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white is, the more lustre do the colors take, and containing the process for the incarnate cotton red the more easy is the unmaddering. The fine dye of Adrianople on cotton yarn. The same whites on sale are not even sufficient; and it is description is found in the treatise of Le Pileur right to give them at least one ley, one exposure d’Apligny; but this process has not completely on the grass, or one immersion in oxygenated succeeded. muriatic acid, and to let them also soak some Three processes are employed for giving blue hours in water acidulated with sulphuric acid. in the art of calico-printing. The first of these Very frequently, several leys and several immer- processes is used for dyeing cloth whose ground sions must be given. Thus the dressing (paste) is to be blue or green; and, whenever they bear is completely removed, the remaining coloring colors which are to be kept from varying in the matter of the cloth is destroyed, which, by fix- vat, these are covered with the white reserve. ing in a very durable manner, that of the mad If the cloth is to retain a white ground, and der, might render the unmaddering a diffi- bear blue figures, of one shade, or of several, cult operation; and thus also the greater number the second of these processes is had recourse to. of the stains formed during the maddering, to Sometimes one or two colors are joined to the which the name of madder spots are given, are blue thus made; but, in this case, they must be prevented.

applied after the blue dyeing, because there is These stains, almost indelible, very common on not a color which may not be either destroyed, certain kinds of cotton cloth, and of a color per or powerfully altered, in the operations which it fectly similar to what madder gives to those requires. parts of the cloth impregnated with oil, seem to Lastly, in other circumstances, a blue is to be arise from a combination with grease or oil, put on cloth covered with a pattern, all of whose analogous to what takes place in the prepara- parts are already colored, and which leaves tions of Turkey red. It is very probable that merely small spaces to color blue. For this they are produced by the grease employed in purpose, the blue is used which is applied with the parou, or by the soap which must be em- the pencil (small brush). This blue of applicaployed in bleaching. The combination which tion is thickened with gum, and put upon the in that case may be formed on the stuff, resists pencil. It may be printed on, by covering with the subsequent operations well; and it will be canvas the frame which contains the thickened seen, in the process for the Adrianople red, that color, and removing the regenerated indigo with the action of alkaline solutions, even pretty con a scraper before applying the plate ; but only centrated, is insufficient to destroy the combina- small objects of a slightly intense blue, which tion of the oil with the cotton. A strong ley, rarely succeeds, can be thus applied. run off very hot, does not afford a complete Bancroft says, that he has substituted sugar guarantee against these spots, although it may for the sulphuret of arsenic with success; be the surest means of avoiding them. It would which would be advantageous, on account of the be of great consequence for calico printers to be price and poisonous qualities of this substance. able to exclude from weaving and bleaching both The experiment did not succeed with us. The grease and soap.

blue of application has been attempted to be The Adrianople red has a lustre, which it is prepared by means of the oxide of tin; but the difficult to imitate by all the processes hitherto degree of concentration of the alkaline solution described. It has, besides, the property of resist- adequate to the solution of the oxide and the ing more completely the action of the different indigo has not been hitherto ascertained, so as to re-agents, as alkalies, soap, alum, acids. Vogler be susceptible of thickening with the gums. This acknowledges that by his numerous processes point once determined, a pencil blue will be he has not been able to obtain a red possessing a had, which will possess the very great advantage durability equal to that of Adrianople, although of not occasioning a bulky deposite, which alhe formed one much more permanent than the ways embarrasses the vessels where this blue is false Adrianople reds, which are often used for made in the ordinary processes, and which, howthe siamoises and other red goods.

ever well washed, causes a considerable waste of Aquafortis (dilute nitric acid) is, according to the indigo. the same author, the surest and most expeditious In printing on cloth, ground indigo with oxide means for distinguishing the true red of Adrian- of tin, and passing the cloth through a solution ople from the spurious. It is sufficient to plunge of oxide of tin in potash, delft-ware blues may a thread of the latter into it. It is soon seen to be made in a single vat. We have been able to grow pale, and in less than a quarter of an hour make in this way only light blues. Were this it becomes white, whilst the true Adrianople red process brought to the point of producing more remains an hour without being affected, and it substantial blues, it would afford great advannever loses the color entirely, which only turns tages. orange.

