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Papaver Rhoeas

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Fig. 9.

Pentadactylos Risas

I, Clark Sculp

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that the writing disappears when it is caft into the fire. It must be obferved, at the fame time, that as it is of a fiender confiftency, and eafily torn, it is more an object of curiofity than use.

PAPER MADE FROM LINEN RAGS is manufactu red through all Europe. This kind of paper was utterly unknown to the ancients. By what nation and at what period the art of making our modern paper was difcovered, we are ignorant. The merit has been afcribed to different nations without any authority. All we know is that no book has been found written on this paper antecedent to A. D. 1270. It is difcovered to have been in Germany in 1312, and in England in 1320 and 1342. SECT. I. Of the Art of PAPER-MAKING in EU

ROPE.

To give a concife view of this fubject, it is neceffary to proceed with all the important parts of the operation in their order.

The felection of the rags and arranging them into different lots, according to their quality, and to the demand of the paper-mill, is the first bufinefs. They are then placed on an iron grate, which covers a large cheft, where they are beat, and otherwife turned, till the filth and duft pafs through the bars of the grate and fall into the cheft.

The number of lots in the felection of rags muft be proportioned to the mafs from which the felection is made, and to the kinds of paper produced by the mill. Some mills, the work of which is confiderable, make 9 lots of their rags, five of which respect the fineness, and the reft of the cleannefs and the colour. In ordinary mills there are 4 lots, and in fome only two.

It was formerly thought neceffary to bring the rags to a state of putrefaction; and this method univerfally prevailed till within these few years; but it is now entirely given up. That it was inferior to the method now in practice, is very evi dent; the rotting of the rags was peculiarly ab. furd, as the paper made of fermented ftuff could neither be fo ftrong nor fo durable, as that which is made in the common way without putrefaction.

The dufter is made in the form of a cylinder, 4 feet in diameter, and 5 feet in length. It is altogether covered with a wire net, and put in motion by its connection with fome part of the machinery. A convenient quantity of rags before the felection is inclofed in the dufter, and the rapidity of its motion separates the duft from them, and forces it through the wire. It is of confiderable advantage to use the dufter before selection, as it makes that operation less pernicious to the felectors. The tables for cutting off the knots and ftitching, and for forming them into a proper shape, are erected in the fame place with the cutting table. The furface both of these and of the cutting table is composed of a wire net, which in every part of the operation allows the remaining duft and refuse of every kind to escape.

The rags are again carried from the cutting table back to the dufter, and thence to the engine, where, in general, they are in the space of fix hours reduced to the ftuff proper for making paper. The hard and foft of the fame quality are placed In different lots; but they can be reduced to ftuff

at the fame time, provided the foft he put fomewhat later into the engine.

The ENGINE is that part of the MILL which performs the whole action of reducing the rags to pafte, or, as it may be termed, of trituration. The number of the engines depend on the extent of the paper-work, on the force of water, or on the conftruction of the machinery.

It will afford a fufficien: idea of the work, to give in detail a defcription of the different parts of the engine. See Plate CCLXVII. Fig. 1. repre fents the chapiter which covers the roller. It is 4 feet 3 inches in length, and 2 feet 8 inches in breadth. The fuperior part is pierced with two openings running crofs-wife, 1, 2, 3, 4, into which enter the chaffes or wicker frames, fig 6. and 7; the firft, made of wire-cloth, enters into the opening 3 and 4; the ad, made of hair-cloth, and strengthened with several cross-bars of wood, enters into the opening 1, 2, ferves to retain the fmall pieces of rags which efcape through the first, and prevents them from falling into the dalot or holefcupper, fig. 2. This hole-tcupper is placed across the vat of the engine, parallel to the axle of the roller; the part 9 enters into the notch of the chapiter; and the extremity / enters into the open. ing k of the tunnel kl (fig. 3.), by which means the water dashed through the wicker-frames by every revolution of the roller, is precipitated into the canal fb, and lofes itself below the engine. The figures 4, 9, and 10. represent the roller in perfpective, in plane, and in profile. It is two feet in diameter, and 2 feet 3 inches in length. The trundle head A is 16 inches in diameter, about half as much in length, and furnished with fpindles of iron, which are fcrewed to the end of the trundle head, made alfo of iron. The teeth or blades of the roller are 27 in number, and fitted ftrongly into the wood which composes its body, parallel to its axis. They are of that thicknefs as to leave as much empty space as they occupy. The exterior face of each of the blades fhould be made round, and divided into two parts, with a longitudinal motion, as in the profile a a a, fig_10.

