Note 2 — Chapter I

Plata-piña, or simply piña, is the name given to silver not entirely purified from the mercury which adheres to it in the process of amalgamation. Amalgamation is effected by mixing the ore, after it has been ground, with salt and quicksilver; treading the whole together by men or cattle; then allowing it to repose in cerco, or in the enclosure in which it has been trodden, for a month or six weeks. At the expiration of this time the quicksilver is supposed to have combined with all the silver in the mass, and to have formed a perfect amalgam, called pella, which is separated by washing away the mud and refuse of the ore. The pella, thus procured, is white, and so liquid that, by putting it into a strong bag a considerable quantity of the mercury is made, by pressure, to escape, leaving the amalgam of a solid consistence. It is decomposed by a red heat; and the mercury being distilled, it may again be applied to the same purpose as before. In this process, however, there is usually a great waste of quicksilver on account of the bad apparatus employed; and the fixed metal or silver which remains is what is called piña. This piña is usually sold by the miner in round masses larger than cannon-balls; and these balls of silver are, by the trader who does not venture on smuggling, carried to the government smelter stationed at the mines, (an office for many years back honourably filled at Cerro Pasco by a learned and good man, Don Toribio de Oyorzabal,) by whom they are cast into the foundery, and, being there melted down and sufficiently purified, are now cast into bars, which are stamped as being of a proper ley or standard purity: after which they may be conveyed to the mint for coinage.