The Vat and Mould.—The pulp being prepared, is conveyed from the beaters to the working vat, where it is diluted with water. The vat is a wooden or stone vessel about 5 feet square and 4 feet deep, being somewhat wider at the top than at the bottom. A steam-pipe is supplied to the vat, so that the pulp and water may be heated to a convenient temperature for working, and an agitator is also furnished to keep the pulp and water uniformly mixed. The mould in which the pulp is raised from the vat to form a sheet of paper, consists of a wooden frame, neatly joined at the corners, with wooden bars running across, about 1½ inch apart, and flush with the top edge of the frame. Across these again, in the length of the frame, wires are laid, about fifteen or twenty in an inch, which are placed parallel to each other. A series of stronger wires are laid along the cross-bars, to which the other wires are fastened; these give to what is termed "laid" paper, the ribbed or "water-marked" lines noticeable in hand-made paper. Upon the mould is fitted a movable frame, called the deckle or deckel, which must fit very neatly or the edges of the paper will be rough. The mould and deckle form together a kind of shallow tray of wire. Sometimes the mould is divided by narrow ribs of wood, so that two or four sheets of paper may be made in one operation. Connected with the vat is a slanting board, called the bridge, with copper fillets attached lengthwise upon it, so that the mould may slide easily along the bridge.
Making the Paper.—When preparing for work, the vat-man stands on one side of the vat, and has on his left hand a smaller board, one end of which is fastened to the bridge, while the other rests on the side of the vat. An assistant, called the coucher, is at hand, whose duty it is to handle the frames or moulds containing the pulp after they have passed through the hands of the vat-man or maker. The latter now takes in his hand a mould, and lays it upon the deckle; he then dips the mould, with its deckle in its proper place, into the vat of agitated pulp, and lifts up as much of the pulp as will form a sheet of paper. This, as will be readily seen, requires the greatest dexterity, since the workman has nothing but his sense of feeling to guide him. It is said, however, that practice gives him such a nicety of feeling in this respect that he can make sheet after sheet of the largest-sized drawing papers with a difference in weight of not more than one or two grains in any two of them. Great skill is also required to hold the mould in a perfectly horizontal position, otherwise during the felting and settling of the pulp the sheet of paper would be thicker on one part than another. The mould being held lengthwise, that is, with the long parallel wires running from right to left hand, he gives the mould a gentle shake from his chest forward and back again, which is called the fore-right shake; this shake takes place across the wires, not in the direction of their length. He next gives a shake from right to left, and back again, the respective movements thus propelling the pulp in four directions. The vat-man now pushes the mould along the small board on his left, and removes the deckle, which he connects to another mould and proceeds to form another sheet of paper, and so on. The coucher, taking the first mould in hand, turns it upside down upon a piece of woollen felt-cloth, then removing the mould, he takes another piece of felt and lays it over the sheet and returns the mould by pushing it along the bridge to the vat-man, when he receives in return a second mould to be treated as before.
In the above way felts and paper are laid alternately until a pile of six or eight quires is produced, which is afterwards submitted to pressure in a very powerful press. When sufficiently compressed, the machine is relaxed, and the felts are then drawn out, on the opposite side, by an operative, called a layer, who places the felts one by one upon a board, and the sheets of paper upon another board. The coucher then uses the felts again for further operations. Two men and a boy only are employed in this part of the work. In the evening all the paper made during the day is put into another press, and subjected to moderate pressure to obliterate the felt marks and expel a further portion of the water. On the following day the paper is all separated, which is called parting, again pressed, and is then transferred to the drying-loft. The drying is effected by suspending the sheets of paper upon a series of ropes, attached to wooden supports; ropes of cow-hair are used for the purpose, as this material does not stain the paper.
Sizing and Finishing.—When the paper is dry, it is taken down and laid carefully in heaps ready for sizing, which is the next operation to which the paper is subjected. The preparation of the size from animal skins, etc., is described in Chapter XI. When preparing to size the paper, the workman takes several quires of the paper, and carefully spreads the sheets out in the liquid size, which is placed in a large tub, taking care that each sheet is uniformly moistened before introducing the next. The superfluous size is afterwards pressed out, and the paper then "parted" into separate sheets, which are again subjected to pressure, and finally transferred to the drying-room, where they are allowed to dry slowly. When dry, the paper is conveyed to the finishing-house, to be again pressed and looked over by women, who, being furnished with small knives, pick out knots and other imperfections and separate the perfect from the imperfect sheets. The paper is now again pressed, and then handed to the finisher, to be counted into reams and packed, the reams being afterwards pressed and finally tied up and conveyed to the warehouse for sale. When the paper is required to be hot-pressed, this is done by placing each sheet of paper alternately between two smoothed sheets of pasteboard, and between each group of fifty pasteboards is placed a hot plate of iron, and the pile then submitted to heavy pressure, whereby the surface of writing paper acquires a fine, smooth surface.
[CHAPTER XIII.]
MAKING PAPER BY MACHINERY.
The Fourdrinier Machine.—Bertrams' Large Paper Machine.—Stuff Chests.—Strainers.—Revolving Strainer and Knotter.—Self-cleansing Strainer.—Roeckner's Pulp Strainers.—The Machine Wire and its Accessories.—Conical Pulp Saver.—The Dandy Roll.—Water Marking.—De la Rue's Improvements in Water-marks.—Suction Boxes.—Couch Rolls.—Press Rolls.—Drying Cylinders.—Smoothing Rolls.—Single Cylinder Machine.
The Fourdrinier Machine.—It is just ninety years since Louis Robert, a Frenchman, devised a machine for making a continuous web of paper on an endless wire-cloth, to which rotary motion was applied, thus producing a sheet of paper of indefinite length. The idea was subsequently improved upon by Messrs. Fourdrinier, who adopted and improved upon M. Robert's machine, and with the valuable aid of Mr. Bryan Donkin, a young and gifted machinist, in the employ of Mr. Hall, engineer, of Dartford, constructed a self-acting machine, or working model, in 1803, which, from its effectiveness and general excellency of workmanship, created at the time a profound sensation. This machine was erected at Frogmore, Hertfordshire; and in 1804 a second machine was made and put up at Two-Waters, Herts, which was completely successful, and the manufacture of continuous paper became one of the most useful and important inventions of the age. From that period the "Fourdrinier," with some important improvements introduced by Mr. Donkin, gradually, but surely, became established as an absolutely indispensable machine in every paper-mill all over the world. Although the machine has been still further improved from time to time, those of recent construction differ but little in principle from the original machine. An illustration of the machine is shown in Fig. 25, the detailed parts of which are expressed on the engraving.