The axis AB of the roller (fig. 4. and 9.) has two parts perfectly rounded in A and in B, which perform the office of pivots. Thefe pivots reft in the fockets A and B (fig. 8.) in the middle of the levers OAH and OBH. By means of thefe levers they raife at pleafure, or lower the axis of the roller, and fit it exactly, and in a parallel manner to the plate. The plates (fee fig. 5.) are made of steel cut into channels, in fuch a manner as to corref pond with the blades of the roller. Their channels are not perpendicular, but oblique; and their are two rows of them, bx, xd, confifting of feven or eight blades each on one plate.-Those in bx, for the purpote of changing the plate, lie in an oppofite direction to thofe in xd. The levers are kept in their pofition near the vat by bands of iron, MN and mn; between which they are made higher or lower by the cogged wheel H, which fupports one of the extremities. Wedges N n are likewife employed to fix the levers at a convenient height above the plates. Finally, every engine is fupplied with a small flide door, which is occafionally raised to carry the prepared ftuff by means

of

of the fcuppers of wood to the general repofito

ries.

Fig. 5. is placed in the vat fig. 8.; the roller (fig. 4.) is placed above it in fuch a manner that the pivots reft in the fockets of the levers; the feupper (fig. 2.) and the chapiter are difpofed in the manner above mentioned. The engine is charged with a proper quantity of rags, and fresh water is admitted by a spigot placed at one of the corners. In this fituation, when the engine is put in motion, the roller turning upon its axis draws the water and the rags by the leaft inclined plane, and making them pafs between its blades and the channels of the plate, dafhes them against the chapiter and the wicker frames; and, in fhort, part of them falls back into the engine, and returns into the circulation. The caufe of this circulation is evidently the continual void occafioned by the movement of the roller on the one fide, and the return of the water and the stuff on the other.

As all the rags are not thrown towards the part Bd of the chapiter, from whence they might fall back into the engine, but a part of them to a greater diftance; it is neceffary to have the wicker frames formerly defcribed, not only to prevent their lofs, but to allow the dirty water to efcape. The fpigot at the corner of the engine continually fupplies this waste of water. This operation would be fufficient to whiten the rags, although the rollers were raised confiderably from the plate; and therefore the force and action of the rollers reducing them to ftuff must be much more effectual. It requires great fkill to conduct the engine, whether it be with regard to the first quantity, to the proper time for adding the fofter rags, to the augmenting or diminishing the water in proportion to the trituration; or, finally, to knowing exactly when the ftuff is reduced to a proper confifteney.

When the stuff is brought to perfection, it is conveyed into a general repofitory, which fupplies the vat from which the fheets of paper are form ed. This vat is made of wood, and generally about 5 feet in diameter, and 24 in depth. It is kept in temperature by means of a grate introduced by a hole, and furrounded on the infide of the vat with a case of copper. For fuel to this grate, they use charcoal or wood; and, frequently to prevent smoke, the wall of the building comes in contact with one part of the vat, and the fire has no communication with the place where they make the paper.

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Every vat is furnished on the upper part with planks, inclosed inwards, and even railed in with wood, to prevent any of the ftuff from running over in the operation. Acrofs the vat is a plank which they call the trapan, pierced with holes at one of the extremities, and refting on the planks which furround the vat.

The forms or moulds are compofed of wirecloth, and a moveable frame. It is with thefe that they fetch up the stuff from the vat, in order to form the sheets of paper. The fides of the form are made of oak, which is previously fleeped in water, and otherwife prepared, to prevent warping. The wire-cloth is made larger than the fheet of paper, and the excefs of it on all fides is covered with a moveable frame. This frame is

necessary to retain the ftuff of which the paper is made on the cloth: and it must be exactly adapted to the form, otherwife the edges of the paper will be ragged and badly finished. The wirecloth of the form is varied in proportion to the fineness of the paper and the nature of the stuff.

