or silver fish, when washed in a sea-shell, left certain particles, which seemed to silver the surface.
Seeing
that they much resembled the brightness of the pearl, he thought of
applying them, mixed with mucilage, inside some small balls of glass.
Having succeeded, he gave the strange name of essence of the East to
his production. The argentine is a very common, white little fish,
which is found abundantly in the rivers of Italy, France, and Germany.
In order to extract the essence of the East, they are washed,
while tightly compressed, in a vase of very pure water. The result is a
material of silvery colour which, when taken from the water, dried and
compressed, is again immersed in another vase, and after a few days the
liquid is decanted and the precipitate gathered with care.
Eighteen thousand argentine yield five hundred grammes of essence of the East.
In
order to prevent the decomposition of this animal substance, they had
recourse to various chemical expedients, which for a long time
remained secret to all but the inventors. Now, the most usual plan is
to add ammoniacal liquid or volatile alkali to the decanted mass.
The pearls of France in glass, and those of Rome in wax, are both made of the essence of the East ; but
the process adopted in Rome differs very much from the French method,
and perhaps is connected with a tradition more ancient than the
invention of Jacquin.
