rises into the operculum, there is put into the ampulla one lozenge or two ;
these are made of soap, cut into small pieces and mixed together with
powdered argol, and then heated in a pot over a gentle fire ; or else the
contents are stirred with a hazel twig split at the bottom, and in both cases
the aqua effervesces, and soon after again settles. When the powerful vapour
appears, the aqua gives off a kind of oil, and the operculum becomes red. But,
lest the vapours should escape from the ampulla and the operculum in that
part where their mouths communicate, they are entirely sealed all round.
The aqua is boiled continually over a fiercer fire, and enough charcoal must be
put into the furnace so that the live coals touch the vessel. The ampulla is
taken out as soon as all the aqua has been distilled, and the silver, which is dried
by the heat of the fire, alone remains in it ; the silver is shaken out and put
in an earthenware crucible, and heated until it melts. The molten glass is
extracted with an iron rod curved at the lower end, and the silver is made
