OF SOUTH CAROLINA. 281 
The gangue in the veins requires crushing, and often a high degree of levigation, in order to lib- 
erate the gold. 'To accomplish this there are two or three machines incommon use. Fig, 43 is the 
Chilian mill, which consists of a stone wheel, about five feet in diameter, and shaped like a mill- 
stone. ‘This is fixed upon an axis, upon which it turns, very close to a vertical shaft, which also 
revolves. The floor is composed of hard stone, enclosed by staves, so as to retain the water and 
ore placed under the wheel. It is obvious that when this passes over the ore, an enormous crush- 
ing and grinding force is exerted; and, for very refractory ores, it is an excellent contrivance. Mer- 
cury is placed with the ore, in the mill, or the amalgamation takes place as the ground ore and 
water passes off. 
e 
