In the utmost latitude of the word, may be defined, The art of tingeing cloth, stuff, or other matter, with a permanent colour, which penetrates the sublance thereof.—It is, however, commonly restrained to the art of tingeing silk, wool, cotton, and linen, with different colours; and, as such, is practised as a trade by those who do not meddle with any of the other branches, as staining of leather, &c.
The dyeing art is of great antiquity; as appears from the traces of it in the oldest sacred, as well as profane, writers. The honour of the invention is attributed to the Tyrians; though what lessens the merit of it is, that it is said to have owed its rise to chance. The juices of certain fruits, leaves, &c. accidentally crushed, are supposed to have furnished the first hint: Pliny assure us, that even in his time the Gauls made use of no other dyes: it is added, that coloured earths, and minerals, washed and soaked with rain, gave the next dyeing materials.—But purple, an animal juice, found in a shell-fish called marces*, conchylium, and purpura, seems from history to have been prior to any of them. This indeed was reserved for the use of kings and princes; private persons were forbidden by law to wear the least scrap of it. The discovery of its tingeing quality is said to have been taken from a dog, which having caught one of the purple-fishes among the rocks, and eaten it up, stained his mouth and beard with the precious liquor; which struck the fancy of a Tyrian nymph so strongly, that she refused her lover Hercules any favours till he had brought her a mantle of the same colour.
Pliny seems to ascribe the invention of the art of dyeing wool to the Lydians of Sardis: "Inferre lanas Sardibus Lydi;" where the word inferre must be understood. But a modern critic suspects a false reading here; and, not without reason, for Lydi, substitutes Lydda, the name of a city on the coast of Phoenicia, where the chief mart of the purple dye was.
After the Phoenicians, the Sardinians seem to have arrived at the greatest perfection in the dyeing art; inasmuch, that sauan saepinam, Sardinian dye, passed into a proverb among the Greeks. Till the time of Alexander, we find no other sort of dye in use among the Greeks but purple and scarlet.—It was under the successors of that monarch, that these people applied themselves to the other colours; and invented, or at least perfected, blue, yellow, green, &c.—For the ancient purple, it has been long lost; but the perfection to which the moderns have carried the other colours, abundantly indemnifies them of the loss. It is still, however, greatly to be doubted whether the permanency of the modern colours at all equals that of the ancient ones; though it is certain, that the former greatly exceed them in brightness.
Sect. I. Theory of Dyeing.
Before we can enter into any consideration of the true theory of dyeing, it is necessary to make the following observation concerning the practice, namely, That salts are almost the only means we are acquainted with by which any colouring sublance can be made to fix itself upon those matters which are the common subjects of dyeing. A solution of cochineal, for instance, will of itself impart no permanent colour to a piece of woollen cloth put into it. The red colour of the cochineal will indeed stain the cloth while it remains immersed in the solution; but as soon as it is taken out and washed, this temporary stain will immediately vanish, and the cloth become as white as before. If now the cloth is dipped in the solution of any saline sublance, alkalies alone excepted, and then immersed in the solution of cochineal for some time, it will come out permanently coloured; nor will the colour be discharged even by washing with soap and water. If a quantity of salt is added to the solution of cochineal, and the cloth put in without being impregnated with any saline sublance, the effect will be the same; the cloth will come out coloured; only in this last case, it must be well dried before washing it with soap, or most of the colour will be discharged.
By comparing this with what is delivered under the article Colour-Making, p. 13, 14, we shall be able to agree in a pretty rational theory of dyeing. It is there remarked, that a saline sublance, (solution of tin in aqua regia), had a surprising power of coagulating the colouring matter of certain solutions, such as cochineal, Brazil-wood, logwood, &c. If therefore a piece of cloth is previously impregnated with this solution, and put into the colouring one, it is plain that some part of the colouring matter will be coagulated by the solution remaining in the cloth, in the very same manner that it would have been if a small quantity of the saline solution had been poured into the other. The cloth therefore will take up a part of the colouring matter, which cannot be discharged but by entirely discharging the solution of tin. This, however, seems to unite itself with the cloth very firmly, so that scarce a particle of colour will be discharged by washing in plain water, or even with soap; nor can the whole be taken out, without boiling the cloth in a solution of fixed alkali. Though solution of tin produces this coagulation in the most remarkable manner, it is not to be doubted that the same power is possessed in some degree by most of the neutrals and imperfect salts. Alum possesses it very considerably, though not so much as solution of tin; and hence that salt is very much used in dyeing, as well as sugar of lead, which also has a very strong power of coagulation. The process of dyeing, therefore, seems to be most analogous to that of the coagulation or curdling of milk. Before it has suffered this change, the milk is easily miscible with water; but after it is once coagulated, the curd, or caesous part, is very difficultly soluble in any liquid whatever. In like manner, the colouring matter in the solution of cochineal, before the cloth is put in, is easily soluble in water, and may be diffused through any quantity of fluid; but no sooner is the cloth dipped in it, than the saline substance contained in the cloth coagulates that part of the colouring matter which lies in immediate contact with it; and, as all the fluid successively comes into contact with it, the whole of the colour is by degrees coagulated and deposited on the cloth.
