WHOLE VOL. THE WEST INDIES VAZQUEZ DE ESPINOSA 627 



end of the narrowest point, and set them in ovens specially made 

 for the purpose ; when they start the fire, the mercury goes out 

 through the hole as vapor or smoke, but nothing is lost, thanks to 

 the preparation made. 



After the fire has severed the mercury from his friend the silver, 

 the cone (pifia) of pure silver comes out the size and shape of a 

 loaf of very white sugar, for silver looks very white and spongy. 

 Each cone is usually of 40 silver marks, slightly more or less ; that 

 is the ordinary product from one container ; but if the grade and 

 richness of the ore permit, they may get two cones, as happened at 

 the beginning when the rich range was first exploited ; the same 

 is true of certain new mines ; but ordinarily it is only one. They 

 make up a bar by melting two together. The silver refined by the 

 mercury process is so fine and white that it is always above the 2,380 

 grade ; and to make it fit for use by the silversmiths, they reduce 

 the grade to the 11 dineros and 4 grains which is the legal sterling 

 standard, by addition of copper or other alloy. 



Chapter XI 



Of Other Processes Used to Extract the Silver from the Ore 

 Dust, and of the Quantity of Mercury Used Every Year. 



1657. The silver which is extracted and collected from the ore dust, 

 is much finer than that which they get first from the ore ; it is the 

 most delicate part that runs ofif with the mud and ore dust in the 

 first washings and rewashings of the ore in the tubs. Of this dust, 

 which contains much silver that has passed through and escaped the 

 mercury process, they treat every year more than 300,000 quintals, 

 roasting it in more than 200 (700?) furnaces maintained for this 

 purpose on the Potosi and Tarapaya ranges. Thus they recover a 

 large amount of silver, which will amount each year to over 300,000 

 pesos ; this is the finest and highest-grade silver of all that is handled. 

 Together with it they recover more than 2,000 quintals of mercury 

 carried off with it in the ore dust ; this amount, plus over 6,000 more 

 brought from the Huancavelica mines, is used up every year at 

 Potosi alone in the reduction of the ore and the silver. 



After this silver has been run into bars, the Assayer takes a bit 

 from each and weighs it by itself to see what grade it is. He puts 

 each bit of silver into a receptacle made of ashes from ground burnt 

 bones, cast in a mold, each with its label ; these are like the little 

 molds used by the silversmiths in casting silver or gold. These jars 

 or molds are used for the assay sample and when they take it for 

 the assay, His Majesty collects his royal 20 percent. 



