P.

OPOBALSAM, is the balsam of Peru in a dry state.

OPOPONAX, is a gum-resin resembling gum ammoniac. It is occasionally used in medicine.

ORANGE DYE, is given by a mixture of red and yellow dyes in various proportions. Annotto alone dyes orange; but it is a fugitive colour.

ORCINE, is the name of the colouring principle of thelichen dealbatus. The lichen dried and pulverized is to be exhausted by boiling alcohol. The solution filtered hot, lets fall in the cooling, crystalline flocks, which do not belong to the colouring matter. The supernatant alcohol is to be distilled off, the residuum is to be evaporated to the consistence of an extract, and triturated with water till this liquid will dissolve no more. The aqueous solution reduced to the consistence of syrup, and left to itself in a cool place, lets fall, at the end of a few days, long brown brittle needles, which are to be freed by pressure from the mother water, and dried. That water being treated with animal charcoal, filtered and evaporated, will yield a second crop of crystals. These are orcine. Its taste is sweet and nauseous; it melts readily in a retort into a transparent liquid, and distils without undergoing any change. It is soluble in water and alcohol. Nitric acid colours it blood-red; which colour afterwards disappears. Subacetate of lead precipitates it completely. Its conversion into the archil red is effected by the action of an alkali, in contact with the air. When dissolved, for example, in ammonia, and exposed to the atmosphere, it takes a dirty brown red hue; but when the orcine is exposed to air charged with vapours of ammonia, it assumes by degrees a fine violet colour. To obtain this result, the orcine in powder should be placed in a capsule, alongside of a saucer containing water of ammonia; and both should be covered by a large bell glass; whenever the orcine has acquired a darkbrown cast, it must be withdrawn from under the bell, and the excess of ammonia be allowed to volatilize. As soon as the smell of ammonia is gone, the orcine is to be dissolved in water; and then a few drops of ammonia being poured into the brownish liquid, it assumes a magnificent reddish-violet colour. Acetic acid precipitates the red lake of lichen.

ORES (Mines, Fr.;Erze, Germ.); are the mineral bodies which contain so much metal as to be worth the smelting, or being reduced by fire to the metallic state. The substances naturally combined with metals, which mask their metallic characters, are chiefly oxygen, chlorine, sulphur, phosphorus, selenium, arsenic, water, and several acids, of which the carbonic is the most common. Some metals, as gold, silver, platinum, often occur in the metallic state, either alone, or combined with other metals, constituting what are called native alloys.I have described in the articleMine, the general structure of the great metallic repositories within the earth, as well as the most approved methods of bringing them to the surface; and in the articleMetallurgy, the various mechanical and chemical operations requisite to reduce the ores into pure metals. Under each particular metal, moreover, in its alphabetical place, will be found a systematic account of its most important ores.Relatively to the theory of the smelting of ores, the following observations may be made. It is probable that the coaly matter employed in that process is not theimmediateagent of their reduction; but the charcoal seems first of all to be transformed by the atmospherical oxygen into the oxide of carbon; which gaseous product then surrounds and penetrates the interior substance of the oxides, with the effect of decomposing them, and carrying off their oxygen. That this is the true mode of action, is evident from the well-known facts, that bars of iron, stratified with pounded charcoal, in the steel cementation-chest, most readily absorb the carbonaceous principle to their innermost centre, while their surfaces get blistered by the expansion of carburetted gases formed within; and that an intermixture of ores and charcoal is not always necessary to reduction, but merely an interstratification of the two, without intimate contact of the particles. In this case, the carbonic acid which is generated at the lower surfaces of contact of the strata, rising up through the first bed of ignited charcoal, becomes converted into carbonic oxide; and this gaseous matter, passing up through the next layer of ore, seizes its oxygen, reduces it to metal, and is itself thereby transformed once more into carbonic acid; and so on in continual alternation. It may be laid down, however, as a general rule, that the reduction is the more rapid and complete, the more intimate the mixture of the charcoal and the metallic oxide has been, because the formation of both the carbonic acid and carbonic oxide becomes thereby more easy and direct. Indeed the cementation of iron bars, into steel will not succeed, unless the charcoal be so porous as to contain, interspersed, enough of air to favour the commencement of its conversion into the gaseous oxide; thus acting like a ferment in brewing. Hence also finely pulverized charcoal does not answer well; unless a quantity of ground iron cinder or oxide of manganese be blended with it, to afford enough of oxygen to begin the generation of carbonic oxide gas; whereby the successive transformations into acid, and oxide, are put in train.

I have described in the articleMine, the general structure of the great metallic repositories within the earth, as well as the most approved methods of bringing them to the surface; and in the articleMetallurgy, the various mechanical and chemical operations requisite to reduce the ores into pure metals. Under each particular metal, moreover, in its alphabetical place, will be found a systematic account of its most important ores.

Relatively to the theory of the smelting of ores, the following observations may be made. It is probable that the coaly matter employed in that process is not theimmediateagent of their reduction; but the charcoal seems first of all to be transformed by the atmospherical oxygen into the oxide of carbon; which gaseous product then surrounds and penetrates the interior substance of the oxides, with the effect of decomposing them, and carrying off their oxygen. That this is the true mode of action, is evident from the well-known facts, that bars of iron, stratified with pounded charcoal, in the steel cementation-chest, most readily absorb the carbonaceous principle to their innermost centre, while their surfaces get blistered by the expansion of carburetted gases formed within; and that an intermixture of ores and charcoal is not always necessary to reduction, but merely an interstratification of the two, without intimate contact of the particles. In this case, the carbonic acid which is generated at the lower surfaces of contact of the strata, rising up through the first bed of ignited charcoal, becomes converted into carbonic oxide; and this gaseous matter, passing up through the next layer of ore, seizes its oxygen, reduces it to metal, and is itself thereby transformed once more into carbonic acid; and so on in continual alternation. It may be laid down, however, as a general rule, that the reduction is the more rapid and complete, the more intimate the mixture of the charcoal and the metallic oxide has been, because the formation of both the carbonic acid and carbonic oxide becomes thereby more easy and direct. Indeed the cementation of iron bars, into steel will not succeed, unless the charcoal be so porous as to contain, interspersed, enough of air to favour the commencement of its conversion into the gaseous oxide; thus acting like a ferment in brewing. Hence also finely pulverized charcoal does not answer well; unless a quantity of ground iron cinder or oxide of manganese be blended with it, to afford enough of oxygen to begin the generation of carbonic oxide gas; whereby the successive transformations into acid, and oxide, are put in train.

ORPIMENT (Eng. and Fr.,Yellow sulphuret of arsenic;Operment,Rauschgelb, Germ.); occurs in indistinct crystalline particles, and sometimes in oblique rhomboidal prisms; but for the most part, in kidney and other imitative forms; it has a scaly and granular aspect; texture foliated, or radiated; fracture small granular, passing into conchoidal; splintery, opaque, shining, with a weak diamond lustre; lemon, orange, or honey yellow; sometimes green; specific gravity, 3·44 to 3·6. It is found in floetz rocks, in marl, clay sand-stone, along with realgar, lead-glance, pyrites, and blende, in many parts of the world. It volatilizes at the blowpipe. It is used as a pigment.The finest specimens come from Persia, in brilliant yellow masses, of a lamellar texture, called golden orpiment.Artificial orpiment is manufactured chiefly in Saxony, by subliming in cast-iron cucurbits, surmounted by conical cast-iron capitals, a mixture in due proportions of sulphur and arsenious acid (white arsenic). As thus obtained, it is in yellow compact opaque masses, of a glassy aspect; affording a powder of a pale yellow colour. Genuine orpiment is often adulterated with an ill-made compound; which is sold in this country by the preposterous name of king’s yellow. This fictitious substance is frequently nothing else than white arsenic combined with a little sulphur; and is quite soluble in water. It is therefore a deadly poison, and has been administered with criminal intentions and fatal effects. I had occasion, some years ago, to examine such a specimen of king’s yellow, with which a woman had killed her child. A proper insoluble sulphuret of arsenic, like the native or the Saxon, may be prepared by transmitting sulphuretted hydrogen gas through any arsenical solution. It consists of 38·09 sulphur, and 60·92 of metallic arsenic, and is not remarkably poisonous. The finestkinds of native orpiment are reserved for artists; the inferior are used for the indigo vat. They are all soluble in alkaline lyes, and in water of ammonia.

The finest specimens come from Persia, in brilliant yellow masses, of a lamellar texture, called golden orpiment.

Artificial orpiment is manufactured chiefly in Saxony, by subliming in cast-iron cucurbits, surmounted by conical cast-iron capitals, a mixture in due proportions of sulphur and arsenious acid (white arsenic). As thus obtained, it is in yellow compact opaque masses, of a glassy aspect; affording a powder of a pale yellow colour. Genuine orpiment is often adulterated with an ill-made compound; which is sold in this country by the preposterous name of king’s yellow. This fictitious substance is frequently nothing else than white arsenic combined with a little sulphur; and is quite soluble in water. It is therefore a deadly poison, and has been administered with criminal intentions and fatal effects. I had occasion, some years ago, to examine such a specimen of king’s yellow, with which a woman had killed her child. A proper insoluble sulphuret of arsenic, like the native or the Saxon, may be prepared by transmitting sulphuretted hydrogen gas through any arsenical solution. It consists of 38·09 sulphur, and 60·92 of metallic arsenic, and is not remarkably poisonous. The finestkinds of native orpiment are reserved for artists; the inferior are used for the indigo vat. They are all soluble in alkaline lyes, and in water of ammonia.

