bark tied up in a bag, as that of the alum employed in the preparation. The stuff is then to be turned as usual through the boiling liquor, until the color appears to have acquired sufficient intensity. One pound of clean powdered chalk for every 100 pounds of stuff is then to be mixed with the dyeing bath, and the operation continued for eight or ten minutes longer, for the purpose of raising and brightening the color.

210. To communicate a beautiful orange yellow to woollen stuffs, ten pounds of quercitron bark, tied up in a bag, for every hundred pounds of stuff, are to be put into the bath with hot water. At the end of six or eight minutes, an equal weight of murio-sulphate of tin is to be added, and the mixture well stirred for two or three minutes. The cloth, previously scoured, and thoroughly wetted, is then immersed in the dyeing liquor, and quickly turned for a few minutes. By this process the coloring matter fixes on the cloth so effectually, that, after the liquor begins to boil, the highest yellow may be produced in less than fifteen minutes.

211. High shades of yellow, similar to those obtained from quercitron bark by the above process, are frequently given with young fustic and dyers' spirit; but this color is much less beautiful and permanent, while it is more expensive than what is obtained from the bark.

212. A fine bright, or golden yellow is obtained by employing ten pounds of quercitron bark, for each 100 pounds of cloth, the bark being first boiled a few minutes, and then adding seven or eight pounds of murio-sulphate of tin, with about five pounds of alum. The cloth is to be dyed in the same manner as in the process for the orange-yellow. Bright yellows of less body are produced by employing a smaller proportion of bark, as well as by diminishing the quantity of muro-sulphate of tin and alum. And indeed every variety of shade of pure bright yellow may be given by varying the proportions of the ingredients.

213. The lively delicate green shades, so much admired, are produced by the addition of tartar, with the other ingredients. The tartar must be added in different proportions, according to the shade which is wanted. For a full bright yellow, delicately inclining to green, it will be proper to employ eight pounds of bark, six of murio-sulphate of tin, with six of alum, and four of tartar. An additional proportion of alum and tartar renders the yellow more delicate, and inclines it more to the green shade; but when this lively green shade is wanted in the greatest perfection, the ingredients must be used in equal proportions. The delicate green lemon yellows are seldom required to have much fulness or body. Ten pounds of bark, with an equal quantity of the other ingredients, are sufficient to dye 300 or 400 pounds of stuffs.

214. Of Dyeing Silk Yellow.—Weld is seldom employed to give a yellow dye to silk, but when this is desired, the process differs a little from the former. The silk being scoured, alumed, and rinsed in the manner usual for dyeing bright colors, a bath is prepared, by boiling weld in water, in the proportion of double the weight of the silk for a quarter of an hour, and straining

off the liquor into a vat, where it is suffered to cool till the hand can be held in it. Then the silk is dipped and turned, till the color is found uniform. While this is going on, the old weld is boiled with a fresh quantity of water, and, after the silk has been dipped, one half of the exhausted bath is taken out, and the vat filled up with the second decoction. The temperature of the fresh bath may be a little higher than that of the former, but should not be too great, lest the color already fixed be dissolved. The stuff is to be turned as before, and then taken out of the bath. Some soda is to be dissolved in a part of the second decoction, and a larger or smaller quantity of the solution is to be added to the bath, according to the intensity of the shade wanted. The color is examined by taking out a skein, and wringing it.

215. To produce shades having more of a gold color, anotta is added in proportion to the depth of color required. Lighter shades, such as pale lemon color, are obtained by previously whitening the silk, and regulating the proportion of the ingredients of the bath by the shade required. To give a yellow, with a green tinge, a little indigo is added to the bath, if the silk has not been previously azured; to prevent the greenish shade being too deep, the silk should be more slightly alumed than usual.

216. Dr. Bancroft informs us that all the shades of yellow can be given at a cheaper rate by quercitron bark than by weld. To dye with this bark, a quantity of it powdered, and enclosed in a bag, in proportion to the shade wanted, from one to two pounds for every pound of silk, is put into the vat while the water is cold. Heat is applied, and when the bath is rather more than blood-warm, or of the temperature 100°, the silk, after being first alumed, is immersed and dyed in the usual way. A deeper shade may be given by adding a small quantity of chalk or pearl-ashes towards the end of the operation. To produce a more lively yellow, a small portion of murio-sulphate of tin may be employed, but it should be used cautiously, as it is apt to diminish the lustre of the silk.

