MECHANICS AND USEFUL ARTS. 83 



of the engine, which when set in motion gives the ball an oscillating 

 motion, causing it to travel back and forth the entire length of the 

 trough in which the quartz is placed, at the rate of about 600 feet per min- 

 ute. At one end of the trough are small apertures or slats, through 

 which the quartz, after being crushed to the size of large peas, is 

 forced by'the motion of the ball, falling into a stationary cast iron ket- 

 tle or mortar of about 3 feet diameter. Into this kettle is inserted a 

 tolerably close-fitting cast iron half-sphere, or perhaps more properly 

 a pestle. By the operation of the machinery two motions, gyrating 

 and rotary, are given to this pestle. As the crushed quartz passes 

 from the trough into the mortar, it is (such is the theory of the inven- 

 tor) pulverized to an impalpable powder, and passed out at the 

 bottom into an amalgamator immediately beneath. The amalgamator 

 consists of a cast or wrought iron cylinder of any given length and 

 size, placed horizontally, with steam-tight heads at both ends, and 

 resting on hollow journals cast on the heads, through which the pul- 

 verized quartz is received into and discharged from the amalgamating 

 cylinder. 



Berden's Quartz Crusher and Amalgamator. In this machine, the 

 crusher is an iron ball or globe, weighing five thousand pounds, and 

 some thirty inches in diameter, which revolves in a mammoth cup, 

 not unlike a potash kettle, which is obliquely suspended from and 

 strongly secured to a heavy wooden framework, which should be firm- 

 ly imbedded in the earth or fastened to an unyielding platform resting 

 thereon. This cup or basin is made to revolve by an ordinary appli- 

 cation of steam-power by means of a belt, and thus the ball, continu- 

 ally seeking the lowest position, revolves without changing its place, 

 being attached by a pin to a stem in the centre of the cup. A stream 

 of water is conducted into the cup from above, and forms a pool of 

 some three or four pailfuls around and under the ball. The mer- 

 cury is of course under the ball, and the quartz is shoveled into the 

 pan or may be poured in from a hopper above. So far, gold-miners 

 will recognize it as an improved Chilian Mill, of extraordinary pow- 

 er. But beneath the pan or cup or rather in a cavity at the bottom 

 thereof, formed expressly to this end, a small fire is made, which (be- 

 ing fed /with air through half a dozen orifices at regular intervals sur- 

 rounding it,) is fanned into lively action by the revolution of the cup, 

 and heats the quicksilver moderately without heating essentially the water, 

 continually pouring in above it, dashing about and running off, sur- 

 charged with the pulverized quartz. The effect of this contrivance is 

 claimed to be the perfect amalgamation of the gold (or other precious 

 metal) with the thus enlivened and expanded quicksilver without sub- 

 liming that metal and causing it to pass off as vapor. By this means 

 it is claimed that the very last particle of gold is extracted from the 

 quartz and held by the mercury, ensuring a product per ton of quartz 

 three or four times as great as has hitherto been secured ; so that the 

 owners of this machine may make money faster by washing the " tail- 

 ings " or already pulverized and exhausted quartz at any gold-digging 

 already worked, than can be obtained by other machines from rich 

 quartz not previously exhausted. 



