Patio
Patio : Spanish, a courtyard. A medieval process for extracting silver from argentite, Ag2S. The ore was mixed with salt, mercury, and roasted pyrites, which contains cupric sulfate. This mixture was crushed by stones dragged by mules walking on the paved floor of a courtyard. The overall reactions are: Ag2S + 2NaCl + 2Hg + CuSO4 = 2Ag + Hg2Cl2 + CuS + Na2SO4 ; 2Ag + 2Hg = Hg2Ag2. (Check source for accuracy of chemical formula)