217. To dye silk of an aurora or orange color, after having been properly scoured, it may be immersed in an alkaline solution of anotta, the strength of which is to be regulated by the shade required. The temperature of the bath should be between that of tepid and boiling water. When the desired shade is obtained, the silk is to be twice washed and beetled, to free it from the superfluous coloring matter, which would injure the beauty of the color. When raw silk is to be dyed, that which is naturally white should be selected, and the bath should be nearly cold; for otherwise the alkali, by dissolving the gum of the silk, destroys its elasticity. Silk is dyed of an orange color by anotta, but if a redder shade be wanted, it is procured by alum, vinegar, or lemon juice. These colors are beautiful, but do not possess permanency.

218. Of Dyeing Cotton and Linen Yellow.The process commonly observed in dyeing cotton and linen yellow, is by scouring it in a bath prepared in a lie with the ashes of green wood. It is afterwards washed, dried, and alumed, with

one-fourth of its weight of alum. After remaining in twenty-four hours, it is taken out of the aluming and dried, but not washed. The cotton is then dyed in a weld bath, in the proportion, of one pound and a quarter of weld for each pound of cotton, and turned in the bath till it has acquired the desired color.

219. After being taken out of the bath, it is soaked for an hour and a half in a solution of sulphate of copper, in the proportion of onefourth of the weight of the cotton, and then immersed, without washing, for nearly an hour, in a boiling solution of white soap, after which it is well washed and dried.

220. A deeper yellow is communicated to cotton, by omitting the process of aluming, and employing two pounds and a half of weld for each pound of cotton. To this is added a dram of verdigris, mixed with part of the bath. The cotton is then to be dipped and worked till the color become uniform. It is then taken out of the bath, and a little solution of soda added, after which it is returned, and kept for fifteen minutes. It is then wrung out and dried.

221. Other shades of yellow may be obtained by varying the proportion of ingredients. Thus, a lemon color is dyed by using only one pound of weld for every pound of cotton, and by diminishing the proportion of verdigris, or using alum as a substitute.

222. Dr. Bancroft recommends a superior process, and less expensive. He also objects to the use of salts of copper, as deepening the yellow. One pound of acetate of lead, and three pounds of alum, are to be dissolved in a sufficient quantity of warm water. The cotton or linen, after being properly rinsed, is to be soaked in this mixture, heated to the temperature of 100°, for two hours. It is then taken out, moderately pressed over a vessel, to prevent the waste of the aluminous liquor. It is then dried in a stove heat, and, after being again soaked in the aluminous solution, it is wrung out and dried a second time. Without being rinsed, it is to be barely wetted with lime water, and afterwards dried; and if a full, bright, and durable yellow is wanted, it may be necessary to soak the stuff in the diluted aluminous mordant, and, after drying, to wet it a second time in the lime water. After it has been soaked for the last time, it should be well rinsed in clean water, to separate the loose particles of the mordant, which might injure the application of the coloring matter. By the use of the lime-water, a greater proportion of alumina combines with the stuff, besides the addition of a certain proportion of lime.

223. In the preparation of the dyeing bath, from twelve to eighteen pounds of powdered quercitron bark are enclosed in a bag, for every 100 pounds of stuff, varying the proportion according to the depth of shade required. The bark is put into the water while it is cold; and, immediately after, the stuff is immersed and turned for an hour, or an hour and a half, during which the water should be gradually heated, and the temperature raised to about 120. At the end of this time the heat is increased, and the dyeing liquor brought to a boiling temperature; but at this temperature the stuff must remain in

it only for a few minutes. It is then taken out, rinsed, and dried.

224. Dr. Bancroft remarks, that, when the aluminous mordant is employed without the addition of water, one soaking only, and an immersion in lime water, may be sufficient; but he is of opinion that greater advantage is derived from the application of a more diluted mordant at two different times, or even by a more frequent immersion of the stuff alternately in the aluminous mordant, and lime water, and drying it after each immersion. By this treatment he found that the color always acquired more body and durability.

