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white is, the more lustre do the colors take, and the more easy is the unmaddering. The fine whites on sale are not even sufficient; and it is right to give them at least one ley, one exposure on the grass, or one immersion in oxygenated muriatic acid, and to let them also soak some hours in water acidulated with sulphuric acid. Very frequently, several leys and several immersions must be given. Thus the dressing (paste) is completely removed, the remaining coloring matter of the cloth is destroyed, which, by fixing in a very durable manner, that of the madder, might render the unmaddering a difficult operation; and thus also the greater number of the stains formed during the maddering, to which the name of madder spots are given, are prevented.

These stains, almost indelible, very common on certain kinds of cotton cloth, and of a color perfectly similar to what madder gives to those parts of the cloth impregnated with oil, seem to arise from a combination with grease or oil, analogous to what takes place in the preparations of Turkey red. It is very probable that they are produced by the grease employed in the parou, or by the soap which must be employed in bleaching. The combination which in that case may be formed on the stuff, resists the subsequent operations well; and it will be seen, in the process for the Adrianople red, that the action of alkaline solutions, even pretty concentrated, is insufficient to destroy the combination of the oil with the cotton. A strong ley, run off very hot, does not afford a complete guarantee against these spots, although it may be the surest means of avoiding them. It would be of great consequence for calico printers to be able to exclude from weaving and bleaching both grease and soap.

The Adrianople red has a lustre, which it is difficult to imitate by all the processes hitherto described. It has, besides, the property of resisting more completely the action of the different re-agents, as alkalies, soap, alum, acids. Vogler acknowledges that by his numerous processes he has not been able to obtain a red possessing a durability equal to that of Adrianople, although he formed one much more permanent than the false Adrianople reds, which are often used for the siamoises and other red goods.

Aquafortis (dilute nitric acid) is, according to the same author, the surest and most expeditious means for distinguishing the true red of Adrianople from the spurious. It is sufficient to plunge a thread of the latter into it. It is soon seen to grow pale, and in less than a quarter of an hour it becomes white, whilst the true Adrianople red remains an hour without being affected, and it never loses the color entirely, which only turns orange.

The Adrianople red, which for a long time came to us through our Levant trade only, stimulated the industry of our artisans; but the attempts were for a long time fruitless, or success was confined to a small number of dyehouses. Abbé Mazeas published experiments which threw much light on this dye; and the government promulgated in 1765, from information that it had procured, an instruction under the title of Memoir,

containing the process for the incarnate cotton red dye of Adrianople on cotton yarn. The same description is found in the treatise of Le Pileur d'Apligny; but this process has not completely succeeded.

Three processes are employed for giving blue in the art of calico-printing. The first of these processes is used for dyeing cloth whose ground is to be blue or green; and, whenever they bear colors which are to be kept from varying in the vat, these are covered with the white reserve.

If the cloth is to retain a white ground, and bear blue figures, of one shade, or of several, the second of these processes is had recourse to. Sometimes one or two colors are joined to the blue thus made; but, in this case, they must be applied after the blue dyeing, because there is not a color which may not be either destroyed, or powerfully altered, in the operations which it requires.

Lastly, in other circumstances, a blue is to be put on cloth covered with a pattern, all of whose parts are already colored, and which leaves merely small spaces to color blue. For this purpose, the blue is used which is applied with the pencil (small brush). This blue of application is thickened with gum, and put upon the pencil. It may be printed on, by covering with canvas the frame which contains the thickened color, and removing the regenerated indigo with a scraper before applying the plate; but only small objects of a slightly intense blue, which rarely succeeds, can be thus applied.

Bancroft says, that he has substituted sugar for the sulphuret of arsenic with success; which would be advantageous, on account of the price and poisonous qualities of this substance. The experiment did not succeed with us. The blue of application has been attempted to be prepared by means of the oxide of tin; but the degree of concentration of the alkaline solution adequate to the solution of the oxide and the indigo has not been hitherto ascertained, so as to be susceptible of thickening with the gums. This point once determined, a pencil blue will be had, which will possess the very great advantage of not occasioning a bulky deposite, which always embarrasses the vessels where this blue is made in the ordinary processes, and which, however well washed, causes a considerable waste of the indigo.

