MINUNG. 283 
quartz is a common cowhide, laid down in a trough with the 
hairy side wp, and the grain of the hair against the course of 
the water. The gold is then caught in the hair. Sheep-hides 
have been used in the same manner, recalling to mind the 
Golden Fleece. The hides, however, are inferior to the 
blankets for this purpose, and are never used in the best mills. 
The methods of amalgamating are numerous. Among them 
are amalgamation in the battery, amalgamation with the cop- 
per plate, amalgamating bowls, and patent amalgamation of 
many kinds. 
Tn many mills quicksilver is placed in the battery, two 
ounces of quicksilver for one of goid; and about two-thirds of 
the gold is caught thus. The copper plate in quartz-mills is 
made in the same manner as in placer-sluices, under which 
head a description of the plate may be found. Some amalga- 
mating bowls or basins are little Chilean mills and arastras, 
made of cast-iron. One plan of amalgamation is to use a cast- 
iron bow] about four feet in diamcter and a foot deep. Near 
the bottom are horizontal iron arms, which revolve and stir 
the quicksilver and pulverized quartz together. Four or five 
of these bowls sit in a row but at different levels: the bottom 
of the first bowl being level with the top of the second, and so 
on. The pulverized quartz passes through them all. Under 
each bowl a fire is kept up, because heat forms the action of 
amalgamation. If there be any pyrites in the quartz, some 
common salt is thrown in to assist in releasing the gold from 
the embraces of the sulphurets, and preparing it to be seized 
by the mercury. Another amalgamating bowl revolves on an 
axis that stands at an angle of about seventy-five degrees to 
the horizon, so that the material in the bowl is continually 
moving; and the bottom is divided by little compartments, 
which make a constant riffle. In other bowls the pulverized 
quartz is forced with water through the mercury. The methods 
of amalgamation differ very much, and a book might be filled 
with a description and discussion of the processes used at 
different quartz-mills i: California. 