The application of the chromate of lead on The Adrianople red, which for a long time came Turkey red cloth, forms a brilliant style of calico to us through our Levant trade only, stimulated printing, now carried to high perfection at the the industry of our artisans; but the attempts establishment of Messrs. Monteith at Glasgow. were for a long time fruitless, or success was Nitrate of lead is dissolved in liquid tartaric confined to a small number of dyehouses. Abbé acid, of a specific gravity about 1.250 : this soMazeas published experiments which threw much lution is thickened with gum, and applied with light on this dye; and the government promul- the block to cloth previously dyed Turkey red. gated in 1765, from information that it had pro- Whenever the paste is dried, the cloth is slowly cured, an instruction under the title of Memoir, passed through an aqueous solution, nearly sa

urated, of chloride of lime, kept at the tempe- with this liquid, and renews it for each dip. rature of about 100° in a stone trough. The The cotton is dyed of a very agreeable yellow. tartaric acid, disengaging the chlorine, discharges When the colors are not sufficiently deep, the the color of the Turkey red at the points of ap- cotton may be repassed through stronger soluplication; while the nitrate of lead, or rather tions. perhaps the oxide of lead, remains attached to Chaptal recommends, for making the colors the cloth. This is immediately washed, and evenly, to pass at once no more than one-fourth then passed through a solution of bichromate of kilogramme of cotton, to employ weak solutions potast, by means of the padding machine. of sulphate of iron, to dip the cotton first in a

An orange color was a few years ago given to solution of potash, then in one of sulphate of goods in calico printing, by means of the crys- iron, repeating these alternate dips as often as tals of hydrosulphuret of soda and antimony, shall be requisite to arrive at the desired shade, wbich are hence called orange crystals. But the and to use the greatest care in impregnating and use of the alkaline solution of sulphuret of anti- squeezing the cotton equably. mony had been long known and practised by the A fresh-butter yellow is produced, by passing Lancashire printers.

the cotton through slightly oxidised acetate of To produce violets on printed calicoes, the iron, mixed with nitrate of iron, which may be acetate of iron diluted with water is impressed, made to incline more to red, the greater the proand they are maddered. This color is less easily portion of the latter salt. degraded in the dyeing bath than the reds. It With nitrate of iron alone, diluted with water, may also be kept boiling for a longer time, so as a pretty clear yellow may be had, which rises to raise the deep shades. The bath becomes quickly. If the cotton be impregnated with nivery foul ; the color comes out of it very dull, trate of iron little diluted, allowed to dry, and and assumes lustre only by exposure on the grass, then washed, it retains a very deep tint, similar and ebullition with bran water; it is even rare to that of rust. for the white to become beautiful again. But The rust-yellow, which is printed on cloth, is these inconveniences are obviated by dunging made with two parts of sulphate of iron, and with a strong heat, which acts less upon this one part of acetate of lead. By mixing with mordant than upon that employed for the reds. this, different proportions of highly oxidised

For lilac, a mordant is printed on, composed oxide of iron, shades bordering on red may be of very dilute acetate of iron, mixed with a procured. stpall quantity of acetate of alumina.

Cotton dyed by these processes takes very Few of the yellows produced from vegetable different colors in the dye-baths. That which substances can acquire upon cotton permanence received a faint yellow color by the process of comparable to that of the colors producible from Chaptal, becomes of a walnut hue in the decocmadder; and they never acquire this quality tion of galls. When the color is deeper it bewithout losing their lustre. When a color rather comes mouse-gray; with tan, or quercitron, it fast than brilliant is wanted the cotton is colored affords a yellow. When passed through a dewith oxide of iron, by impregnating it with any coction of equal parts of nut-galls, sumach, logof the various solutions of this metal. The pro- wood, and weld, the cotton becomes of a dirty cesses employed for this dye are very numerous, gray-white. When dried, and passed through a and their shades may obviously be greatly mul- strong solution of sulphate of iron, it assumes tiplied, by varying the state of oxidation of the the bluish-gray color, which is called æil de roi. metal, or the nature of the acid which holds it Bancroft describes a topical color (couleur in solution; as also by slight changes in the d'application), which is obtained from querciproportions of the materials, and in the mani- tron. A strong decoction of quercitron is made, pulations. :*

