78 



horizontal is about six feet in diameter, and has near 

 its circumference a groove of eighteen inches deep, 

 in which the ore is placed ; through the centre passes 

 a vertical cylinder connected with a cog-wheel turn- 

 ed by water. The vertical stone is about four feet 

 in diameter and ten or fifteen inches thick, and is 

 furnished with a horizontal axis which permits it to 

 turn freely within the groove. When the ore is 

 sufficiently pulverized, a proportionate quantity of 

 quicksilver is added to it, which is immediately 

 amalgamated with the gold ; to moisten the mass 

 and incorporate it more fully a small stream of wa- 

 ter is then directed above it, v/hich also serves to 

 carry off the amalgam into reservoirs placed beneath 

 the stone. The gold combined with the mercury 

 falls to the bottom of these reservoirs in the form of 

 whitish globules ; the mercury is next evaporated 

 by heat, and the gold appears in its true colour and 

 in all its brilliancy. In each of these mills upwards 

 of two thousand weight of ore is daily ground and 

 amalgamated. 



As the digging of the stone ore obtained from the 

 mines is very expensive, from the number of work- 

 men and the materials required, it is pursued only 

 by the rich ; but it furnishes a much greater profit 

 than the lavadero^ or the ore procured by the wash- 

 ing of auriferous sands, which is practised only by 

 the poorer class, and those who cannot aíFord the 

 necessary expenses for mining. The washing is 

 performed in the following manner : the earth or 

 sand containing particles of gold is put into a vessel 



