MiN^iNG. 283 



quartz is a common cowhide, laid down in a trough with the 

 hairy side up, 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 amalo^amating^ are numerous. Amono- them 

 are amalgamation in the battery, amalgamation with the cop- 

 per plate, amalgamating bowls, and patent amalgamation of 

 manv kinds. 



Tn many mills quicksilver is placed in the battery, two 

 ounces of quicksilver for one of gold ; 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 bowl about four feet in diameter and a foot deep. Kear 

 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 i California. 