To account for the strong adhesion of the colour to the dyed cloth, several hypotheses have been formed. One is, That the fibres of wool, silk, &c. are hollow tubes; that the colouring matter enters them; and, after being there coagulated, flows itself through the fine transparent sides of the tubes.—Another considers these filaments as solid lengthwise, but having all round their sides an infinite number of small pores like the extremities of the fine absorbing and exhaling vessels of the human body. In these pores, according to the hypothesis, the colour is lodged; and as the pores are placed exceedingly close to one another, the fine threads appear to our eyes of one uniform colour.—A third is, That the fibres are solid, or at least with respect to us may be considered as such. The saline substance, whatever it is, that is employed to make the colour strike, sinks into the surface, partly corrodes and unites itself with it into a third kind of substance no longer soluble in plain water, nor even easily by soap, but which still preserves its coagulating quality. According to this hypothesis, the dye lies entirely on the outside of the fluff, and continues as long as the effect of the salt continues upon the fibres of the matter to be dyed.
Concerning the truth of these hypotheses, or indeed any others that can be invented, it is impossible to bring any decisive proof. It seems, however, more probable that the process of dyeing is accomplished by a coagulation of the colouring matter itself, rather than by any agglutination of it to the fibres by means of a Mr Hellot's vitriolated tartar, as Mr Hellot supposes. According to this gentleman's theory, a vitriolated tartar is generated in every process for dyeing, and proceeds from the acid of the alum and alkaline basis of the tartar used in the preparations, or in some of the dyeing ingredients themselves. He supposes that the pores of the fluff are cleansed and enlarged by the preparatory salts, and by the boiling water, in such a manner as to receive the colouring particles, which particles are afterwards detained by the contraction of the pores occasioned by cold; and further, that these pores are lined with a saline crust of tartar or vitriolated tartar.
On this theory, the translator of the Chemical Dictionary has the following observations. "Mr Hellot has not shown that pure fixed alkali is incapable of producing the effects which he attributes to his tartar and vitriolated tartar; and both these salts, though they are difficult of solution, and require a great quantity of water for this purpose, will yet dissolve at last; and therefore, if the colouring particles were fixed chiefly by means of these salts, they might be washed out by a large quantity of water; which we find to be contrary to experience.
"We shall find it more difficult to substitute a true theory, than to refute that of Mr Hellot. Many experiments ought to be previously made. Nevertheless it may be observed, That the colorific particles of most substances used in dyeing seem to be insoluble in water, in spirit of wine, and even in alkaline lixiviums; that their diffusion thro' these liquids is caused merely by their adhesion to certain gummosus and resinous particles: and that they may be disengaged from those gummosus and resinous matters, by applying a piece of fluff to which they have a greater adhesive power, which seems to be the case of the root-coloured and blue dyes; or by applying another substance to which these particles have a greater power of adhesion; such as the earth of alum, in those dyes where that salt is used, together with some other substance, as fixed or volatile alkali, capable of decomposing alum; or as the ferruginous earth of the green vitriol in black dyes, to which the colorific particles of the galls adhere; which earths are capable of applying themselves and of adhering to the fluffs. The separation of the colouring particles from the gummosus and resinous matters is probably facilitated by the addition of acids and neutral salts, which may coagulate in some measure the vegetable matters, and leave the colorific particles disengaged; so that they may apply themselves to the fluff, or to the earths above-mentioned."