In printing on cloth, ground indigo with oxide of tin, and passing the cloth through a solution of oxide of tin in potash, delft-ware blues may be made in a single vat. We have been able to make in this way only light blues. Were this process brought to the point of producing more substantial blues, it would afford great advantages.

The application of the chromate of lead on Turkey red cloth, forms a brilliant style of calico printing, now carried to high perfection at the establishment of Messrs. Monteith at Glasgow. Nitrate of lead is dissolved in liquid tartaric acid, of a specific gravity about 1:250: this solution is thickened with gum, and applied with the block to cloth previously dyed Turkey red. Whenever the paste is dried, the cloth is slowly passed through an aqueous solution, nearly sa

turated, of chloride of lime, kept at the temperature of about 100° in a stone trough. The tartaric acid, disengaging the chlorine, discharges the color of the Turkey red at the points of application; while the nitrate of lead, or rather perhaps the oxide of lead, remains attached to the cloth. This is immediately washed, and then passed through a solution of bichromate of potash, by means of the padding machine.

An orange color was a few years ago given to goods in calico printing, by means of the crystals of hydrosulphuret of soda and antimony, which are hence called orange crystals. But the use of the alkaline solution of sulphuret of antimony had been long known and practised by the Lancashire printers.

To produce violets on printed calicoes, the acetate of iron diluted with water is impressed, and they are maddered. This color is less easily degraded in the dyeing bath than the reds. It may also be kept boiling for a longer time, so as to raise the deep shades. The bath becomes very foul; the color comes out of it very dull, and assumes lustre only by exposure on the grass, and ebullition with bran water; it is even rare for the white to become beautiful again. But these inconveniences are obviated by dunging with a strong heat, which acts less upon this mordant than upon that employed for the reds. For lilac, a mordant is printed on, composed of very dilute acetate of iron, mixed with a small quantity of acetate of alumina.

Few of the yellows produced from vegetable substances can acquire upon cotton permanence comparable to that of the colors producible from madder; and they never acquire this quality without losing their lustre. When a color rather fast than brilliant is wanted the cotton is colored with oxide of iron, by impregnating it with any of the various solutions of this metal. The processes employed for this dye are very numerous, and their shades may obviously be greatly multiplied, by varying the state of oxidation of the metal, or the nature of the acid which holds it in solution; as also by slight changes in the proportions of the materials, and in the manipulations. **

In order to obtain a deep color, Chaptal treads the cotton in a solution of sulphate of iron, marking from 12° to 15° Baumé. He squeezes it very slightly but equably. As soon as the whole portion (lot) is dipped, it is repassed, hank by hank, through the same solution, and immediately afterwards through a solution of potash, marking the same number of degrees. The color of the cotton becomes of a dirty blue-green, which changes in a few minutes to an agreeable golden yellow. At each dipping the vessel into which the cottons are plunged must be emptied, in order that the color may be equal and uniform.

For a pale and very soft yellow, he treads the cotton in a solution of sulphate of iron, marking three degrees, and repasses it as in the preceding process. On the other hand, he prepares a liquor with solution of potash, marking from two to three degrees, to which he adds solution of alum till he observes that the flocks are no

longer dissolved. He impregnates the cotton

with this liquid, and renews it for each dip. The cotton is dyed of a very agreeable yellow. When the colors are not sufficiently deep, the cotton may be repassed through stronger solutions.

Chaptal recommends, for making the colors evenly, to pass at once no more than one-fourth kilogramme of cotton, to employ weak solutions of sulphate of iron, to dip the cotton first in a solution of potash, then in one of sulphate of iron, repeating these alternate dips as often as shall be requisite to arrive at the desired shade, and to use the greatest care in impregnating and squeezing the cotton equably.

A fresh-butter yellow is produced, by passing the cotton through slightly oxidised acetate of iron, mixed with nitrate of iron, which may be made to incline more to red, the greater the proportion of the latter salt.

With nitrate of iron alone, diluted with water, a pretty clear yellow may be had, which rises quickly. If the cotton be impregnated with nitrate of iron little diluted, allowed to dry, and then washed, it retains a very deep tint, similar to that of rust.

The rust-yellow, which is printed on cloth, is made with two parts of sulphate of iron, and one part of acetate of lead. By mixing with this, different proportions of highly oxidised oxide of iron, shades bordering on red may be procured.

