PAPER then introduced, and fires are started under- neath. The digestion is completed in about six hours, when the contents are suddenly emptied with violence, under a pressure of 65 Ibs. to the square inch, into a sheet-iron cylin- der at the side of the boiler. It is now in the form or condition of half stuff, and is passed through a washing engine ; and if it is imme- diately used upon the spot, it is also passed through a bleaching engine and mingled with rag pulp in the beating engine, in the propor- tion of from 60 to 80 per cent., when it is formed into paper in the same way as pure rag pulp. If the wood pulp is to be trans- ported to a distance, it is only passed through the washing engine, and made temporarily into a thick kind of paper on a cylinder machine for the purpose of drying and giving it a con- venient form for transportation. A method of mechanically making wood pulp was invented several years ago by Heinrich Yoelter of Wur- temberg, and there are in Germany more than 30 establishments using his machines. The defibrer or mill consists of a coarse cylindrical stone, revolving rapidly, against which billets of wood are held by springs. The action of water which flows through the mill assists in reducing the fibre so finely that the subsequent chemical treatment is simple. The mechanical is, however, inferior to the chemical method, as it breaks up the fibres into shorter particles, so that not half as much can be mixed with rag pulp. The woods which furnish the best fibre, that is, the longest and the best adapted to felting, are pine and fir ; but it is more diffi- cult to separate the resin from them than from other woods; and as poplar and basswood, among the soft woods, make the whitest pulp, they are usually preferred. 6. Cane. Thearun- dinaria macrosperma, the kind of cane which grows in the Dismal swamp and along the rivers of North and South Carolina, and also along the Mississippi, is about 12 ft. high, near- ly white, and composed of tough strong fibres. The supply of this material is immense, and the American fibre company have patented meth- ods for converting it into, paper pulp. The Norfolk fibre company, near Norfolk, Va., and the Cape Fear fibre company, near Wilmington, N. C., are working under these patents. The Norfolk company's works are on the Dismal swamp canal and Norfolk and Weldon railroad, about 4 m. from Portsmouth. The cane is dis- integrated by the Lyman process, patented in August, 1858. Strong cast-iron cylinders, 22 ft. long and 12 in. inside diameter, having strong heads at both open ends, are laid horizontally on heavy frames. Each cylinder has a dome on the top to give steam room. The cane, after having been stripped and cleaned, is introduced into both ends, and the covers fastened, when steam is admitted into the cylinders, or "guns" as they are called, until a pressure of 180 Ibs. to the square inch is reached. This pressure is maintained for about 12 minutes, when by pulling a trigger the covers are suddenly un- fastened, and the steam rushes out with a tre- mendous explosion, carrying the disintegrated cane before it. A target placed about 30 ft. from the guns receives the charge, which is reduced to a mass of brown sugary-smelling fibre. The report is equal to that of a large cannon, and may be heard many miles. The concussion of the air is so great that it is im- possible to stand in the gun room without sup- port. A gun loaded with 100 Ibs. of cane can be discharged every 15 minutes. Four guns of the size above described can turn out from 16 to 24 tons of stuff in 24 hours. Nearly the full weight of the dry cane is obtained in fibres having somewhat the appearance of oakum, and in this form will make a strong spongy paper, easily saturated with liquids, and suitable for roofing and wrapping paper, boards, &c. The material may also be bleached and treat- ed after the manner of rags, and made into a strong white paper. 7. Manila and jute. These fibres are products of eastern Asia, and are made into ropes and coarse bagging, which after being worn reach the paper maker. The raw material of course may also be used. The butts of the jute have recently been utilized. The process of manufacture for both materials is much the same. They are boiled in rotary boilers, although for jute butts some prefer stationary boilers like those for waste paper, believing that the revolving motion injures the fibre. The material is usually treated with milk of lime, from 15 to 25 Ibs. of lime, and sometimes 50 Ibs., being used for every 100 Ibs. of raw material. If boiled with caus- tic soda, like straw, the fibres may be obtained pure and bleached and made into white paper. For ordinary brown paper the pulp may be washed and beaten ready for the machine in one engine. By partial bleaching a fine buff color may be imparted. Both Fourdrinier and cylinder machines are used in making manila and jute papers. The cylinder machine causes the fibres to be laid in one direction, so that the paper has much less strength in one than in the other direction. MANUFACTURE OF PAPER. For wrapping, writing, or printing paper, the pulp, prepared with or without size, is carried to a vat and mingled with sufficient water to make it thin enough for spreading. Up to nearly the beginning of the present century paper was made by hand. In this process the workman uses, holding it in both hands, a shallow mahogany box somewhat larger than the sheet of paper, covered with parallel wires placed near together, and crossed by a few others. The wires thus arranged produced what is called "laid paper," but with a woven wire cloth the product is known as "wove pa- per." The " water mark " upon paper, used to designate the peculiar kinds, is produced by coarse wires of the required figures attached to the moulds, so as to cause the layer of fibre to be somewhat thinner on their lines. Various devices formerly made use of in this way gave names to the sorts of paper to which they