But, in whatever way the salts used in dyeing do act, it is certain they are capable, except in a very few instances, of fixing and giving a lustre and permanency to the colour which otherwise could never be obtained. The exception to this general rule most commonly known, is that of indigo. This is a fine blue fecula produced by fermentation from the leaves of the Indian plant called axil. It is very difficult of solution; however, it may be dissolved by alkaline salts, concentrated oil of vitriol, orpiment, or combinations of sulphur with quicklime. If a quantity of indigo is dissolved in a fixed alkali, (for volatile alkalies will not dissolve it), the solution is always green, which is the natural colour produced in all vegetable blues by the alkali; but if any piece of fluff is put into this solution, though it remains green while immersed in the liquid, the moment it comes in contact with the air, the dissolving power of the alkali is totally destroyed; the indigo is precipitated upon the cloth, resumes its native colour, and dyes the cloth blue.
The cause of this precipitation is very difficult to be investigated. Perhaps it may be owing to an attraction of fixed air by the alkali from the atmosphere, which renders the salt unable to dissolve the indigo any longer. The adhesion of the colour seems merely owing to an attraction between it and the cloth; for the alkaline salt can contribute nothing to this, but would. would rather have the contrary effect. Perhaps, however, the great solvent power possessed by alkaline salts, by perfectly clearing away every kind of foreign matter, may bring the indigo and cloth into nearer contact with each other, than when it is dissolved in any other way; and consequently the attraction will in these cases be the stronger. This seems to have some probability; for when indigo is dissolved in vitriolic acid, as in dyeing Saxon blue, the colour is much more easily discharged.
Another exception is in the juices of some vegetables, such as the nuts of the anacardium. This produces, without addition, a most deep and lasting black, never to be washed out or discharged by any means whatever. Several other plants are to be found in different parts of the world, which give an indelible black stain upon linen without addition; and the colouring matter of these seems to adhere by means of a very tenacious gluten, with which it is mixed, and which, when once thoroughly dried, can never be again dissolved. In this respect, these black staining colours seem analogous to the purpura of the ancients; which stained indelibly without addition, and was of an exceedingly viscous and adhesive nature.
Sect. II. Practice of Dyeing.
§ 1. Of the colouring materials, and ingredients for fixing the colours.
The materials for dyeing different colours are so many and various, that an enumeration of them all is scarce to be expected. The same difference, however, takes place among the materials for dyeing which we have observed to take place among those for Colour-Making. Some ingredients produce durable colours, which cannot be discharged either by exposure to the air, or by washing with soap; others, though they may be made to stand the action of soap pretty well, cannot by any means be enabled to resist the action of the air. These are distinguished by the different names of true and false, permanent and fading, &c.; nor is there any method yet discovered of giving the false colours an equal degree of durability with the true ones. This hath been attempted by mixing a permanent and a fading colour together; in which case it was thought that the former would impart somewhat of its durability to the latter; but this hath always been found to misguide; the fading colour soon flying off, and leaving the permanent one behind. The same hath also been attempted by dyeing a piece of stuff partially with a fading colour, and then completing the dye with a permanent one. In this case, it was hoped, that the fading colour being covered over, and defended from the injuries of the air, by the permanent one, would necessarily become equally durable, or at least remain a much longer time than if the stuff was dyed with it alone. But this also hath been found ineffectual; and the fading colour hath been dissipated as soon when covered with a permanent one, as when left without any such cover. Solution of tin in aqua regia will give most of these fading colours an high degree of beauty, and some share of durability, though even that is not able to make them equal to the others.—The most permanent dyes we have are cochineal and gum lac for fine reds and scarlets; indigo and woad for blue; and, when mixed in different proportions with cochineal, or prac- tic lac, for purple and violet colours. Weld, and some other vegetables, for yellow; and madder for coarse reds, purples, and blacks.—The fading colours are much more numerous. In this class are included Brazil-wood, logwood, peach-wood, red-wood, saffron, turmeric root, annatto, archil, &c. &c.
