[Footnote 2: This is utterly absurd, as the mercury must be the same in _quality_ as before, the _quantity_ only being _weakened_.]
On the evaporation of the mercury, nothing remains but a spongy lump of contiguous grains of silver, very light and almost mouldering, called _la pinna_ by the Spaniards. These masses must be carried to the king's receipt or mint, to pay the royal fifth; and are there cast into ingots, on which are stamped the arms of the crown, the place where cast, and their weight and fineness. All these ingots, having paid the fifth, are sure to be without fraud or deceit; but it is not so with the _pinnas_, as these have often iron, sand, or some other matter contained within them, to increase their weight; Hence, prudence requires that these should be opened, and made red hot in a fire; for, if falsified, the fire will turn them black or yellow, or melt them more easily. This trial by fire is also necessary to extract moisture, which they contract in places where they are purposely laid to render them heavier, as also for separating the mercury with which the bottom of the mass is always more or less impregnated. The weight of these _pinnas_ may be increased nearly a third, by dipping them while red hot into water. It also sometimes happens that the same mass of pinna may be of different fineness in different parts.
The ore, or stones taken from the mines, or the _mineray_, as it is called in Peru, from which the silver is extracted, is not always of the same nature, consistence, and colour. Some are white and grey, mixed with red or bluish spots, called _plata blanca_ or white silver; of which sort the one in the Lipes mines mostly consists. For the most part, some little grains of silver are to be discerned, and very often small branches are seen, ramifying along the layers of the stone. Some ores are as black as the dross of iron, and in which no silver is to be seen, which is called _negrillo_ or blackish ore. Sometimes the ore is rendered black by admixture of lead, and is called _plombo ronco_, or coarse lead, in which the silver appears as if scratched by something harsh. This ore is generally the richest in silver, and from it also the silver is got at the smallest charge; as instead of having to be moulded or kneaded with quicksilver, it has only to be melted in furnaces, where the lead evaporates by the force of fire, and the silver remains pure behind. From this sort. of mines, the Indians drew their silver before the coming of the Spaniards, having no knowledge of the use of mercury, and they accordingly only wrought those mines of which the ore would melt; and, having but little wood, they heated their furnaces with _ylo_, the dung of the _Llamas_ or Peruvian sheep, placing their furnaces on the sides of mountains, that the wind might render their fires fierce.