90 PEARLS [CH. 



middle of the 18tli century large quantities of pearls 

 were obtained from these shellfish in the river Tay. 



The Scotch pearl fishery was stimulated again in 

 1860. The Irish fishery seems to have died out — the 

 shellfish being much less common now than formerly. 

 In 1906 the value of the pearls collected from the 

 shellfish in the British Islands was put down as 

 £3000. Xo elaborate system of boats and dredges 

 is used and probably all the shellfish are obtained by 

 wading and feeling for the individual specimens. 



On the continent the fishing has been carried on 

 for a long time in the rivers of Finland. The pearls 

 find their way chiefly into Russia. The fi-esh-water 

 pearl mussel is also very common in the rivers of 

 Germany and Bohemia. Quite recently the origin 

 of pearls in these shellfish has been investigated 

 in great detail by the Germans : reference will be 

 made to their discoveries in a later chapter. The 

 fishing has been very regular and carefully looked 

 after in these countries. The rivers are inspected in 

 springtime and the fishing takes place in summer. 

 At the same time the recent pollution of water by 

 factories has caused the usual decrease in the number 

 of mussels. Pearls have also been obtained from the 

 French rivers and in fact from many others in Europe 

 which lack of space prevents us from mentioning. 



The total value of pearls obtained on the con- 

 tinent of Europe in 1906 was about £20,000. 



