PAPER, a material made in thin sheets from a pulp of rags, esparto grass, straw, wood or other fibers, and used for writing or printing on, or for wrapping. The earliest paper was doubtless that made from the Egyptian papyrus, whence all similar writing material is named. Many books and newspapers have been printed entirely of one ma terial, such as bamboo, straw, jute, Phonnium toutx, maize leaves, esparto, etc. In Japan a species of mulberry osier is grown specially for its bark for paper making. Only two vegetable fibers have come into general use for paper making; these are esparto and wood pulp. The best sources of fiber are linen and cotton rags for white pa per and hempen cordage for brown. A caustic soda or soda-ash is required in the preparation of many fibers.
Raw fibers may be divided into four classes: (1) that which is easily re duced and easily bleached; (2) that which is difficult to bleach; (3) that which is difficult to reduce but easily bleached; and (4) that wherein perfect bleaching effects the integrity of the fiber. The longer the fibers and the more intricate the mixture of them when wet, the stronger will be the sheet of paper when dry. The culms of various cereal grasses are employed where obtainable; rice straw in Asia, wheat, oat, and other kinds of straw in Europe. Straw was used a century ago for paper making, but its extensive use is of comparatively recent date. The deficiency in the sup ply of rags and the absence of any cheap substance to supplement esparto have led to a great run on wood pulp for the pa per mills in most countries. Its manu facture and use dates practically back only to about 1870; indeed its general adoption may be referred to 10 years later. The conifers giving the strongest and toughest fiber seem to be best adapted for conversion into pulp, though many other species are used. The pro duction has centered chiefly in America and the two Scandinavian countries, Norway and Sweden. They also make a large quantity of paper and paste board for export. Wood pulp is now the principal ingredient in cheap paper. It is deficient in fiber, but a moderate ad mixture of rags, esparto, or other fib rous material strengthens it. Much of the paper made is used up a second time. Cotton and linen rags are the mainstays of the paper maker, and all countries draw largely on these waste substances. In order to reduce the price many mak ers introduce into their pulp sawdust and various mineral matters, such as kaolin or china clay.
The varieties of paper made are chiefly the following four classes: (1) news and printing papers; (2) writing papers of various kinds, blue, cream and yellow laid, and wove and tinted, and for ac count books, etc.; (3) wrapping or pack ing papers, brown and purple, heavy manila for cartridges and bags; (4) mis cellaneous, such as light copying, tissue, and pottery papers, blotting and filter ing, cigarette, etc. Lastly, there are all kinds of cardboards and millboards made. The principal kinds of papers embrace 2,000 names of various kinds and quali ties. In 1'772 there were 60 varieties of
paper made from as many different ma terials, and 10 or 12 years later the num ber had been extended to 103. In those days all paper was manufactured by hand, each sheet separately. The rags were pulped in mortars by trip-hammers, and several days were required to turn out a sample of dry finished paper. The workman dipped a rectangular sieve or mould into the vat and deposited the sheet of fluid pulp on a piece of felt to dry.
This simple mode of manufacture, which is still largely practiced in Hol land and Italy, has been superseded very generally by continuous machines, and only a small quantity of paper for spe cial books, editions de luxe, etc., besides a superior writing, bank-note, and draw ing paper is now made by hand. The various machines for making paper in continuous lengths are wonderful pro ductions of mechanical skill. These machines consist of contrivances for causing an equal supply of pulp to flow on an endless wire-gauze apron, which revolves and carries on the paper till it is received on an endless sheet of felt, passing around and between large couching cylinders. At the Pittsburgh Exhibition there was a roll 14 miles long, 18 inches wide, and weighing 2,658 pounds. Some of the machines are 75 to 100 feet long and 120 inches wide, requiring a building to themselves, and making a sheet of paper 7 feet in width. In the United States, for fine book-work, the paper receives a white coating after it has been made; the finish thus given to the surface renders possible the il lustrations seen in our best magazines. The productive power of a modern paper making machine is very great; it moves at a rate of from 20 to 200 feet per min ute, spreading pulp, couching, drying and calendering as it goes, so that the stream of pulp flowing in at one end is in two minutes passed out as finished paper at the other.
Paper Production of the World.—In the United States great progress has been made in paper manufacture. The first mill was established in 1690 on ground now included within Philadelphia. In 1770 there were 40 paper mills in Pennsylvania, New Jersey, and Dela ware, and only three or four in New England. In Great Britain and Eu rope there are over 3,000 mills; Canada has, in recent years become a chief pro ducer of pulp for paper. In 1918 the product in that country was valued at $119,309,434. In 1919 nearly 150,000 tons were exported.
The United States leads all nations in paper production, between 9 and 10 million tons annually. In 1909 news print paper was included in the free tariff list. Much of the wood pulp was obtained from Canada until the war when shortage of help made it neces sary to obtain the material from Scan dinavia. The blockade cut off this supply and paper prices in the United States rose to prohibitive figures. In 1919 and 1920 the United States Government warned great users of paper that they must reduce their demands on the market supply.
The production of newsprint paper in 1919 was over 1,000,000 tons.