Page:Popular Science Monthly Volume 90.djvu/845

 Making Pearls to Order

A Japanese plan for putting oysters systematically to work

���The work on the oyster farm is done almost entirely by women. Here are women divers, with no other equipment than their baskets, bringing up pearl-oysters from the deep-sea beds

��OXE of the queerest farms in the world is situated on the Island of Tatokuj ima, in the Bay of Ago, Japan. The farm lands lie fathoms deep in water, and the crops are lustrous pearls.

Oyster shells are lined with a smooth coating which is commonly called mother- of-pearl, or nacre. The oyster builds up this lining layer on layer.

If any foreign substance — even a grain of sand — happens to enter the shell of an oyster the oyster immediately begins to allay the irritation it causes by surround- ing it with the material it uses to build up the lining of its shell. This process the oyster keeps up year after year.

Pearls are not made by oysters alone. Any mol- lusk may form them, but pearls formed by common oysters and clams are not particu- larly attractive.

On the farm at Tato- kujima the first steps toward the production of the pearls are taken during July and August of en ' - ^"herever the larvae

���A perfect pearl of the "Oriental" variety. The seed inserted inside the shell was covered over with shell-lining

��of the pearl-oysters have been found most abundant, small pieces of rock and stone are placed. In a little while oyster-spat will be attached to these rocks. Then the rocks are removed to beds which have been prepared for them in deep waters. If they are left in shallow water during the winter the oysters may perish from the cold. They are left in the deep water beds un- disturbed for three years. Then they are taken out of the sea, and into each oyster is introduced a small seed-pearl or a small round piece of nacre which serves as the nucleus for a future pearl. The oysters are then returned to the sea where they remain for four years. At the end of that time they are taken out and the harv^est of pearls is reaped. During the four years the oyster has been busily^ engaged in piling layer on layer of nacre around the bit of foreign substance which was so artfully in- troduced into its shell. The work of the oys- ter-farm is done princi- pally by women. The divers remain under water incredible lengths of time.

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