TESTACEOUS FISHES. 125 



of the pearl-oyster, has a large, strong, whitish shell, rough and 

 hard on the outside, but smooth and polished within. From this 

 is taken the substance called mother-of-pearl, of which so many 

 beautiful trinkets are made. This is nothing more than the in- 

 ternal coats of the shell, which resemble the pearl in colour and 

 consistence. There are many pearl fisheries in Asia and America ; 

 but the principal are those in the Persian Gulf. The pearls 

 there produced are the most beautiful, and consequently fetch 

 the highest prices. 



The pearl fishery is one of the most destructive employments 

 in which any of the human species can be occupied. It is said 

 that the best divers will continue three quarters of an hour under 

 water, but many find that fifteen minutes quite exhaust their 

 strength. Every diver descends perfectly naked, except a net 

 fastened to his neck, for the purpose of containing the oysters, 

 and is let down by a rope, with a stone of forty or fifty pounds' 

 weight fastened to it, to keep him at the bottom. 



The wretched people who attend these fisheries are generally 

 slaves, and are mostly cut off in the prime of life ; for the pressure 

 of the air upon the lungs at the bottom of the water, is too great 

 for the human frame to sustain ; and a consumption is almost 

 always the consequence. Thus an insignificant glittering gem 

 is obtained at the expense of a number of lives. 



Shell-fish of the multivalve kind are too numerous to admit of 

 investigation in this place ; and of so many various species, that 

 a naturalist would be ba fried to make a judicious selection 

 Every one is an object of curiosity ; all of them claim the diver 

 sity of Nature's works, and the wonders of Creative Wisdom. 

 13 L 2 