filtered, and evaporated at a gentle heat, and, In order to obtain a deep color, Chaptal treads when it is reduced to less than one-half, it is the cotton in a solution of sulphate of iron, mark- allowed to cool to the temperature of the living ing from 12° to 15o Baumé. He squeezes it body. After this, one-fourth of acetate of aluvery slightly but equably. As soon as the whole mina is mixed with this liquid. The mixture is portion (lot) is dipped, it is repassed, hank by thickened with as much gum as is necessary to hank, through the same solution, and immedi- prevent its running during the impression, but ately afterwards through a solution of potash, not so much as to obstruct its penetrating the marking the same number of degrees. The stuff. The color obtained by this application color of the cotton becomes of a dirty blue-green, has neither as much intensity, nor as much perwhich changes in a few minutes to an agreeable manence, as that procured by previously impreggolden yellow. At each dipping the vessel into nating the stuff with the mordant. Both qualiwhich the cottons are plunged must be emptied, ties may, however, be increased by a mixture of in order that the color may be equal and uni- nitrate of copper and nitrate of lime.

Quercitron ought undoubtedly to be considered For a pale and very soft yellow, he treads the as a very useful substance in dyeing ; yet the cotton in a solution of sulphate of iron, mark- attempts which we know to have been made, ing three degrees, and repasses it as in the pre- with the precautions prescribed by Bancroft

, ceding process. On the other hand, he prepares especially in reference to the temperature of the a liquor with solution of potash, marking from bath, seem to us to prove that the color derived two to three degrees, to which he adds solution from it is inferior in permanence to that prodıof alum till he observes that the flocks are no cible from weld. A purer and more lively color longer dissolved. He impregnates the cotton may be obtained from quercitron, by adopting


the process which Chaptal 'has given for fustic madder, provided the mordant has bien satu(yellow wood).

rated with the latter, for otherwise a mixed color For dyeing cotton yellow, preparatory to would be produced. printing, the first thing is to scour it in a bath The operations required for restoring the white prepared with a lixivium of the ashes of green are much longer, and demand much nicer máwood, then to wash and dry it. It is alumed nagement, after welding than after maddering. with the fourth of its weight of alum. After See Dyeing, par. 203. twenty-four hours it is taken out of the aluming By the following method we procure red coand dried, without washing. A weld bath is lors, beautiful and permanent, without employthereafter prepared, at the rate of one part and a ing ley, oils, or galls :-Lime slaked in the air quarter of weld for one of cotton. In this the is to be dissolved in cold acetic acid. The socotton is dyed, by turning it round the sticks, lution niarks from 50 to 6°; and it is reduced to 20 and working it with the hands, till it has acquired by the addition of water. Equal parts of this soluthe wished-for shade. It is taken out of this tion and acetate of alumina are mixed. The latter is bath to be macerated for an hour and a balf in prepared by pouring five kilogrammes of acetate a solution of sulphate of copper or blue vitriol, of lead into a solution of twenty kilogrammes of in the proportion of one-fourth of this salt to one alum for 175 kilogrammes of water. The above part of cotton. It is next thrown, without wash- mixture is made tepid, and the cottons, merely ing it, into a boiling solution of white soap, made scoured with care, are passed through it. They in the same proportions. After being well stirred, are dried, thoroughly washed, dried and madit is to be boiled for nearly an hour, after which dered with three-fourths of a kilogramme of it must be well washed and dried.

madder for one kilogramme of cotton. They If a deeper yellow, bordering on jonquille, be are brightened with ley and soap, then passed wanted, the cotton is not passed through the through a solution of tin, and revived with soap aluming, but two parts and a half of weld are alone, in the proportion of twelve kilogrammes employed to one of cotton, with the addition of of soap for 100 kilogrammes of cotton. a little verdigris dissolved in a portion of the Very durable reds may be had by passing the bath. The cotton is plunged into it, and worked, cotton through this mordant, after having subtill it has taken a uniform color. It is lifted mitted it to oiling without galling. They are out of the bath that a little soda ley may be even very deep. But on passing the cotton poured in, when it is again immersed and turned which has received a single oil and four leys through the bath for a full quarter of an hour. through a mixture of acetate of alumina, with It is then withdrawn, wrung, and dried. one-fourth, one-twe fth, or one-eighteenth of