ORYCTNOGNOSY, is the name given by Werner to the knowledge of minerals; and is therefore synonymous with the English term Mineralogy.

OSTEOCOLLA, is the glue obtained from bones, by removing the earthy phosphates with muriatic acid, and dissolving the cartilaginous residuum in water at a temperature considerably above the boiling point, by means of a digester. It is a very indifferent article.

OSMIUM, is a metal discovered by Mr. Tennant in 1803, among the grains of native platinum. It occurs also associated with the ore of iridium. As it has not been applied to any use in the arts, I shall reserve any chemical observations that the subject may require for the articlePlatinum.

OXALATES, are saline compounds of the bases with

OXALIC ACID (Acide oxalique, Fr.;Sauerkleesaüre, Germ.); which is the object of a considerable chemical manufacture. It is usually prepared upon the small scale by digesting four parts of nitric acid of specific gravity 1·4, upon one part of sugar, in a glass retort; but on the large scale, in a series of salt-glazed stoneware pipkins, two-thirds filled, and set in a water bath. The addition of a little sulphuric acid has been found to increase the product. 15 pounds of sugar yield fully 17 pounds of the crystalline acid. This acid exists in the juice of wood sorrel, theoxalis acetosella, in the state of a bi-oxalate; from which the salt is extracted as an object of commerce in Switzerland, and sold under the name of salt of sorrel, or sometimes, most incorrectly, under that of salt of lemons.Some prefer to make oxalic acid by acting upon 4 parts of sugar, with 24 parts of nitric acid, of specific gravity 1·220, heating the solution in a retort till the acid begins to decompose, and keeping it at this temperature as long as nitrous gas is disengaged. The sugar loses a portion of its carbon, which combining with the oxygen of the nitric acid, becomes carbonic acid, and escapes along with the deutoxide of nitrogen. The remaining carbon and hydrogen of the sugar being oxidized at the expense of the nitric acid, generate a mixture of two acids, the oxalic and the malic. Whenever gas ceases to issue, the retort must be removed from the source of heat, and set aside to cool; the oxalic acid crystallizes, but the malic remains dissolved. After draining these crystals upon a filter funnel, if the brownish liquid be further evaporated, it will furnish another crop of them. The residuary mother water is generally regarded as malic acid, but it also contains both oxalic and nitric acids; and if heated with 6 parts of the latter acid, it will yield a good deal more oxalic acid at the expense of the malic. The brown crystals now formed being, however, penetrated with nitric, as well as malic acid, must be allowed to dry and effloresce in warm dry air, whereby the nitric acid will be got rid of without injury to the oxalic. A second crystallization and efflorescence will entirely dissipate the remainder of the nitric acid, so as to afford pure oxalic acid at the third crystallization. Sugar affords, with nitric acid, a purer oxalic acid, but in smaller quantity, than saw-dust, glue, silk, hairs, and several other animal and vegetable substances.Oxalic acid occurs in aggregated prisms when it crystallizes rapidly, but in tables of greater or less thickness when slowly formed. They lose their water of crystallization in the open air, fall into powder, and weigh 0·28 less than before; but still retain 0·14 parts of water, which the acid does not part with except in favour of another oxide, as when it is combined with oxide of lead. The effloresced acid contains 20 per cent. of water, according to Berzelius. By my analysis, the crystals consist of three prime equivalents, of water = 27, combined, with one of dry oxalic acid = 36; or in 100 parts, of 42·86 of water with 57·14 of acid. The acid itself consists of 2 atoms of carbon = 12, + 3 of oxygen = 24; of which the sum is, as above stated, 36. This acid has a sharp sour taste, and sets the teeth on edge; half a pint of water, containing only 1 gr. of acid, very sensibly reddens litmus paper. Nine parts of water dissolve one part of the crystals at 60° F. and form a solution, of spec. grav. 1·045, which when swallowed acts as a deadly poison. Alcohol also dissolves this acid. It differs from all the other acid products of the vegetable kingdom, in containing no hydrogen, as I demonstrated (in my paper upon the ultimate analysis of organic bodies, published in the Phil. Trans. for 1822), by its giving out no muriatic acid gas, when heated in a glass tube with calomel or corrosive sublimate.Oxalic acid is employed chiefly for certain styles of discharge incalico-printing, (which see), and for whitening the leather of boot-tops. Oxalate of ammonia is an excellent reagent for detecting lime and its salts in any solution. The acid itself, or the bi-oxalate of potash, is often used for removing ink or iron-mould stains from linen.A convenient plan of testing the value of peroxide of manganese for bleachers, &c., originally proposed by Berthier, has been since simplified by Dr. Thomson, as follows. In a poised Florence flask weigh 600 grains of water, and 75 grains of crystallized oxalicacid; add 50 grains of the manganese, and as quickly as possibly afterwards from 150 to 200 grains of concentrated sulphuric acid. Cover the mouth of the flask with paper, and leave it at rest for 24 hours. The loss of weight it has now suffered, corresponds exactly to the weight of peroxide of manganese present; because the quantity of carbonic acid producible by the reaction of the oxalic acid with the peroxide, is precisely equal to the weight of the peroxide, as the doctrine of chemical equivalents shows.

Some prefer to make oxalic acid by acting upon 4 parts of sugar, with 24 parts of nitric acid, of specific gravity 1·220, heating the solution in a retort till the acid begins to decompose, and keeping it at this temperature as long as nitrous gas is disengaged. The sugar loses a portion of its carbon, which combining with the oxygen of the nitric acid, becomes carbonic acid, and escapes along with the deutoxide of nitrogen. The remaining carbon and hydrogen of the sugar being oxidized at the expense of the nitric acid, generate a mixture of two acids, the oxalic and the malic. Whenever gas ceases to issue, the retort must be removed from the source of heat, and set aside to cool; the oxalic acid crystallizes, but the malic remains dissolved. After draining these crystals upon a filter funnel, if the brownish liquid be further evaporated, it will furnish another crop of them. The residuary mother water is generally regarded as malic acid, but it also contains both oxalic and nitric acids; and if heated with 6 parts of the latter acid, it will yield a good deal more oxalic acid at the expense of the malic. The brown crystals now formed being, however, penetrated with nitric, as well as malic acid, must be allowed to dry and effloresce in warm dry air, whereby the nitric acid will be got rid of without injury to the oxalic. A second crystallization and efflorescence will entirely dissipate the remainder of the nitric acid, so as to afford pure oxalic acid at the third crystallization. Sugar affords, with nitric acid, a purer oxalic acid, but in smaller quantity, than saw-dust, glue, silk, hairs, and several other animal and vegetable substances.

Oxalic acid occurs in aggregated prisms when it crystallizes rapidly, but in tables of greater or less thickness when slowly formed. They lose their water of crystallization in the open air, fall into powder, and weigh 0·28 less than before; but still retain 0·14 parts of water, which the acid does not part with except in favour of another oxide, as when it is combined with oxide of lead. The effloresced acid contains 20 per cent. of water, according to Berzelius. By my analysis, the crystals consist of three prime equivalents, of water = 27, combined, with one of dry oxalic acid = 36; or in 100 parts, of 42·86 of water with 57·14 of acid. The acid itself consists of 2 atoms of carbon = 12, + 3 of oxygen = 24; of which the sum is, as above stated, 36. This acid has a sharp sour taste, and sets the teeth on edge; half a pint of water, containing only 1 gr. of acid, very sensibly reddens litmus paper. Nine parts of water dissolve one part of the crystals at 60° F. and form a solution, of spec. grav. 1·045, which when swallowed acts as a deadly poison. Alcohol also dissolves this acid. It differs from all the other acid products of the vegetable kingdom, in containing no hydrogen, as I demonstrated (in my paper upon the ultimate analysis of organic bodies, published in the Phil. Trans. for 1822), by its giving out no muriatic acid gas, when heated in a glass tube with calomel or corrosive sublimate.

Oxalic acid is employed chiefly for certain styles of discharge incalico-printing, (which see), and for whitening the leather of boot-tops. Oxalate of ammonia is an excellent reagent for detecting lime and its salts in any solution. The acid itself, or the bi-oxalate of potash, is often used for removing ink or iron-mould stains from linen.

A convenient plan of testing the value of peroxide of manganese for bleachers, &c., originally proposed by Berthier, has been since simplified by Dr. Thomson, as follows. In a poised Florence flask weigh 600 grains of water, and 75 grains of crystallized oxalicacid; add 50 grains of the manganese, and as quickly as possibly afterwards from 150 to 200 grains of concentrated sulphuric acid. Cover the mouth of the flask with paper, and leave it at rest for 24 hours. The loss of weight it has now suffered, corresponds exactly to the weight of peroxide of manganese present; because the quantity of carbonic acid producible by the reaction of the oxalic acid with the peroxide, is precisely equal to the weight of the peroxide, as the doctrine of chemical equivalents shows.

