Dyeing, generally signifies the art of tinging cloth, stuff, or other matter, with a permanent colour, by penetrating its sub-Stance. It is, however, usually confined to the art of imparting different colours to wool, silk, linen and cloth.
The materials for dyeing are so various and numerous, that our limits oblige us to be concise. The .same difference, indeed, prevails among the dyeing, as among the colouring matters. Some ingredi-ents produce durable colours, which cannot be discharged, either by exposure to air, or by washing with soap. Others, though they may withstand the action of soap, cannot resist that of the air. These are distinguished by the different appellations of true and false, per-manent and fading, etc.; nor has any method been hitherto discovered, of imparting to false colours a durability, equal to that of the true ones.
This object has often been attempted, by combining a permanent with a fading colour, in the expectation that the former would communicate some portion of its durability to the latter; which nevertheless uniformly faded, heav-ing the cloth dyed with the perma-nent colour. In some cases, however, which have been already ex-plained, the volatile colour imparts its property to that which would otherwise continue in a fixed state. A solution of tin in aqua regia will, it is affirmed, give to many the fading colours a high degree beauty, and some portion of dura-' bility, though much inferior to others.
The most permanent dyes we have, are cochineal and gum-for fine red and scarlet colours ; indigo and woad, for blue; and, when mixed with different pro-portions of cochineal, or gum-lac, for purple and violet colours.— Dyers-weed, and some other v tables, for yellow ; and madder for coarse reds, purples, and blacks. The fading colours are far more numerous, and include Brazil-wood, logwood, red-wood, fustic, turmeric root, anotto, archil, etc.
The whole of the operative part of dyeing depends on the application of certain colours, which the workmen call primitive, and which are five in number, namely, blue, red, yellow, fawn, or root-colour, and black. Eachof these furnishes a- variety of intermediate shades, both according to the nature of the ingredients, and the acid or alkaline substances with which they are mixed. Two only of these five colours, should be prepared with ingredients producing no colour of themselves ; but which, by then-peculiar acidity, and the fineness of the earth they contain, dispose the pores of the substance to re-ceive the dye. The colours which more particularly require such auxiliary process, are red and low, together with those derived from them. Black is obtained by a particular preparation ; but blue and faun colour require none, at least for wool; it being only neary to scour and soak this sub-stance well; then to immerse it in the dyeing vat, stirring it well about, and permitting it to remain for a longer or shorter time, in proportion as the colour is intended to be more or less deep. - The ingredients used in dyeing blue consist of pastel, woad, and indigo.
1. Pastel (Isatis tinctoria), is prepared by gathering it when ripe, suffering it to rot, and then working it up into balls for drying ; winch weigh in general from 150 to 200 pounds, and resemble a collection of small dry lumps of earth, intermixed with the fibres of plants. In order to extract the colour, it is necessary to provide large wooden vats, from 12 to 16 in diameter, and 6 or 7 feet high, or of a magnitude proportioned to the quantity intended to be
The preparation of the bine-Tat is the most difficult process in the art of dyeing; and the practi-cal directions given by those who understand it, are either defective, or- mis-stated. - The copper-cauldron should be placed as near to the vat as possible, and tilled with pond-water ; to which, if it be not sufficiently putrid, may be added 2 or 3 pounds of hay, together with. 8 pounds of brown madder, or of the bark of the root. The fire should be lighted about three o'clock in the morning, and the mixture boil for an hour and a half, or two hours, when the liquor is, by means of a spout, conveyed into the vat, in which a peck of wheaten bran is previously in-fused. The pastel-balls are next to be put in, separately, while the liquor is running into the vat, in order that they may be the more easily broken and stirred with the rake, which is a semi - circular wooden instrument, having a long handle. The mixture is occasionally agitated, till the vat has re-ceived all the hot liquor; and, as soon as the vessel is nearly half full, it should be covered with a ltd, somewhat larger than its own circumference. A cloth should be likewise thrown over it, in order to confine the heat; after which the whole should be suffered to subside for four hours ; when it ought to be uncovered, in order to give it air, and to mix it thoroughly. No lime, as is generally, though falsely directed by dyers, should be put into the vat, but a small air-hole left on the top : the stirring and agitation may once more be repeated, at the expiration of three or four hours.
