In Constantinople there are some persons, particularly Armenians, who devote themselves to the preparation of cosmetics, and obtain large sums of money from those desirous of learning this art. Amongst these cosmetics is a black dye for the hair, which, according to Landerer, is prepared in the following manner:-- Finely pulverized galls are kneaded with a little oil to a paste, which is roasted in an iron pan until the oil vapors cease to evolve, upon which the residue is triturated with water into a paste, and heated again to dryness. At the same time a metallic mixture, which is brought from Egypt to the commercial marts of the East, and which is termed in Turkish _Rastiko-petra_, or _Rastik-Yuzi_, is employed for this purpose. This metal, which looks like dross, is by some Armenians intentionally fused, and consists of iron and copper. It obtains its name from its use for the coloration of the hair, and particularly the eyebrows--for _rastik_ means eyebrows, and _yuzi_ stone. The fine powder of this metal is as intimately mixed as possible with the moistened gall-mass into a paste, which is preserved in a damp place, by which it acquires the blackening property. In some cases this mass is mixed with, the powder of odorous substances which are used in the seraglio as perfumes, and called _harsi_, that is, pleasant odor; and of these the principal ingredient is ambergris. To blacken the hair a little of this dye is triturated in the hand or between the fingers, with which the hair or beard is well rubbed. After a few days the hair becomes very beautifully black, and it is a real pleasure to see such fine black beards as are met with in the East among the Turks who use this black dye. Another and important advantage in the use of this dye consists therein, that the hair remains soft, pliant, and for a long time black, when it has been once dyed with this substance. That the coloring properties of this dye are to be chiefly ascribed to the pyrogallic acid, which can be found by treating the mass with water, may be with certainty assumed. LITHARGE HAIR DYE. Powdered litharge, 2 lbs. Quicklime, 1/2 lb. Calcined magnesia, 1/2 lb. Slake the lime, using as little water as possible to make it disintegrate, then mix the whole by a sieve. ANOTHER WAY. Slaked lime, 3 lbs. White lead in powder, 2 lbs. Litharge, 1 lb. Mix by sifting, bottle, and well cork. _Directions_ to be sold with the above.--"Mix the powder with enough water to form a thick creamy fluid; with the aid of a small brush; completely cover the hair to be dyed with this mixture; to dye a light brown, allow it to remain on the hair four hours; dark brown, eight hours; black, twelve hours. As the dye does not act unless it is moist, it is necessary to keep it so by wearing an oiled silk, india-rubber, or other waterproof cap.