Chapter I: Introductory (2)

Agriculturists and agricultural chemists know that _alumina_ constitutes three eighths or more of a fruitful soil; some vegetables, likewise, contain this earth in their composition. _Iron_ is also a component part of many soils, particularly those in which a _red_ colour is predominant; hence it is, probably, a component part of all drugs used for browns, fawns, and blacks. It will be seen what affinity cotton has for _iron_ in the dye of _buff_[4] upon cotton; and it seems reasonable to conclude that this metal not only produces the black, grey, and brown hues, but, with lime, forms a component part of the drugs themselves which give the brown dyes. It may be here also mentioned, that the _red_ colour of the blood has been by many chemists supposed to arise from the iron which it contains; MR. BRANDE, however, does not, from his own experiments, conclude this to be the fact. The blood of animals is, nevertheless, occasionally used for dyeing, as will be seen under _Adrianople red_. See KIRWAN _on Manures_, _&c._ and DAVY'S _Agricultural Chemistry_.

From the acids or oxygen combined with alkalies, earths, or metals, almost innumerable mordants, as we have seen, are formed; and upon the correct and proper application of these to the cloth or other matters to be dyed, depends the goodness and permanence of the colours. The dyer cannot, therefore, be too scrupulously attentive to this portion of his art.

In dyeing the student ought also to remember, that the material to be dyed combines intimately, in numerous instances, with alumina or other mordants; in the case of alumina it, in some instances, takes up from one twelfth to one fourth of its weight of alum, leaving the alum bath nearly tasteless. So also will rich extract of American bark, or even weld, when the proportion of weld is in weight more than two to one of the wool, form a triple compound with the cloth and alum, of permanent duration.

All these preliminaries the author considers of the first importance to be understood, and he has, therefore, mentioned them again and again. For so doing he is sure that he shall be excused in the dye-house, although not perhaps by the critics, whose candour he nevertheless respectfully solicits.

We now proceed to the _application of mordants_. In regard to muslins and calicoes, the alum is to be mixed with gum and carried to the piece, as will be described below in the _Calico-Printers' mordant_, and then immersed in the dye-bath: it thus receives the base or mordant. If the base be alum and the dye-bath madder, then, where the block strikes the pattern with the alumine base, the colour will come out _red_; the other parts will clean and bleach white. If alum and iron form the base, the colour will be purple; if iron alone be applied, and galls, sumach, logwood, &c. are the component parts of the dye-bath, then it will be _black_.

_The Calico-Printers' mordant or base of alum for yellow and red goods, either for printing or dyeing; and on compound colours._

Take one gallon of soft and pure water, of a heat of 150°, three pounds of common alum, one pound and a half of sugar (acetate) of lead; mix these together, and let them stand for two or three days, so that they may incorporate, often stirring them during that interval; then add two ounces of pearl-ash, and the same quantity of clean powdered chalk or whiting. After a time the clear liquor, now become _an acetate of alum_, must be drawn off. When used, it is thickened either with paste, flour, or gum arabic, or senegal; four pounds of either of the gums to each gallon of liquor[5]. A block or a press similar to a copper-plate press for paper, but much larger, and having the copper plates in proportion, is employed to spread the acetate of alum from a utensil called a sieve, which is, however, not porous, while a boy or girl called a _Teerer_, works it smooth; when smooth on the sieve, the printer applies his block, and charges it with the acetate of alum; the block thus charged, is correctly put on the cotton cloth, which is laid upon a blanket spread upon a table; it is then struck with a mallet once or twice, by which, or by the pressure of the rolling-press, if copper-plate, the acetate of alum is driven into the pores of the cloth. The cloth thus prepared, is hung up in a hot stove, and dried by a high degree of heat. The goods are now ready, if for _red_, for the _madder_; and if for _yellow_, for the _weld_ copper. Sometimes, however, lately, the colour is previously prepared, and applied at once in more instances than are prudent. To the above mordant, _M'Kernan_ adds three ounces of _sulphate of copper_, omitting the potash; and he adds, "When the colour is wanting on the scarlet cast, omit the sulphate of copper."