Cotton dyed by these processes takes very different colors in the dye-baths. That which received a faint yellow color by the process of Chaptal, becomes of a walnut hue in the decoction of galls. When the color is deeper it becomes mouse-gray; with tan, or quercitron, it affords a yellow. When passed through a decoction of equal parts of nut-galls, sumach, logwood, and weld, the cotton becomes of a dirty gray-white. When dried, and passed through a strong solution of sulphate of iron, it assumes the bluish-gray color, which is called œil de roi.

Bancroft describes a topical color (couleur d'application), which is obtained from quercitron. A strong decoction of quercitron is made, filtered, and evaporated at a gentle heat, and, when it is reduced to less than one-half, it is allowed to cool to the temperature of the living body. After this, one-fourth of acetate of alumina is mixed with this liquid. The mixture is thickened with as much gum as is necessary to prevent its running during the impression, but not so much as to obstruct its penetrating the stuff. The color obtained by this application has neither as much intensity, nor as much permanence, as that procured by previously impregnating the stuff with the mordant. Both qualities may, however, be increased by a mixture of nitrate of copper and nitrate of lime.

Quercitron ought undoubtedly to be considered as a very useful substance in dyeing; yet the attempts which we know to have been made, with the precautions prescribed by Bancroft, especially in reference to the temperature of the bath, seem to us to prove that the color derived from it is inferior in permanence to that producible from weld. A purer and more lively color may be obtained from quercitron, by adopting

the process which Chaptal has given for fustic (yellow wood).

For dyeing cotton yellow, preparatory to printing, the first thing is to scour it in a bath prepared with a lixivium of the ashes of green wood, then to wash and dry it. It is alumed with the fourth of its weight of alum. After twenty-four hours it is taken out of the aluming and dried, without washing. A weld bath is thereafter prepared, at the rate of one part and a quarter of weld for one of cotton. In this the cotton is dyed, by turning it round the sticks, and working it with the hands, till it has acquired the wished-for shade. It is taken out of this bath to be macerated for an hour and a half in a solution of sulphate of copper or blue vitriol, in the proportion of one-fourth of this salt to one part of cotton. It is next thrown, without washing it, into a boiling solution of white soap, made in the same proportions. After being well stirred, it is to be boiled for nearly an hour, after which it must be well washed and dried.

If a deeper yellow, bordering on jonquille, be wanted, the cotton is not passed through the aluming, but two parts and a half of weld are employed to one of cotton, with the addition of a little verdigris dissolved in a portion of the bath. The cotton is plunged into it, and worked, till it has taken a uniform color. It is lifted out of the bath that a little soda ley may be poured in, when it is again immersed and turned through the bath for a full quarter of an hour. It is then withdrawn, wrung, and dried.

Lemon yellow is made by the same process, except that only one part of weld is used (for one of cotton), while the quantity of verdigris can be diminished in proportion, or even entirely omitted, and aluming put in its place. Thus the shades of yellow may be varied in many ways. The operations on linen yarn are the same.

For the yellow colors, on printed cotton goods, these are impregnated, by means of engraved plates, with the mordant described in treating of madder, formed by the mixture of acetate of lead and alum: the yellow color induced on the parts not impregnated with the acetate of alumina is to be afterwards destroyed by the action of bran, and exposure on the grass. The same mordant may be successfully employed for cotton and linen which is to be dyed yellow.

In order to obtain from weld the whole color that it can yield, it must be boiled for threequarters of an hour; the bundles of weld are now taken out of the bath, after which the cloths are passed through it, at a temperature a little below ebullition. They should not remain in it more than twenty minutes.

When the same piece of cloth is to exhibit the colors produced by both madder and weld, it is necessary to begin with the maddering, and not to print on the mordant intended for the weld till the operations of the madder are finished. This rule is founded on the property which madder possesses of fixing itself in the room of the yellow of weld; so that if the maddering be long continued, after dyeing with weld, the color of the latter entirely disappears. Weld, on the contrary, does not affect the color produced by

madder, provided the mordant has been saturated with the latter, for otherwise a mixed coler would be produced.

The operations required for restoring the white are much longer, and demand much nicer management, after welding than after maddering. See DYEING, par. 203.