OXIDES, are neutral compounds, containing oxygen in equivalent proportion.

OXISELS, are salts, consisting of oxygenated acids and oxides, to distinguish them from theHALOSELS, which are salts consisting of one of the archæal elements; such as chlorine, iodine, bromine, &c. combined with metals. SeeSalt.

OXYGEN(Oxigène, Fr.;Sauerstoff, Germ.); is a body which can be examined only in the gaseous form; for which purpose it is most conveniently obtained in a pure state by exposing chlorate of potash, or red oxide of mercury, in a glass retort, or recurved tube, to the heat of a spirit lamp; 100 grains of the salt yield 115 cubic inches of gas. One pound of nitre, ignited in an iron retort, gives out about 1200 cubic inches of oxygen, mixed with a little nitrogen. The peroxide of manganese also affords it, either by ignition alone in an iron or earthen retort, or by a lamp heat in a glass retort, when mixed with sulphuric acid. Oxygen is void of taste, colour, and smell. It possesses all the mechanical properties of the atmosphere. Its specific gravity is 1·1026 compared to air 1·0000; whence 100 cubic inches of it weigh 33·85 grains. Combustibles, even iron and diamonds, once kindled, burn in it most splendidly. It forms 21 parts in 100 by volume of air, being the constituent essential to the atmospheric functions of supporting animal and vegetable life, as well as flame.The full development of this subject in its multifarious relations, will be discussed in my forthcoming new system of chemistry.Oxygenated-Muriatic, andOxymuriatic, are the names originally given by the French chemists, from false theoretical notions, to chlorine, which Sir H. Davy proved to be an undecompounded substance.

The full development of this subject in its multifarious relations, will be discussed in my forthcoming new system of chemistry.

Oxygenated-Muriatic, andOxymuriatic, are the names originally given by the French chemists, from false theoretical notions, to chlorine, which Sir H. Davy proved to be an undecompounded substance.

PACKFONG, is the Chinese name of the alloy called white copper, orGerman silver.

PACO, or PACOS, is the Peruvian name of an earthy-looking ore, which consists of brown oxide of iron, with imperceptible particles of native silver disseminated through it.Padding machine

PACO, or PACOS, is the Peruvian name of an earthy-looking ore, which consists of brown oxide of iron, with imperceptible particles of native silver disseminated through it.

Padding machine

PADDING MACHINE (Machine à plaquer, Fr.;Klatsch, orGrundirmaschine, Germ.); in calico-printing, is the apparatus for imbuing a piece of cotton cloth uniformly with any mordant. Infig.774.A B C Drepresents in section a cast-iron frame, supporting two opposite standards aboveM, in whose vertical slot the gudgeonsa b, of two copper or bronze cylindersE F, run; the gudgeons ofEturn upon fixed brasses or plummer blocks; but the superior cylinderFrests upon the surface of the under one, and may be pressed down upon it with greater or less force by means of the weighted leverd e f g, whose centre of motion is atd, and which bears down upon the axle ofF.Kis the roller upon which the pieces of cotton cloth intended to be padded are wound; several of them, being stitched endwise together. They receive tension from the action of a weighted belto,n, which passes round a pulleynupon the end of the rollerK. The troughG, which contains the colouring matter or mordant, rests beneath the cylinder upon the tableL, or other convenient support. About two inches above the bottom of the trough, there is a copper dip-rollerC, under which the cloth passes, after going round the guide rollerm. Upon escaping from the trough, it is drawn over the half-round stretcher-bar atI, groovedobliquely right and left, as shown atN, whereby it acquires a diverging extension from the middle, and enters with a smooth surface between the two cylindersE F. These are lapped round 6 or 7 times with cotton cloth, to soften and equalize their pressure. The piece of goods glides obliquely upwards, in contact with one third of the cylinderF, and is finally wound about the uppermost rollerH. The gudgeon ofHrevolves in the end of the radiush,k, which is jointed atk, and movable by a mortise atialong the quadrantal arc towardsl, as the rollerKbecomes enlarged by the convolutions of the web. The under cylinderEreceives motion by a pulley or rigger upon its opposite end, from a band connected with the driving-shaft of the printshop. To ensure perfect equability in the application of the mordant, the goods are in some works passed twice through the trough; the pressure being increased the second time by sliding the weightgto the end of the leverd f.A view of a padding machine in connexion with the driving mechanism is given underHot Flue; see alsoStarching Machine.

A view of a padding machine in connexion with the driving mechanism is given underHot Flue; see alsoStarching Machine.

PAINT. SeeRouge.

PAINTS, GRINDING OF. There are many pigments, such as common orpiment, or king’s yellow, and verdigris, which are strong poisons; others which are very deleterious, and occasion dreadful maladies, such as white lead, red lead, chrome yellow, and vermillion; none of which can be safely ground by hand with the slab and muller, but should always be triturated in a mill. The emanations of white lead cause, first, that dangerous disease thecolica pictonum, afterwards paralysis, or premature decrepitude and lingering death.Colour-millColour-millFigs.775,776,777,778.exhibit the construction of a good colour-mill in three views;fig.775.being an elevation shown upon the side of the handle, or where the power is applied to the shaft;fig.776.a second elevation, taken upon the side of the linec,d, of the plan or bird’s-eye view,fig.777.The frame-workA Aof the mill is made of wood or cast iron, strongly mortised or bolted together; and strengthened by the two cross iron barsB,B.Fig.778.is a plan of the millstones. The lying or nether millstoneC,fig.776, is of cast iron, and is channelled on its upper face like corn millstones. It is fixed upon the two iron barsB,B; but may be preferably supported upon the 3 points of adjustable screws, passing up through bearing-bars. The millstoneCis surrounded by a large iron hoopD, for preventing the pasty-consistenced colour from running over the edge. It can escape only by the sluice holeE,fig.776., formed in the hoop; and is then received in the tubXplaced beneath.The upper or moving millstoneF, is also made of cast iron. The dotted lines indicate its shape. In the centre it has an aperture with ledgesG,G; there is also a ledge upon its outer circumference, sufficiently high to confine the colour which may occasionally accumulate upon its surface. An upright iron shaftHpasses into the turning stone, and gives motion to it. A horizontal iron bevel wheelK,figs.776,777., furnished with 27 wooden teeth, is fixed upon the upper end of the upright shaftH. A similar bevel wheelL, having the same number of teeth, is placed vertically upon the horizontal iron axisM,M, and works into the wheelK. This horizontal axisM,Mbears, at one of its ends, a handle or winchN, by which the workman may turn the millstoneF; and on the other end of the same axis, the fly-wheelOis made fast, which serves to regulate the movements of the machine. Upon one of the spokes of the fly-wheel there is fixed, in like manner, a handleP, which may serve upon occasion for turning the mill. This handle may be attached at any convenient distance from the centre, by means of the slot and screw-nutJ.The colour to be ground is put into the hopperR, below which the bucketSis suspended, for supplying the colour uniformly through the orifice in the millstoneG. A cord or chainT, by means of which the bucketSis suspended at a proper height for pouring out the requisite quantity of colour between the stones, pulls the bucket obliquely, and makes its beak rest against the square upright shaftH. By this means the bucket is continually agitated in such a way as to discharge more or less colour, according to its degree of inclination. The copper cisternX, receives the colour successively as it is ground; and, when full, it may be carried away by the two handlesZ,Z; it may be emptied by the stopcockY, without removing the tub.

Colour-mill

Figs.775,776,777,778.exhibit the construction of a good colour-mill in three views;fig.775.being an elevation shown upon the side of the handle, or where the power is applied to the shaft;fig.776.a second elevation, taken upon the side of the linec,d, of the plan or bird’s-eye view,fig.777.

The frame-workA Aof the mill is made of wood or cast iron, strongly mortised or bolted together; and strengthened by the two cross iron barsB,B.Fig.778.is a plan of the millstones. The lying or nether millstoneC,fig.776, is of cast iron, and is channelled on its upper face like corn millstones. It is fixed upon the two iron barsB,B; but may be preferably supported upon the 3 points of adjustable screws, passing up through bearing-bars. The millstoneCis surrounded by a large iron hoopD, for preventing the pasty-consistenced colour from running over the edge. It can escape only by the sluice holeE,fig.776., formed in the hoop; and is then received in the tubXplaced beneath.

The upper or moving millstoneF, is also made of cast iron. The dotted lines indicate its shape. In the centre it has an aperture with ledgesG,G; there is also a ledge upon its outer circumference, sufficiently high to confine the colour which may occasionally accumulate upon its surface. An upright iron shaftHpasses into the turning stone, and gives motion to it. A horizontal iron bevel wheelK,figs.776,777., furnished with 27 wooden teeth, is fixed upon the upper end of the upright shaftH. A similar bevel wheelL, having the same number of teeth, is placed vertically upon the horizontal iron axisM,M, and works into the wheelK. This horizontal axisM,Mbears, at one of its ends, a handle or winchN, by which the workman may turn the millstoneF; and on the other end of the same axis, the fly-wheelOis made fast, which serves to regulate the movements of the machine. Upon one of the spokes of the fly-wheel there is fixed, in like manner, a handleP, which may serve upon occasion for turning the mill. This handle may be attached at any convenient distance from the centre, by means of the slot and screw-nutJ.

