[Illustration: SAWING LOGS INTO 16-INCH LENGTHS PRIOR TO GRINDING THEM INTO PULP]
THE HEATER IN A PULP MILL WHERE THE WOOD PULP IS MIXED WITH CLAY]
[Illustration: A MODERN FOURDRINIER PAPER-MAKING MACHINE]
THE MAKING of paper is closely related to that of textiles. In each case the same basic materials are used. A mass of interlacing fibers is formed into a continuous sheet, but the method of interlacing the fibers and holding them together is entirely different. Paper resembles felt more closely than any other form of fabric. The fibers are not woven but are matted together and compressed. In the case of felt the fibers of wool or hair are held together mainly by the microscopic barbs that they possess while paper fibers are held together by means of sizing.
Although paper gets its name from papyrus the latter was not paper, for it was a felt of pith rather than fiber. The ancients produced a very fair writing material from the rushlike plants that grew in the swamps along the Nile. The stem of the papyrus was stripped of its bark and the pith was cut into thin ribbons which were laid side by side to form a sheet. Over these and at right angles to them was laid another layer of pith ribbons. The material was then soaked in water, pressed into a continuous sheet and dried. These sheets were then pasted together and rolled up into scrolls. Unquestionably they played a most important part in the civilization of ancient Egypt, providing, as they did, a ready means of recording knowledge and disseminating it among the people.
Like so many inventions that are of vital importance to modern civilization, paper is a Chinese invention. The Chinese made paper from the fibers of trees, a material to which we have reverted in recent years. The invention dates from about 150 A. D., when some one devised a process of reducing the bark of the mulberry tree to a pulp, beating it and boiling it in lye and then matting the fibers on a screen and pressing them into a finished sheet. The process was introduced into Europe by the crusaders in the 12th Century. In 1150 a paper-making plant was established in Italy and soon the new writing material was being made in increasing quantities and became a common article throughout Europe. It was not until the end of the 18th Century that machinery for making paper came into use.