though one of the seven original or prismatic colours, is among dyers a compound of blue and yellow. Of the European methods of dyeing green, and of the principles on which these methods are founded, a sufficient account will be found in the Encyclopedia, under the articles Colour-making and Dying, and, in this Supplement, under Animal and Vegetable Substances; but it may be worth while, in this place, to insert the method practised at Afracan, in giving to cotton yarn that beautiful green colour for which the oriental cotton is so justly admired.
The principal dye is the blue, which is employed both for cotton and silk. To prepare it, the indigo or blue dye-stuff is finely pounded, and dissolved in water by a gentle heat in large earthen jars, fifteen of which stand in brick-work over the fire-place, at the distance of about an ell and a half from each other. About two pounds are put into each vessel. Five pounds of soda finely pounded, together with two pounds of pure lime and one pound of clarified honey, are added to each; when these ingredients have been well mixed, the fire is strengthened; and when the whole begins to boil, the dye is stirred carefully round in all the vessels, that every thing may be completely dissolved and mixed. After the first boiling the fire is slackened, and the dye is suffered to stand over a gentle heat, while it is continually stirred round: this is continued even after the furnace is cooled, till a thick scum arises in the neck of each jar, and soon after disappears. The dye is then allowed to stand two days, until the whole is incorporated, and the dye thickens.
The dyers assert, that with this dye they can produce three shades of blue, and that, as the dyeing particles gradually diminish, they can dye also a green colour by the addition of yellow.
When a manufacturer gives cotton yarn to a blue dyer, he first boils it at home in a ley of soda (kalakar), then dries it, washes it, and dries it again. The blue dyer lays this yarn to steep in pure water, presses out the superfluous water with the hands, and then immediately begins to dip it in the blue jars, often wringing it till it is completely penetrated by the dye. This first tint is generally given to yarn in such jars as have had their colouring matter partly exhausted. It is then dried, rinsed, and again dried; after which, it is put into the fresh blue dye, properly saturated; and, after the colour has been sufficiently heightened, it is dried for the last time.
For a yellow dye, the dyers of Afracan employ partly saw-wool, brought from Russia, and partly the leaves of the kiflar beige, or sumach. The process is as follows: The yarn is first boiled for an hour in a strong ley of soda; it is then dried, afterwards rinsed and laid wet to steep for twelve hours in a solution of alum with warm water. When it has been dried in the air, it is laid to soak several times in troughs with the dye which has been boiled thick in kettles from the above-mentioned plants, till it has acquired the wished-for colour, care being taken to dry it each time it is soaked. It is then rinsed in running water, and dried for the last time.
On this yellow colour a green is often dyed. After the yarn has been dyed yellow, it is given out to the blue dyer, who immediately dips it in the blue jars, the dye of which has been already partly exhausted; and if the green colour is not then sufficiently high, the operation is repeated, the yarn being dried each time. See Neue Nordische Beiträge, by Professor Pallas; or Philosophical Magazine, no. 2.