If the ingredients, after these operations, be not yet ready and come to, that is, if the blue does not rise to the surface, but continues to foam, it will then be necessary, after working the mixture well, to let it stand an hour and a halt longer; care being, taken during that time to observe it minutely, in case it should cast blue. The vat is then to be filled up with water, and a sufficient quantity of indigo, dissolved in a ley of pot-ash, pure water, bran and madder. The vat being again covered, at the end of three hours a pattern is to be immersed in the liquor for a similar space of time, when it is to be taken out, to inspect the state of the vat. This pattern, when first taken out, should be of a green colour, but instantly turn blue; if the green be bright and good, the vat is to be stirred again, and then covered up, with the addition of a few handfuls of bran. Three hours after, the same operation is to be repeated, with the addition of more bran, if necessary, when it is to be covered up for an hour and a half longer; and, as soon as it subsides, another specimen is to be immersed in it for an hour, when it must be examined, to ascertain the stale of the pastel. If the former be of a good green, when taken out, and turn suddenly to a deep blue, on being exposed to the air, another pattern is to be put in, to discover the effect, of the vat; which, if the colour be sufficiently high, is to be tilled with hot water, or (which is preferable, if it can be procured), with the liquor of an old madder-vat, and then stirred again. Now the vat is to be once more covered for an hour ; after which the stuffs to be dyed should be immers( d.
Woad is the next article in the making of a blue colour : the mode of preparing it differs in no respect from the preceding one, just described, excepting that it is weaker, and yields less colour.
Indigo is the last ingredient in dyeing blues. The vat is about 5 feet high, 2 feet in diameter, and somewhat narrower towards the bottom. being surrounded by a wall, and having a vacancy for the embers. A vat of this size requires from 2 to 5, or even (6lbs. of indigo ; and this operation is conducted as follows : 1. About 15 gallons of river water are put into a copper to boil for about halfanhour, together with 2lbs. of pot-ash, 2 oz. of madder, and a handful of bran. 2. Immerse 2lbs. of indigo in apail of cold water, in order to separate the solid from the volatile particles, which will immediately rise to the surface. The watery liquor is then poured off, and the indigo, settled at the bottom of the pail, should be tri-turated in an. iron mortar, with the addition of a small quantity of hot water, that ought to be shaken from side to side; and the floating particles of indigo, which are those most finely pounded, must be poured into another vessel. In this. manner, the indigo remaining in the mortar is continually reduced, fresh water being repeatedly added, till the whole is pulverized so finely as to rise to the surface.
The liquor which had, daring; the above stated preparation, been, boiling in the copper, is. now poured into the vat, together with the indigo, when the whole is well stirred with a rake., the vat closely covered, and surrounded with embers. If this operation commence in the afternoon, the embers must be renewed in the evening, and also in the morning and evening of the following day, in the course of which it should be twice gently stirred. Similar measures ought to be pursued on the third day, in order to preserve an uniform heat, and intimately mix the ingredients. A brassy scum will then be perceived to rise to the surface, in several detached parts: by conti-nuing the heat on the fourth day, the scum becomes more coherent; and the froth, occasioned by stir-ring the liquor, appears blue, while the latter is of a deep green. As soon as it assumes this appearance, the vat should be rilled; for which purpose a fresh liquor must be prepared, by putting 5 gallons of water into a copper, together with a pound of pot-ash, and half an oz. of madder. When these ingredients have boiled half an hour, the decoction is poured into the vat, the whole well stirred, and, if it produce much froth, it will be in a proper state for working the next day. This may likewise be ascertained by the brassy or scaly crust, which floats on the surface of the liquor; and, farther, if on blowing, or stirring, the latter with the hand, it assume a deep green colour, while the surface appears of a brownish blue.
After the vats have been thus prepared, the dyeing of woollen or silken stuffs is very easy; no other process being required, than immersing them in warm water, wringing, and then steeping them in the vat for a longer or shorter time, according to the deepness of the colour intended to be imparted. The stuffs should be occasionally opened, that is, taken out of the vat, wrung over it, and exposed to the air for a minute or two, till it become blue: for it must be observed, that, in all the solutions of indigo, or other dyeing materials above described, the blue colour is produced only by exposure to the air, and the stuff, on being first drawn out of the liquor, always appears green, and will retain that tinge, unless it be exposed to the air. In dyeing blue, therefore, it is necessary to let the colour thus change previously to a second immersion, that tire shade may be the better distinguished, as dark blues require to be repeatedly dip-ped. - The method of dyeing cotton or linen blue, varies so little from that already described, as to render any tardier directions unnecessary.