Lemon yellow is made by the same process, lime, various very lively shades are obtained. except that only one part of weld is used For making a dead red without lustre, termed (for one of cotton), while the quantity of verdi- in some places burned red, or Indian red, on gris can be diminished in proportion, or even account of its resemblance to that of Indian entirely omitted, and aluming put in its place. handkerchiefs, the cotton is scoured, boiled for Thus the shades of yellow may be varied in half an hour in lime water, passed through an oil many ways. The operations on linen yarn are mixed with some intestinal liquor, and through

three leys. It is washed well and turned through For the yellow colors, on printed cotton goods, a mordant composed of a tepid solution of these are impregnated, by means of engraved twelve kilogrammes and a half of alum, to plates, with the mordant described in treating of which four kilogrammes of acetate of lead have madder, formed by the mixture of acetate of been added ; and'a moment afterwards, hálf a lead and alum: the yellow color induced on the kilogramme of soda in powder, and 0-244 kiloparts not impregnated with the acetate of alu- grammes of sal-ammoniac. It is washed wih mina is to be afterwards destroyed by the action care, and maddered with its own weight of of bran, and exposure on the grass. The same madder. If the color be poor, it is passed once mordant may be successfully employed for cot more through an oil, two leys, the same mordant, ton and linen which is to be dyed yellow. and a maddering. It may be brightened with

In order to obtain from weld the whole color soda and soap. The lime alone produces the that it can yield, it must be boiled for three- difference between this color and the preceding. quarters of an hour; the bundles of weld are It renders the colors more permanent, but now taken out of the bath, after which the cloths duller. are passed through it, at a temperature a little The durable rose (color) is produced by taking below ebullition. They should not remain in it cotton passed through the oils, and which has more than twenty minutes.

received more numerous but weaker leys. It is When the same piece of cloth is to exhibit the galled with a ley of sumach (lessive de simac?) colors produced by both madder and weld, it is in which two kilogrammes and a half of gallnecessary to begin with the maddering, and not nuts have been boiled; and alumed with sevento print on the mordant intended for the weld teen kilogrammes and a half of alum. It is now till the operations of the madder are finished. washed, dyed with madder of the best quality, This rule" is founded on the property which the madder bath being whitened (blanchi) with madder possesses of fixing itself in the room of two kilogrammes of the oxide of tin, that prethe yellow of weld; so that if the maddering becipitates from the solution of this metal in nitric long continued, after dyeing with weld, the color acid. It is brightened with weak ley and soap, of the latter entirely disappears. Weld, on the dried, and passed through a liquor formed of a contrary, does not affect the color produced by solution of ein (in nitric acid at 32°, diluted with

the same.

an equal volume of water), reduced to 4°. It is shades required; they are then successively dyed dow washed and brightened in a solution of fif- red, yellow, or some other color, recurring to the teen kilogrammes of soap, till the color be rosed bath from which most effect is wished to be obin perfection.

tained. When the color is found to be of the On passing the cotton through soap of wool desired shade, it is passed, for a shorter or longer made with soda, taking the same pains as with time, through the bath of walnut peels, of a the soapy liquor prepared for the red, and using strength adjusted to its purpose. This browning very weak leys in the interval, then washing the is likewise had recourse to for silk; but the bath cotton, and treating it by the same process as for must be hardly tépid, in order to avoid the inedyeing wool scarlet, it assumes a scarlet tint, qualities to which it is so liable. paler than that of wool, but pretty brilliant. For the different shades of marrone the cotton

Cotton dyed red may, moreover, be made to is galled, passed with the ordinary manipulation pass through all the shades, down to the palest through water, into which a greater or less quanorange. For this purpose, pure nitric acid is tity of the black cask (tonne au noir) has been diluted with two-fifths (three-fifths ?) of water; poured. It is next worked in a bath in which chips of tin are oxidised in it till the liquor verdigris has been dissolved ; and a welding is grows opal, and the solution is employed at dif- given it. It is dyed in a bath of fustic, to which ferent strengths, from 20 to 20°.

a solution of soda and alum is sometimes added. Poerner made a great many researches on the When the cotton which has received these premethods which may be employed to dye cotton parations has been well washed, a good madderby means of brasil

, employing different mor- ing is given it. It is then passed through a weak dants, as alum, solution of tin, sal ammoniac, solution of sulphate of copper, and lastly through potash, &c., in the bathi, or in the preparation of soap water. the stuff; but he did not obtain colors which The cinnamon and mordoré colors are given could resist the action of soap, although some of to linen and cotton by commencing the dyeing them stood pretty well the action of the air and with verdigris and weld ; they are next passed washing with water. He recommends us to dry through a solution of sulphate of iror., which is in the shade the cottons which have received called the security bath (bain d'assurance), and these colors.