The colour to be ground is put into the hopperR, below which the bucketSis suspended, for supplying the colour uniformly through the orifice in the millstoneG. A cord or chainT, by means of which the bucketSis suspended at a proper height for pouring out the requisite quantity of colour between the stones, pulls the bucket obliquely, and makes its beak rest against the square upright shaftH. By this means the bucket is continually agitated in such a way as to discharge more or less colour, according to its degree of inclination. The copper cisternX, receives the colour successively as it is ground; and, when full, it may be carried away by the two handlesZ,Z; it may be emptied by the stopcockY, without removing the tub.

PAINTS, VITRIFIABLE. SeePorcelain,Pottery, andStained Glass.

PALLADIUM; a rare metal, possessed of valuable properties; was discovered in 1803, by Dr. Wollaston, in native platinum. It constitutes about 1 per cent. of the Columbian ore, and from1⁄4to 1 per cent. of the Uralian ore of this metal; occurring nearly pure in loose grains, of a steel-gray colour, passing into silver white, and of a specific gravity of from 11·8 to 12·14; also as an alloy with gold in Brazil, and combined with selenium in the Harz near Tilkerode. Into the nitro-muriatic solution of native platinum, if a solution of cyanide of mercury be poured, the pale yellow cyanide of palladium will be thrown down, which being ignited affords the metal. This is the ingenious process of Dr. Wollaston. The palladium present in the Brazilian gold ore may be readily separated as follows: melt the ore along with 2 or 3 parts of silver, granulate the alloy, and digest it with heat in nitric acid of specific gravity 1·3. The solution containing the silver and palladium, for the gold does not dissolve, being treated with common salt or muriatic acid, will part with all its silver in the form of a chloride. The supernatant liquor being concentrated and neutralized with ammonia, will yield a rose-coloured salt in long silky crystals, the ammonia-muriate of palladium, which being washed in ice-cold water, and ignited, will afford 40 per cent. of metal.The metal obtained by this process is purer than that by the former; and if it be fused in a crucible along with borax, by the heat of a powerful air-furnace or forge, a button of malleable and ductile palladium will be produced. When a slip of it is heated to redness, it takes a bronze-blue shade of greater or less intensity, as the slip is cooled more or less slowly; but if it be suddenly chilled, as by plunging it into water, it resumes instantly its white lustre. This curious phenomenon depending upon oxidizement and de-oxidizement, in different circumstances, serves at once to distinguish palladium from platinum.Pure palladium resembles platinum, but has more of a silver hue; when planished by the hammer into a cup, such as that of M. Bréant, in the museum of the Mint at Paris, it is a splendid steel-white metal, not liable, like silver, to tarnish in the air. Another cup made by M. Bréant, weighing 2 lbs. (1 kilogramme), was purchased by Charles X., and is now in thegarde-meubleof the French crown. The specific gravity of this metal, when laminated, is stated by Dr. Wollaston at 11·8, and by Vauquelin at 12·1. It melts at from 150° to 160° Wedgewood; and does not oxidize at a white heat. When a drop of tincture of iodine, is let fall upon the surface of this metal, and dissipated over a lamp flame, a black spot remains, which does not happen with platinum. A slip of palladium has been used with advantage to inlay the limbs of astronomical instruments, where the fine graduated lines are cut, because it is bright, and not liable to alteration, like silver.There are a protoxide and peroxide of palladium. The proto-chloride consists of 60 of metal and 40 of chlorine; the cyanide, of 67 of metal, and 33 of cyanogen.

The metal obtained by this process is purer than that by the former; and if it be fused in a crucible along with borax, by the heat of a powerful air-furnace or forge, a button of malleable and ductile palladium will be produced. When a slip of it is heated to redness, it takes a bronze-blue shade of greater or less intensity, as the slip is cooled more or less slowly; but if it be suddenly chilled, as by plunging it into water, it resumes instantly its white lustre. This curious phenomenon depending upon oxidizement and de-oxidizement, in different circumstances, serves at once to distinguish palladium from platinum.

Pure palladium resembles platinum, but has more of a silver hue; when planished by the hammer into a cup, such as that of M. Bréant, in the museum of the Mint at Paris, it is a splendid steel-white metal, not liable, like silver, to tarnish in the air. Another cup made by M. Bréant, weighing 2 lbs. (1 kilogramme), was purchased by Charles X., and is now in thegarde-meubleof the French crown. The specific gravity of this metal, when laminated, is stated by Dr. Wollaston at 11·8, and by Vauquelin at 12·1. It melts at from 150° to 160° Wedgewood; and does not oxidize at a white heat. When a drop of tincture of iodine, is let fall upon the surface of this metal, and dissipated over a lamp flame, a black spot remains, which does not happen with platinum. A slip of palladium has been used with advantage to inlay the limbs of astronomical instruments, where the fine graduated lines are cut, because it is bright, and not liable to alteration, like silver.

There are a protoxide and peroxide of palladium. The proto-chloride consists of 60 of metal and 40 of chlorine; the cyanide, of 67 of metal, and 33 of cyanogen.

PALM OIL (Huile de palme, Fr.;Palmöl, Germ.); is obtained, in Guinea and Guyana, by expressing, as also by boiling, the fruit of theavoira elais. It has an orange colour, a smell of violets, a bland taste, is lighter than water, melts at 84° Fahr., becomes rancid and pale by exposure to air, dissolves in boiling alcohol, and consists of 69 parts of oleine, and 31 of stearine, in 100. It is employed chiefly for making yellowsoap. It may be bleached by the action of either chlorine or oxygen gas, as also by that of light and heat.Palm oil, quantity of,Imported.Retained forconsumption.Exported.Year.Cwts.Cwts.Cwts.1835.260,151242,73330,9151836.277,017234,35734,3791837.223,329214,000Duty, 1s.3d.per cwt.

Palm oil, quantity of,

Duty, 1s.3d.per cwt.