2.- The next of the primitive colours to be considered is Bed, of which there are many shades and varieties; but the principal are scarlet, crimson, and madder-red. The process to be adopted for obtaining these colours, essentially differs from that of blues; as the former require a peculiiar preparation of the stuffs to be dyed, on the exactness of which, the goodness of the colour in a great measure depends. These preparatory ingredients consist of alum, tartar, aqua-fortis, or a solution of tin in this acid. Galls and alkaline salts are also sometimes added, though they do not materially contribute to the colour.
There are three kinds of scarlet, namely, that dyed with kermes, with cochineal, and with gum-lac.
The first of these, called Vene-tian scarlet, is the most permanent, but the least bright: it is also apt to be less spotted than the others ; but, on account of the difficulty of procuring the insects which afford the colour, it is very seldom, if ever, used in this country.
The second kind of scarlet, namely, that dyed with cochineal, is less permanent than the Venetian scarlet, though the drug is procured at a more reasonable price. It is, however, very difficult to dye the true cochineal scar-let: the success of this opt. ration equally depends upon the choice of the material, the Water cro-ployed, and the method of preparing a solution of tin, which is the only ingredient by which that delicate colour can be produced. To eight ounces of spirit of nitre an equal quantity of river-water is to be added ; in this mixture are to be gradually dissolved half an ounce of the purest and whitest sal-ammoniac, and two drams of purified salt-petre. An ounce of , tin, reduced to grains, by being dropped into cold water while melting, is next to be added drop by droptotheliquor thus prepared \ the first being perfectly dissolved before a second is introduced. The solution resembles that of gold, and, if fine tin be employed, will be perfectly transparent, without any dust or sediment. With this liquor are to be mixed such proportions of cochineal as may he thought proper, and the stuffs dyed in the colour will acquire a most beautiful scarlet.
The scarlet produced by gum lac, though not so bright as cochineal, is more permanent; the best lac is that which is of a blackish brown colour on the outside, and white within. The process of preparing this colour is very difficult; but the best method, we believe, is that of previously mixing the gum with comfrey, or other mucilagi-nous roots. These should be dried, finely pulverized, afterwards boiled for fifteen minutes in the proportion of half a dram to a quart of water, then strained through a linen cloth while hot, poured upon levigated gum-lac, and passed through a hair sieve. The whole is then digested in a moderate heat for twelve hours ; and the gum remaining at the. bottom should be stirred seven or eight times. The liquor thus impregnated with a fine crimson colour, is afterwards poured into a vessel, sufficiently capacious to hold four tiroes the quan-tity, and filled up with cold water. On adding a small proportion of a strong solution of ahum, the coloured mucilage subsides: and, should any tinge remain in the liquor, it may be precipitated by gradual additions of alum, nil it become perfectly colourless. As soon as the crimson mucilage has entirely subsided, the clear water must be carefully decanted, the re-mainder tiltered, and the fluid v suffered to evaporate. If the whole. of the colour should not be extract-ed by the first operation, it ought repeated, till the residuum changes to a pale straw -colour.
In order to dye scarlet with this extract of gum-lac, the requisite proportion of the latter dried and pulverized, is to be put into an earthen or block-tin vessel; a little hot water poured upon it; and, when it is well moistened, a proper quantity of the composition added; the whole being stirred with a glass pestle. By this means the powder, which before was of a dark, dusky purple, acquires an exceedingly bright scarlet colour. A solution of the crystals of tartar is then to be poured into the liquor, and as soon as it begins to boil, the cloth is to be repeated!)' immersed in it, according to the common method. The remainder of the operation is to be performed in the same man-net as if cochineal had been employed.
Crimson is the colour produced by cochineal, with alum and tartar only, without any solution of tin. For this dye, two ounces and a half of alum, with an ounce and a half of white tartar, are to be taken, for every pound of wool; and being put into a cauldron with a pro-par quantity of water, the solution should boil before the stuff is dipped. The wool is then im-mersed into the boiling liquor, where it continues two hours; after which it is to he taken out, wrung gently, rinsed in water, and put into a hag. A fresh liquor is next prepared for the dye, in which an ounce of finely-powdered cochineal is used for every pound of wool : when this decoction boils, the stuff is immersed, and managed in the manner already directed for scarlet. For producing the finest crimson dye, however, the wool is again to be dipped in a weak lixivium, made of equal parts of sal-ammoniac and pearl-ashes.
