But as the process of paper-making must necessarily be comparatively slow when practised by hand machinery has been resorted to, which has nearly sup planted the old method. We believe France has the honor of the invention, although it has been greatly improved in England by Messrs. Donkin and Co. That in most general use there is after Fourdrinier, who invented the endless web of wire. One of these machines can produce 25 superficial feet of paper per minute ; and it is this which enables England to enter into competition with the foreign market, which it could not other wise do, on account of the difference in the value of manual labor. In the old me thod, it took three months after receive ing the rags into the mill to complete the paper: by the machine, they can receive the rags on one day, and deliver the paper made from them on the next.
The stuff, having been prepared and bleached in an expeditious manner by machinery, is emptied into the chest, or tub, as before, and from thence is de livered gradually into the vat, where it is kept in continual motion by means of revolving fans, called hogs. Nearly at the top of the vat there is a gate, which can be raised or lowered at pleasure, by means of which the flow of stuff is regu lated on to the lip or trough, from which it falls upon the endless web of fine wire, which is kept continually moving in a horizontal direction over a series of re volving rollers, and is placed imme diately under the hanging lip of the trough, so that the pulp may have the shortest distance possible to fall. These revolving rollers prevent the wire web from falling in or bagging, and keep it level ; and as it is preserved at a due tenison from side to side, it has all the appearance of a table. A leather strap, or ledge of wood, on each side, forms the boundary line of the paper, answer ing the purpose of the deckle in the hand-making process; these are mov able, according to the intended width of the paper. The long cascade or con tinuous stream of pulp, regulated with t reference to the proposed thickness of the paper to be made, thus gently de scends on this moving wire plane, which is perpetually travelling onward and on ward; and, for its more perfect equaliza tion, a second movement is resorted to, by means of a sort of crank, which gives the web a jerking motion at short inter vals, and diffuses the liquid pulp un varyingly over the surface. At the end nearest to the trough the pulp is, of course, perfectly fluid ; but, as the web travels on, the moisture partially sinks through the fine apertures of the webbing, and the material coagulates. There has
been a fashion prevalent of late years of having paper barred or ribbed: this ap pearance is given at this juncture. While yet moist, just before passing from the wire webbing, it is subjected to the pres sure of a wire roller, which gives the in dentations of the stripes or lines ; this cylinder is called a dandy; from this it travels to a web of cloth or felt, during which advance it is subjected to heavy pressures, from passing between rollers covered with felt, and called the pressing rollers. This process answers to the wet press in the ; and for merly this was the termination of the la bors of the machines, the remaining work of drying, &c., being accomplished by hand. But an incalculable improve ment took place in the addition of the drying rollers. These are three cylinders of polished metal, which effect in a few moments the perfect drying of the paper: while yet moist it passes over the first moderately warm ; again over the second, of larger diameter, of greater warmth ; and again over the third, with an aug mented heat The paper is now perfectly dry, and any casual inequalities are re moved from its surface. The final action of this wonderful machine is to wind the paper round a last roller or reel, which when full, is exchanged for another, and so on successively.
Here the work of the machine is finish ed; and the paper, being in long webs of many yards, requires to be cut into sheets. After different methods had been tried, a supplementary machine has been invented, which receives the web from off the reel on to a drum, cuts it into sheets of proper length with a circu lar knife, continually revolving, while the divided web proceeds ; and these sheets are received and placed in regular heaps by children.
In this country, machining is more used than in Europe. In the year 1848, eight patents were granted for improve ments in machines used in manufactur ing, cutting, and performing other opera tions on paper.
One of these patents is for improved machinery for grinding the pulp. The machine much resembles mills for grind ing grain. It is so arranged that the pulp is kept in circulation through the mill, passing in at the eye and out at the edges, until the whole is properly pre pared.