PEARLS, ARTIFICIAL. These are small globules or pear-shaped spheroids of thin glass, perforated with two oppo site holes, through which they are strung, and mounted into necklaces, &c., like real pearl ornaments. They must not only be white and brilliant, but exhibit the ir ridescent reflections of mother of pearl. The liquor employed to imitate the pearly lustre, is called the essence of the East (essence d'orient), which is prepared by throwing into water of ammonia the brilliant scales, or rather the lamelice, se parated by washing and friction, of the scales of a small river fish, the blay, called in French ablette. These scales digested in ammonia, having acquired a degree of softness and flexibility which allow of their application to the inner surfaces of the glass globules, they are introduced by suction of the liquor containing them in suspension. The ammonia is volatilized
in the act of drying the globules.
Some manufacturers employ ammonia merely to prevent the alteration of the scales ; that when they wish to make use of them they suspend them in a well clarified solution of isinglass, then pour a a drop of the mixture into each bead, and spread it round the inner surface. It is doubtful whether, by this method, the same lustre and play of colors can be obtained as by the former. It seems, moreover, to be of importance for the suc cess of the imitation, that the globules be formed of a bluish, opalescent, very thin glass, containing but little potash and ox ide of lead. In every manufactory of ar tificial pearls, there must be some work men possessed of great experience and dexterity. The French excel in this in genious branch of industry.