they are wrung out and dried. When dry they To Brown, who is engaged with much zeal in are galled in the proportion of 122 grammes of the arts, we are indebted for a process which is gall-nuts per kilogramme; they are once more used for a crimson on cotton in some manufac- dried, alumed as for red, and maddered. When tories.

they are dyed and washed, they are passed A solution of tin is prepared in the following through very hot soap water, in which they ate proportions :-Nitric acid four parts ; muriatic turned round the sticks till they are sufficiently acid two parts; tin one part; water two parts. brightened. Decoction of fustic is sometimes The liquids are to be mixed, and the tin dis- added to the aluming. solved in them, by adding it in small bits at a By taking cotton which had received the retime.

quisite preparations for the Adrianople red, and As the best colors that can be given to linen had been galled, then passing it through nitrate and cotton are derived from madder, attention of iron, galling it anew, and aluming, Chaptal must be paid to the methods described, in treat- obtained a pretty nacaret. He prepares the niing of madder, for rendering this dye more dura- trate of iron with the aquafortis of commerce, ble, and its color may be deepened by different diluted with half its weight of water, into which black baths. For some hazels and snuff colors, he plunges fragments of iron, which he removes a browning is given, after the welding and the whenever he perceives the solution slackering. madder bath, with soot, to which gall nuts and The liquor is now of a yellowish red, strongly fustic are joined. Soot is sometimes mixed with acid, and marks from 400 to 50° on the aëromethis bath, and a browning is moreover given with ter of Baumé. See Dyeing, 180. solution of sulphate of iron.

If after galling the cotton that has passed Walnut peels are occasionally substituted for through the oils it is alumed in a bath, to which solutions of iron in browning colors. They have one-eighth of this solution of iron, for one of cot. a great advantage for the wools intended for ton, is added, the cotton comes out black, and (tapisseries) tapestry. The color does not be- takes a violet sloe color by the maddering and come yellow by long exposure to the air, as brightening. happens to the brownings from iron; but it keeps James Thomson, esq., of Primrose Hill, F.R.S. long without alteration. It has indeed a dull obtained, in the years 1813 and 1815, two patone, suitable for shadows, and for representing tents for certain improvements in calico printing. the flesh in old figures, which would produce His processes, which are very elegant, have since merely gloomy colors, without lustre, on cloths. been extensively and advantageously employed. The goodness of this color, however, and its The following is an outline of his specifications. cheapdess, ought to extend its use for the sombre That for 1813 is thus stated :colors which are sometimes in fashion, at least on First, Mix or combine with the acid called oxcommon stuffs.

ymuriatic acid (or dephlogisticated acid of sea A great number of shades are made at the salt) and water, some of the alkaline salts or earths Gobelins by means of this browning. To pro- bereinafter-named, which shall weaken or suspend cure an assortment of thein, a bouillon is first the power of the said acid in such proportion that given to the woollen yarns with tartar and alum it shall not, in such mixed or combined state, of of different degrees of strength, according to the itself, and without any farther operation, be able

to remove the Turkey red color from the cloth, the cloth, I saturate more or less with some alor materially to impair it, within the moderate kaline salt, earth, or metallic oxide or calx, for space of time taken up in the performance of which they have a weaker affinity or attraction the process hereinafter described.

than they have for the alkali or earth with which Secondly, Print, stamp, pencil, or otherwise I have combined the oxymuriatic acid : for inapply to those parts of the said cloth, which are stance, I unite the sulphuric acid with potassa, intended to be either wholly, or in a greater or so as to form the acid sulphate of potassa (or less degree, deprived of their red color, some other acid vitriolated tartar), or with aluminous earth, acid, or metallic oxide, or calx, which has a to form alum. The muriatic acid I combine greater affinity or attraction for the alkaline salt with tin, or copper, or zinc, forming inuriate of or earth with which the oxymuriatic acid is tin, muriate of copper, or muriate of zinc. In mixed or combined, than that acid itself pos- like manner, the nitric acid may be combined with sesses : and if any one of the stronger or more the aluminous earth, or with the volatile alkali, powerful acids be employed, which is either of or with the metals, or oxides of copper, or zinc, a corrosive nature and cannot be safely used, or or iron, or mercury; and I take care, when I of a volatile nature and cannot be used conve use acidulous compounds of such corrosive niently, such acid must be combined with alka- acids, not to suffer the acid so far to predominate lies, earths, metals, or metallic oxides or calces, as to render the compound injurious. In like so as to form neutral salts, acid salts, or metallic manner I combine the volatile acids, or such as salts, which shall not be too corrosive or too might evaporate too speedily, with some alkaline volatile; and such alkalies, earths, metals, or salt or earth, or metallic oxide or calx, for which metallic oxides, or calces only, must be employed, they have a weaker affinity' or attraction than as have a weaker affinity or attraction for the they have for the alkali or earth with which I same acid than that acid has for the alkaline have combined the oxymuriatic acid : for insalt or earth with which the oxymuriatic acid has stance, I combine the acetic acid with the earth been mixed or combined.

