Besides the number of persons who arrive in Ceylon in the fishing season for the purpose of speculating in pearls, there are also numerous Indian artisans who are very expert in piercing and drilling pearls, and who practise their trade on the spot on economical terms. A writer thus describes their operations: "A machine made of wood, and of a shape resembling an obtuse inverted cone, about six inches in length and four in breadth, is supported upon three feet, each twelve inches long. In the upper flat surface of this machine holes or pits are formed to receive the larger pearls, the smaller ones being beat in with a little wooden hammer. The drilling instruments are spindles of various sizes, according to that of the pearls; they are turned round in a wooden head by means of a bow handle, to which they are attached. The pearls being placed in the pits which we have already mentioned, and the point of the spindle adjusted to them, the workman presses on the wooden head of the machine with his left hand, while his right is employed in turning round the bow handle. During the process of drilling, he occasionally moistens the pearl by dipping the little finger of his right hand in a cocoa-nut filled with water, which is placed by him for that purpose; this he does with a dexterity and quickness which scarcely impede the operation, and can only be acquired by much practice. They have also a variety of other instruments both for cutting and drilling the pearls. To clean, round, and polish them to that state in which we see them, a powder, made of the pearls themselves, is employed. These different operations in preparing the pearls occupy a great number of the black men in various parts of the island. In the black town, or pettah of Columbo, in particular, many of them may every day be seen at this work, which is well worth the attention of any European who is not already acquainted with it."
MOTHER-OF-PEARL, or NACRE, is the hard, silvery, internal layer of several kinds of shells, especially oysters, the large varieties of which in the Indian seas secrete this coat of sufficient thickness to render the shell an object of manufacture. The genus of shell-fish, Pentadinæ, furnishes the finest pearls as well as mother-of-pearl: it is found round the coasts of Ceylon, near Ormus in the Persian Gulf, at Cape Comorin, and in some of the Australian seas. The dealers in pearl-shells consider the Chinese from Manilla to be the best: they are fine, large, and very brilliant, with yellow edges. Fine large shells of a dead white are supplied by Singapore. Common varieties come from Bombay and Valparaiso, from the latter place with jet black edges. South Sea pearl-shells are common, with white edges. The beautiful dark-green pearl-shells called ear-shells or sea-ears are more concave than the others, and have small holes round the margin: they are the coverings of the Haliotis, which occurs in the Californian, South African, and East Indian seas.
In the Indian collection of the Great Exhibition in London, specimens of the finest pearl-shells were shown, known in commerce as flat-shells, ear-shells, green snail-shells, buffalo-shells, Bombay shells. It is stated that the shores of the Sooloo Islands afford the finest shells.
The beautiful tints of mother-of-pearl depend upon its structure; the surface being covered with a multitude of minute grooves, which decompose the reflected light. Sir David Brewster, who was the first to explain these chromatic effects, discovered, on examining the surface of mother-of-pearl with a microscope, "a grooved structure, like the delicate texture of the skin at the top of an infant's finger, or like the section of the annual growths of wood as seen upon a dressed plank of fir. These may sometimes be seen by the naked eye; but they are often so minute that 3,000 of them are contained in an inch." It is remarkable that these iridescent hues can be communicated to other surfaces as a seal imparts its impress to wax. The colors may be best seen by taking an impression of the mother-of-pearl in black wax; but "a solution of gum-arabic or of isinglass (white glue), when allowed to indurate upon a surface of mother-of-pearl, takes a most perfect impression from it, and exhibits all the communicable colors in the finest manner, when seen either by reflection or transmission. By placing the isinglass between two finely-polished surfaces of good specimens of mother-of-pearl, we obtain a film of artificial mother-of-pearl, which, when seen by single lights, such as that of a candle, or by an aperture in the window, will shine with the brightest hues."
It is in consequence of this lamellar structure that pearl-shells admit of being split into laminæ for the handles of knives, for counters, and for inlaying. Splitting, however, is liable to spoil the shell, and is therefore avoided as much as possible. The different parts of the shell are selected as near as possible to suit the required purposes, and the excess of thickness is got rid of at the grindstone. In preparing the rough pearl-shell, the square and angular pieces are cut out with the ordinary brass-back saw, and the circular pieces, such as those for buttons, with the annular or crown-saw, fixed upon a lathe-mandrel. The pieces are next ground flat upon a wet grindstone, the edge of which is turned with a number of grooves, the ridges of which are less liable to be clogged than the entire surface, and hence grind more quickly. If the stone be wetted with soap and water, it is less liable to be clogged. The pieces are finished on the flat side of the stone, and are then ready for inlaying, engraving, polishing, &c. Cylindrical pieces are cut out of the thick part of the shell, near the hinge, and are rounded on the grindstone preparatory to being turned in the lathe. Counters, silk-winders, &c., are smoothed with Trent sand or pumice-stone and water on a buff-wheel or hand-polisher, and are finished with rotten-stone moistened with sulphuric acid, which develops finely the striated structure of the shell. For inlaid works, the surface is made flat by filing and scraping; then pumice-stone is used, and after this putty-powder, both on buff-sticks with water; and the final polish is given with rotten-stone and sulphuric acid, unless tortoise-shell, or some other substance liable to be injuriously affected by the acid, be present in the inlay. In turned works, fine emery-paper, rotten-stone and acid or oil are used. The pearl handles for razors are slightly riveted together in pairs, then scraped, sand-buffed on the wheel with Trent sand and water; thirdly, gloss-buffed on the wheel with rotten-stone and oil, or sometimes with dry chalk rubbed on the same wheel; and fourthly, they are handed up, or polished with dry rotten-stone and the naked hand.