Wool readily takes the alum at a boiling heat; _common alum_ is in many instances proper for wool; and in others, where it might be improper, it is corrected by the use of argol or cream of tartar.

_Yellow_ and _red_ produce _orange_; _red_ and _blue_, _purple_; but upon _cotton_, a scarlet, purple, or crimson cannot be produced in any way equal to those colours in wool or silk. _Yellow_ and _blue_ form the _green_.

_On Bleaching Linen, Cotton, &c._

We cannot enter with much minuteness into this part of the subject, more especially as the _art of bleaching_ is usually a separate one from that of _dyeing_. Yet as in fact the arts of _dyeing_ and of _bleaching_ depend in a great degree on the same principles, some notice of bleaching, in a treatise on dyeing, seems absolutely necessary.

Linen, cotton, and other cloths, were for ages deprived of their colour, in other words, bleached, rendered white, by a tedious process. Thus, the article to be bleached being boiled in a solution of pot-ash, was washed, and then spread on the grass in a field, watered occasionally, and, thus exposed to the atmosphere for two or three months, became white. This method is, however, in part, if not now entirely, dispensed with. M. Berthollet, an ingenious French chemist, to whose valuable work on dyeing we have before alluded, employed what was then called _oxygenated muriatic acid_, now _chlorine_, to perform in a few days what before took months to accomplish. His method was as follows. To six pints of powdered oxide of manganese he added sixteen of muriate of soda, (common salt) and twelve of concentrated sulphuric acid diluted with an equal quantity of water. These were placed in a leaden retort and distilled: the product was _oxygenated muriatic acid_, or _chlorine_, which being conducted to a vessel containing the material to be dyed, produced the same effects as the former tedious process, and bleached as much, in two or three days, as was before done in two or three months. This process has been since much further improved by the use of a combination of chlorine with lime, called _chloride_, or _oxymuriate of lime_. This article is at present used in almost all the bleaching grounds in the United Kingdom. It appears, therefore, that upon the use of the agent, _chlorine_, does the expedition and whiteness of modern bleaching principally depend. Yet it ought, nevertheless, to be stated, that although, in the hands of scientific and judicious persons, chlorine is one of the most powerful agents in bleaching that ever was discovered, still, in the hands of bungling and avaricious persons, it may contribute greatly to the destruction of the cloth; and therefore, even now, a demand is occasionally heard for the old method of bleaching.

These processes constitute the art of the bleacher; the dyer has seldom any thing to do with them except in piece-goods or rough cambric, which he has sometimes to dye black as they come from the bleacher's in a state which they call _once boucked_; and sometimes he has them just as they come from the weaver; in which case, if for black, they need not be bleached white, but should be boiled in pot-ash, to take out the grease, &c.

_On the theory relative to fast and fugitive colours._

Many attempts have been made by chemical philosophers to account for the permanence or want of permanence of various colours, when imparted to cloths and other bodies as a dye. Among these, HELLOT, D'APLIGNY, and others of the old, and BERTHOLLET, BANCROFT, HENRY, and others of the modern school, may be mentioned.

The power of resisting vegetable acids, alkalies, and soap, and, above all, the action of air and light, constitutes the durability of a colour. But this property has a very unequal standard, according to the nature of the colour and the species of the stuff.

There is no obscurity in the action of water, alkalies, acids, and soap: for a solution is effected by means of these agents, or a small portion of acid or alkali unites to the combination, which forms the colour. But this is not the case with the action of light and air. Till lately, however, it was not known in what this action consisted.

Of the two principles which compose atmospheric air, it is only the _oxygen_ gas which acts on the colouring particles. It combines with them, and thus impairs their colour or makes them fade. But its action is soon chiefly exerted on the hydrogen which enters into their composition, and it thereby forms water. This effect may be compared to a feeble combustion. Hence the carbon, which enters into the composition of the colouring particles, becomes predominant, and the colour usually passes to yellow, dun, or brown, or other appearances.

Light promotes this decomposition of the colouring particles, which frequently takes place only with its concurrence, and thus it contributes to the destruction of the colour. Heat also favours the same result, but less efficaciously so, unless it have a certain intensity.