of alum, so as to form acetate of alumina,-or Thirdly, After the said acid, oxides, neutral with copper, forming acetate of copper,-or with salts, acid salts, or metallic salts, so directed to zinc, forming acetate of zinc. The carbonic acid be printed, stamped, pencilled, or otherwise ap- may also be fixed and combined with an alkali, plied to the cloth as aforesaid, are sufficiently as with soda, for example, forming carbonate of dry, immerse the cloth in the solution of the said soda, which may be used, though with less adoxymuriatic acid, so mixed or combined with vantage than the preceding combinations. Those some of the alkaline salts or earths hereinafter- acids which are not corrosive nor volatile, and named as aforesaid. When the acid or oxide, which consequently are used with most advaneither in its simple or combined state, has been tage in their simple or combined state, may, applied to parts of the cloth, it immediately however, be united like the preceding to the alseizes upon and combines with the alkaline salt kalies, earths, metals, or metallic oxides or calces, or earth with which the oxymuriatic acid bas for which they have a weaker affinity or attraction been mixed or combined, and disengages that than they have for the alkali or earth with which acid, which almost instantaneously deprives of the oxymuriatic acid has been united. Thus the their color those parts of the cloth to which the tartaric acid may be combined with potassa, to said acids or oxides, in their simple or combined form cream of tartar,--and the oxalic acid with state, have been so printed, stamped, pencilled, potassa, to form salt of sorrel,—and these two salts or otherwise applied as aforesaid.

may be employed in the process, though it is Lastly, Wash or otherwise remove all the said not necessary so to combine the two acids; hut, acids, oxides, or salts, by the usual processes. on the contrary, the acids may be used alone. For the more fully explaining and illustrating The combinations which I prefer, as uniting the invention herein before described, I add the the greatest number of advantages upon the following remarks :- The alkaline salts or earths whole, are, the supersulphate of potassa (or acid which I mix or combine with the oxymuriatic vitriolated tartar), the sulphate of copper or blue acid, in order to suspend or prevent its action on vitriol, the muriate of lin or sal jovis, the nitrate those parts of the red cloth which are intended of copper, and the muriate of copper. But I to retain their color, are the alkaline salts of po- prefer to any single combination a mixture of tassa and soda, or the calcareous, magnesian, the supersulphate of potassa, with the tartaric or barytic, or strontitic earths, of which I prefer the citric acids. calcareous earth.

Lastly, I employ, uncombined, such metallic The acids which I apply to the parts intended oxides or calces as approach in their properties to be made white, or to those places on the cloth to the nature of acids, and are capable of comintended to be deprived of their red color, in a bining either with the alkaline salts of potassa greater or less degree, are any of the vegetable, or soda, or with the calcareous, magnesian, or mineral, or animal acids, which have a stronger strontitic earths, or of disengaging them, or any attraction for the alkaline salt or earth with which of them, from their combination with oxymurithe oxymuriatic acid has been mixed or com- atic acid : such, for instance, is the oxide of arbined, than that acid itself has; such, for in- senic, or common white arsenic, and the oxides stance, are the citric, oxalic, tartaric, malic, ben- of tin and tungsten. zoic, sulphuric, sulphurous, phosphoric, fluoric, It is evident, from what I have set forth in the boracic, nitric, muriatic, arsenic, tungstic, succi- preceding part of this specification, that this nic, and carbonic acids.

process admits of great variety in its application, The stronger acids, or such as might corrode according to the combinations I make use of

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