PAPER CUTTING. Mr. T. B. Crompton, of Farnworth, Lancashire, who obtained a patent in May, 1821, for proposing to conduct the newly formed web of paper in the Fourdrinier machine over heated cylinders, for the purpose of drying it expeditiously, in imitation of the mode so long practised in drying calicoes, obtained, along with Enoch Miller, another, in May, 1828, for cutting the endless web of paper lengthwise, by revolving circular blades, fixed upon a roller, parallel to a cylinder, round which the paper is lapped, and progressively unwound.A patent had been obtained two months before, for certain improvements in cutting paper, by Mr. Edward Cowper, consisting of a machine, with a reel on which the web of paper of very considerable length has been previously wound, in the act of being made in a Fourdrinier’s machine; this web of paper being of sufficient width to produce two, three, or more sheets, when cut.The several operative parts of the machine are mounted upon standards, or frame-work, of any convenient form or dimensions, and consist: of travelling endless tapes to conduct the paper over and under a series of guide rollers; of circular rotatory cutters for the purpose of separating the web of paper into strips equal to the widths of the intended sheets; and of a saw-edged knife, which is made to slide horizontally for the purpose of separating the strips into such portions or lengths as shall bring them to the dimensions of a sheet of paper.Paper cutting machineThe end of the web of paper from the reela,fig.779.is first conducted up an inclined planebby hand; it is then taken hold of by endless tapes extended upon rollers, as in Mr. Cowper’sPrinting Machine, which see. These endless tapes carry the web of paper to the rollerc, which is pressed against the rollerdby weighted levers, acting upon the plummer blocks that its axle is mounted in. The second rollerdmay be either of wood or metal, having several grooves formed round its periphery for the purpose of receiving the edges of the circular cutterse, (seeCard-cutting) mounted upon an axle turning upon bearings in the standards or frame.In order to allow the web of paper to proceed smoothly between the two rollersc,d, a narrow rib of leather is placed round the edges of one or both of these rollers, for the purpose of leaving a free space between them, through which the paper may pass without wrinkling.From the first rollerc, the endless tapes conduct the paper over the secondd, and then under a pressing rollerf, in which progress the edges of the circular knivese, revolving in the grooves of the second rollerd, cut the web of paper longitudinally into strips of suchwidths as may be required, according to the number of the circular cutters and distances between them.The strips of paper proceed onward from between the knife rollerdand pressing rollerf, conducted by tapes, until they reach a fourth rollerg, when they are allowed to descend, and to pass through the apparatus designed to cut them transversely; that is, into sheet lengths.The apparatus for cutting the strips into sheets is a sliding knife, placed horizontally upon a frame ath, which frame, with the knifee, is moved to and fro by a jointed rodi, connected to a crank on the axle of the pulleyk. A flat board or platelis fixed to the standard frame in an upright position, across the entire width of the machine; and this board or plate has a groove or opening cut along it opposite to the edge of the knife. The paper descending from the fourth rollergpasses against the face of this board, and as the carriage with the knife advances, two small blocks, mounted upon rods with springsm m, come against the paper, and hold it tight to the board or platel, while the edge of the knife is protruded forward into the groove of that board or plate, and its sharp saw-shaped teeth passing through the paper, cut one row of sheets from the descending strips; which, on the withdrawing of the blocks, falls down, and is collected on the heap below.The power for actuating this machine is applied to the reverse end of the axle, on which the pulleykis fixed, and a bandn,n,n,n, passing from this pulley over tension wheelso, drives the wheelqfixed to the axle of the knife rollerd; hence this roller receives the rotatory motion which causes it to conduct forward the web of paper, but the other rollerscandf, are impelled solely by the friction of contact.The rotation of the crank on the axle ofk, through the intervention of the crank-rodi, moves the carriageh, with the knife, to and fro at certain periods, and when the spring blocksmcome against the grooved platel, they slide their guide rods into them, while the knife advances to sever the sheets of paper. But as sheets of different dimensions are occasionally required, the lengths of the slips delivered between each return of the knife are to be regulated by enlarging or diminishing the diameter of the pulleyk, which will of course retard or facilitate the rotation of the three conducting rollers,c,d,f, and cause a greater or less length of the paper to descend between each movement of the knife carriage.The groove of this pulleyk, which is susceptible of enlargement, is constructed of wedge-formed blocks passed through its sides, and meeting each other in opposite directions, so that on drawing out the wedges a short distance, the diameter of the pulley becomes diminished; or by pushing the wedges further in, the diameter is increased; and a tension wheelpbeing suspended in a weighted frame, keeps the band always tight.As it is necessary that the paper should not continue descending while it is held by the blocksm,mto be cut, and yet that it should be led on progressively over the knife rollerd, the fourth rollerg, which hangs in a leverj, is made to rise at that time, so as to take up the length of paper delivered, and to descend again when the paper is withdrawn. This is effected by a rodr, connected to the crank on the shaft of the aforesaid rollerk, and also to the under part of the leverj, which lever hanging loosely upon the axle of the knife rollerd, as its fulcrum, vibrates with the under rollerg, so as to effect the object in the way described.The patentee states that several individual parts of this machine are not new, and that some of them are to be found included in the specifications of other persons, such as the circular cutterse, which are employed by Mr. Dickinson (Card-cutting), and the horizontal cutterh, by Mr. Hansard; he therefore claims only the general arrangement of the parts in the form of a machine for the purpose of cutting paper, as the subject of his invention.Paper cutting machineThe machine for cutting paper contrived by John Dickinson, Esq. of Nash Mill, was patented in January, 1829. The paper is wound upon a cylindrical rollera,fig.780., mounted upon an axle, supported in an iron frame or standard. From this roller the paper in its breadth is extended over a conducting drumb, also mounted upon an axle turning in the frame or standard, and after passing under a small guide roller, it proceeds through a pair of drawing or feeding rollersc, which carry it into the cutting machine.Upon a tabled,d, firmly fixed to the floor of the building, there is a series of chisel-edged knivese,e,e, placed at such distances apart as the dimensions of the cut sheets of paper are intended to be. These knives are made fast to the table, and against them a series of circular cuttersf,f,f, mounted in a swinging frameg,g, are intended to act. The length of paper being brought along the table over the edges of the knives, up to a stoph, the cutters are then swung forwards, and by passing over the paper against the stationary knives, the length of paper becomes cut into three separate sheets.The frameg,g, which carries the circular cuttersf,f,f, hangs upon a very elevated axle, in order that its pendulous swing may move the cutters as nearly in a horizontal line as possible; and it is made to vibrate to and fro by an eccentric, or crank, fixed upon a horizontal rotatory shaft extending over the drumb, considerably above it, which may be driven by any convenient machinery.The workmen draw the paper from between the rollersc, and bring it up to the stoph, in the intervals between the passing to and fro of the swing-cutters.The following very ingenious apparatus for cutting the paper web transversely into any desired lengths, was made the subject of a patent by Mr. E. N. Fourdrinier, in June, 1831, and has since been performing its duty well in many establishments.Paper cutting apparatusPaper cutting apparatusFig.781.is an elevation, taken upon one side of the machine; andfig.782.is a longitudinal section.a,a,a,a, are four reels, each covered with one continuous sheet of paper; which reels are supported upon bearings in the frame-workb,b,b.c,c,c, is an endless web of felt-cloth passed over the rollersd,d,d,d, which is kept in close contact with the under side of the drume,e, seen best infig.782.The several parallel layers of paper to be cut, being passed between the drume, and the endless feltc, will be drawn off their respective reels, and fed into the machine, whenever the driving-band is slid from the loose to the fast pulley upon the end of the main shaftf. But since the progressive advance of the paper-webs must be arrested during the time of making the cross cut through it, the following apparatus becomes necessary. A discg, which carries the pin or stud of a cranki, is made fast to the end of the driving shaftf. This pin is set in an adjustable sliding piece, which may be confined by a screw within the bevelled graduated groove, upon the face of the discg, at variable distances from the axis, whereby the eccentricity of the studi, and of course the throw of the crank, may be considerably varied. The crank studiis connected by its rodj, to the swinging curvilinear rackk, which takes into the toothed wheell, that turns freely upon the axle of the feed drume,e. From that wheel the armsm,m, rise, and bear one or more pallsn, which work in the teeth of the great ratchet wheelo,o, mounted upon the shaft of the drume.Moveable bladeThe crank-plategbeing driven round in the direction of its arrow, will communicate a see-saw movement to the toothed arck, next to the toothed wheellin gearing with it, and an oscillatory motion to the armsm,m, as also to their surmounting palln.In its swing to the left hand, the catch of the pall will slide over the slope of the teeth of the ratchet wheelo; but in its return to the right hand, it will lay hold of these teeth, and pull them, with their attached drum, round a part of a revolution. The layers of paper in close contact with the under half of the drum will be thus drawn forward at intervals, from the reels, by the friction between its surface and the endless felt, and in lengths corresponding to the arc of vibration of the pall. The knife for cutting these lengths transversely is brought into action at the time when the swing arc is making its inactive stroke, viz., when it is sliding to the left over the slopes of the ratchet teetho. The extent of this vibration varies according to the distance of the crank studi, from the centref, of the plateg, because that distance regulates the extent of the oscillations of the curvilinear rack, and that of the rotation of the drume, by which the paper is fed forwards to the knife apparatus. The proper length of its several layers being by the above described mechanism carried forward over the bedrof the cutting knife or shearsr,v, whose under bladeris fixed, the wipers, in its revolution with the shaftf, lifts the tail of the levert, consequently depresses the transverse movable bladev(as shown infig.783.), and slides the slanting blades across each other obliquely, like a pair of scissors, so as to cause a clean cut across the plies of paper. But just before the shears begin to operate, the transverse boardudescends to press the paper with its edge, and hold it fast upon the bedr. During the action of the upper bladev, against the underr, the fall boardu, is suspended by a cord passing across pullies from the armyof the bell-crank levert,t. Whenever the lifter cams, has passed away from the tail of the bell-crankt, the weightz, hung upon it, will cause the bladev, and the pinching boardu, to be moved up out of the way of the next length of paper, which is regularly brought forward by the rotation of the drume, as above described. The upper blade of the shears is not set parallel to the shaft of the drum, but obliquely to it, and is, moreover, somewhat curved, so as to close its edge progressively upon that of the fixed blade. The bladevmay also be set between two guide pieces, and have the necessary motion given to it by levers.

A patent had been obtained two months before, for certain improvements in cutting paper, by Mr. Edward Cowper, consisting of a machine, with a reel on which the web of paper of very considerable length has been previously wound, in the act of being made in a Fourdrinier’s machine; this web of paper being of sufficient width to produce two, three, or more sheets, when cut.

The several operative parts of the machine are mounted upon standards, or frame-work, of any convenient form or dimensions, and consist: of travelling endless tapes to conduct the paper over and under a series of guide rollers; of circular rotatory cutters for the purpose of separating the web of paper into strips equal to the widths of the intended sheets; and of a saw-edged knife, which is made to slide horizontally for the purpose of separating the strips into such portions or lengths as shall bring them to the dimensions of a sheet of paper.

Paper cutting machine

The end of the web of paper from the reela,fig.779.is first conducted up an inclined planebby hand; it is then taken hold of by endless tapes extended upon rollers, as in Mr. Cowper’sPrinting Machine, which see. These endless tapes carry the web of paper to the rollerc, which is pressed against the rollerdby weighted levers, acting upon the plummer blocks that its axle is mounted in. The second rollerdmay be either of wood or metal, having several grooves formed round its periphery for the purpose of receiving the edges of the circular cutterse, (seeCard-cutting) mounted upon an axle turning upon bearings in the standards or frame.

In order to allow the web of paper to proceed smoothly between the two rollersc,d, a narrow rib of leather is placed round the edges of one or both of these rollers, for the purpose of leaving a free space between them, through which the paper may pass without wrinkling.

