MIXING. 265 



digs up part of it, to see whether the gold has not found its 

 way into cracks scarcely perceptible on the surface. "Dry 

 digging," as a mode of mining, must not be confounded with 

 " dry diggings," a kind of mining-ground which has been de- 

 scribed near the beginning of this chapter. 



Knife-mining differs a little from dry digging. In the latter, 

 a shovel is used to strip off the barren dirt ; whereas the knife- 

 mining is practised in those places where the gold is deposited 

 in crevices in rocks along the banks of streams, without any 

 covering of barren dirt, so that the knife alone is used in sera- 

 ping out the dirt; and afterward the dirt, being placed in a 

 pan, may be washed in water, which is never used in dry dio-- 

 ging. 



§ 195. Puddling-Box.—The puddhng-box is a rough wood- 

 en box, about a foot deep and six feet square, and is^used for 

 dissolving very tough clay. The clay is thrown into the box, 

 with water, and a miner stirs the stuff with a hoe until the 

 clay is all thoroughly dissolved, when he takes a plug from an 

 auger-hole about four inches from the bottom, and lets the thin 

 solution of the clay run off, while the heavier material, inclu- 

 ding the gold, remains at the bottom. He then puts in the 

 plug again, fills up the box with water, throws in more clay, 

 and repeats the process again and again untU night, when he 

 cleans up with a cradle or pan. The puddhng-box is used 

 only in small mining operations, and never with the sluice, or 

 in hydraulic claims. 



§ 196. QuicJcsilver-Machine,—ThQ quicksilver-machme, or 

 Burke rocker, is a cradle about seven feet long, two feet wide, 

 and two feet high. In the bottom are a number of compart- 

 ments, aU contaming quicksilver. One man rocks the machine 

 without cessation. A constant stream of water pours into the 

 machine at its head. The riddle extends the whole length of 

 the machine ; and the stones, after being washed clean, fall off 

 the riddle at the lower end. One man is employed constantly 

 working with a shovel to keep the dirt on the riddle under the 

 stream of water, and in throwing off the big stones. K the 

 12 



