NACRE AND PEARLS. 221 
were so full of promise that populous towns soon sprang up in the 
neighbourhoods. In the reign of Charles V. America sent home to 
Spain pearls to the value of £160,000, and even now the fisheries 
yield some £60,000 a year. The mode of diving is much the same 
as in the Asiatic waters. The divers go down naked, and can 
remain from twenty-five to thirty seconds; in this time they are 
not able to secure more than two or three shells. They descend 
eleven or twelve times in succession, and thus gather thirty or 
forty oysters in a day. 
The pintadines are carried to the shore, where they are piled 
on grass mats in the sun; the mollusks soon die, and begin to 
decompose. After ten days, when this process is complete, and 
the tissue of the animal has thoroughly given way, they are thrown 
into tanks of sea water, where they are opened and washed; in this 
state they are handed to the dealers. The valves furnish nacre, and 
in the parenchyma the pearls are found. 
To secure the nacre the valves are cleansed, the thick, rough 
exterior of the shell is removed, either, as we have said, by a sharp 
instrument like a chisel, or by an acid liquid; in this manner, plates 
of nacre are obtained, which vary in thickness, according to the 
age of the mollusk. 
Three kinds of mother-of-pearl are known in commerce: silver- 
face, bastard-white, and bastard-black. The first is brought in 
cases of 250 or 300 lbs., from India, China, and Peru. The other 
two kinds are more or less coloured, and are not so valuable. 
The pearls are by far the most important product of the work. 
They are generally found in the fleshy substance of the animal; 
sometimes, though rarely, they are fixed to the valve, and when 
this is the case they are detached by pincers. To secure the 
precious globules which are embedded in the mollusk, the putrified 
flesh is boiled, and the whole of the contents of the pan is passed 
through a fine sieve; in this way very few pearls escape detection. 
Yet some do; for months after the fishing is over miserable 
Indians may be seen searching the heaps of putrified matter for 
seed-pearls which had passed the workmen unobserved. 
Baroques are the pearls which are found adhering to the valves; 
these are always irregular in shape, and are sold by weight. Virgixz 
