64 The Silver Mines, i$c. 



disappeared with their swollen cheeks to bring up fresh loads 

 of the precious ore. 



We will now follow the ore to the grinding and amalga- 

 mating works, where it has to undergo sundry operations 

 before the silver bar is cast and ready for export. 



In many establishments the crushing of the ore is done in 

 a very primitive style by the aid of large circular stones, 

 worked by mules or horses, but at Messrs. Jump and Con- 

 roy's hacienda, a small steam engine works a number of 

 massive Chilian mills with a power and regularity far exceed- 

 ing that of the more primitive means. Each mill consists 

 of a pair of stones 6 to 10 feet high, working perpendicularly 

 in a circular trough, on the same principle as we have most 

 of us seen adopted in madder mills at home. 



Water being supplied to aid the crushing process, a kind 

 of mortar is produced, which is thence transferred to the 

 "circos," or circular walled pits, in which it is trampled by the 

 feet of 8 or 10 horses driven round by an energetic driver. 

 Stationed on a central block of stone, he cracks his whip 

 furiously, and, on finding its report to fail, jumps into the 

 puddle, and applies still more persuasive arguments. The 

 increased trampling aids the more effectual combination of 

 the ore and salt, with which latter the ' ' circo " has been 

 previously charged. 



After many days similar trampling a certain amount of 

 mercury is added, and the same trampling and mixing pro- 

 cess continued for some weeks. After this a stream of water 

 is forced through the circo, thereby clearing the less heavy 

 muddy particles from the amalgam of silver and mercury. 

 The latter, by its own specific gravity, is precipitated into 

 pits, along a channel, in which men are placed to agitate the 

 stream and retard the progress of the precious contents. 

 These they trample into leathern bags previously placed at 

 the bottom of each hole or well. 



Great care is taken to wash and examine the feet of both 

 men and horses during these trampling processes, as other- 

 wise much amalgam might be carried away. 



The circo being thus thoroughly washed out, the bags 

 containing the amalgam are carried to the inner storerooms 

 of the establishment, where by pounding the amalgam the 

 mercury is in a great measure pressed through the pores 

 of the leather and deposited in a receptacle below. 



The mass still remaining in the leathern bag, not yet 

 pure, is now poured into rough moulds like cheese presses. 