From the first rollerc, the endless tapes conduct the paper over the secondd, and then under a pressing rollerf, in which progress the edges of the circular knivese, revolving in the grooves of the second rollerd, cut the web of paper longitudinally into strips of suchwidths as may be required, according to the number of the circular cutters and distances between them.

The strips of paper proceed onward from between the knife rollerdand pressing rollerf, conducted by tapes, until they reach a fourth rollerg, when they are allowed to descend, and to pass through the apparatus designed to cut them transversely; that is, into sheet lengths.

The apparatus for cutting the strips into sheets is a sliding knife, placed horizontally upon a frame ath, which frame, with the knifee, is moved to and fro by a jointed rodi, connected to a crank on the axle of the pulleyk. A flat board or platelis fixed to the standard frame in an upright position, across the entire width of the machine; and this board or plate has a groove or opening cut along it opposite to the edge of the knife. The paper descending from the fourth rollergpasses against the face of this board, and as the carriage with the knife advances, two small blocks, mounted upon rods with springsm m, come against the paper, and hold it tight to the board or platel, while the edge of the knife is protruded forward into the groove of that board or plate, and its sharp saw-shaped teeth passing through the paper, cut one row of sheets from the descending strips; which, on the withdrawing of the blocks, falls down, and is collected on the heap below.

The power for actuating this machine is applied to the reverse end of the axle, on which the pulleykis fixed, and a bandn,n,n,n, passing from this pulley over tension wheelso, drives the wheelqfixed to the axle of the knife rollerd; hence this roller receives the rotatory motion which causes it to conduct forward the web of paper, but the other rollerscandf, are impelled solely by the friction of contact.

The rotation of the crank on the axle ofk, through the intervention of the crank-rodi, moves the carriageh, with the knife, to and fro at certain periods, and when the spring blocksmcome against the grooved platel, they slide their guide rods into them, while the knife advances to sever the sheets of paper. But as sheets of different dimensions are occasionally required, the lengths of the slips delivered between each return of the knife are to be regulated by enlarging or diminishing the diameter of the pulleyk, which will of course retard or facilitate the rotation of the three conducting rollers,c,d,f, and cause a greater or less length of the paper to descend between each movement of the knife carriage.

The groove of this pulleyk, which is susceptible of enlargement, is constructed of wedge-formed blocks passed through its sides, and meeting each other in opposite directions, so that on drawing out the wedges a short distance, the diameter of the pulley becomes diminished; or by pushing the wedges further in, the diameter is increased; and a tension wheelpbeing suspended in a weighted frame, keeps the band always tight.

As it is necessary that the paper should not continue descending while it is held by the blocksm,mto be cut, and yet that it should be led on progressively over the knife rollerd, the fourth rollerg, which hangs in a leverj, is made to rise at that time, so as to take up the length of paper delivered, and to descend again when the paper is withdrawn. This is effected by a rodr, connected to the crank on the shaft of the aforesaid rollerk, and also to the under part of the leverj, which lever hanging loosely upon the axle of the knife rollerd, as its fulcrum, vibrates with the under rollerg, so as to effect the object in the way described.

The patentee states that several individual parts of this machine are not new, and that some of them are to be found included in the specifications of other persons, such as the circular cutterse, which are employed by Mr. Dickinson (Card-cutting), and the horizontal cutterh, by Mr. Hansard; he therefore claims only the general arrangement of the parts in the form of a machine for the purpose of cutting paper, as the subject of his invention.

Paper cutting machine

The machine for cutting paper contrived by John Dickinson, Esq. of Nash Mill, was patented in January, 1829. The paper is wound upon a cylindrical rollera,fig.780., mounted upon an axle, supported in an iron frame or standard. From this roller the paper in its breadth is extended over a conducting drumb, also mounted upon an axle turning in the frame or standard, and after passing under a small guide roller, it proceeds through a pair of drawing or feeding rollersc, which carry it into the cutting machine.

Upon a tabled,d, firmly fixed to the floor of the building, there is a series of chisel-edged knivese,e,e, placed at such distances apart as the dimensions of the cut sheets of paper are intended to be. These knives are made fast to the table, and against them a series of circular cuttersf,f,f, mounted in a swinging frameg,g, are intended to act. The length of paper being brought along the table over the edges of the knives, up to a stoph, the cutters are then swung forwards, and by passing over the paper against the stationary knives, the length of paper becomes cut into three separate sheets.

The frameg,g, which carries the circular cuttersf,f,f, hangs upon a very elevated axle, in order that its pendulous swing may move the cutters as nearly in a horizontal line as possible; and it is made to vibrate to and fro by an eccentric, or crank, fixed upon a horizontal rotatory shaft extending over the drumb, considerably above it, which may be driven by any convenient machinery.

The workmen draw the paper from between the rollersc, and bring it up to the stoph, in the intervals between the passing to and fro of the swing-cutters.

The following very ingenious apparatus for cutting the paper web transversely into any desired lengths, was made the subject of a patent by Mr. E. N. Fourdrinier, in June, 1831, and has since been performing its duty well in many establishments.

Paper cutting apparatus

Fig.781.is an elevation, taken upon one side of the machine; andfig.782.is a longitudinal section.a,a,a,a, are four reels, each covered with one continuous sheet of paper; which reels are supported upon bearings in the frame-workb,b,b.c,c,c, is an endless web of felt-cloth passed over the rollersd,d,d,d, which is kept in close contact with the under side of the drume,e, seen best infig.782.

The several parallel layers of paper to be cut, being passed between the drume, and the endless feltc, will be drawn off their respective reels, and fed into the machine, whenever the driving-band is slid from the loose to the fast pulley upon the end of the main shaftf. But since the progressive advance of the paper-webs must be arrested during the time of making the cross cut through it, the following apparatus becomes necessary. A discg, which carries the pin or stud of a cranki, is made fast to the end of the driving shaftf. This pin is set in an adjustable sliding piece, which may be confined by a screw within the bevelled graduated groove, upon the face of the discg, at variable distances from the axis, whereby the eccentricity of the studi, and of course the throw of the crank, may be considerably varied. The crank studiis connected by its rodj, to the swinging curvilinear rackk, which takes into the toothed wheell, that turns freely upon the axle of the feed drume,e. From that wheel the armsm,m, rise, and bear one or more pallsn, which work in the teeth of the great ratchet wheelo,o, mounted upon the shaft of the drume.

Moveable blade

The crank-plategbeing driven round in the direction of its arrow, will communicate a see-saw movement to the toothed arck, next to the toothed wheellin gearing with it, and an oscillatory motion to the armsm,m, as also to their surmounting palln.In its swing to the left hand, the catch of the pall will slide over the slope of the teeth of the ratchet wheelo; but in its return to the right hand, it will lay hold of these teeth, and pull them, with their attached drum, round a part of a revolution. The layers of paper in close contact with the under half of the drum will be thus drawn forward at intervals, from the reels, by the friction between its surface and the endless felt, and in lengths corresponding to the arc of vibration of the pall. The knife for cutting these lengths transversely is brought into action at the time when the swing arc is making its inactive stroke, viz., when it is sliding to the left over the slopes of the ratchet teetho. The extent of this vibration varies according to the distance of the crank studi, from the centref, of the plateg, because that distance regulates the extent of the oscillations of the curvilinear rack, and that of the rotation of the drume, by which the paper is fed forwards to the knife apparatus. The proper length of its several layers being by the above described mechanism carried forward over the bedrof the cutting knife or shearsr,v, whose under bladeris fixed, the wipers, in its revolution with the shaftf, lifts the tail of the levert, consequently depresses the transverse movable bladev(as shown infig.783.), and slides the slanting blades across each other obliquely, like a pair of scissors, so as to cause a clean cut across the plies of paper. But just before the shears begin to operate, the transverse boardudescends to press the paper with its edge, and hold it fast upon the bedr. During the action of the upper bladev, against the underr, the fall boardu, is suspended by a cord passing across pullies from the armyof the bell-crank levert,t. Whenever the lifter cams, has passed away from the tail of the bell-crankt, the weightz, hung upon it, will cause the bladev, and the pinching boardu, to be moved up out of the way of the next length of paper, which is regularly brought forward by the rotation of the drume, as above described. The upper blade of the shears is not set parallel to the shaft of the drum, but obliquely to it, and is, moreover, somewhat curved, so as to close its edge progressively upon that of the fixed blade. The bladevmay also be set between two guide pieces, and have the necessary motion given to it by levers.