With regard to the salts made use of in dyeing, it has been but too often customary to jumble together such a quantity of different ones, that it was not only impossible to know in what particular salt the virtue resided, but often the efficacy of the whole hath been totally destroyed, and the colour entirely spoiled by such injudicious management. It is proper, therefore, where a mixture of two or more salts is intended to be made for dyeing, first to try the change of colour produced by each of the salts upon the colouring substance. If the colours are nearly alike, the mixture may be safely made as to that particular. But if the two colours produced by the different salts are very different from one another, to mix them together must be very injudicious. Thus, suppose you want to dye scarlet, solution of tin in aqua regia produces the necessary change of colour on the decoction of cochineal, and converts it into a high flame-colour, which shews it to be a proper ingredient; but, to the solution of tin, it would surely be the greatest absurdity to add a quantity of saccharum saturni, the effect of which is to change the colour of cochineal to a dull purple. But, tho' the salts taken separately should produce a colour nearly similar, another thing must be regarded, namely, whether they can be mixed with safety to one another. It is the nature of many salts to destroy one another whenever they come into perfect contact by being dissolved in water. Thus, solution of tin and saccharum saturni destroy one another; and so do solution of tin, and tartar, or cream of tartar. To mix these together must therefore be absurd; and yet we find this last mixture ordered in almost every receipt for dyeing scarlet. It is also to be observed, that a mixture of different salts ought never to be made, out of a notion that the colour will keep the better on that account; for most commonly it will keep the worse. A single salt will answer for this purpose, better than a hundred. A mixture should only be made where it is necessary to produce the colour desired; and if a dyer proceeds in this simple manner, he may not only attain to great perfection in the art from his own experience without being taught by others, but even make considerable discoveries; as dyeing is at present far enough from being brought to perfection.—The salts chiefly to be used in dyeing are fixed alkalies; solutions of tin in the vitriolic and marine acids, and in aqua regia; sugar of lead; cream of tartar; alum; oil of vitriol; and solution of iron in the acetic acid. By means of these, almost all kinds of colours may be dyed at an easy rate, and with very little trouble.
§ 2. Of the manner of using the ingredients, and of producing the different colours.
As the art of dyeing is, by the principles above laid down, reduced to a great degree of simplicity, almost all the directions for the practice will be contained in the following general rule.
Having cleaned the substance to be dyed as well as possible, and made choice of the salt proper for produc- cing the colour desired, dissolve the salt in water, and steep the substance in that solution for 24 hours. Then take it out; and, without wringing, hang it up to dry, but without heat: and for this it will be proper to allow a pretty long time; for the more perfectly the salt penetrates the cloth, the more durable will the colour be. Having then prepared a coloured solution or decoction, put the cloth into it. The less heat that is applied during the time the cloth remains in the dye, the finer the colour will be, but the longer time will be required for completing the operation. If time cannot be spared, so that a strong heat must be applied, it will be necessary to roll the cloth during the time of dyeing, or the colour will be in danger of proving unequal.
After the dyeing is completed, rinse the cloth in cold water, but do not wring it severely; and then hang it up to dry.
In this way may be dyed a great variety of colours, on wool, silk, cotton, and linen, without any variation in the process. Solution of tin in the vitriolic acid will produce all degrees of red, from the palest pink or rose-colour, to the highest crimson and scarlet; and that on all the above-mentioned substances without exception.
A method of producing these fine colours upon cotton and linen, as well as wool, hath been a great deliberation in dyeing; but by the abovementioned solution these substances may be dyed of the most beautiful red, crimson, and scarlet colours, as any one may very readily satisfy himself by a trial. The same thing may be done by solution of tin in aqua regia; but unless the nitrous acid prevails greatly in the mixture, the colours produced by this last will incline more to the purple than the former. With solution of tin in the marine acid, they incline remarkably to purple, and are likewise deficient in lustre. The two first solutions therefore are capital ingredients in dyeing red.
The same preparations will also serve for dyeing all other colours, blue and green only excepted. Thus, a piece of cloth prepared with solution of tin in the vitriolic acid, if boiled in a decoction of cochineal, will come out of a scarlet colour; if with turmeric, weld, saffron, or many of the common yellow flowers, it will come out of different degrees of yellow; with Brazilwood, peach-wood, &c., it will give a fine purplish crimson; with logwood, a fine deep purple, &c.; and by combining these together in different ways, an infinity of different shades may be produced.
