PAPERMAKING

formation of a matted or felted sheet, usually of cellulose fibres, from water suspension on a wire screen. Paper is the basic material used for written communication and the dissemination of information. In addition, paper and paperboard provide materials for hundreds of other uses, such as wrapping, packaging, toweling, insulating, and photography. The word paper is derived from the name of the reedy plant papyrus, which grows abundantly along the Nile River in Egypt. In ancient times, the fibrous layers within the stem of this plant were removed, placed side by side, and crossed at right angles with another set of layers similarly arranged. The sheet so formed was dampened and pressed. Upon drying, the gluelike sap of the plant, acting as an adhesive, cemented the layers together. Complete defibring, an indispensable element in modern papermaking, did not occur in the preparation of papyrus sheets. Papyrus was the most widely used writing material in ancient times, and many papyrus records still survive. Additional reading Encyclopaedic coverage of every aspect of the chemical industry is provided by Herman F. Mark et al. (eds.), Encyclopedia of Chemical Technology, 3rd ed., 31 vol. (197884), formerly known as Kirk-Othmer Encyclopedia of Chemical Technology, with a 4th edition begun in 1991; Ullmann's Encyclopedia of Industrial Chemistry, 5th, completely rev. ed., edited by Wolfgang Gerhartz et al. (1985 ); and Thorpe's Dictionary of Applied Chemistry, 4th ed., 12 vol. (193756). American Paper and Pulp Association, The Dictionary of Paper, 3rd ed. (1965), is a compilation of terms and definitions relating to paper and paper manufacture. K.W. Britt (ed.), Handbook of Pulp and Paper Technology, 2nd ed. rev. (1970), contains 61 articles grouped in nine sections describing the most important features of pulp and paper manufacturing technology. A multivolume textbook that has gone through several editions is J.N. Stephenson (ed.), Pulp and Paper Manufacture, 4 vol. (195055); each volume covers a particular area of the industry: pulp manufacture, stock preparation, paper manufacture, and finishing and converting. James P. Casey, Pulp and Paper: Chemistry and Chemical Technology, 2nd ed. rev., 3 vol. (196061), emphasizes the chemistry of papermaking and is noteworthy as a review of published literature with extensive references. A two-volume work intended as a textbook for students and prepared under the auspices of the Joint Textbook Committee of the Technical Association of the Pulp and Paper Industry is Pulp and Paper Science and Technology, ed. by C. Earl Libby (1962). S.A. Rydholm, Pulping Processes (1965), is a standard reference work in the field, of interest primarily to specialists in pulping. Dard Hunter, Papermaking: The History and Technique of an Ancient Craft, 2nd ed. rev. (1957), is a classic account of handmade paper over the centuries since its invention in China early in the Christian era. Kenneth W. Britt The Editors of the Encyclopdia Britannica