I'fS 
LECTURE XL 
be real ones, va,lned at a very high sum. The 
servant, who put the Marquis upon this stra- 
tagem, had previously assured his master that 
these pearls withstood heat and moisture ; that 
they were not easily scratched, and that their 
weight was the same with that of real pearls. 
This anecdote, which is detailed by Professor Beck- 
man, proves that artificial pearls did not become 
common, even in France, till many years^after 
their first invention. 
The trade of artificial pearl-making is still car- 
ried on at Paris by the descendants of Jacquin the 
original inventor, but they are also made in many 
other parts of Europe, and with several variations 
as to the colour and kind of the glass, and other 
minute particulars. 
The Mytilus margaritiferus of Linnteus, or 
great Pearl Muscle, is not the only shell which 
produces pearls. A species of the genus call- 
ed M}}a, and which is the Mya margaritifera of 
Linnaeus, also produces pearls, though, in ge- 
neral, of a fill' smaller size, and of inferior qua- 
lity. This shell is commonly called the European 
pearl Muscle, and much resembles the common 
river muscle, though of a different genus. It is 