The preparation of the ingre-dients for mudder-red is always, with alum and tartar, the proportions of which are by no means ascertained even by dyers. The more general practice is, to put 5 ounces of alum and one of red tartar to every pound of worsted, a twelfth part of acid water being likewise added, and the wool boiled for two hours in this solution, in which worsted is to be kept for a week ; but cloth will be sufficient-ly saturated in four days. A fresh liquor is then prepared for dyeing this wool; and when the water is nearly boiling, half a pound of the finest madder is to be thrown in for every pound of wool} being carefully stirred and well mixed in the copper, previously to immersing the stuff, which is to be kept in the liquor for an hour ; daring which the latter must not boil, lest it should tarnish the colour.
The third primitive colour is Yellow, for obtaining which there are ten different ingredients ; but four of these only yield a good and permanent dye, namely, dyers-weed, or, as the dyers call it, weld, savory, dyers* green - weed, and fenu-greck. The first of these, namely, weld in general affords the truest yellow, and is therefore preferred to all the others. Savory and dyers' green-weed, being naturally somewhat green, are more advantageously employed for dyeing that colour ; and the la6t yields different shades of yellow.
In order to dye worsted and stuffs yellow, they undergo the usual preparation with tartar and alum: of the latter 4 ounces are allowed to every pound of wool, or 25 lbs. to every 100 ; of the former, one ounce is sufficient for yellow; after dissolving both, the wool is boiled in the same manner as in the preceding colour. A fresh liquor is next to be made for the welding or yellowing, in the proportion of 5 or 61bs. of dyers'-weed to every pound of stuff. Some in-close the drug in a clean woolleu bag, to prevent it from mixing with the cloth to be dyed ; and, in order to keep the bag down in the copper, they lay a cross of heavy wood over it. Others boil the weld in the liquor, till the water has imbibed all its colour, and the drug sinks to the bottom, when the stuff is suspended in a net: others, again, take the weld out, as soon as it is boiled. According to the shade required, other vegetables are occasionally mixed with that drug. By varying the proportions of the salts employed, as well as the quantity of colouring ingredients, and the time of boiling, different shades may be produced,
The fourth primitive colour is that denominated by dyers the fawn, or root colour. It is a kind of brown, and the process tor dyeing it is widely different from those just described; the wool merely requir-ing a simple immersion in water, as already directed for blue. The materials employed consist of the green shell of the walnut, the root of the walnut-tree, the bark of al-der, santal or saunders-wood, sumach, and soot. - The green walnut-shells are collected, when the nuts are thoroughly ripe ; they are put into tubs or casks, which are afterwards filled with water, and are thus preserved till the succeeding year.
Santal, or saunders-wood, is much inferior to walnut-shells; because, if used in too large a quantity, it stiffens, and consequently injures the wool. It is in general mixed with galls, sumach, and al-der-bark, without which its colour could not be extracted : and though it yields very little with alum and tartar, it is nevertheless used in large quantities, on account of the solidity of its colour, which is na-turally a yellow-reddish brown.
The best of the different ingre-dients employed in dyeing fawn-colours, is the bark or rind of the walnut-tree. Its shades are uncommonly fine ; its colours solid ; and it renders the wool dyed in it flexible and soft. A cauldron half full of water is placed over the fire; and as soon as it grows warm, bark is added in proportion to the quantity of sturfs intended to be dyed, and the lightness or depth of the shades required. It is then boiled for about a quarter of an hour, when the cloths, being previously moistened with warm water, are immersed, frequently turned, and well stirred, till they have sufficiently imbibed the colour. They are aired, dried, and dressed in the usual manner.
Next to the rind or bark, the root of the walnut-tree is the best dye for a fawn-colour : it also affords a variety of shades, similar to those produced by the bark, for which it is frequently substituted. The root, however, requires a different process : A cauldron is filled about three parts full of river-water, into which the root is immersed, after being tied up in a bag. When the liquor is very hot, the wool or stuff is plunged into it, repeatedly turned, and occasionally aired. The lighter stuffs are next to be dipped, till the colour is completely extracted. During this operation, proper care should be taken to prevent the liquor from boiling, as in such case the piece first immersed would imbibe the whole of the colour.
The process of dyeing with the bark of alder, is nearly the same as that pursued With walnut-roots; the boiling of it is at first not very material, as this drug very freely communicates its colour. It is chiefly used for worsteds, imparting shades darkened with copper. . and for wool that is not required to be very dark, as it equally withstands the effects of the sun and rain.
