THE DYER.

The art of the Dyer consists in tinging cloth, stuffs, or other substances, with a permanent colour, which penetrates its substance. Dyeing differs from bleaching, which is not the giving of a new colour, but brightening an old one. It differs, also, from painting, printing, or stamping, because the colours in these only reach the surface.

The origin of the art of dyeing is involved in the same kind of obscurity which pervades the history of all those arts connected with the common wants and necessaries of life. Accident, probably, furnished a multitude of instances of observation, which enabled the rudest people to imitate the colours of birds and beasts. The bruising of a fruit, a flower, a leaf, is one of the most natural and obvious occurrences to which we should look for the first notion of applying vegetable juices to dyeing, and the knowledge of tingent properties of various herbs, was thus early acquired. The art of dyeing, probably, made considerable progress antecedent to the period in which regular history begins. Moses speaks of stuffs dyed blue, and purple, aud scarlet, and of sheep-skins dyed red.

That the people of this country were acquainted with the art of dyeing wool,, yam, and cloth, of different colours, at a very early period, will need no proof here. The art of dyeing the scarlet colour, however, by a small insect, of the kermes or cochineal kind, appears to have been discovered by A. D. 1000.

By an act of parliament, passed in 15 1, for abolishing certain deceitful stuff used in dyeing cloth, we find logwood, or blackvvood, of late .years brought into this realm, expressly prohibited; " the colours thereof, being false and deceitful to the Queen's subjects at home, and discreditable beyond sea to our merchants and dyers." Its use was again prohibited in 1497, as well as in the reign of James. But in 1661, the different laws, prohibiting its use, were repealed, it being found that " the ingenious industry of these times hath taught the Dyers of England the art of fixing the colours made of logwood, alias blackwood, so as that, by experience, they are found as lasting and serviceable as the colours made with any other sort of dyeing- wood.

The mystery of the art of dyeing, consists chiefly in chemical processes ; and it comprises a vast collection of chemical experiments.

The substances principally subjected to this art, are wool, hair, silk, cotton, hemp, and flax. Of these, the animal productions,
namely, wool, hair, and silk, take the dye more readily than the vegetable substances, cotton, hemp, and flax, because they seem to
havee a stronger attraction for the colouring particles of the various dyes employed. Wool is naturally of a greasy nature and requires to be scoured before it is submitted to the process of dyeing.

Silk, previously to dyeing must be washed with soap and warm water., and then in a cold solution of alum and water. Cotton and linen require bleaching and scouring in alkaline ley. After this, they must be steeped in a strong solution of stain and water, then washed in clear water, and afterwards rinsed in a decoction of galls, or some other astringent, as hot as the workman can bear.

The first step of dyeing is the application of what is termed a mordant : that is, something must be employed to make the substances
take the dye : for by merely immersing them in the dyeing liquor, they will seldom take or retain a deep dye.

Different mordants are used for the same goods, and for preparing goods for the different colouring drugs. Alum is the most extensively useful, being always employed for linens and cottons. For the dying of silk and wool, metallic solutions are more frequently¦used as mordants, because they have a stronger attraction for animal than vegetable substances.

In dyeing, there are but three simple colours, the red, yellow, and blue; all other colours are compounded of these. Different shades or tints of the same colour are produced by using different drugs, or by varying the quantity of colouring particles.

Cochineal, kermes, and gum-lac, amongst the animal productions; and madder, archil, carthanius, and Brazil-wood, amongst the vegetable, are the. chief substances employed as red dyes.

All the substances employed for dyeing yellow colours, are vegetable productions; and tihe principal blue dyes, are from indigo, woad, logwood, and Prussian blue. Compound colours are produced sometimes, hy mixing the. simple colours in the dyeing liquor, and sometimes by dyeing the stuff first in a bath of one simple colour, then in another.

The principal substances employed to give a black colour, are galls, which contain the astringent principle, or tannin, and an acid,
called the gallic acid, and the red oxide of iron. The black colour is produced by the combination of the astringent principle; with
the oxide of iron in conjunction with the acid and fixed on the stuff.

Logwood is not to be considered as affording a black dye, but it is much employed to give a lustre to black colours. Of the substances employed in dyeing brown, walnut-peels and sumach are the principal.

Scarlet dyeing in general, is a distinct and separate branch of trade; the materials being of that delicate kind, as easily to be injured by any accidental admixture of other colours, and part of the apparatus being somewhat different from common dyeing.

A dye house, which should be set down as near as possible to a stream of water, should be spacious and well lighted. It should be floored with plaster.; and proper means should be adopted to carry off water, or spent baths, by channels or gutters ;so that every operation may be conducted with the utmost attention to cleanliness. The size and position of the caldrons are to be regulated by the nature and extent of the operations for which they are designed. Excepting for scarlet and other delicate colours, in which tin is used as a mordant, the caldrons should be of brass or copper. Brass being less apt than copper, to be acted on by chemical agents, and to communicate spots to the stuffs, is fitter for the purpose of a dyeing vessel. It is of the greatest consequence that the coppers or caldrons be well cleaned for every operation ; and that vessels of a large size should be furnished at the bottom with a pipe and a stop-cock for the greater convenience of emptying them. There must be a hole in the wall or cChimney, above each copper, to admit poles for the purpose of draining the stuffs which are immersed, so that the liquor may fall back into the vessel, and no part may be lost.

Dyes for silk, where a boiling heat is not necessary, are prepared in troughs or backs, which ure long copper or wooden vessels.
The colours which are used for silks are extremely delicate ; they must, therefore, be dried quickly, and not be long exposed to the
action of the air, that there may be no risk of changed : for this purpose, it is necessary to have a drying-room heated with a stove.

Notwithstanding the discoveries of modern chemistry in the art of dyeing, and the permanency with which colours are now affixed to cloths, there yet remain many secrets in this branch of the arts, known bnt to a few persons ; and who, in consequence, have much emolument to themselves : and it will sometimes happen, that with the utmost skill and ingenuity, and the application of chemical principles, too, that the unlettered plodder shall, in the arts excel the most acute practical philosopher of the age.

In London, there are Dyers of all sorts.; some dye only wool, others silk ; some confine themselves to particular colours, such as
scarlet and blues. The scarlet dyeing is said to be the most ingenious and most profitable. The business of a Dyer is laborious and chilly ; the workmen are constantly dabbling in water, hot and cold. Silk-Dyers have the least laborious business : journeymen will earn thirty shillings a week.