prehends two series of operations—the production of the sphere, and the introduction of the coating.
The
spheres are produced by the glass-blower, who by aid of an enameller's
lamp solders the extremity of a tube having the proper diameter, and
blows into the tube when the substance is of the right consistency. In
this way very regular little spheres are obtained, that serve for the
composition of the ordinary quality of false pearls.
In
pearls of great beauty the tube employed is slightly opalescent, and
the glass-blower, besides, gives to the little spheres, while they are
yet malleable, certain slight perceptible inequalities of surface, by
gently tapping them with a small iron bar. This gives them a yet
greater resemblance to natural pearls, which are very seldom absolutely
regular.
No
mention is made in ancient writers of artificial pearls being made,
and it is not till we come down to the beginning of the sixteenth
century that we find Venice had then established a reputation for this
branch of industry.
At
first the glass balls were filled with various materials, generally
with a base of mercury. But in the year 1680 a rosary-maker named
Jacquin conceived the idea of using, in the place of this mercurial
mixture, a harmless substance that produced an infinitely more perfect
colour.
This substance, the essence of orient, is formed