The felts are pieces of woollen cloth spread over every fheet of paper, and upon which the fheets are laid to detach them from the form, to prevent them from adhering together, to imbibe part of the water with which the stuff is charged, and to transmit the whole of it when placed under the action of the prefs. The two fides of the felt are differently raised: that of which the hair is longeft is applied to the fheets which are laid down; and any alteration of this difpofition would produce a change in the texture of the paper. The ftuff of which the felts are made should be fufficiently strong, in order that it may be ftretched exactly on the fheets without forming into folds; and, at the fame time, fufficiently pliant to yield in every direction, without injury, to the wet paper. As the felts have to refift the reiterated efforts of the preis, it appears neceffary that the warp be very ftrong, of combed wool, and well twifted. On the other hand, as they have to imbibe a certain quantity of water, and to return it, it is neceffary that the woof be of carded wool, and drawn out into a flack thread. -Thefe are the utenfils, together with the prefs, which are used in the apartment where the sheets of paper are formed.

The vat being furnished with a fufficient quantity of ftuff and of water, two inftruments are employed to mix them; the one of which is a fimple pole, and the other a pole armed with a piece of board, rounded and full of holes. This operation is repeated as often as the ftuff falls to the bottom. In the principal writing mills in England, they use for this purpose what is called a hog, which is a machine within the vat, that by means of a fmall wheel on the outfide, is made to turn conftantly round, and keep the stuff in perpetual motion. When the ftuff and water are properly mixed, it is easy to perceive whether the previous operations have been complete. When the ftuff floats clofe, and in regular flakes, it is a proof that it has been well triturated; and the parts of the rags which have escaped the rollers alfo appear.

After this operation the workman takes one of the forms, furnished with its frame, by the middle of the fhort fides, and fixing the frame round the wire-cloth with his thumbs, he plunges it obliquely 4 or 5 inches into the vat, beginning by the long fide, which is nearest to him. After the immerfion he raifes it to a level: by these movements he fetches up on the form a fufficient quantity of ftuff; and as foon as the form is raised the water efcapes through the wire-cloth, and the fuperfluity of the ftuff over the fides of the frame. The fibrous parts of the ftuff arrange themselves regularly on the wire-cloth of the form, not only in proportion as the water escapes, but also as the workman favours this effect by gently fhaking the form. Afterwards, having placed the form on a piece of board, the workman takes off the frame or deckle, and glides this form towards the couch

er;

er; who, having previously laid his felt, places it with his left hand in an inclined fituation, on a plank fixed on the edge of the vat, and full of holes. During this operation, the workman applies his frame, and begins a fecond fheet. The coucher feizes this inftant, takes with his left hand the form, now fufficiently dry, and laying the fheet of paper upon the felt, returns the form by gliding it along the trapan of the vat.

They proceed in this manner, laying alternately a fheet and a felt, till they have made fix quires of paper, which is called a poft; and this they do with fuch fwiftness, that, in many forts of paper, two men make upwards of 20 pofts in a day. When the last fheet of the poft is covered with the last felt, the workmen about the vat unite together, and fubmit the whole heap to the action of the prefs. They began at first to prefs it with a middling lever, and afterwards with a lever about 15 feet in length. After this operation, another perfon feparates the fheets of paper from the felts, laying them in a heap; and feveral of thefe heaps collected together are again put under the prefs.

The exchange is the next operation. It is conducted in a hall contiguous to the engine, fupplied with feveral preffes, and with a long table. The workman arranges on this table, the paper newly fabricated, into heaps; each heap containing 8 or 10 of thofe laft under the prefs, kept separate by a woollen felt. The prefs is large enough to receive two of them at once, placed the one at the other's fide. When the compreffion is judged fufficient, the heaps of paper are carried back to the table, and the whole turned fheet by fheet, -in fuch a manner that the furface of every fheet is exposed to a new one; and in this fituation they are again brought under the prefs. It is in conducting these two operations fometimes to 4 or 5 times, or as often as the nature of the paper requires, that the perfection of the Dutch plan confifts. If the ftuff be fine, or the paper flender, the exchange is lefs frequently repeated. In this operation, it is neceffary to alter the fituation of the heaps, with regard to one another, every time they are put under the prefs; and alfo, as the heaps are highest toward the middle, to place fmall pieces of felt at the extremities, to bring every part of them under an equal preffure. A fingle man, with 4 or 5 preffes, may exchange all the paper produced by two vats, provided the previous preffing at the vats be well performed. The work of the exchange generally lasts about two days on a given quantity of paper.

and conftruct their lattices with great exactnessBy thefe means the Dutch paper is dried equally, and is extremely fupple for the fizing. They prevent the cords from imbibing the water by covering them with wax. In ufing fuch cords, the moisture does not continue in the line of contact between the paper and the cord, which prevents the fheets from ftretching in that particular place by its weight, and from the folds which the moifture in the fubfequent operations might occafion. The Dutch alfo employ cords of confiderable thickness, and place fewer of them under the fheets; by which means they diminish the points of contact, and give a freer and more equal circulation to the air.

