366 THE OCEAN WORLD. 



a grain of sand even, round which has been deposited in concentric 

 layers tlie beautiful and much-prized gem. 



The Chinese, and other Eastern nations, are said to turn this fact 

 in the natural history of this bivalve to practical use in making pearls 

 and cameos. By introducing into the mantle of the mollusc, or into 

 the interior of its body, a round grain of sand, glass, or metal, they 

 induce a deposit which in time yields a pearl, in the one case free, 

 and in the other adhering to the shell. In some cases pearls are said 

 to be produced in whole chaplets by the insertion of grains of quartz 

 connected by a string into the mantle of a species of Meleagi-ina ; in 

 other cases, a dozen enamelled figures of Buddha seated have been 

 produced by inserting small plates of embossed metal in the valves of 

 the same species. 



The pearls are very small at first ; they increase by annual layers 

 deposited on the original nucleus, their brilliancy and shade of colour 

 varying with that of the nacre from which they are produced. Some- 

 times they are diaphanous, silky, lustrous, and more or less iridescent j 

 occasionally they turn out dull, obscure, and even smoky. 



The pearl oyster is met with in very different latitudes ; they are 

 found in the Persian Gulf, on the Arabian coast, and in Japan, in che 

 American seas, and on the shores of California, and in the islands of 

 the South Sea ; but the most important fisheries are found in the Bay 

 of Bengal, Ceylon, and other parts of the Indian Ocean. The Ceylon 

 fisheries are under Government inspection, and each year, before the 

 fisheries commence, an ofiicial inspection of the coast takes place. 

 Sometimes the fishing is undertaken on account of the State, at 

 other times it is let to parties of speculators. In 1804 the pearl 

 fishery was granted to a capitalist for ^120,000; but, to avoid im- 

 poverishing all the beds at once, the same part of the gulf is not 

 fished every year. 



The great fishery for mother-of-pearl Pintadines {Mekagrina mar- 

 garitifera) takes place in the Gulf of Manaar, a large bay to the north- 

 east of the island : it commences in the month of February or March, 

 and continues thirty days, taken collectively, and occupies 250 boats, 

 which come from different parts of the coast ; they reach the ground 

 at daybreak, the time being indicated by a signal gun. Each boat's 

 crew consists of twenty hands, and a negro. The rowers are ten in 

 number. The divers divide themselves into two groups of five men 

 each, who labour and rest alternately ; they descend from forty to 

 fifty feet, seventy being the very utmost they can accomplish, and 

 eighty seconds the longest period the best divers can remain under 