It is concluded, therefore, that colours are more or less fixed in the air, according to the greater or less tendency which the colouring particles have to undergo this change[6]. Hence the utility of _mordants_ in rendering _fugitive_ colours _fast_.

_To prove the colours of Dyed Stuffs, &c._

The natural proofs of a dye's being effectual, are exposure to the air, to the sun, or to rain. If the colour be not changed by such exposure after twelve or fourteen days, it may be considered as fixed. These proofs are not, however, adapted to every colour: for some resist the action of air, light, and rain, yet are nevertheless injured by certain acids. There are also colours which do not resist the natural proofs and yet remain unchanged by acids.

Colours may be arranged in this respect in three classes: the first class is tried with _alum_, the second with _soap_, the third with _tartar_. For the proof with _alum_, half an ounce of this salt must be dissolved in a pint of water in an earthen pipkin, and into this liquor is to be put half a quarter of an ounce of the dyed thread or stuff, the whole being boiled about five minutes; it is then to be washed clean with water. Thus are tried _crimson_, _scarlet_, _flesh-colour_, _violet_, _ponceau_, _peach-blossom_, different shades of _blue_, and other colours bordering on these.

The next proof consists in boiling a quarter of an ounce of _soap_ in a pint of water, with half a quarter of an ounce of the dyed stuff or thread for five minutes. With this proof all sorts of _yellow_, _green_, _madder-red_, _cinnamon_, and similar colours are to be tried.

The proof with _tartar_ consists in boiling one ounce of that salt, previously powdered very fine, with a quarter of an ounce of dyed thread or stuff, in a pint of water for five minutes. This proof is used for all colours bordering upon _fallow_, or _hair-brown_.—_Journal of Science_, vol. xxii. 219.

But notwithstanding these general rules may be given for _dye-tests_, yet so many are the niceties in this art, that, after all, nothing but long practice combined with scientific knowledge, will enable the dyer to become in this respect, a complete and successful artist.

_On dye-houses and the water proper for dyeing._

The _dye-house_ should be as spacious as possible, according to the quantity of work intended to be done in it; it should be also as near as possible to a clear running stream. The floor should be a mixture of lime and cement, and sufficiently inclining, so that water, the old contents of the vats, &c. &c. may run off freely when thrown down.

A dyer cannot be too particular in regard to the _water_ which he uses. Some pump, well, and other spring waters, contain _iron_; this is injurious to many colours, while for black, brown, slates, and grey, it is very advantageous. It has been supposed that some dyers succeed in dyeing even the very same colour in a superior manner, in consequence of the peculiar purity or other properties of the water which they use.

To discover whether water contains iron or not, a little tincture of galls or prussiate of potash must be dropped into it; if a purple or blue tinge be produced in the water, we may be assured that it does contain iron.

For dyeing delicate colours, the water, which ought to be chosen for such purpose the purest and best, should be heated with bran in a bag, when much of the contents of the water inimical to dyeing will rise to the top in the form of a scum, and should be taken off just before the water boils. Instead of bran, a little alum will answer the same purpose when it is not inimical to the colour intended to be dyed.

The boiling point of water is at the degree of 212° of _Fahrenheit's thermometer_; the freezing point is at 32° of the same instrument; blood heat is at 98°.

_Miscellaneous observations._

The limits and price of this manual preclude the possibility of our giving plates to explain some of the machinery and utensils which are now employed in dyeing. To inform a _dyer_ what kind of coppers, casks, and vats are necessary, would seem to be superfluous; and the pupil may soon acquire such knowledge in the dye-house. Should a dyer find it his interest to undertake a branch of his art of which he has not any previous knowledge, he had better engage a man who understands it; if, however, he thinks himself competent to manage it, but is unacquainted with the best modern utensils appropriated to that particular branch, he had better get a dyer's labourer who has been used to it; a man of sufficient intelligence may be found with due encouragement to perform this part. It may just be added, that _Ure's Berthollet_ and Mr. _M'Kernan's_ work, both contain numerous explanatory _plates_ of the utensils and machinery which are described and recommended in those works.

