1with ore in the scorifier and
afterward again separated from it in the cupel;
the other, by which it is first melted in the triangular earthen crucible and
afterward mixed with lead in the scorifier, and later separated from it in the
cupel. Now let us consider which is more suitable for each ore, or, if neither
is suitable, by what other method in one way or another we can assay it.
the other, by which it is first melted in the triangular earthen crucible and
afterward mixed with lead in the scorifier, and later separated from it in the
cupel. Now let us consider which is more suitable for each ore, or, if neither
is suitable, by what other method in one way or another we can assay it.
We justly begin with a gold ore, which we assay by both methods, for
if it is rich and seems not to be strongly resistant to fire, but to liquefy easily,
one centumpondium of it (known to us as the lesser weights),27 together with
one and a half, or two unciae of lead of the larger weights, are mixed together
and placed in the scorifier, and the two are heated in the fire until they are
well mixed. But since such an ore sometimes resists melting, add a little
salt to it, either sal torrefactus or sal artificiosus, for this will subdue it, and
prevent the alloy from collecting much dross; stir it frequently with an iron
rod, in order that the lead may flow around the gold on every side, and absorb
it and cast out the waste. When this has been done, take out the alloy and
cleanse it of slag; then place it in the cupel and heat it until it exhales all
the lead, and a bead of gold settles in the bottom.
if it is rich and seems not to be strongly resistant to fire, but to liquefy easily,
one centumpondium of it (known to us as the lesser weights),27 together with
one and a half, or two unciae of lead of the larger weights, are mixed together
and placed in the scorifier, and the two are heated in the fire until they are
well mixed. But since such an ore sometimes resists melting, add a little
salt to it, either sal torrefactus or sal artificiosus, for this will subdue it, and
prevent the alloy from collecting much dross; stir it frequently with an iron
rod, in order that the lead may flow around the gold on every side, and absorb
it and cast out the waste. When this has been done, take out the alloy and
cleanse it of slag; then place it in the cupel and heat it until it exhales all
the lead, and a bead of gold settles in the bottom.
If the gold ore is seen not to be easily melted in the fire, roast it and
extinguish it with brine. Do this again and again, for the more often you
roast it and extinguish it, the more easily the ore can be crushed fine, and the
more quickly does it melt in the fire and give up whatever dross it possesses.
extinguish it with brine. Do this again and again, for the more often you
roast it and extinguish it, the more easily the ore can be crushed fine, and the
more quickly does it melt in the fire and give up whatever dross it possesses.