The fize for paper is made of the shreds and pairings got from the tanners, curriers, and parchment-makers. All the putrefied parts, and the lime, are carefully feparated from them, and they are inclofed into a kind of basket, and let down by a rope and pully into the cauldron. This is a late invention, and ferves two valuable purposes. It makes it easy to draw out the pieces of leather when the fize is extracted from them by boiling, or easy to return them into the boiler if the operation be not complete. When the fubftance is fufficiently extracted, it is allowed to fettle for fome time; and it is twice filtered before it is put into the veffel into which they dip the paper.

Immediately before the operation, a certain quantity of alum is added to the fize. The workman takes a handful of the fheets, smoothed and rendered as fupple as poffible, in his left hand, dips them into the veffel, and holds them separate with his right, that they may equally imbibe the fize. After holding them above the veffel for a fhort space of time, he feizes on the other fide with his right hand, and again dips them into the veffel. When he has finished 10 or 12 of these handfuls, they are submitted to the action of the prefs. The fuperfluous fize is carried back to the veffel by a small pipe. The veffel in which the paper is fized is made of copper, and furnished with a grate, to give the fize, when neceffary, a due temperature; and a piece of thin board or felt is placed between every handful as they are laid on the table of the prefs.

As foon as the paper is fized, it is the practice of fome paper-makers to carry it immediately to the drying houfe, and hang it, before it cools, theet by fheet, on the cords. The paper, unless particular attention be paid to the lattices of the drying houfe, is apt to dry too faft; whereby a great part of the fize goes off in evaporation; or if too The fheds for drying the paper are in the neigh-flow it falls to the ground. The Dutch drying bourhood of the paper-mill; and are furnished with a vast number of cords, on which they hang the fheets both before and after the fizing. The fheds are furrounded with moveable lattices, to admit a quantity of air fufficient for drying the paper. The cords of the fhed are stretched as much as poffible; and the paper, 4 or 5 fheets of it together, is placed on them by a wooden inftrument, refembling a pick-ax. The principal difficulty in drying the paper, confifts in gradually admitting the external air, and in preventing the cords from imbibing moisture. With regard to the first of these, the Dutch use very low fheds,

houses are the beft to prevent these inconveniences. But the exchange after the fizing, which is generally practifed in Holland, is the best remedy. They begin this operation on the handfuls of paper, either while they are ftill hot, or otherwife, as they find it convenient. But after the exchange, they are careful to allow the heaps to be altogether cold before they are fubmitted to the prefs. Without this precaution, the fize would either be wholly fqueezed out by the prefs of the exchange, or the furface of the paper become very irregular. It is of confequence that the paper, ftill warm from the fizing, grow gradually firm,

under

under the operation of the exchange, in proportion as it cools. By this method it receives that varnish which is afterwards brought to perfection under the prefs, and in which the excellency of the paper, either for writing or drawing, chiefly confifts. It is in confequence of the exchanging and preffing that the Dutch paper is foft and equal, and that the fize penetrates into the body of it, and is extended equally over its surface.

The exchange after the fizing ought to be conducted with the greatest skill and attention. because the grain of the paper then receives impreffions which can never be eradicated. When the fized paper is also exchanged, it is poffible to hang more theets together on the cords of the drying houfe. The paper dries better in this condi. tion, and the fize is preferved without any fenfible wafte, because the sheets of paper mutually prevent the rapid operation of the external air. And as the fize has already penetrated into the paper, and is fixed on the furface, the infenfible progrefs of a well conducted drying houfe renders all the good effects more perfect, in proportion as it is flowly dried. If, to thefe confiderations, be added the damage done to the paper in drying it. immediately after the prefs of the fizing room, whether it be done in raising the hairs by separat. ing the fheets, or in cracking the furface, it is evident that the trouble of the fecond exchange is infinitely overpaid by the advantage.