All solutions and decoctions of _Brazil wood_, _logwood_, _fustic_, _&c_. should always be prepared in the same quantity and proportion, and one measure be invariably set apart for each. This observation is meant more particularly to apply to drugs in stock, always kept in a state of preparation ready for any process or work which may occur. The drugs just named may be kept in a prepared state; but _weld boiled_ will not keep, nor will some others which are mentioned in the body of the work.

_Weld_, as it will not keep, should be used thus: a copper in proportion to the size of the work should always be used; and as weld will bear boiling and re-boiling, it can be boiled by the half bundle or more according as it may be wanted, whether you work little or much. If you are exact and near in your estimate, practice will soon render you perfect in any branch. It should be observed too, that to _dye to pattern_ cannot be the result of a receipt, without a great latitude be left for the judgment.

The most difficult part of dyeing is that of _light drabs_, _stone drabs_, _&c_.

Nothing but _practice_ will qualify you for this and all pattern dyeing: the way, and the only good way to obtain practice, is to work with all possible regularity. In the dyeing of fancy cloths in the clothing districts of Yorkshire, Gloucestershire, and other fine cloth manufactories, the _manufacturers_ who dye their own cloths, as well as _dyers_ of the greatest eminence, always number, measure, weigh, and time all the component parts of their various processes of dyeing. Such in fact ought to be the universal practice; and then a person of ordinary abilities may soon be able to perfect his processes and obtain the best results.

Hence, however, it is very necessary that the dyer should have a competent knowledge of chemistry and drugs, that he may be able to judge of the goodness of the articles which he uses, and of the numerous and extraordinary combinations into which they enter. To _chemistry_, in particular, every able and scientific dyer must be largely indebted; for this reason it is that we have endeavoured, in this _introductory chapter_, to sketch some of the most important facts in this universal and interesting science.

In possession of these qualifications, and working upon the above plan, the dyer can never be far from the desired result in all his processes. His deviations, if any, will be few, as from his knowledge, he will soon perceive the first approach of any incorrectness, and be able to adjust it generally without much inconvenience.

The _chemical terms_ now introduced into treatises on dyeing are chiefly taken from the Greek language, and are used in such a manner as to convey, by their etymology, an idea of the nature of the substances to which they are applied. _Oxygen_ implies the producer of acid: _hydrogen_, the producer of _water_; _nitrogen_, the producer of _nitre_, &c. The term _gas_ has been explained above. _Caloric_ is a term used by chemists for heat; but caloric is used in a more extensive signification than the term heat, thus: although a gas might possess no sensible heat, yet being in a gaseous state, it is assumed to contain a certain portion of caloric which keeps it in its gaseous state; the same observation will apply to liquids whether aqueous, oleous, or metallic.

_All the measures mentioned in this work unless otherwise described, are those usually called in this country_ WINE MEASURE, _and not those which have been introduced by a late act of parliament_, _called_ IMPERIAL MEASURES.

[2] Cochineal was at first supposed to be a _grain_, which name it still retains by way of eminence among dyers. URE.

[3] For the cultivation of Woad in England, see Parish's paper in vol. xii. of the Bath Society's Report, or Tilloch's Mag. vol. xxxviii.

[4] What are called _iron moulds_ in cotton, linen, &c. are, it is well known, nothing but the marks of a _buff_ colour, usually left by ink and other matters which contain iron: acids, of course, dissolve, and discharge these buff colours; the _oxalic acid_ does so without decomposing the cloth.

[5] "_Acetate of Alumina_ is now most frequently made for the Calico-Printers by dissolving alum in a solution of crude acetate of lime, (pyrolignite); a gallon of the acetate, of specific gravity, 1.050 or 1.060, being used with two pounds and three-quarters of alum. A sulphate of lime is formed, which precipitates, while an acetate of alumina mixed with some alum floats above. The acetate of alumina employed as a mordant for chintz, is still commonly made by the mutual decomposition of alum and acetate of lead."—_Ure's Berthollet_, vol. ii. p. 331.

[6] Berthollet.