propel-repel ejector mechanism.
