Leaving theory now, let us approach the practice of separation itself and descend to particular kinds. Observe that the separation of metals rightly comes first of all. We shall therefore teach it next in the following way.

On the Separation of Metals from Their Ores.

1. By melting powders.

Metals can be separated from their ores in many ways: by boiling or smelting, or by fusion with melting powders such as alkali salt, litharge, fluxing salt, glass gall, slag, rock salt and saltpetre. Let them be put into an earthen vessel or crucible and melted in a furnace. The metal will settle as a regulus at the bottom of the vessel, while the matter of the ore rises and becomes slag. Drive this metallic regulus in the furnace under a reverberatory heat until all the metal is pure and freed from every impurity and slag. In this way the metal is thoroughly digested and, so to speak, refined or cleansed of all impurity and slag. An ore of this kind sometimes contains more than one metal. Copper and silver, copper and gold, lead and silver, tin and silver, and other such combinations are frequently found in one mineral. A sign of this appears if the metallic regulus, after reverberation, is dissolved in a cupel by the proper method. There all the imperfect metals are separated, such as copper, iron, tin and lead. They pass into fumes together with the lead, of which the amount added should be twice that of the regulus; only refined silver and gold remain in the cupel. The same is also found when the metallic king is melted and cast into bullets: in that casting the mixed metals separate, since the best and heaviest always sinks to the bottom, while the lighter stands above it.

2. By strong waters and so forth.

Two or three mixed metals can also be separated in a sharp, strong water, and one extracted, drawn out and dissolved from another. If both metals dissolve together, one of them can be struck down and precipitated in that solution, like sand or calx, with a suitable salt, and thus separated.

3. By sulphur.

The remarkable power of sulphur in separation.

Metals can also be separated by melting, through this process. Make the metals melt. Once they are fluid, cast in one ounce of thoroughly sublimed and purified sulphur for every pound of metal. It will burn there, and in the same action draw the lighter metal upwards, leaving the heavier at the bottom. Let them stand together in this state to cool. Two metals will thus be found in one regulus, no longer mixed as before but opposite one another, divided by sulphur as by a wall. Just as oil keeps two bodies of water apart so that they cannot unite and mix, so sulphur separates metals. Sulphur is therefore a singular arcanum worthy of exceptional praise.

4. By quicksilver.

Volatile and fugitive metals, such as gold and silver, when they are to be separated from ores and cannot be held and subdued either in fire or in strong waters, must be amalgamated, separated and extracted by quicksilver. Afterwards the quicksilver must be drawn off and separated by distillation from the calx of the metal, gold or silver.

In this way the other metals too, such as gold, silver, copper, iron, tin and lead, as well as things prepared from them, such as red electrum, white magnesia, aurichalcum, ash-coloured lead, laton, cauldron metal and part-with-part, and all transmuted metals of this kind, are drawn off and separated from foreign matter in their pulverised state by quicksilver. For it is the nature and condition of quicksilver to amalgamate and unite completely with metals, sooner or later with one or another according to the greater or lesser kinship of the metal with its nature.