For the coarse reds produced from madder, the solutions of tin are not found to answer. The proper salts for these are alum and cream of tartar. In dyeing with madder, it is always necessary, more than when any other ingredient is used, to let the heat be gentle; because the root, besides the red colour it contains, has also a great quantity of brownish matter in it, which is extracted by strong boiling, and debases every colour with which it is mixed. Sugar of lead produces a purple with this root; which, however, will be brightened by an addition of alum and sal ammoniac. A dark purple may also be produced from madder by mixing alum with a little solution of iron in the vegetable acids, particularly the acetic. With regard to blue colours, they are only to be dyed by means of indigo. This substance may be dissolved, as we have already observed, by alkaline salts, concentrated acids, and orpiment. The first of these produces the common blues; the second, the Saxon blue; and the third, the blue which is used in calico-printing.—The method of dyeing the common blue requires only the stuff to be dipped in a solution of indigo in the alkaline salt; and if the liquor is hot, the dyeing will be over almost instantaneously. For cotton and linen, another method hath been used. Lime is added to the pot-ash, and the strength of the alkali being by this means increased, the indigo is very soon dissolved. Some raisins are now to be beat in a brafs or marble mortar to a pulp, and thrown into the solution of the indigo as soon as taken off the fire. It soon throws up a copper-coloured scum to the surface; and the cotton being now put into the liquor, receives the colour in an instant. This is a very beautiful blue; but in what manner the raisins act, is a matter which yet remains to be determined. If a piece of cloth is dipped in a solution of copper in the nitrous acid, and then boiled in logwood, it will come out of a purplish blue colour. This dye, however, has very little beauty or durability, and is therefore scarcely worthy of notice.
Common green vitriol or copperas is thought to improve blue colours in general; but on what foundation, is not very apparent. By means of it, however, the colour of Prussian blue may be struck upon cloth in such a manner as to produce a temporary stain of exceeding great beauty; and could any method of fixing this colour be fallen upon, it would undoubtedly be a most valuable acquisition. The method is, to digest some Prussian blue in fixed alkali till the colour is extracted. In this solution dip the cloth intended to be dyed, and dry it; then let it lie for a little time in a weak solution of copperas, and it will immediately become of a most beautiful blue colour. This colour, however, is discharged by washing with soap, and even with simple water.
A receipt was published by Mr Woulfe, in the Philosophical Transactions, for an improved method of dyeing the Saxon blue; which is done by dissolving indigo in concentrated oil of vitriol. The only improvement in Mr Woulfe's process, consisted in digesting the oil of vitriol and indigo in the heat of boiling water instead of a land-heat, because the latter was often found to spoil the colour. After the indigo is dissolved, the solution may be weakened at pleasure with water; and any piece of stuff then dipped in it will imbibe the colour, in proportion to the strength of the solution. This dye is very beautiful; but will neither keep its colour, nor stand washing with soap: unless great care is taken, it is also very apt to prove unequal.
Green colours are to be produced only by a mixture Green colour of blue and yellow; for there is no ingredient yet discovered, that will, by itself, give a good green dye. Sap-green will indeed communicate its own colour to cloth of any kind, and for that purpose is used in some places; but the colours dyed with this ingredient are by no means eligible. It is common first to dye the cloth blue with indigo, and then yellow with any yellow colouring ingredient; by which means a green colour is produced. For the dyeing of Saxon green, however, it is necessary to produce a particular kind of Woulfe's yellow from Indigo. This is obtained by dissolving receipt for indigo in spirit of nitre. Mr Woulfe recommends an ounce and a half of powdered indigo to be mixed with two ounces of spirit of nitre diluted with four times its quantity. quantity of water. The mixture is then to stand for a week; and, at the end of that space, must be digested in a sand-heat for an hour or more; after which, four ounces more of water is to be added: the solution, when filtered, will be of a fine yellow colour.—Strong spirit of nitre is apt to set fire to indigo; for which reason, as well as to hinder the mixture from frothing up, it must be diluted with water. Two ounces and an half of strong spirit of nitre will set fire to one ounce and an half of indigo; but if the acid is highly concentrated, a less quantity will serve.
If the indigo be digested 24 hours after the spirit of nitre is poured on it, it will froth and boil over; but, after standing a week or less, it has not that property.
One part of the solution of indigo in the acid of nitre, mixed with four or five parts of water, will dye silk or cloth of the palest yellow colour, or of any shade to the deepest, and that by letting them boil more or less in the colour. The addition of alum is useful, as it makes the colour more lasting. According as the solution boils away, more water must be added.
None of the colour in the operation separates from the water, but what adheres to the silk or cloth; of consequence, this colour goes far in dyeing.
Cochineal, Dutch litmus, archil, cudbear, and many other colouring substances, treated in this manner, will all dye silk and wool of a yellow colour.
The indigo which remains undissolved in making Saxon blue, and collected by filtration, if digested with spirit of nitre, dyes silk and wool of all shades of brown inclining to a yellow.
