358 THE OCEAN WORLD. 



by the other fisheries of the neighbourhood, the sum total yielded by 

 the Arabian coast would probably not fall short of 350,000. 



In South America similar fisheries exist. Before the Mexican 

 conquest the pearl fisheries were located between Acapulco and the 

 Gulf of Tehuantepec ; subsequently they were established round the 

 Islands of Cubagua, Margarita, and Panama. The results became 

 so full of promise that populous cities were not slow to raise them- 

 selves round these several places. 



Under the reign of Charles Y., America sent to Spain pearls valued at 

 160,000; in the present day they are estimated to be worth 60,000. 

 In the places mentioned, the divers descend into the sea quite naked ; 

 they remain there from twenty-five to thirty seconds, during which 

 space they can only secure two or three pintadines. They dive in 

 this way a dozen times in succession, which gives an average of 

 between thirty and forty bivalves to each diver. 



The bivalve is carried on shore, and piled up on mats of Espartero 

 grass. The mollusc dies, and soon becomes decomposed ; it requires 

 ten days to be thoroughly disorganized. When in a thoroughly 

 corrupt state, they are thrown into reservoirs of sea-water, when they 

 are opened, washed, and handed over to the dealers. The valves 

 furnish nacre, and the parenchyma the pearls. 



The valves are cleansed, 5ind piled up in tuns or casks ; by raising 

 their external surface plates of nacre are obtained more or less thick, 

 according to the age of the mollusc. 



Nacre of three kinds are distinguishable in commerce : silver-faced, 

 bastard white, and bastard black. The first are sold in cases of 

 two hundred and fifty to two hundred and eighty pounds ; they are 

 brought from the Indies, from China, and Peru. The ships of 

 various nations import these shells as ballast. The second is delivered 

 in casks of two hundred and fifty pounds weight ; it is a yellowish 

 white, and sometimes greenish ; sometimes red, blue, and green. 



Pearls form by far the most important product of the animal. 

 When they are adherent to the valves they are detached with pincers ; 

 but, habitually, they are found in the parenchyma of the animal. In 

 this case the substance is boiled, and afterwards sifted, in order to ob- 

 tain the most minute of the pearls; for those of considerable size are 