PAPER-HANGINGS, called more properly by the French,papiers peints. The art of making paper-hangings,papier de tenture, has been copied from the Chinese, among whom it has been practised from time immemorial. The English first imported and began to imitate the Chinese paper-hangings; but being exposed till very lately to a high excise duty upon the manufacture, they have not carried it to that extent and pitch of refinement which the French genius has been enabled to do, unchecked by taxation. The first method of making this paper was stencilling; by laying upon it, in an extended state, a piece of pasteboard having spaces cut out of various figured devices, and applying different water colours with the brush. Another piece of pasteboard with other patterns cut out was next applied, when the former figures were dry, and new designs were thus imparted. By a series of such operations, a tolerable pattern was executed, but with no little labour and expense. The processes of the calico printer were next resorted to, in which engraved blocks of the pear or sycamore were employed to impress the coloured designs.Paper-hangings may be distinguished into two classes; 1. those which are really painted, and which are designed in France under the title ofpapiers peints, with brilliant flowers and figures; and 2. those in which the designs are formed by foreign matters applied to the paper, under the name ofpapier tontisse, or flock paper.The operations common to paper-hangings, of both kinds, may be stated as follows:—1. The paper should be well sized.2. The edges should be evenly cut by an apparatus like the bookbinder’s press.3. The ends of each of the 24 sheets which form a piece, should be nicely pasted together; or a Fourdrinier web of paper should be taken.4. Laying the grounds, is done with earthy colours or coloured lakes thickened with size, and applied with brushes.An expert workman, with one or two children, can lay the grounds of 300 pieces in a day. The pieces are now suspended upon poles near the ceiling, in order to be dried. They are then rolled up and carried to the apartment where they are polished, by being laid upon a smooth table, with the painted side undermost, and rubbed with the polisher. Pieces intended to be satined, are grounded with fine Paris plaster, instead of Spanish white; and are not smoothed with a brass polisher, but with a hard brush attached to the lower end of the swing polishing rod. After spreading the piece upon the table with the grounded side undermost, the paper-stainer dusts the upper surface with finely powdered chalk of Briançon, commonly called talc, and rubs it strongly with the brush. In this way the satiny lustre is produced.THE PRINTING OPERATIONS.Blocks about two inches thick, formed of three separate boards glued together, of which two are made of poplar, and one (that which is engraved) of pear-tree or sycamore,are used for printing paper-hangings, as for calicoes. The grain of the upper layer of wood should be laid across that of the layer below. As many blocks are required as there are colours and shades of colour. To make the figure of a rose, for example, three several reds must be applied in succession, the one deeper than the other, a white for the clear spaces, two and sometimes three greens for the leaves, and two wood colours for the stems; altogether from 9 to 12 for a rose. Each block carries small pin points fixed at its corners to guide the workman in the insertion of the figure exactly in its place. An expert hand places these guide pins so that their marks are covered and concealed by the impression of the next block; and the finished piece shows merely those belonging to the first and last blocks.In printing, the workman employs the sameswimming-tubapparatus which has been described under block printing (seeCalico-printing), takes off the colour upon his blocks, and impresses them on the paper extended upon a table in the very same way. The tub in which the drum or frame covered with calf-skin is inverted, contains simply water thickened with parings of paper from the bookbinder, instead of the pasty mixture employed by the calico-printers. In impressing the colour by the block upon the paper, he employs a lever of the second kind, to increase the power of his arm, making it act upon the block through the intervention of a piece of wood, shaped like the bridge of a violin. This tool is calledtasseauby the French. A child is constantly occupied in spreading colour with a brush upon the calf-skin head of the drum or sieve, and in sliding off the paper upon a wooden trestle or horse, in proportion as it is finished. When the piece has received one set of coloured impressions, the workman, assisted by his little aid called atireur(drawer), hooks it upon the drying-poles under the ceiling. A sufficient number of pieces should be provided to keep the printer occupied during the whole at least of one day, so that they will be dried and ready to receive another set of coloured impressions by the following morning.All the colours are applied in the same manner, every shade being formed by means of the blocks, which determine all the beauty and regularity of the design. A pattern drawer of taste may produce a very beautiful effect. The history of Psyche and Cupid, by M. Dufour, has been considered a masterpiece in this art, rivalling the productions of the pencil in the gradation, softness, and brilliancy of the tints.When the piece is completely printed, the workman looks it all over, and if there be any defects, he corrects them by the brush or pencil, applying first the correction of one colour, and afterwards of the rest.A final satining, after the colours are dried, is communicated by the friction of a finely polished brass roller, attached by its end gudgeons to the lower extremity of a long swing-frame; and acting along the cylindrical surface of a smooth table, upon which the paper is spread.Oblong brushThefonduor rainbow style of paper-hangings, which I have referred to this place in the articleCalico-printing, is produced by means of an assortment of oblong narrow tin pans, fixed in a frame, close side to side, each being about one inch wide, two inches deep, and eight inches long; the colours of the prismatic spectrum, red, orange, yellow, green, &c., are put, in a liquid state, successively in these pans; so that when the oblong brushA,B, with guide ledgesa,b,c, is dipped into them across the whole of the parallel row at once, it comes out impressed with the different colours at successive pointse,e,e,e, of its length, and is then drawn by the paper-stainer over the face of the woollen drumhead, or sieve of the swimming tub, upon which it leaves a corresponding series of stripes in colours, graduating into one another like those of the prismatic spectrum. By applying his block to thetear, the workman takes up the colour in rainbow hues, and transfers these to the paper.f,f,f,fshow the separate brushes in tin sheaths, set in one frame.At M. Zuber’s magnificent establishment in the antient château of Rixheim, near Mulhouse, where the most beautiful Frenchpapiers peintsare produced, and where I was informed that no less than 3000 blocks are required for one pattern, I saw a two-colour calico machine employed with great advantage, both as to taste and expedition. Steam-charged cylinders were used to dry the paper immediately after it was printed, as the colours, not being so rapidly absorbed as they are by calico, would be very apt to spread.The operations employed for common paper-hangings, are also used for making flock paper, only a stronger size is necessary for the ground. The flocks are obtained from the woollen cloth manufacturers, being cut off by their shearing machines, calledlewisesby the English workmen, and are preferred in a white state by the French paper-hanging makers, who scour them well, and dye them of the proper colours themselves. When they are thoroughly stove-dried, they are put into a conical fluted mill, like that for making snuff, and are properly ground. The powder thus obtained is afterwards sifted by a bolting-machine, like that of a flour mill, whereby flocks of different degrees of fineness are produced. These are applied to the paper after it has undergone all theusual printing operations. Upon the workman’s left hand, and in a line with his printing table, a large chest is placed for receiving the flock powders: it is seven or eight feet long, two feet wide at the bottom, three feet and a half at top, and from 15 to 18 inches deep. It has a hinged lid. Its bottom is made of tense calf-skin. This chest is called thedrum; it rests upon four strong feet, so as to stand from 24 to 28 inches above the floor.The block which serves to apply the adhesive basis of the velvet-powders, bears in relief only the pattern corresponding to that basis, which is formed with linseed oil, rendered drying by being boiled with litharge, and afterwards ground up with white lead. The French workmen call this mordant theencaustic. It is put upon the cloth which covers the inverted swimming tub, in the same way as the common colours are, and is spread with a brush by thetireur(corruptly styledtearerby some English writers). The workman daubs the blocks upon the mordant, spreads the pigment even with a kind of brush, and then applies it by impression to the paper. Whenever a sufficient surface of the paper has been thus covered, the child draws it along into the great chest, sprinkling the flock powder over it with his hands; and when a length of 7 feet is printed, he covers it up within the drum, and beats upon the calf-skin bottom with a couple of rods to raise a cloud of flock inside, and to make it cover the prepared portion of the paper uniformly. He now lifts the lid of the chest, inverts the paper, and beats its back lightly, in order to detach all the loose particles of the woolly powder.By the operation just described, the velvet-down being applied every where of the same colour, would not be agreeable to the eye, if shades could not be introduced to relieve the pattern. To give the effect of drapery, for example, the appearance of folds must be introduced. For this purpose, when the piece is perfectly dry, the workman stretches it upon his table, and by the guidance of the pins in his blocks, he applies to the flock surface a colour in distemper, of a deep tint, suited to the intended shades, so that he dyes the wool in its place. Light shades are produced by applying some of his lighter water-colours.Gold leaf is applied upon the above mordant, when nearly dry; which then forms a proper gold size; and the same method of application is resorted to, as for the ordinary gilding of wood. When the size has become perfectly hard, the superfluous gold leaf is brushed off with a dossil of cotton wool or fine linen.The colours used by the paper-hangers are the following:—1.Whites.These are either white-lead, good whitening, or a mixture of the two.2.Yellows.These are frequently vegetable extracts; as those of weld, or of Avignon or Persian berries, and are made by boiling the substances with water. Chrome yellow is also frequently used, as well as theterra di Siennaand yellow ochre.3.Redsare almost exclusively decoctions of Brazil wood.4.Bluesare either prussian blue, or blue verditer.5.Greens, are Scheele’s green, a combination of arsenious acid, and oxide of copper; the green of Schweinfurth, or green verditer; as also a mixture of blues and yellows.6.Violetsare produced by a mixture of blue and red in various proportions, or they may be obtained directly by mixing a decoction of logwood with alum.7.Browns, blacks, and grays.Umber furnishes the brown tints. Blacks are either common ivory or Frankfort black; and grays are formed by mixtures of prussian blue and Spanish white.All the colours are rendered adhesive and consistent, by being worked up with gelatinous size or a weak solution of glue, liquefied in a kettle. Many of the colours are previously thickened, however, with starch. Sometimes coloured lakes are employed. SeeLakes.