The so

By the following method we procure red colors, beautiful and permanent, without employing ley, oils, or galls:-Lime slaked in the air is to be dissolved in cold acetic acid. lution marks from 5° to 6°; and it is reduced to 2° by the addition of water. Equal parts of this solution and acetate of alumina are mixed. The latter is prepared by pouring five kilogrammes of acetate of lead into a solution of twenty kilogrammes of alum for 175 kilogrammes of water. The above mixture is made tepid, and the cottons, merely scoured with care, are passed through it. They are dried, thoroughly washed, dried and maddered with three-fourths of a kilogramme of madder for one kilogramme of cotton. They are brightened with ley and soap, then passed through a solution of tin, and revived with soap alone, in the proportion of twelve kilogrammes of soap for 100 kilogrammes of cotton.

Very durable reds may be had by passing the cotton through this mordant, after having submitted it to oiling without galling. They are even very deep. But on passing the cotton which has received a single oil and four leys through a mixture of acetate of alumina, with one-fourth, one-twe fth, or one-eighteenth of lime, various very lively shades are obtained.

For making a dead red without lustre, termed in some places burned red, or Indian red, on account of its resemblance to that of Indian handkerchiefs, the cotton is scoured, boiled for half an hour in lime water, passed through an oil mixed with some intestinal liquor, and through three leys. It is washed well and turned through a mordant composed of a tepid solution of twelve kilogrammes and a half of alum, to which four kilogrammes of acetate of lead have been added; and a moment afterwards, hálf a kilogramme of soda in powder, and 0.244 kilogrammes of sal-ammoniac. It is washed wi h care, and maddered with its own weight of madder. If the color be poor, it is passed once more through an oil, two leys, the same mordant, and a maddering. It may be brightened with soda and soap. The lime alone produces the difference between this color and the preceding. It renders the colors more permanent, but duller.

The durable rose (color) is produced by taking cotton passed through the oils, and which has received more numerous but weaker leys. It is galled with a ley of sumach (lessive de sumac?) in which two kilogrammes and a half of gallnuts have been boiled; and alumed with seventeen kilogrammes and a half of alum. It is now washed, dyed with madder of the best quality, the madder bath being whitened (blanchi) with two kilogrammes of the oxide of tin, that precipitates from the solution of this metal in nitric acid. It is brightened with weak ley and soap, dried, and passed through a liquor formed of a solution of tin (in nitric acid at 32°, diluted with

an equal volume of water), reduced to 4°. It is now washed and brightened in a solution of fifteen kilogrammes of soap, till the color be rosed in perfection.

On passing the cotton through soap of wool made with soda, taking the same pains as with the soapy liquor prepared for the red, and using very weak leys in the interval, then washing the cotton, and treating it by the same process as for dyeing wool scarlet, it assumes a scarlet tint, paler than that of wool, but pretty brilliant.

Cotton dyed red may, moreover, be made to pass through all the shades, down to the palest orange. For this purpose, pure nitric acid is diluted with two-fifths (three-fifths?) of water; chips of tin are oxidised in it till the liquor grows opal, and the solution is employed at different strengths, from 2o to 20o.

Poerner made a great many researches on the methods which may be employed to dye cotton by means of brasil, employing different mordants, as alum, solution of tin, sal ammoniac, potash, &c., in the bath, or in the preparation of the stuff; but he did not obtain colors which could resist the action of soap, although some of them stood pretty well the action of the air and washing with water. He recommends us to dry in the shade the cottons which have received these colors.

To Brown, who is engaged with much zeal in the arts, we are indebted for a process which is used for a crimson on cotton in some manufactories.

A solution of tin is prepared in the following proportions :-Nitric acid four parts; muriatic acid two parts; tin one part; water two parts. The liquids are to be mixed, and the tin dissolved in them, by adding it in small bits at a time.

As the best colors that can be given to linen and cotton are derived from madder, attention must be paid to the methods described, in treating of madder, for rendering this dye more durable, and its color may be deepened by different black baths. For some hazels and snuff colors, a browning is given, after the welding and the madder bath, with soot, to which gall nuts and fustic are joined. Soot is sometimes mixed with this bath, and a browning is moreover given with solution of sulphate of iron.