Sumach possesses nearly the same properties as the bark or rind of the walnut-tree; its colour is not so deep, somewhat inclining to green, but is solid and permanent. Where dark colours are required, sumach is frequently substituted for nut-galls, in which case a greater proportion becomes necessary. - These different substances, however, are not unfrequently mingled together, and, as they are of a similar nature, and differ only in degree, it is easy to obtain various shades.
With respect to the method of compounding the different ingredients with pulverized saunders-ei'ood; A lbs. of the latter are to be put into a copper, with half a pound of powdered nut-galls, 12lbs. of alder-bark, and 10 lbs. of sumach. The whole is to be boiled, when a small portion of water should be added, to check the boiling : after immersing the cloth, stirring, and turning it repeatedly, it is aired, and washed in river-water. The quantities of these ingredients maybe increased, or diminished, according to the depth of the shade required.
The last substance employed in dyeing the fawn-colour, is soot, which is not only less solid than the others, but also hardens, and imparts a very disagreeable smell to the wool, or stuff, dyed in it: it is therefore seldom, if ever used, unless the other ingredients cannot be easily procured.
The fifth, and last, of the primitive colours, is black, which includes a great variety of shades. In order to impart a good black to woollen stuffs, they should be first dyed of as deep a blue as possible, which is called the ground, and is to be performed in the manner already directed. - As soon as the cloth is taken out of the vat, it ought to be well washed in river-water, and afterward scoured at the fulling-mill. Next, the dyeing process is performed as follows : For every cwt. of cloth, l01bs. of logwood cut into chips, and an equal quantity of Aleppo gall-nuts pulverized and inclosed in a bag, are to be put into a cauldron of a moderate size, where the whole is boiled for twelve hours in a sufficient quantity of water. A third part of this liquor is then to be poured into another cauldron, with 21lbs. of verdigrease, when the cloth is to be immersed for two hours, being repeatedly turned and stirred, the liquor in the mean time boiling very slowly, or rather, gently simmering. At the expiration of that time, the stuff* is to be taken out, and the second part (being another third) of the liquor added to the first third, together with 8lbs. of copperas. The fire beneath the cauldron is then to be diminished, and the copperas left for half an hour to dissolve; the liquor being gradually cooling: after which the cloth is to be immersed for another hour, repeatedly turned as before, then removed and cooled.
The remainder of the liquor is next to be mixed with the first two-thirds ; and the bag carefully expressed 5 when fifteen or twenty pounds of sumach are to be added, together with two pounds of cop-peras. The whole is then made to boil 5 and, a small quantity of water being added to cool, the stuff is again immersed for two hours 9 at the end of which time it is to he taken out, cooled, and steeped in the dye for an hour longer, being frequently turned. The cloth is then to be carried to the fulling-mill, and well scoured, till the water runs from it perfectly colourless. As soon as this operation, is performed, a fresh liquor should be prepared with the necessary quantity of dyers'-weed, which is only once to be boiled, and when cool, the cloth dipped into it. This last decoction softens the texture, and renders the colour a most beautiful black. Few dyers, however, lake so much pains; for they are satisfied with dipping the cloth, when blue, in a decoction of nutgalls falls and boiling the. whole for two hours. The stuff is then washed, and after adding some copperas and logwood to the liquor, the cloth is Main immersed for two hours, at the end of which it is washed, scoured, dried, and pressed.
A patent was granted to Mr. James Bayley, of St. Leonard's, Shoreditch, dyer, for his invention of a machine for dyeing, staining, or printing handkerchiefs, etc. -The patentee employs frames of wood, brass, copper, or other metals, on the faces of which are small blocks, projecting in such a manner that, when the face of one frame is placed against that of another frame, the blocks are all exactly opposite, and correspond with other : thus, an handkerchief, etc. being put between, and the frames fastened together, the dye will he ceommunicated to every part of it, excepting those places which' come between the blocks, and retain their original colour. These frames are provided with handles for raising them out of the copper, etc. by means of pullies ; and may be put together to ,any number, a to the length of the article to be dyed} as they are conjoined I on both sides with planks, having screws and nuts at each and. for the purpose of keeping themsteady.
