The salt which we call sal-anificiosus,25 is made from a libra each of vitriol,
alum, saltpetre, and sulphur not exposed to the fire, and half a libra of salammoniac ; these ingredients when crushed are heated with one part of lye made
from the ashes used by wool dyers, one part of unslaked lime, and four
parts of beech ashes. The ingredients are boiled in the lye until the whole
has been dissolved. Then it is immediately dried and kept in a hot place,
lest it turn into oil ; and afterward when crushed, a libra of lead-ash is mixed
with it. With each libra of this powdered compound one and a half unciae
of the copper is gradually sprinkled into a hot crucible, and it is stirred
rapidly and frequently with an iron rod. When the crucible has cooled and
been broken up, the button of gold is found.
The second method for parting is the following. Two librae of sulphur
not exposed to the fire, and four librae of refined salt are crushed and mixed ;
a sixth of a libra and half an uncia of this powder is added to a bes of granules
made of lead, and twice as much copper containing gold ; they are heated
together in an earthen crucible until they melt. When cooled, the button is
taken out and purged of slag. From this button they again make granules,
to a third of a libra of which is added half a libra of that powder of which I
have spoken, and they are placed in alternate layers in the crucible ; it is
well to cover the crucible and to seal it up, and afterward it is heated over a
gentle fire until the granules melt. Soon afterward, the crucible is taken off
the fire, and when it is cool the button is extracted. From this, when purified
and again melted down, the third granules are made, to which, if they weigh
a sixth of a libra, is added one half an uncia and a siciliens of the powder,
and they are heated in the same manner, and the button of gold settles at the
bottom of the crucible.
The third method is as follows. From time to time small pieces of
sulphur, enveloped in or mixed with wax, are dropped into six librae of the
molten copper, and consumed ; the sulphur weighs half an uncia and a
sicilicus. Then one and a half sicilici of powdered saltpetre are dropped
into the same copper and likewise consumed ; then again half an uncia and a
sicilicus of sulphur enveloped in wax ; afterward one and a half sicilici of
lead-ash enveloped in wax, or of minium made from red-lead. Then immediately the copper is taken out, and to the gold button, which is now mixed
with only a little copper, they add stibium to double the amount of the button ;
these are heated together until the stibium is driven off ; then the button,
together with lead of half the weight of the button, are heated in a cupel.
until it is fit for cupellation with lead, except in one case where the final stage is accomplished
by amalgamation. The lore of the old refiners was much after the order of that of modern
cooks—they treasured and handed down various efficacious recipes, and of those given here
most can be found in identical terms in the Probierbüchlein, some editions of which, as mentioned before, were possibly fifty years before De Re Metallica. This knowledge, no doubt,
lccumulated over long experience ; but, so far as we are aware, there is no description of
sulphurizing copper for this purpose prior to the publication mentioned.
nSal artificiosus. The compound given under this name is of quite different ingredients from the stock fluxes given in Book VII under the same term. The method of
preparation, no doubt, dehydrated this one ; it would, however, be quite effective for its
purpose of sulphurizing the copper. There is a compound given in the Probierbüchlein identical
with this, and it was probably Agricola's source of information.
