MINING. 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 scra- 
ping out the dirt; and afterward the dirt, being placed in a 
pan, may be washed in water, which is never used in dry dig- 
ging. 
§ 195. Puddling-Box.—The puddling-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 until night, when he 
cleans up with a cradle or pan. The puddling-box is used 
only in small mining operations, and never with the sluice, or 
in hydraulic claims. 
§ 196. Quicksilver-Machine.—The quicksilver-machine, 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, all containing quicksilver. One man rocks the machine 
without cessation. A constant stream of water pours into the 
iaachine 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. If the 
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