ARTIFICIAL PEARLS.—The art of making artificial pearls has been brought to such perfection in Paris, that even jewellers and pawnbrokers have occasionally had a difficulty in deciding between the artificial and the real. The origin of this successful imitation is given as follows: A French bead-maker named Jaquin, observing that when the small fish called ablette, or bleak (Cyprinus alburnus), was washed, the water was filled with fine silver-colored particles, collected some of these for the purposes of his trade. He found that the soft shining powder thus obtained had, to a remarkable degree, the lustre of pearls; hence, he called it essence of pearl, or essence d'orient. He first made small beads of gypsum and covered them with this substance; they were greatly admired and eagerly sought after; but it was found that this pearly coat, when exposed to heat, separated itself from the bead, and attached itself to the skin of the wearer in a manner that was anything but pleasant. The ladies themselves, it is said, suggested to Jaquin the making of hollow glass beads, and covering the inside with essence of pearl. This he did, and established a manufacture, of which some idea may be gained by the following account. Slender tubes of glass are first prepared, called girasols, a term applied to opal, and sometimes to the stone called cat's-eye, and given to these tubes because the glass is of a peculiar bluish tint. From these the artist blows minute globules, to the extent of from two to six thousand per day, not caring to make them all perfectly regular or free from blemish, because the natural pearls are not so. The pearl essence is then mixed with a solution of isinglass, and is blown while hot into each bead by means of a fine glass pipe. The solution is spread equally over the whole internal surface, by shaking the pearls in a vessel placed over the table where the workman sits, and to which he gives motion by his foot. When the varnish is equally diffused and dry, the beads are filled with white wax; this gives them the necessary weight and solidity, and renders them less fragile. They are then bored with a needle, and threaded on strings for sale. The holes in the finer sort are lined with thin paper, that the thread may not adhere to the wax.
To produce one pound of scales no fewer than 4,000 fishes are required; but this quantity of scales only yields four ounces of pearl essence. The fish are about four inches long; they are sold at a cheap rate in the markets after being deprived of their scales. The value of a pound of washed scales in the Chalonnais is from fifteen to twenty-five livres. The early manufacturers suffered great inconvenience from not knowing how to preserve the scales from putrefaction, and consequently being obliged to use the essence immediately it was obtained, lest it should acquire the intolerable odor of decayed fish. Attempts were made to preserve them in spirit of wine or brandy, but those liquors wholly destroyed their lustre. At length it was discovered that these fishy particles can be kept for a long time in solution of ammonia, and this enables the manufacturers of artificial pearls to carry on a considerable traffic with distant places where the fish is plentiful, the supply from the Seine, though abundant, being insufficient for the purposes of the trade of Paris. Down to a late period, the heirs of M. Jaquin continued to manufacture pearls to a considerable extent, in the Rue de Petit Lion, at Paris. An elaborate account of this art is given by De Beost, in a work entitled, "L'Art d'imiter les Perles fines," from which most English descriptions of this manufacture have been obtained.
ARTIFICIAL PEARLS IN THE MUSSEL (MYA MARGARITIFERA).
In a recent number of the "Journal of the Society of Arts," it was stated that an "oyster, or rather a mussel, of the species known to naturalists as the mya margaritifera, in which the artificial pearls are formed by the Chinese, had recently been sent to England. These pearls are only obtained near Ning-po, and until lately very little was known of the manner in which they were formed; and the account first published by Sir Joseph Banks was generally questioned. The Hermes steamer, however, on a late visit to that place, was able to obtain several live ones, in which, on being opened, several pearls, as many as eighteen or twenty, were found in the course of formation. The one sent only contains simple pearls adhering to the shell. It appears they are formed by introducing some pieces of wood or baked earth into the animal while alive, which, irritating it, causes it to cover the extraneous substance with a pearly deposit. Little figures made of metal are frequently introduced, and, when covered with the deposit, are valued by the Chinese as charms. These figures generally represent Buddha in the sitting position, in which that image is most frequently portrayed. Several specimens have, it is said, been preserved alive in spirits, and others slightly opened, so as to show the pearls."