MINING. 243 



is not careful to catch ail that he coiihh His purpose is to 

 draw the largest possible revenue per day from his claim. He 

 does not intend to spend many years in mining, or if he does 

 he has become thriftless and improvident. In either case, he 

 wishes to derive the utmost immediate profit from his mine. 

 If his claim contain a dollar to the ton, and he can save five 

 dollars by slowly washing only six tons in a day, while he 

 might make ten dollars by rapidly washing fifteen tons in a 

 day, he will prefer the latter result, though he will lose twice 

 as much of the precious metal by the fast as by the slow mode 

 of working. The object of the miner is the practical dispatch 

 of work, and his success will depend to a great extent upon 

 the amount of dirt which he can wash within a given space of 

 time. He regrets that any of the gold should be wasted, but 

 his regret is because it escapes from his sluice and his pocket, 

 rather than because it is lost to industry and commerce. 



S 179. Tiie Sluice. — The board-sluice is a Ions; wooden 

 trough, through which a constant stream of water runs, and 

 into which the auriferous dirt is thrown. The water carries 

 away the clay, sand, gravel, and stones, and leaves the gold in 

 the bottom of the sluice, where it is caught by its gravity and 

 by quicksilver. The board-sluice is the great washing ma- 

 chine, and the most important instrument used in the placer 

 mining of California. It washes nearly all the dirt and catches 

 nearly all the placer gold of the country. It was invented 

 here, although it had previously been used elsewhere ; it lias 

 been more extensively employed here than in any other country, 

 and it can be used here to more advantage than elsewhere. It 

 is not less than fifty feet long, nor less than a foot wide, made 

 of boards. The width is usually sixteen or eighteen inches ; 

 and never exceeds five feet. The leno-th is ordinarily several 

 hundred and sometimes several thousand feet. It is made 

 in sections or "boxes" twelve or fourteen feet long. The 

 boards are an inch and a half thick, and are sawn for that 

 special purpose, the bottom boards being four inches wider at 

 one end than the other. The narrow end of one box therefore 