225. Chaptal proposes a process for communicating to cotton a nankeen yellow, which, while it affords a durable color, has the advantage of being cheap and simple. When cotton is immersed in a solution of any salt of iron, it has so strong an affinity for the oxide, that it decomposes the salt, combines with the iron, and assumes a yellow color. The process recommended by Chaptal is this:-The cotton to be dyed is put into a cold solution of sulphate of iron, of the specific gravity of 102. It is afterwards wrung out, and immediately immersed in a lie of potassa of the specific gravity of 1:01. This lie must previously have been saturated with a solution of alum. When the stuff has been kept for four or five hours in this bath, it may be taken out, washed, and dried. By varying the proportion of sulphate of iron, every variety of shade may be obtained.

226. The following curious process for dyeing linen of a durable yellow, as practised in the east, is given in the Encyclopædia Britannica. The object of this process, which is tedious, is to increase the affinity between the alumina and the stuff, so that it may adhere with sufficient force to produce a permanent color. For this purpose three mordants are employed: these are oil, tan, and alum. The cotton is soaked in a bath of oil, mixed with a weak solution of soda. Animal oil, as it is found to answer best, is preferred. Glue has also been tried, and is found to answer very well. The soda must be in the caustic state, as it then combines with the oil, and produces on the cloth an equal absorption. The stuff is then to be washed, and afterwards put into an infusion of nut-galls of the white kind; the infusion should be used hot. The tan combines with the oil, while the gallic acid carries off any alkali which may adhere to the cloth. When the stuff is removed from the bath, it should be quickly dried; too great an excess of galls beyond a proper proportion with the oil should be avoided, as it is apt to darken the color. After this preparation the stuff is to be immersed in a solution of alum; and, in consequence of the affinity which exists between tan and alumina, the alum is decomposed, and its earth combines with the tan

OF DYEING BROWN..

227. The substances employed in dyeing browns are very numerous, but those chiefly used are sumach, walnut-peels, and walnut-roots.

On separating the bark from the ligneous substance of the walnut-root, says Berthollet, in relating some experiments on the subject, the former

yielded in equal weight a liquor much more charged with color. The bark of the wood of walnut also exhibited properties approaching to those of walnut-peels, but its decoction formed a blackish precipitate with sulphate of iron. Walnut-peels exercise a lively action on oxide of iron, dissolving it, and forming a liquor as black as ink. If boiled along with clean filings they do not attack them; but, if left exposed to the air, the liquor becomes soon black.

The coloring matter of walnut-peels has a great disposition to combine with wool. It gives it a very durable walnut or dun color, and mordants appear to add little to its permanence, but they may vary its shades, and give them more lustre. By preparing the stuff with alum, a richer and livelier color may be obtained.

Walnut-peels are of excellent use, because they give agreeable and very durable shades, and, being employed without any mordant, they preserve the softness of the wool, and require but one simple, and not expensive, operation. Walnut-peels are gathered when the nuts are entirely ripe. Large casks or tubs are filled with them, and a sufficiency of water is poured on them to cover their surface. In this state they may be kept a year and upwards. At the Gobelins, where a very extensive and varied use is made of this ingredient, it is kept for two years before it is employed. It is found then to furnish much more color. It has a very unpleasant putrid odor.

The peels may also be used which are taken from the nuts before they are ripe; but they do not keep so long.

228. The following are the results of M. Berthollet's experiments on sumach (rhus coriaria) :— The infusion of sumach is of a dun color, bordering on green. It speedily becomes green in the air. When it is recent, the solution of potassa produces little change on it. The acids clear up its color, and render it yellow. Solution of alum makes it turbid, producing a scanty yellow precipitate, while the liquor remains yellow.

Acetate of lead forms instantly an abundant yellowish precipitate, which takes a brown color on its surface; the liquor remains of a clear yellow.

Sulphate of copper affords a copious yellowishgreen precipitate, which, after some hours, changes to a brown-green. The liquor remained clear, and a little yellow.

Sulphate of zinc of commerce rendered the liquor turbid, blackening it, and forming a deep blue precipitate.

Pure sulphate of zinc deepened the color much less; only a slight dun deposite, verging on brown, took place.

