and to wash it with warm water. Finally, it is placed in a bowl, and, when
dry, the granules or leaves are rubbed against a touchstone at the same time
as a touch-needle, and considered carefully as to whether they be pure or
alloyed. If they are not pure enough, the granules or the leaves, together
with the cement which attracts silver and copper, are arranged alternately
in layers in the same manner, and again heated ; this is done as often as is
necessary, but the last time it is heated as many hours as are required to
cleanse the gold.
Some people add another cement to the granules or leaves. This cement
lacks the ingredients of metalliferous origin, such as verdigris and vitriol, for
if these are in the cement, the gold usually takes up a little of the base metal ;
or if it does not do this, it is stained by them. For this reason some very
rightly never make use of cements containing these things, because brick
dust and salt alone, especially rock salt, are able to extract all the silver and
copper from the gold and to attract it to themselves.
It is not necessary for coiners to make absolutely pure gold, but to heat
it only until such a fineness is obtained as is needed for the gold money which
they are coining.
The gold is heated, and when it shows the necessary golden yellow colour
and is wholly pure, it is melted and made into bars, in which case they are
either prepared by the coiners with chrysocotta, which is called by the Moors
borax, or are prepared with salt of lye made from the ashes of ivy or of
other salty herbs.
The cement which has absorbed silver or copper, after water has been
poured over it, is dried and crushed, and when mixed with hearth-lead and
de-silverized lead, is smelted in the blast furnace. The alloy of silver and
lead, or of silver and copper and lead, which flows out, is again melted in the
cupellation furnace, in order that the lead and copper may be separated from
the silver. The silver is finally thoroughly purified in the refining furnace,
and in this practical manner there is no silver lost, or only a minute quantity.
There are besides this, certain other cements20 which part gold from
silver, composed of sulphur, stibium and other ingredients. One of these
compounds consists of half an uncia of vitrìol dried by the heat of the, are
and reduced to powder, a sixth of refined salt, a third of stibium, half a libra
20The processes involved by these " other " compounds are difficult to understand,
because of the lack of information given as to the method of operation. It might be thought
that these were five additional recipes for cementing pastes, but an inspection of their
internal composition soon dissipates any such assumption, because, apart from the lack of
bnckdust or some other similar necessary ingredient, they all contain more or less sulphur.
After describing a preliminary treatment of the bullion by cupellation, the author says :
" Then the silver is sprinkled with two unciae of that powdered compound and is
" stirred. Afterward it is poured into another crucible .... and violently shaken.
" The rest is performed according to the process I have already explained." As he has
already explained four or five parting processes, it is not very clear to which one this refers.
In fact, the whole of this discussion reads as if he were reporting hearsay, for it lacks in every
respect the infinite detail of his usuai descriptions. In any event, if the powder was introduced into the molten bullion, the effect would be to form some silver sulphides in a regulus
of different composition depending upon the varied ingredients of different compounds.
The enriched bullion was settled out in a " lump " and treated " as I have explained,"
which is not clear.