Another patent was lately grant-ed to Mr.SAMUELGbeaxri:,;, of Manchester, for a new invented process of dyeing and staining colours upon cloth. - The process is shortly this: For dyeing black, Mr. G. takes,tar and iron liquor, adding to each galon three quarters of a pound of line flour, which he boils to the consistence of a paste, and then puts into a tub that hums, part of a rolling- .press. the common construction. The goods are pass-i:d through the paste between two rollers, which diffuses it equally and completely over the whole piece. They are next dried in a hot stove, afterwards soaked in a liquor made of cow-dung and water, scalding hot in the copper, then washed and rinsed in clean water. Lastly, the goods are dyed in a decoction of sumach, madder, logwood, or other dyeing drugs, in the, usual manner. The patentee also employs other mordants, such as iron liquor, paste, or gum, alum, etc. - The chief improvement in this patent, consists in employing, instead of the usual methods, a rolling-prcss to fix the mordant on the cloth, which renders the process somewhat of a middle kind between dyeing and calico-printing
The art of dyeing, though in its infancy, has lately been considerably improved, in consequence of the numberless discover.. ? made, chiefly by French el Among other useful facts, the enumeration of which would filll a volume, we shall at present only mention one, of the greatest importance to dyers. M. M. Gvyton and Van Mons have found, by repeated experiments, that the acid of wolfram. affords one of the most effectual means of precipitating the colour-ing matter of vegetables. The former, in particular, observed that this acid not only rendered the colour of silks dyed with the juice of aloe more brilliant, but also imparted to them (according to the different strength of the acid employed), a variety of shades, horn the most delicate lilac to. the most beautiful violet, and from the deepest orange to the most lively red. But he ingenuously adds,.
that, in the different trials he thus made with wool, the resuit did not give him equal satisfaftion.
By the 1 Rich. III. c. 4, all dyers are enjoined to dye both the cloth and the list, on pain of for-feiture.—By the 3 and 4 Ed w. VI. c. 2, if any cloth be dyed with archil, or with Brazil-wood, with intent to tinge either wool or cloth with a false colour, a fine of 20s. is thereby incurred. - Dyers are also obliged, by the 23 Eliz. c. 9, to affix a seal of lead to cloths, with the letter M, to shew that they are well maddered, or, in default thereof, they are liable to pay a fine of 3s. 4d. And if they use logwood in dyeing, they incur a fine of 20l. Severe penalties are also imposed by the 13 Geo. I. c. 24, on dyers who do not dye cloths throughout with Woad, indigo, and madder, or who omit to put marks to the cloth dyed:
Among the latest publications that have appeared on this subject, we shall mention only the Art of Dyeing, translated from the French of Berthollet, by Mr. Hamilton (2 vols. 8vo. 12s.) published about the year 1793; and Mr. Haigh's Dyer's Guide, (l2mo. 3s. 6d.) - For an account of the different methods of dyeing particular substances, we refer the reader to the articles, Bones, Hats,Leather,Marble, Paper, "Wood, etc.
Dyeing. - A fine orange-yellow tinge may be imparted to silk or cotton, by grinding anotta on a moistened slab, and boiling it in double its weight of pearl-ash and water: the liquor is then suffered to settle for about half a hour ; when it is drawn off, while hot, into a proper vat; and the stuff immersed, till it acquire the requisite shade. In order to heighten and fix the colour, it will be proper to dissolve some cream of tartar in hot water, and to add the solution to the liquor, so as to render it slightly acid : after which, the stuff may be rinsed, and dried in the usual manner.
A beautiful Saxon-blue, for silk and woollen cloths, may be prepared by gradually pouring from five to eight parts of sulphuric acid on one part of finely pulverized indigo. The mixture must be suffered to stand for 24 hours ; at the expiration of which, the effervescence will subside : the solution is then to be diluted with water, when it will be fit for dyeing.
Black: A hot decoction of Aleppo galls, in water, is first to be prepared in a proper vessel, in which cotton or silk stuffs, previously soaked in warm water, must be worked for some time. The superfluous liquid is now to be expressed, and the cloths should be immersed in a black dye, made by steeping alder-bark, and iron hoops for several months, in a cask of water ; or they may be plunged into a solution of iron in vegetable acids. When the stuffs are thoroughly wetted, they must be wrung out, and afterwards soaked in a decoction of logwood, to which a little verdigrease is added. The last mentioned process ought to be repeated, till the colouring particles be sufficiently imbibed : during the intervals, it will be proper to rinse the cloths in water, and to dry them, in order to fix the colour.