Muriate of soda produced no sensible change at first; but, after some hours, the liquor was a little turbid, and its color had become somewhat clearer.

Sumach acts like nut-galls on solution of silver, whose metal it reduces; a result promoted by the action of light. We have already dwelt at sufficient length on the explanation of this phenomenon, as well as the general properties of astrinSumach affords of itself a fawn-color bordering on green; but it communicates to cot

gents.

tou stuffs several very permanent colors, when they are combined with mordants.

229. Sanders, or sandal-wood, is also employed for the purpose of giving a fawn-color. There are three kinds of this wood, the white, the yellow, and the red. The last only, which is a compact heavy wood, brought from the Coromandel coast, is used in dyeing. By exposure to the air it becomes of a brown color; when employed in dyeing, it is reduced to fine powder, and it yields a fawn-color with a brownish shade, inclining to red.

The quantity of cotoring matter, however, which it yields of itself is small, and it is said that it gives harshness to woollen stuffs. When it is mixed with other substances, as sumach, walnut-peels, or galls, the quantity of coloring matter is increased; it gives a more durable color, and produces considerable modifications in the coloring matter with which it is mixed. Sandal-wood yields its coloring matter to brandy, or diluted alcohol, more readily than to water.

230. Soot communicates to woollen stuffs a fawn or brown color, of a lighter or deeper shade, in proportion to the quantity employed; but the color is fading, and its affinity for wool is not great; and, besides leaving a disagreeable smell, it renders the fibres harsh. In some manufactories, it is employed for browning certain colors, and it produces shades which could not otherwise be readily obtained.

231. In dyeing with walnut-peels, a quantity proportioned to the quantity of stuff, and the intensity of shade wanted, is boiled for fifteen minutes in a copper. All that is necessary in dyeing with this substance is, to moisten the cloth or yarn with warm water, previously to their immersion in the copper, in which they are to be carefully stirred till they have acquired the proper shade. This is the process, if the aluminous mordant be not employed. In dyeing cloth, it is usual to give the deepest shades first, and the lighter ones afterwards; but, in dyeing woollen yarn, the light shades are given first, and the deeper ones afterwards. A fresh quantity of peels is added each time.

232. Berthollet made a number of experiments to ascertain the difference of color obtained from the simple decoction of walnutpeels, and the addition of metallic oxides as mordants. The oxide of tin, he informs us, yielded a clearer and brighter fawn-color than that of the simple decoction. The oxide of zinc produced a still clearer color, inclining to ash or gray. The color from oxide of lead had an orange cast, while that from oxide of iron was of a greenish brown.

233. A fawn-color, which has a shade of green, is obtained from sumach alone; but to cotton stuffs, which have been impregnated with printers' mordant, or acetate of alumina, sumach communicates a good and durable yellow.

234. Vogler employed the tincture of sanderswood for dyeing patterns of wool, silk, cotton, and linen, having previously impregnated them with a solution of tin, and afterwards washing and drying them. Sometimes he used the solution unmixed, and at other times added six or ten parts of water, and in whatever way he em

conclude, that the greens composed therewith, will prove greatly superior to any which can result from the dull muddy yellow of old fustic; and, in point of expense, it is certain that the bark, murio-sulphate of tin, and alum, necessary to dye a given quantity of cloth in this way, will cost less than the much greater quantity (six or eight times more) of fustic, with the alum necessary for dyeing it in the common way, the sulphate of indigo being the same in both cases. But in dyeing with the bark, the vessel is only to be filled and heated once; and the cloth, without any previous preparation, may be completely dyed in half an hour; whilst in the common way of producing Saxon greens, the copper is to be twice filled; and to this must be joined the fuel and labor of an hour and a half's boiling and turning the cloth, in the course of preparation, besides nearly as much boiling in another vessel to extract the color of the fustic; and after all, the dyeing process remains to be performed, which will be equal in time and trouble to the whole of the process for producing a Saxon green with the bark; so that this color obtained from bark will not only prove superior in beauty, but in cheapness, to that dyed with old fustic. 240.-Of Dyeing Silk Green.-In communicating to silk the green color, it requires very great caution to prevent the stuff from being spotted and striped. Silk intended for greens is hoiled as for the ordinary colors; for light shades, however, it should be boiled thoroughly

as for blue.

