628 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I02 



They assay them in a jewelers' furnace at his direction ; the 

 indications are easily recognized. He appHes a very hot flame which 

 melts the metal contained in each mold ; and if the silver contains 

 copper, tin, or lead, the intensity of the flame makes it go up in 

 smoke and disappear, leaving the silver purified and very fine. When 

 it is in this state, even though liquid and molten, and the jar is 

 turned upside down, not a drop falls out ; by this and by its color, 

 the Assayer knows when it is refined. Then he takes the jars from 

 the flame and with a very accurate balance reweighs each sample 

 or bit by itself ; and according to the shrinkage or loss in weight, 

 he determines the grade of each bar ; if it has lost little or nothing, 

 its sterling quality is recognized ; and the others are graded according 

 to the loss or shrinkage shown by the bit or sample. This assay 

 and weighing is done where there is not a breath of wind or other 

 interference that can afifect the accuracy and precision of the weighing, 

 for on that depends the determination of the grade of each bar. 

 They always take the assay of many bars together ; otherwise it 

 would be a very hard and tiring operation. After doing this, each 

 bar is graded and marked according to the bit taken from it, with 

 certainty, so that by this test they know the grade, price, and value 

 of each bar. 



1658. This is the way in which its fineness and standard are known. 

 Before becoming a bar, it passes through and sufifers great torture, 

 for in their covetousness for it, men go where it is ever since they 

 have made acquaintance with it ; they bore into the bowels and center 

 of the earth, bursting open the strongboxes in which Nature created 

 it, given it for its defense and preservation. To get it out, much 

 suffering is endured ; they carry it off to the mills where they grind 

 and pound with heavy hammers the rock and ore in which it took 

 form ; then they sift it, and after sifting it they dump it into troughs 

 or containers with lime, salt, iron-water (agua de hierro), and the 

 other materials mentioned, to scour it ; according as is required, 

 they knead it and tread upon it many times, going over it all again, 

 and then they set that ferret, mercury, upon it, for him to search 

 out and appropriate the silver in all the mud in which it lies ; then 

 they put the flame to it to help the mercury ; and after the amalga- 

 mation, they wash it in tubs, as has been said. Then when the mer- 

 cury and silver are clean, they give it the water-cure torture (tor- 

 mento de toca), separating the mercury from the silver; for this 

 they put that dough or putty of the two amalgamated metals into a 

 linen cloth and garrot it hard, squeezing the mercury out ; and since 

 not all of it comes out, they apply fire to it, and thus they get it 



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