Note 509 — Chapter CVIII
Clements R. (Clements Robert) Markham translation
The ancient Peruvians knew of gold, silver, copper, tin, and quicksilver. They took the silver from mines which were not very deep, abandoning them as soon as the hardness of the ore offered a resistance sufficient to withstand their imperfect tools. They not only knew native silver, but also its chemical combinations, such as the sulphate, antimonial silver, etc. They also knew how to extract the pure metal from these compounds by fusion, or in portable stoves.