502 



Cratfurt? of Natural 



tion of the grooves,' says Sir David, ' is in 

 every case at right angles to the line joining 

 the common image and the coloured image ; 

 hence in irregularly-formed mother-of-pearl, 

 where the grooves are often circular, and 

 have every possible direction, the coloured 

 images appea_r irregularly scattered round 

 the ordinary image. In the real pearl these 

 coloured images are crowded into a small 

 space round the common image, partly on 

 account of the spherical form of the pearl ; 

 and the various hues are thus blended into 

 a white unformed light, which gives to this 

 substance its high value as an ornament.' 

 Pearls, however, at least the most valuable, 

 are not perfectly solid, and are certainly 

 translucent. In fact, in a split pearl we 

 find the transparency to be considerable. 

 ' Upon taking a split pearl,' says Sir Everard 

 Home, ' and putting a candle behind the 

 cell, the surface of the pearl became imme- 

 diately illuminated ; and upon mounting 

 one with coloured foil behind the cell, and 

 by putting a candle behind the foil, the 

 outer convex surface became universally of 

 a beautiful pink colour.' If we take a split 

 pearl and set it in a ring with the divided 

 surface outwards, and look at this through a 

 magnifying glass, this central cell becomes 

 very conspicuous, and the different layers of 

 which the pearl is composed are also beauti- 

 fully displayed. It is the brilliancy above 

 described that distinguishes the real from 

 the factitious pearl a lustre which no art 

 can altogether give, though often attempted 

 with considerable success." 



Much valuable information on the subject 

 of pearls and pearl fisheries is also given in 

 Mr. M'Culloch's Commercial Dictionary, to 

 which work we are indebted for most of the 

 following particulars. Pearls should be 

 chosen round, of a bright translucent silvery 

 whiteness, free from stains and roughness. 

 Having these qualities, the largest are of 

 course the most valuable. The larger ones 

 have frequently the shape of a pear ; and 

 when these are otherwise perfect, they are 

 in great demand for ear-rings. Pearls were 

 in the highest possible estimation in ancient 

 Rome ; but, owing partly to the changes of 

 manners and fashions, and still more, pro- 

 bably, from the admirable imitations that 

 may be obtained at a very low price, they 

 are now less esteemed, and comparatively 

 cheap. When the pearls dwindle to the 

 size of small shot, they are denominated 

 seed pearls, and are of little value. One of 

 the most remarkable pearls of which we 

 have any authentic account was bought by 

 Tavernier, at Catifa, in Arabia, a fishery 

 famous in the days of Pliny, for the enor- 

 mous sum of 110,00<W. I It is pear-shaped, 

 regular, and without blemish. The diameter 

 is *63 inch at the largest part, and the length 

 from two to three inches. Very good imi- 

 tations of pearls have been made with hol- 

 low glass globules, the inside of wluch is 

 covered with a liquid called pearl essence, 

 and then filled with white wax : the essence 

 is composed of the silver-coloured particles 

 which adhere to the scales of the Bleak (Cy- 

 prinus alburnus) 



The Pearl Oyster is fished in various parts 



of the world, particularly on the west coast 

 of Ceylon ; at Tuticoreen, in the province of 

 Tinnevelly, on the coast of Coromandel ; 

 at the Bahrein Islands, in the gulf of Persia ; 

 at the Soloo Islands ; 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 va- 

 rious other places. The most extensive pearl 

 fisheries are those on the several banks not 

 far distant from the island of Bahrein, on 

 the west side of the Persian Gulf ; but Pearl 

 Oysters are found along the whole of the 

 Arabian Coast. The fishing season is divided 

 into two portions the one called the short 

 and cold, the other the long and hot. In 

 the cooler weather of the month of June, 

 diving is practised along the coast in shallow 

 water ; but it is not until the intensely hot 

 months of July, August, and September, that 

 the Bahrein banks are much frequented. 

 The water on them is about seven fathoms 

 deep, and the divers are much inconvenienced 

 when it is cold ; indeed, they can do little 

 when it is not as warm as the air, and it 

 frequently becomes even more so in the 

 hottest months of the summer. When they I 

 dive, they compress the nostrils tightly with I 

 a small piece of horn, which keeps the water 

 out, and stuff their ears with bees' wax for ! 

 the same purpose. They attach a net to ! 

 their waists, to contain the oysters ; and aid ! 

 their descent Dy means of a stone, which 

 they hold by a rope attached to a boat, and 

 shake it when they wish to be drawn up. 

 A person usually dives from twelve to fifteen 

 times a day in favourable weather ; but 

 when otherwise, three or four times only. 

 They continue under water from a minute 

 to a minute and a half, or at most two 

 minutes. The exertion is extremely violent ; 

 and the divers are unhealthy and short-lived. 



PECCARY. (Dicotyles tajacn.) This Pa- 

 chydermatous animal, which at first view 

 has very much the appearance of a small 

 Hog, is a native of South America. It is of 

 a short compact form, thickly covered on the 



upper parts of the body with thick and strong 

 dark-coloured bristles, each marked by yel- 

 lowish-white rings ; and round the neck is 

 generally a whitish band or collar. The 

 bead is rather large ; the snout long ; the 

 ears short and upright ; and the under part 

 of the body nearly naked. Instead of a tail, 



