PEARLS. These are substances form ed by certain bivalve mollusks, consisting of concentric layers of a fine compact na cre, or substance identical with that which lines the inside of the shell ; they are sometimes found free and detached with in the lobes of the' mantle, but most com monly adherent to the nacrous coat of the shell, which on that account is termed "mother of pearl." The species of bi valve which produces the most valuable pearls is the pearl oyster of Ceylon, _Me leagrina margaritifera, Lam. A pure piece is generally spherical, and has a white, or bluish, or yellowish white color, with a peculiar lustre and irridescence, and consists of alternating concentric layers of membrane and carbonate of lime. When steeped in dilute muriatic acid, the carbonate is decomposed with effervescence, and films of membrane re main undissolved.
Pearls were in the highest possible es timation in ancient Rome, and bore an enormous price. Their cost in modern times has very much declined ; partly, no doubt, from changes of manners and fashions, but more, probably, from the admirable imitations of pearls that may be obtained at a very low price. Accord ing to Mr. Milburn, a handsome necklace of Ceylon pearls, smaller than a large pea, cost from $850 to $1,500, but one of pearls about the size of peppercorns may be had for $75 ; the pearls m the former sell at 5} dollars each, and those in the latter at about 871 cents. When the pearls dwin dle to the size of a small shot, they are denominated seed pearls, and are of little value. They are mostly sent to China. One of the most remarkable pearls of which we have any authentie account was bought by Tavernier, at Cat ifit, in Arabia, a fishery famous in the days of Pliny, for the enormous sum of i $50,000 ! It is pear-shaped, regular, and without blemish. The diameter is •68
inch at the largest part, and the length from 2 to 3 inches. It is in the pos session of the shah of Persia.
The pearl oyster is fished in various parts of the world, particularly on the west coast of Ceylon ; at Tuticorin, in the province of Tinnevelly, on the coast of Coromandel ; at the Bahrein Islands, in the Gulf of Persia ; at the Sooloo Isl ands; off the coast of Algiers ; off St. Margarita, or Pearl Islands, in the West Indies, and other places on the coast of Colombia ; and in the Bay of Panama, in the South Sea. Pearls have sometimes been found on the Scotch coast, and in various other places.
The pearl fishery of Tuticorin is mon opolized by the East India Company, and that of Ceylon by Royalty. But these monopolies are of no value, as in neither case does the sum for which the fishery is let equal the expenses incurred in guard ing, surveying, and managing the banks. It is therefore sufficiently obvious that this system ought to be abolished, and every one allowed to fish on paying a moderate licence duty. The fear of ex hausting the banks is quite ludicrous.
The fishery would be abandoned as un profitable long before the breed of oysters had been injuriously diminished, and in a few years it would be as productive as ever. Besides giving fresh life to .the fishery, the abolition of the monopoly would put an end to some very oppressive regulations enacted by the Dutch more than a century ago.