Paper-hangings may be distinguished into two classes; 1. those which are really painted, and which are designed in France under the title ofpapiers peints, with brilliant flowers and figures; and 2. those in which the designs are formed by foreign matters applied to the paper, under the name ofpapier tontisse, or flock paper.

The operations common to paper-hangings, of both kinds, may be stated as follows:—

1. The paper should be well sized.

2. The edges should be evenly cut by an apparatus like the bookbinder’s press.

3. The ends of each of the 24 sheets which form a piece, should be nicely pasted together; or a Fourdrinier web of paper should be taken.

4. Laying the grounds, is done with earthy colours or coloured lakes thickened with size, and applied with brushes.

An expert workman, with one or two children, can lay the grounds of 300 pieces in a day. The pieces are now suspended upon poles near the ceiling, in order to be dried. They are then rolled up and carried to the apartment where they are polished, by being laid upon a smooth table, with the painted side undermost, and rubbed with the polisher. Pieces intended to be satined, are grounded with fine Paris plaster, instead of Spanish white; and are not smoothed with a brass polisher, but with a hard brush attached to the lower end of the swing polishing rod. After spreading the piece upon the table with the grounded side undermost, the paper-stainer dusts the upper surface with finely powdered chalk of Briançon, commonly called talc, and rubs it strongly with the brush. In this way the satiny lustre is produced.

THE PRINTING OPERATIONS.

Blocks about two inches thick, formed of three separate boards glued together, of which two are made of poplar, and one (that which is engraved) of pear-tree or sycamore,are used for printing paper-hangings, as for calicoes. The grain of the upper layer of wood should be laid across that of the layer below. As many blocks are required as there are colours and shades of colour. To make the figure of a rose, for example, three several reds must be applied in succession, the one deeper than the other, a white for the clear spaces, two and sometimes three greens for the leaves, and two wood colours for the stems; altogether from 9 to 12 for a rose. Each block carries small pin points fixed at its corners to guide the workman in the insertion of the figure exactly in its place. An expert hand places these guide pins so that their marks are covered and concealed by the impression of the next block; and the finished piece shows merely those belonging to the first and last blocks.

In printing, the workman employs the sameswimming-tubapparatus which has been described under block printing (seeCalico-printing), takes off the colour upon his blocks, and impresses them on the paper extended upon a table in the very same way. The tub in which the drum or frame covered with calf-skin is inverted, contains simply water thickened with parings of paper from the bookbinder, instead of the pasty mixture employed by the calico-printers. In impressing the colour by the block upon the paper, he employs a lever of the second kind, to increase the power of his arm, making it act upon the block through the intervention of a piece of wood, shaped like the bridge of a violin. This tool is calledtasseauby the French. A child is constantly occupied in spreading colour with a brush upon the calf-skin head of the drum or sieve, and in sliding off the paper upon a wooden trestle or horse, in proportion as it is finished. When the piece has received one set of coloured impressions, the workman, assisted by his little aid called atireur(drawer), hooks it upon the drying-poles under the ceiling. A sufficient number of pieces should be provided to keep the printer occupied during the whole at least of one day, so that they will be dried and ready to receive another set of coloured impressions by the following morning.

All the colours are applied in the same manner, every shade being formed by means of the blocks, which determine all the beauty and regularity of the design. A pattern drawer of taste may produce a very beautiful effect. The history of Psyche and Cupid, by M. Dufour, has been considered a masterpiece in this art, rivalling the productions of the pencil in the gradation, softness, and brilliancy of the tints.

When the piece is completely printed, the workman looks it all over, and if there be any defects, he corrects them by the brush or pencil, applying first the correction of one colour, and afterwards of the rest.

A final satining, after the colours are dried, is communicated by the friction of a finely polished brass roller, attached by its end gudgeons to the lower extremity of a long swing-frame; and acting along the cylindrical surface of a smooth table, upon which the paper is spread.

Oblong brush

Thefonduor rainbow style of paper-hangings, which I have referred to this place in the articleCalico-printing, is produced by means of an assortment of oblong narrow tin pans, fixed in a frame, close side to side, each being about one inch wide, two inches deep, and eight inches long; the colours of the prismatic spectrum, red, orange, yellow, green, &c., are put, in a liquid state, successively in these pans; so that when the oblong brushA,B, with guide ledgesa,b,c, is dipped into them across the whole of the parallel row at once, it comes out impressed with the different colours at successive pointse,e,e,e, of its length, and is then drawn by the paper-stainer over the face of the woollen drumhead, or sieve of the swimming tub, upon which it leaves a corresponding series of stripes in colours, graduating into one another like those of the prismatic spectrum. By applying his block to thetear, the workman takes up the colour in rainbow hues, and transfers these to the paper.f,f,f,fshow the separate brushes in tin sheaths, set in one frame.

At M. Zuber’s magnificent establishment in the antient château of Rixheim, near Mulhouse, where the most beautiful Frenchpapiers peintsare produced, and where I was informed that no less than 3000 blocks are required for one pattern, I saw a two-colour calico machine employed with great advantage, both as to taste and expedition. Steam-charged cylinders were used to dry the paper immediately after it was printed, as the colours, not being so rapidly absorbed as they are by calico, would be very apt to spread.

The operations employed for common paper-hangings, are also used for making flock paper, only a stronger size is necessary for the ground. The flocks are obtained from the woollen cloth manufacturers, being cut off by their shearing machines, calledlewisesby the English workmen, and are preferred in a white state by the French paper-hanging makers, who scour them well, and dye them of the proper colours themselves. When they are thoroughly stove-dried, they are put into a conical fluted mill, like that for making snuff, and are properly ground. The powder thus obtained is afterwards sifted by a bolting-machine, like that of a flour mill, whereby flocks of different degrees of fineness are produced. These are applied to the paper after it has undergone all theusual printing operations. Upon the workman’s left hand, and in a line with his printing table, a large chest is placed for receiving the flock powders: it is seven or eight feet long, two feet wide at the bottom, three feet and a half at top, and from 15 to 18 inches deep. It has a hinged lid. Its bottom is made of tense calf-skin. This chest is called thedrum; it rests upon four strong feet, so as to stand from 24 to 28 inches above the floor.

The block which serves to apply the adhesive basis of the velvet-powders, bears in relief only the pattern corresponding to that basis, which is formed with linseed oil, rendered drying by being boiled with litharge, and afterwards ground up with white lead. The French workmen call this mordant theencaustic. It is put upon the cloth which covers the inverted swimming tub, in the same way as the common colours are, and is spread with a brush by thetireur(corruptly styledtearerby some English writers). The workman daubs the blocks upon the mordant, spreads the pigment even with a kind of brush, and then applies it by impression to the paper. Whenever a sufficient surface of the paper has been thus covered, the child draws it along into the great chest, sprinkling the flock powder over it with his hands; and when a length of 7 feet is printed, he covers it up within the drum, and beats upon the calf-skin bottom with a couple of rods to raise a cloud of flock inside, and to make it cover the prepared portion of the paper uniformly. He now lifts the lid of the chest, inverts the paper, and beats its back lightly, in order to detach all the loose particles of the woolly powder.

By the operation just described, the velvet-down being applied every where of the same colour, would not be agreeable to the eye, if shades could not be introduced to relieve the pattern. To give the effect of drapery, for example, the appearance of folds must be introduced. For this purpose, when the piece is perfectly dry, the workman stretches it upon his table, and by the guidance of the pins in his blocks, he applies to the flock surface a colour in distemper, of a deep tint, suited to the intended shades, so that he dyes the wool in its place. Light shades are produced by applying some of his lighter water-colours.

Gold leaf is applied upon the above mordant, when nearly dry; which then forms a proper gold size; and the same method of application is resorted to, as for the ordinary gilding of wood. When the size has become perfectly hard, the superfluous gold leaf is brushed off with a dossil of cotton wool or fine linen.

The colours used by the paper-hangers are the following:—

1.Whites.These are either white-lead, good whitening, or a mixture of the two.

2.Yellows.These are frequently vegetable extracts; as those of weld, or of Avignon or Persian berries, and are made by boiling the substances with water. Chrome yellow is also frequently used, as well as theterra di Siennaand yellow ochre.

3.Redsare almost exclusively decoctions of Brazil wood.

4.Bluesare either prussian blue, or blue verditer.

5.Greens, are Scheele’s green, a combination of arsenious acid, and oxide of copper; the green of Schweinfurth, or green verditer; as also a mixture of blues and yellows.

6.Violetsare produced by a mixture of blue and red in various proportions, or they may be obtained directly by mixing a decoction of logwood with alum.

7.Browns, blacks, and grays.Umber furnishes the brown tints. Blacks are either common ivory or Frankfort black; and grays are formed by mixtures of prussian blue and Spanish white.

All the colours are rendered adhesive and consistent, by being worked up with gelatinous size or a weak solution of glue, liquefied in a kettle. Many of the colours are previously thickened, however, with starch. Sometimes coloured lakes are employed. SeeLakes.

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