Walnut peels are occasionally substituted for solutions of iron in browning colors. They have a great advantage for the wools intended for (tapisseries) tapestry. The color does not become yellow by long exposure to the air, as happens to the brownings from iron; but it keeps long without alteration. It has indeed a dull tone, suitable for shadows, and for representing the flesh in old figures, which would produce merely gloomy colors, without lustre, on cloths. The goodness of this color, however, and its cheapness, ought to extend its use for the sombre colors which are sometimes in fashion, at least on common stuffs.

A great number of shades are made at the Gobelins by means of this browning. To procure an assortment of them, a bouillon is first given to the woollen yarns with tartar and alum of different degrees of strength, according to the

shades required; they are then successively dyed red, yellow, or some other color, recurring to the bath from which most effect is wished to be obtained. When the color is found to be of the

desired shade, it is passed, for a shorter or longer time, through the bath of walnut peels, of a strength adjusted to its purpose. This browning is likewise had recourse to for silk; but the bath must be hardly tépid, in order to avoid the inequalities to which it is so liable.

For the different shades of marrone the cotton is galled, passed with the ordinary manipulation through water, into which a greater or less quantity of the black cask (tonne au noir) has been poured. It is next worked in a bath in which verdigris has been dissolved; and a welding is given it. It is dyed in a bath of fustic, to which a solution of soda and alum is sometimes added. When the cotton which has received these preparations has been well washed, a good maddering is given it. It is then passed through a weak solution of sulphate of copper, and lastly through soap water.

The cinnamon and mordoré colors are given to linen and cotton by commencing the dyeing with verdigris and weld; they are next passed through a solution of sulphate of iron, which is called the security bath (bain d'assurance), and they are wrung out and dried. When dry they are galled in the proportion of 122 grammes of gall-nuts per kilogramme; they are once more dried, alumed as for red, and maddered. When they are dyed and washed, they are passed through very hot soap water, in which they are turned round the sticks till they are sufficiently brightened. Decoction of fustic is sometimes added to the aluming.

By taking cotton which had received the requisite preparations for the Adrianople red, and had been galled, then passing it through nitrate of iron, galling it anew, and aluming, Chaptal obtained a pretty nacaret. He prepares the nitrate of iron with the aquafortis of commerce, diluted with half its weight of water, into which he plunges fragments of iron, which he removes whenever he perceives the solution slackening. The liquor is now of a yellowish red, strongly acid, and marks from 40° to 50° on the aërometer of Baumé. See DYEING, 180.

If after galling the cotton that has passed through the oils it is alumed in a bath, to which one-eighth of this solution of iron, for one of cotton, is added, the cotton comes out black, and takes a violet sloe color by the maddering and brightening.

James Thomson, esq., of Primrose Hill, F.R.S. obtained, in the years 1813 and 1815, two patents for certain improvements in calico printing. His processes, which are very elegant, have since been extensively and advantageously employed. The following is an outline of his specifications. That for 1813 is thus stated :

First, Mix or combine with the acid called oxymuriatic acid (or dephlogisticated acid of sea salt) and water, some of the alkaline salts or earths bereinafter-named, which shall weaken or suspend the power of the said acid in such proportion that it shall not, in such mixed or combined state, of itself, and without any farther operation, be able

to remove the Turkey red color from the cloth, or materially to impair it, within the moderate space of time taken up in the performance of the process hereinafter described.

Secondly, Print, stamp, pencil, or otherwise apply to those parts of the said cloth, which are intended to be either wholly, or in a greater or less degree, deprived of their red color, some other acid, or metallic oxide, or calx, which has a greater affinity or attraction for the alkaline salt or earth with which the oxymuriatic acid is mixed or combined, than that acid itself possesses and if any one of the stronger or more powerful acids be employed, which is either of a corrosive nature and cannot be safely used, or of a volatile nature and cannot be used conveniently, such acid must be combined with alkalies, earths, metals, or metallic oxides or calces, so as to form neutral salts, acid salts, or metallic salts, which shall not be too corrosive or too volatile; and such alkalies, earths, metals, or metallic oxides, or calces only, must be employed, as have a weaker affinity or attraction for the same acid than that acid has for the alkaline salt or earth with which the oxymuriatic acid has been mixed or combined.