Cloth and silk may be dyed green with indigo; but they must first be boiled in the yellow dye, and then in the blue.
Black colours are dyed by preparing the cloth with any solution of iron, (but that in the acetous acid is best,) and then boiling it in a decoction of any astringent vegetable. Those chiefly made use of for the purposes of dyeing, are galls, fumach, logwood, and madder. Of these the last is the most durable; though galls will also produce a pretty lasting colour, if properly managed. Logwood dyes a very pretty, but fading, black colour. It appears, however, from some experiments made by Mr Clegg, that, by a proper preparation of the cloth with fixed alkaline salts, black colours dyed with logwood might be improved both as to beauty and durability.—"I took (says he) two vessels, containing equal measures of a strong astringent liquor, composed of galls and logwood: into one vessel I put a small quantity of pearl-ashes; the other remained as a standard. Pieces of linen and cotton cloth, after maceration in these liquors, were thrown together into a strong solution of copperas; they were soon after taken out, and washed in cold water. When dry, the pieces prepared in ashes were, all of them, much deeper than the others.
"I made use of different kinds of pearl and pot ashes, as well as many kinds of astringents: the ashes had the same effect whatever astringent was made use of, and the strongest alkali always produced the deepest colour; and though ashes used with an astringent, always gave a deeper colour than the same astringent without ashes, yet logwood, which without ashes gave not so deep a colour as galls with them, gave a much deeper black than galls with the same addition.
"There was a remarkable difference in this case between lime and ashes in their effect upon logwood; with lime it gave no blackness, but with ashes it produced a deeper black than any other astringent I made use of.
"Being desirous of trying the duration of colours produced by astringents, in which different quantities of pearl-ashes had been dissolved; in two pints of river water I boiled one ounce of logwood during ten minutes; I then added half an ounce of Aleppo galls, and boiled them together ten minutes longer; the liquor having stood to cool, was decanted off, and divided into six equal quantities. No 1 remained as a standard; into No 2, I put five grains of fine pearl-ashes; No 3, twelve grains; No 4, eighteen grains; No 5, twenty-four grains; No 6, thirty grains. To fix drops of each of these liquors, I added two drops of a saturated solution of copperas. No 2 and 3 struck a deep black; No 1 and 4, black, but inferior to 2 and 3; No 5, a brown black; No 6, brown.
"From this experiment it appears, that No 5 and 6 were spoiled by an over proportion of ashes.—All these colours were tried by writing with them on paper, and the writings have now been exposed six months to the air. In No 5 and 6, the blackness is quite destroyed; No 4 is something faded; No 1, 2, 3, remain nearly as they were, No 2 and 3 being still superior to the standard."
The finest blacks are first dyed blue, with indigo; and afterwards black with solution of iron, and some astringent vegetable, according to the directions already given.
These are the best methods for producing permanent colours of all kinds. As it is necessary, however, often to give another colour to stuffs which have been already dyed, it is plain, that it is as necessary for a dyer to know how to discharge colours, as how to make the cloth imitate them.—Concerning this, it is only necessary to observe, that alkaline salts are in general the best, and, where the colours are well dyed, the only means of discharging them. If a piece of cloth is dyed with logwood, and the colour struck upon it with alum, that colour will be nearly discharged by oil of vitriol, or any other strong acid; but if solution of tin has been employed in striking the colour, acids have then no effect, and alkalies only can be employed. Neither will they discharge the colour totally, but the stuff must be bleached for some time to get out the remainder. If alkaline salts cannot be employed with safety to the stuff, it is then impossible to dye it any other colour than black; unless it be dyed a compound colour, of which the original one is a component part.
Concerning the weight that colours give to silk, (in which it is most taken notice of, being sold by weight, and a commodity of great price,) it is observed, that dyeing one pound of raw silk lofeth four ounces by washing out the gums and the natural sordes; that the same scoured silk may be raised to above thirty ounces from the remaining twelve, if it be dyed black with some materials. Of all the materials used in dyeing, especially of black, nothing increases weight so much as galls, by which black silks are referred to so much weight as they lost by washing out their gum: nor is it counted extraordinary, that blacks should gain about four or five ounces in the dyeing upon each pound. Next to the galls, old stuff increases the weight about 1½ in 12; madder, about DYING of Hairs. See HAYS.
DYING of Leather. See LEATHER.
or Staining, of paper, wood, bone, marble, &c. See BONE, MARBLE, PAPER, WOOD, &c.