When the paper is fufficiently dry, it is carried to the finishing room, where it is preffed, felected, examined, folded, made up into quires, and final ly, into reams. It is here put twice under the prefs; firft, when it is at its full fize, and fecondly, after it is folded. The principal labour of this place, confifts in afforting the paper into different lots, according to its quality and faults; after which, it is made up into quires. The perfon who does this muft poffefs great fkill, and be capable of great attention, because he acts as a check on those who separated the paper into different lots. He takes the sheets with his right hand, folds them, examines them, lays them over his left arm till he has the number requifite for a quire, brings the fides parallel to one another, and places them in heaps under the table. An expert workman, if proper care has been taken in afforting the lots, will finifh in this manner, near 600 quires in a day.

The paper is afterwards collected into reams of 20 quires each, and for the last time put under the the prefs, where it is continued for fo or 12 hours, or as long as the demand of the paper-mill will permit.

A method has lately been discovered of bleaching the rags or ftuff, which will undoubtedly be adopted everywhere in the preparation of writing paper. This discovery was made by Meffrs SCHEELE, BERTHOLLET, and CHAPTAL. See ACID, OXYGENATED MURIATIC, and BLEACH ING, Part II.

Among many other properties of the new acid discovered by Mr Scheele, the most remarkable was, that it deftroyed the colour of every vegetable ⚫ fubftance which was expofed to its action; or, in other words, it bleached them; or, in the language of the dyers, it discharged their colours; that is to

fay, whatever was the colour of any vegetable body that was fubmitted to the action of the oxy. genated muriatic acid, it always became white, or loft its colouring matter.

In 1786, Dr BEDDOES, now profeffor of che miftry in the univerfity of Oxford, published an English translation of the Chemical Effays of Mr Scheele; and thereby made known to the chemifts of Great Britain the power of the oxygenated muriatic acid, to bleach or whiten vegetable fubftances, or to difcharge or decompofe their co lours. But M. Berthollet was the first who thought of rendering the discovery fubfervient to the purposes of manufacture; and he published an Effay on this fubject, in the Annales de Chemie, in 1789.

In the fame work and year, M. CHAPTAL pub. lifhed an account of fome experiments, in which, among many other applications of the oxygenated muriatic acid to purposes useful in the œconomical arts, he gives information of having bleached or whitened coarfe rags used by the paper makers, fo as greatly to improve the quality of the paper into which they were afterwards manufactured. His preparation of this bleaching liquor differs not from Berthollet's, which is as follows: "Take 6 oz. of manganese and 16 oz. of sea-falt, both reduced to a fine powder; mix these accurately, and introduce them into a retort or diftilling veffel: Then take 12 oz. of oil of vitriol and 8 oz. of water, mixed together, and allowed to cool; add these to the other ingredients in the retort, and connect the retort with a cask or receiver, capable of holding 274 gallons of water, but only containing 25 gallons, which is to be impregnated with the gas or vapour of the oxygenated muriatic acid; and proceed to diftillation, firft without, and afterwards with a fire, gradually raised til! the whole acid comes over."

Experiments have been made with this liquor both by fome of the principal paper-makers in the neighbourhood of Edinburgh, and by Meff. CLEMENT and GEORGE TAYLORS of Maidstone in Kent. By the former it was found, that paper made of rags and pulp whitened in this manner, was fuperior to any other made of fimilar mate rials, not only in colour but in fineness of texture. By the latter, its excellence was found to be fo great, that probably, having never heard of Scheele, Berthollet, and Chaptal, and conceiving themfelves to be the firft inventors of it, they obtained a patent for its exclusive use, which other manufactu rers will doubtlefs difregard. The name of this acid is now fhortened to oxy-muriatic. See OxyGEN, OXY-MURIAT, N° 3; and OXY-MURIATIC ACID, § 1-3.

Formerly writing paper could be made only of unprinted linen, but now, in confequence of the above difcoveries, ever printed linen can be made into the fiveft and whiteft paper. In 1795, Mr ELIAS CARPENTER Bermondfey obtained a patent for a metho. of bleaching paper of fuch ma terials in the water-leaf, or feet, and fizing at without dyeing.

In the preparation of the pulp, the coarfer rags are to be macerated for 2 or 3 days in a cautic alkaline jey, and wrought into sheets of paper in the ufual way. A ftrong wooden box is then to

be

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