Silk is not first dyed blue like cloth; but, after a strong aluming, it is washed slightly in the river, and distributed into small hanks, that it may take the dye equably; after which it is turned carefully round the sticks, through a bath of weld. When it is thought that the ground is sufficiently deep, a pattern is tried in the vat, to see if the color has the wished-for tone; if it has not ground enough, decoction of weld is added; and, when it is ascertained that the yellow has reached the proper degree, the silk is withdrawn from the bath, and passed through the vat as for blue.

To render the color deeper, and at the same time to vary its tone, there are added to the yellow bath, when the weld has been taken out, juice of Brasil-wood, decoction of fustet, and anotta. For the very light shades, such as apple-green and celadon-green, a much weaker ground is given than for the other colors. For the light shades, if not for sea-green, it is preferable to dye yellow in baths which have already been used, but in which there is no Brasilwood or fustet, because the silk, perfectly alumed, dyes too rapidly in fresh baths, and is thence subject to take an uneven color. Dr. Bancroft recommends the following process for producing Saxon green at one operation, as the most commodious and certain :

241. A bath is prepared of four pounds of quercitron bark, three pounds of alum, and two pounds of murio-sulphate of tin, with a sufficient quantity of water. The bath is boiled ten or fifteen minutes, and when the liquor is in temperature till the hand can bear it, it is fit for dyeing. By adding different proportions of sul

phate of indigo, various and beautiful shades of green may be obtained, and the color thus produced is both cheap and uniform. Care should be taken to keep the bath constantly stirred, to prevent the coloring matter from subsiding. Those shades which are intended to incline most to the yellow, should be dyed first; and, by adding sulphate of indigo, the green, having a shade of blue, may be obtained.

242. To produce what is called an English green, and which is more beautiful than the ordinary greens, and more durable than Saxon green, Guhliche recommends the following process: He gives the silk, first of all, a clear blue in the cold vat; he steeps it in hot water; washes it in running water; passes it through a weak solution of alum; prepares a bath with the sulphuric solution of indigo, a little of the solution of tin, and a tincture of Avignon berry, made with a vegetable acid. He keeps the silk in this bath till it has assumed the wished-for shade; he then washes and dries in the shade. The lighter hues may be dyed in the sequel. The shades may be varied with more or less blue, or more or less yellow, by the proportions of the indigo solution, and of the yellow substance. When it is wished to give a goslin-green to silk, a light blue is communicated to it, either in the hot vat or in the cold; it is passed through hot water, washed in running water, and while moist it is passed through a bath of anotta.

243. Of Dyeing Cotton and Linen Green.To give a green color to linen and cotton yarns, it is proper to begin with scouring them well; then they must be dyed in the blue vat, cleansed in water, and passed through the weld process.

The strength of the blue and the yellow is proportioned to the color that is wanted. As it is difficult to give uniformity to the cotton velvets in the ordinary blue vat, they are usually dyed yellow with turmeric, and the green is produced with solution of indigo in sulphuric acid.

244. To dye beautiful greens upon cotton, Chaptal recommends that it be first dyed of skyblue color with indigo, dissolved by potassa and orpiment, then macerated in a strong solution of sumach, then dried and soaked in a solution of acetate of alumina, dried again, rinsed, and finally dyed with quercitron bark, in the proportion of twelve pounds to every fifty pounds of cotton. The quercitron is preferred to weld for this purpose, because the color of the former combines better with that of sumach.

245. M. D'Apligny recommends a method of dyeing cotton and linen of a fine sea or applegreen by means of a single bath; it is in substance as follows:-The liquor is prepared by mixing verdigris with a sufficient quantity of vinegar, and keeping the mixture in a bottle well stopped for fifteen days in the heat of a stove, and adding to it, about four hours before using it, a solution of potassa equal in weight to that of the verdigris, keeping it still hot. The cotton goods are first soaked in a warm solution, made by dissolving one ounce of alum in five quarts of water for every pound of cotton. The goods are again taken out, and, after adding the verdigris mixture, they are returned, and passed through the bath till sufficiently dyed.