in Metallurgy, the ore of any metal, particularly of gold, when it has been pounded and prepared for further working.
The manner of preparing the slich at Chremnitz in Hungary, is this. They lay a foundation of wood three yards deep; upon this they place the ore, and over this there are twenty-four beams, armed at their bottoms with iron; these, by a continual motion, beat and grind the ore, till it is reduced to powder. During this operation, the ore is covered with water. There are four wheels used to move these beams, each wheel moving six; and the water, as it runs off, carrying some of the metallic particles with it, is received into several basins, one placed behind another; and finally, after having passed through them all, and deposited some sediment in each, it is let off into a very large pit, almost half an acre in extent; in which it is suffered to stand as long as to deposit all its sediment, of whatever kind, and after this is let out. This work is carried on day and night, and the ore is taken away and replaced by more as often as occasion requires. That ore which lies next the beams, by which it was pounded, is always the cleanest or richest.
When the slich is washed as much as they can, a hundred weight of it usually contains about an ounce, or perhaps but half an ounce of metal, which is not all gold; for there is always a mixture of gold and silver, but the gold is in a larger quantity, and is usually two-thirds of the mixture. They then put the slich into a furnace with some limestone, and slacken, or the scoria of former meltings, and run them together. The first melting produces a substance called leech, which they burn with charcoal, to make it lighter, to open its body, and render it porous, after which it is called rost; to this they add sand in such quantity as they find necessary, and then melt it over again.
At Chremnitz many other methods are practised of reducing gold from its ore, but particularly one, in which they employ no lead during the whole operation; whereas, in general, lead is always necessary, after the before-mentioned processes.