Thirdly, After the said acid, oxides, neutral salts, acid salts, or metallic salts, so directed to be printed, stamped, pencilled, or otherwise applied to the cloth as aforesaid, are sufficiently dry, immerse the cloth in the solution of the said oxymuriatic acid, so mixed or combined with some of the alkaline salts or earths hereinafternamed as aforesaid. When the acid or oxide, either in its simple or combined state, has been applied to parts of the cloth, it immediately seizes upon and combines with the alkaline salt or earth with which the oxymuriatic acid has been mixed or combined, and disengages that acid, which almost instantaneously deprives of their color those parts of the cloth to which the said acids or oxides, in their simple or combined state, have been so printed, stamped, pencilled, or otherwise applied as aforesaid.

Lastly, Wash or otherwise remove all the said acids, oxides, or salts, by the usual processes. For the more fully explaining and illustrating the invention herein before described, I add the following remarks:-The alkaline salts or earths which I mix or combine with the oxymuriatic acid, in order to suspend or prevent its action on those parts of the red cloth which are intended to retain their color, are the alkaline salts of potassa and soda, or the calcareous, magnesian, barytic, or strontitic earths, of which I prefer the calcareous earth.

The acids which I apply to the parts intended to be made white, or to those places on the cloth intended to be deprived of their red color, in a greater or less degree, are any of the vegetable, mineral, or animal acids, which have a stronger attraction for the alkaline salt or earth with which the oxymuriatic acid has been mixed or combined, than that acid itself has; such, for instance, are the citric, oxalic, tartaric, malic, benzoic, sulphuric, sulphurous, phosphoric, fluoric, boracic, nitric, muriatic, arsenic, tungstic, succinic, and carbonic acids.

The stronger acids, or such as might corrode

:

the cloth, I saturate more or less with some alkaline salt, earth, or metallic oxide or calx, for which they have a weaker affinity or attraction than they have for the alkali or earth with which I have combined the oxymuriatic acid for instance, I unite the sulphuric acid with potassa, so as to form the acid sulphate of potassa (or acid vitriolated tartar), or with aluminous earth, to form alum. The muriatic acid combine with tin, or copper, or zinc, forming inuriate of tin, muriate of copper, or muriate of zinc. In like manner, the nitric acid may be combined with the aluminous earth, or with the volatile alkali, or with the metals, or oxides of copper, or zinc, or iron, or mercury; and I take care, when I use acidulous compounds of such corrosive acids, not to suffer the acid so far to predominate as to render the compound injurious. In like manner I combine the volatile acids, or such as might evaporate too speedily, with some alkaline salt or earth, or metallic oxide or calx, for which they have a weaker affinity' or attraction than they have for the alkali or earth with which I have combined the oxymuriatic acid: for instance, I combine the acetic acid with the earth of alum, so as to form acetate of alumina,-or with copper, forming acetate of copper,-or with zinc, forming acetate of zinc. The carbonic acid may also be fixed and combined with an alkali, as with soda, for example, forming carbonate of soda, which may be used, though with less advantage than the preceding combinations. Those acids which are not corrosive nor volatile, and which consequently are used with most advantage in their simple or combined state, may, however, be united like the preceding to the alkalies, earths, metals, or metallic oxides or calces, for which they have a weaker affinity or attraction than they have for the alkali or earth with which the oxymuriatic acid has been united. Thus the tartaric acid may be combined with potassa, to form cream of tartar,-and the oxalic acid with potassa, to form salt of sorrel,-and these two salts may be employed in the process, though it is not necessary so to combine the two acids; but, on the contrary, the acids may be used alone.

The combinations which I prefer, as uniting the greatest number of advantages upon the whole, are, the supersulphate of potassa (or acid vitriolated tartar), the sulphate of copper or blue vitriol, the muriate of tin or sal jovis, the nitrate of copper, and the muriate of copper. But I prefer to any single combination a mixture of the supersulphate of potassa, with the tartaric or citric acids.

Lastly, I employ, uncombined, such metallic oxides or calces as approach in their properties to the nature of acids, and are capable of combining either with the alkaline salts of potassa or soda, or with the calcareous, magnesian, or strontitic earths, or of disengaging them, or any of them, from their combination with oxymuriatic acid: such, for instance, is the oxide of arsenic, or common white arsenic, and the oxides of tin and tungsten.

It is evident, from what I have set forth in the preceding part of this specification, that this process admits of great variety in its application, according to the combinations I make use of;

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